concanavalin-a and HIV-Infections

Topics: Concanavalin A; HIV Infections; Humans; Immunization; Mitogens; Neoplasms; Phytohemagglutinins; Pokeweed Mitogens; Skin Tests

Data from cross-sectional studies suggest that periodontitis in HIV-infected patients is a more destructive form of disease in contrast to the slowly progressing form of adult periodontitis in the general population. We studied prospectively over an 18-month period 30 HIV infected, but asymptomatic, patients and compared the rate of periodontal attachment loss with that of a healthy control group (n = 10) matched for age and plaque index. Every 6 months, each subject was assessed for their clinical status by a physician and CD4+ cell count determined. The proliferative response of peripheral blood lymphocytes was determined by in vitro cultures with PHA and Con A. The periodontal health status was assessed by scoring with plaque index (PI), gingival index (GI), and periodontal disease index (PDI). The control subjects were assessed for periodontal status only. Of the 30 HIV-positive patients whose data were analyzed 14 received Zidovudine (AZT) while the remaining 16 did not. There was no correlation between any clinical parameter measured and periodontal status as determined by PI or GI. However, a significant difference in the change of periodontal disease index (PDI) was observed between the HIV-infected and control groups (P = 0.005). We concluded that HIV-infected patients with pre-existing periodontitis tend to experience a greater rate of attachment loss over time compared with controls.

Topics: Adult; Case-Control Studies; CD4-CD8 Ratio; Cohort Studies; Concanavalin A; Dental Plaque Index; HIV Infections; HIV Seropositivity; Humans; Lymphocyte Activation; Lymphocytes; Male; Periodontal Index; Periodontitis; Phytohemagglutinins; Regression Analysis; Time Factors; Zidovudine

Lectins, which exhibit viral-interaction abilities, have garnered attention in the current pandemic era as potential neutralizing agents and vaccine candidates. Viral invasion through envelope proteins is modulated by N-linked glycosylation in the spike (S) protein. This study demonstrates the biophysical aspects between lectins and high-mannose and -galactose N-glycans to provide insights into binding events.

Topics: Antiviral Agents; Concanavalin A; Coronavirus; Coronavirus Infections; HIV Infections; HIV-1; Host-Pathogen Interactions; Humans; Mannose; Polysaccharides; Spike Glycoprotein, Coronavirus; Viral Envelope Proteins

Topics: Administration, Intravaginal; Animals; Anti-HIV Agents; Anti-Infective Agents, Local; Biological Assay; Calcium Carbonate; Chemical Engineering; Chemistry, Pharmaceutical; Concanavalin A; Cross-Linking Reagents; Drug Delivery Systems; Drug Liberation; Female; Glycogen; HIV Envelope Protein gp120; HIV Infections; HIV-1; Humans; Keratinocytes; Lactobacillus crispatus; Methylmannosides; Mice; Nanoparticles; RAW 264.7 Cells; Swine; Tenofovir; Vagina

Prophylactic vaccines, designed to elicit potent humoral and cellular immune responses to human immunodeficiency virus type 1 (HIV-1) antigens in mucosa, are the important approach to the protection of individuals against HIV-1 infection, since HIV-1 transmission is largely a result of sexual contact. In this study, a novel strategy has been developed to induce HIV-1-specific immune responses, which involves inactivated HIV-1-caputring concanavalin A (Con A)-immobilized nanospheres (HIV-NS) and their interaction with bone marrow (BM)-derived dendritic cells. HIV-NS were taken up by dendritic cells via cytoskeleton-dependent but mannose-binding site-independent phagocytosis. Serial stimulations to unprimed T-cells with HIV-1 gp120-capturing NS-pulsed dendritic cells could induce antigen-specific T-cell response. Intranasal administration of fluorescein isothiocyanate-labeled nanospheres (NS) in mice proved that the particles were taken up into pulmonary dendritic cells. Analysis of mice receiving intranasal immunizations with HIV-NS revealed that the mice efficiently induced the antibodies against HIV-1 in the genital tract and specific cytotoxic T-cells in the spleen. These results suggest that the use of HIV-1-NS may provide a novel and promising approach for the induction of humoral and cellular immune responses to HIV-1.

Topics: Administration, Intranasal; AIDS Vaccines; Animals; Antibody Specificity; Bone Marrow; Coculture Techniques; Concanavalin A; Dendritic Cells; Female; Fluorescein-5-isothiocyanate; Genitalia, Female; HIV Antibodies; HIV Envelope Protein gp120; HIV Infections; HIV-1; Immunization; Interferon-gamma; Lung; Mice; Mice, Inbred BALB C; Nanotubes; Spleen; T-Lymphocytes, Cytotoxic

We have previously reported that concanavalin A-immobilized polystyrene nanospheres (Con A-NS) could efficiently capture HIV-1 particles and that intranasal immunization with inactivated HIV-1-capturing nanospheres (HIV-NS) induced vaginal anti-HIV-1 IgA antibody response in mice. In this study, to evaluate the protective effect of immunization, each three macaques was intranasally immunized with Con A-NS or inactivated simian/human immunodeficiency virus KU-2-capturing nanospheres (SHIV-NS) and then intravaginally challenged with a pathogenic virus, SHIV KU-2. After a series of six immunizations, vaginal anti-HIV-1 gp120 IgA and IgG antibodies were detected in all SHIV-NS-immunized macaques. After intravaginal challenge, one of the three macaques in each of the Con A-NS- and SHIV-NS-immunized groups was infected. Plasma viral RNA load of infected macaque in SHIV-NS-immunized macaques was substantially less than that in unimmunized control macaque and reached below the detectable level. However, it could not be determined whether intranasal immunization with SHIV-NS is effective in giving complete protection against intravaginal challenge. To explore the effect of the SHIV-NS vaccine, the remaining non-infected macaques were rechallenged intravenously with SHIV KU-2. After intravenous challenge, all macaques became infected. However, SHIV-NS-immunized macaques had lower viral RNA loads and higher CD4(+) T cell counts than unimmunized control macaques. Plasma anti-HIV-1 gp120 IgA and IgG antibodies were induced more rapidly in the SHIV-NS-immunized macaques than in the controls. The rapid antibody responses having neutralizing activity might contribute to the clearance of the challenge virus. Thus, SHIV-NS-immunized macaques exhibited partial protection to vaginal and systemic challenges with SHIV KU-2.

Topics: Administration, Intranasal; AIDS Vaccines; Animals; Concanavalin A; Female; Gastrointestinal Tract; HIV Antibodies; HIV Envelope Protein gp120; HIV Infections; Immunity, Mucosal; Immunoglobulins; Macaca mulatta; Nanotubes; Plasma; Polystyrenes; RNA, Viral; SAIDS Vaccines; Simian Acquired Immunodeficiency Syndrome; Simian Immunodeficiency Virus; Vaccination; Vaccines, Inactivated; Vagina; Viral Load

The rhesus macaque model is a useful experimental system to evaluate effects of T-cell autotransfusion and gene therapies for HIV-1 infection and AIDS prior to a clinical trial. To obtain sufficient numbers of primary macaque CD4 T lymphocytes for this purpose, we examined the culture conditions that were needed to optimize ex vivo activation and expansion of macaque primary CD4-enriched peripheral blood mononuclear cells (PBMCs). In this report, we compared the effects of various stimulants on cell expansion, surface expression of CCR5 and CXCR4, and levels of transduction with a Moloney leukemia virus (MoLV) vector encoding the phenotypic selection marker truncated human nerve growth factor receptor (deltaNGFR) alone or with the human anti-HIV-1 tat intrabody sFvhutat2. The use of feeder cells strikingly increased the proliferation rate of macaque CD4-enriched PBMCs in vitro. In the presence of an irradiated rhesus macaque B-lymphoblastoid cell line (BLCL), the highest cell expansion over 21 days was achieved with cells activated by Con A (9648-fold), in turn, from high to low, phytohemagglutinin (PHA) (4855-fold), and anti-CD3/CD28-coated beads (2367-fold). Further studies showed that BLCL feeder cells were more effective than human PBMCs (hPBMCs) in promoting proliferation of macaque CD4-enriched PBMCs activated with Con A and anti-CD3/CD28, respectively. The combined use of both BLCL and hPBMC feeder cells did not further increase cell expansion when compared with the use of BLCL cells alone. In addition, the addition of BLCL-conditioned medium (CM) and hPBMC-CM induced cell growth at a rate higher than did the culture medium alone but not as high as with feeder cells. Con A-activated macaque CD4-enriched PBMCs retained 88% of CXCR4 and 39% of CCR5 expression over 17 days compared with PHA-activated cells (50% for CXCR4, 16% for CCR5) and anti-CD3/CD28-activated cells (34% for CXCR4, 37% for CCR5). Finally, PHA, Con A, and CD3/CD28-coated beads supported comparable levels of MoLV transduction. The results should improve the utility of the rhesus macaque model for the testing of T-cell autotransfusion and gene therapies for HIV-1 infection/AIDS.

Topics: Animals; Antibodies; Blood Transfusion, Autologous; CD28 Antigens; CD3 Complex; CD4-Positive T-Lymphocytes; Cell Line; Concanavalin A; Culture Media, Conditioned; Genetic Therapy; Genetic Vectors; HIV Infections; HIV-1; Immunotherapy; Lymphocyte Activation; Macaca; Moloney murine leukemia virus; Phytohemagglutinins; Receptors, CCR5; Receptors, CXCR4; Recombinant Fusion Proteins; Time Factors; Transduction, Genetic

Lymphocytes isolated from human immunodeficiency virus (HIV)-infected patients have dysregulated cell-cycle control, consisting of increased activation of the cyclin B1/p34 cdc2 complex and abnormal nucleolar structure. To better characterize the molecular features of the HIV-associated cell-cycle perturbations, we performed a detailed analysis of the posttranslational regulation of nucleolin, a key structural protein in the nucleolus. We found that, in concanavalin A-stimulated lymphocytes from HIV-infected patients, the inappropriate activation of the cyclin B1/p34 cdc2 kinase complex is temporally associated with increased threonine phosphorylation, augmented fragmentation, and prominent extranuclear and cell-surface localization of nucleolin. Importantly, increased lymphocyte apoptosis is observed at the time of cell-surface localization of nucleolin. These results may delineate a direct molecular link between abnormal activation of cyclin B1/p34 cdc2 and the changes in the nucleolar structure, thus providing a better molecular definition of HIV-associated cell-cycle dysregulation.

Topics: Apoptosis; Blotting, Western; CDC2 Protein Kinase; Cell Cycle; Concanavalin A; Cyclin B; Cyclin B1; HIV Infections; HIV-1; Humans; Interleukin-2; Lymphocyte Activation; Microscopy, Confocal; Nucleolin; Phosphoproteins; Phosphorylation; Precipitin Tests; Protein Processing, Post-Translational; RNA-Binding Proteins; T-Lymphocyte Subsets; T-Lymphocytes; Threonine

Leptin, the Ob gene product, is an adipocyte hormone that centrally regulates weight control. In addition, other effects of leptin in peripheral tissues have been described. Thus, leptin has been found to regulate reproduction, haematopoiesis and immune function. We have found recently that leptin has a stimulatory effect on human peripheral blood mononuclear cells (PBMC). Monocytes are activated by leptin alone whereas T lymphocytes need a suboptimal stimulus of PHA or ConA before further activation by leptin. These effects are mediated by the long isoform of the leptin receptor, which has been shown to trigger signalling in PBMC. In fact, we have found that human leptin stimulates Janus kinase (JAK)-signal transducer and activator of transcription (STAT), phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways in PBMC. In order to assess possible regulation of the long isoform of the leptin receptor (Ob-R) in mononuclear cells upon activation, we have studied the expression of Ob-R by RT-PCR and Western blotting in PBMC activated in vitro by PHA or ConA and in vivo in HIV-infected patients. We have found that in vitro activation and in vivo HIV infection correlates with an increase in leptin receptor expression in PBMC. Moreover, the leptin receptor is tyrosine phosphorylated in PBMC from HIV-infected patients, suggesting that the leptin receptor is activated. These results are consistent with the suggested role of leptin in modulating the immune response.

Topics: Adolescent; Adult; Carrier Proteins; Cells, Cultured; Child; Concanavalin A; Female; Gene Expression Regulation; Hepatitis C; HIV Infections; Humans; Leptin; Lymphocyte Activation; Male; Phosphorylation; Phytohemagglutinins; Protein Isoforms; Protein Processing, Post-Translational; Receptors, Cell Surface; Receptors, Leptin; Recombinant Proteins; RNA, Messenger; Signal Transduction; T-Lymphocytes

The involvement of CXCR4 and CCR5 coreceptors in apoptosis induced by the HIV envelope (Env) proteins has not been well defined. We found that simian human immunodeficiency virus (SHIV) virus-like particles (VLPs) containing HIV Env proteins preferentially induce apoptosis of cells corresponding to their coreceptor usage in a CD4+ T cell line. We also demonstrated that induction of apoptosis by SHIV VLPs is correlated with coreceptor usage in a non-T cell line. We examined the effects of SHIV VLPs containing Env proteins derived from either a T-cell-tropic HIV (BH10) strain or a dual-tropic HIV (89.6) strain on induction of apoptosis in recombinant CD4+ human osteosarcoma (HOS) cells expressing either CXCR4 (HOS-CD4.CXCR4) or CCR5 coreceptors (HOS-CD4.CCR5). HOS-CD4.CXCR4 or HOS-CD4.CCR5 cells were activated with concanavalin A and cocultured with VLPs. By TUNEL (TdT-mediated dUTP-X nick end labeling) fluorescence staining and flow cytometry assays, SHIV BH10 VLPs were found to preferentially induce apoptosis in HOS-CD4.CXCR4 cells but not in HOS-CD4 or HOS-CD4.CCR5 cells. On the other hand, SHIV 89.6 VLPs induced an elevated level of apoptosis in both HOS-CD4.CXCR4 and HOS-CD4.CCR5 cells in a dose-dependent fashion. These data demonstrate that T-cell-tropic BH10 Env preferentially utilizes CXCR4, but not CCR5, for induction of apoptosis, whereas dual-tropic 89.6 Env induces apoptosis in both CXCR4- and CCR5-containing cell lines.

Topics: Apoptosis; CD4-Positive T-Lymphocytes; Cell Line; Concanavalin A; Gene Products, gag; HIV Envelope Protein gp120; HIV Envelope Protein gp160; HIV Infections; HIV-1; Humans; Receptors, CCR5; Receptors, CXCR4; Tumor Cells, Cultured; Viral Envelope Proteins

Impaired cell-mediated immune reactivity to polyclonal mitogens was determined in HIV-negative homosexual men (HIV-MSM). Results were compared to those we reported in a complex clinical and immunological investigation in the same risk groups 15 years ago, before the onset of the AIDS epidemic in Hungary. Cellular immune reactivity to polyclonal mitogens was studied in 74 HIV-infected or HIV-uninfected homosexual men and heterosexual controls. Lymphocytes in whole-blood cultures were stimulated with various doses of phytohaemagglutinin (PHA), concanavalin-A (Con-A), and pokeweed mitogen (PWM) in a blast transformation assay. A significant difference (p = .0002) in lymphocyte proliferation between HIV-MSM vs. heterosexuals using PWM in both concentrations was found. Proliferative capacity was similar in HIV- MSM and HIV infected males with CD4+ > 500/microl. Con-A and PHA showed a less expressed proliferative response. Decreased lymphocyte reactivity to PWM, similar to the one in early HIV infection, could be observed in HIV-MSM. This HIV-independent mild immunodeficiency in MSM is a sign of an increased susceptibility and predisposes to subsequent HIV infection. It seems, however, that MSM's impaired immune response observed over a period of 15 years is an immunodeficiency not changed by the emerging HIV/AIDS epidemic. Our study provides an explanation why the incidence of new HIV cases in homo-/bisexual individuals is still high (> 70%), and it indicates that it remains high in Hungary.

Topics: Case-Control Studies; Concanavalin A; Europe; Europe, Eastern; HIV Infections; HIV Seronegativity; Homosexuality, Male; Humans; Immune Tolerance; Immunity, Cellular; In Vitro Techniques; Lymphocyte Activation; Male; Phytohemagglutinins; Pokeweed Mitogens; Time Factors

Human immunodeficiency virus (HIV)-induced immune complex load on circulating CD4+ blood lymphocytes is associated with dysfunction and depletion of CD4+ lymphocytes and with increased monocyte/macrophage function. It was investigated whether HAART reduces both the viral load in plasma and the number of immune complex-coated CD4+ lymphocytes in the blood, and whether CD4+ counts are associated with viral load and/or immune complex load.. Twelve HIV+ hemophilia patients before and after conversion to HAART (group 1); eight HIV+ hemophilia patients without antiretroviral therapy (group 2). HIV-1 RNA copies in plasma using NASBA/Nuclisens kits; CD4+ lymphocytes coated in-vivo with immune complexes using flowcytometry on whole blood samples; in-vitro responses of immune complex-coated T lymphocytes in cell culture assays.. After conversion to HAART there was a significant reduction of viral load, CD4+ gp120+, CD4+ IgM+, and CD4+ IgG+ circulating blood lymphocytes and plasma neopterin, paralleled by a significant increase of CD4+ and CD8+ counts. The percentage of immune complex-coated CD4+ lymphocytes of converted patients was significantly associated with CD4+ counts, in-vitro responses to concanavalin A (Con A), pokeweed mitogen (PWM), phytohaemagglutinin (PHA), anti-CD3 and pooled allogeneic stimulator cells, and with plasma neopterin levels.. HAART reduces viral load and HIV-induced immune complex load on circulating CD4+ blood lymphocytes. The results of this study can be interpreted to suggest that HAART increases CD4+ lymphocyte counts in part by counteracting HIV-induced autoimmune phenomena.

Topics: Anti-HIV Agents; Antibodies, Anti-Idiotypic; Antigen-Antibody Complex; Autoantibodies; Autoimmunity; CD4-Positive T-Lymphocytes; Concanavalin A; Drug Therapy, Combination; Hemophilia A; HIV Envelope Protein gp120; HIV Infections; HIV Protease Inhibitors; Humans; Immunoglobulins; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Male; Mitogens; Reverse Transcriptase Inhibitors; RNA, Viral; Viral Load; Viremia

To establish an effective tool for the prevention of HIV-1 transmission, lectin-immobilized polystyrene nanospheres were synthesized and examined for their HIV-1 capture activity. When concanavalin A (Con A) was immobilized on the surface of polystyrene nanospheres (400 nm in diameter) with poly(methacrylic acid) branches and incubated with HIV-1 suspension at room temperature for 60 min, the nanospheres (Con A-NSs) achieved a >3.3 log and a 2.2 log reduction of viral infectivity in HIV-1 (IIIB strain) suspension at a concentration of 2 and 0.5 mg/ml, respectively. Meanwhile, Con A-free nanospheres, which were not immobilized with Con A, achieved only a 0.29 log reduction at 0.5 mg/ ml. Con A-NSs (2 mg/ml) could also reduce the gp120 level of III(B) and HE strains to <7.1% and 5.5% of each control, respectively. The combination of Con A-NS treatment followed by filtration with a microporous membrane efficiently removed virion-free gp120 as well as infectious viral particles from HIV-1 suspension. Electron microscopic examination demonstrated that HIV-1 virions were trapped on the surface of Con A-NSs. Thus, Con A-NSs can capture HIV-1 virions and gp120 with high affinity, and may have potential as an effective tool for the prevention of HIV-1 transmission.

Topics: Concanavalin A; HIV Envelope Protein gp120; HIV Infections; HIV-1; Humans; Microscopy, Electron, Scanning; Microspheres; Polystyrenes; Virion

It has been proposed that the highly conserved human immunodeficiency virus type 1 (HIV-1) envelope gp120 carboxy-terminal sequence, TKAKRRVVEREKR (CT120), may represent a functional mimic of the human leukocyte antigen (HLA) class II DR beta-chain third hypervariable region (HVR3) sequence motif located at position 69-81. Presentation of this potentially pathogenic fragment by HLA class I and/or II molecules, in a manner analogous to the indirect pathway of allorecognition, may induce both widespread cellular activation and also break self-tolerance, resulting in the selective and progressive anti-self HLA class II-directed immune suppression, which is a central feature of HIV-1 infection and the associated acquired immune deficiency syndrome (AIDS). To investigate the functional role of the HIV-1 gp120 C-terminal fragment T cell lines (TCLs) were raised from three healthy HIV-1-seronegative subjects at low risk of HIV-1 exposure, by repeated stimulation with a short synthetic 13-mer CT120 peptide in vitro. Graded concentrations (10[3] to 5 x 10[4]) of CT120 TCLs suppressed the primary 6-day proliferation of autologous PBMCs in response to the soluble antigens tetanus toxoid (TT) and purified protein derivative (PPD). In contrast, CT120 TCLs demonstrated no suppressive effect on 3-day phytohemagglutinin (PHA), concanavalin A (ConA), and pokeweed mitogen (PWM) mitogenic responses. Fractionation of CT120 TCLs into highly purified CD4+ and CD8+ T cell subsets demonstrated that the CD8+ T cell fraction mediated the suppressor effector function. HLA restriction analysis revealed a complex pattern as both anti-HLA class II DR and anti-HLA class I (A, B, C) MAbs inhibited proliferation of oligoclonal CD8+ CT120 TCLs. Strategies aimed at specifically inhibiting such putative immunopathogenic HIV-1-encoded T cell epitopes may be an important consideration for development of future HIV-1 immunotherapy.

Topics: Adult; Amino Acid Sequence; Antibodies, Blocking; Autoimmunity; CD8-Positive T-Lymphocytes; Cell Division; Cells, Cultured; Concanavalin A; Cross Reactions; Dose-Response Relationship, Immunologic; Epitope Mapping; Epitopes; Histocompatibility Antigens Class I; Histocompatibility Antigens Class II; Histocompatibility Testing; HIV Envelope Protein gp120; HIV Infections; HIV Seronegativity; HIV-1; Humans; Immune Tolerance; Leukocytes, Mononuclear; Middle Aged; Molecular Sequence Data; Peptides; Phytohemagglutinins; Pokeweed Mitogens; T-Lymphocyte Subsets; T-Lymphocytes; Tetanus Toxoid; Tuberculin

We find that interleukin-2 (IL-2) production is severely depressed (80-90%) in AIDS T-cells (CD4+ or CD8+) stimulated with anti-CD3 or Con A together with phorbol ester (PMA) or anti-CD28 coactivation. Likewise, the proliferative response of CD4+ T-cells was suppressed, from a mean of 24.6% (HIV+) to 59.1% (AIDS) for PMA with activators OKT3 (anti-CD3), Con A, enterotoxin B or pokeweed mitogen, and 20.2% (HIV+) to 77.8% (AIDS) with anti-CD28 co-activation. Similar degrees of suppression were found with the CD8+ T-cells except for a much greater suppression at the HIV+ stage with anti-CD28 (57.7%), approximately 2.5 times higher than for PMA coactivation. However, when proliferation was induced by the two coactivators combined (PMA plus anti-CD28), much less suppression was observed: 8.5% (HIV+) to 19.0% (AIDS) for CD4+ cells and 8.2% to 26.5%, respectively, for CD8+ cells. The data suggest that during HIV infection the CD28 pathway becomes most defective, but can be bypassed to some extent by the less-impaired PMA pathway. The IL-2 (+PMA) signal in HIV+ and AIDS cells was also significantly less suppressed suggesting that the disregulation in HIV infection is more prominent prior to the IL-2 stage of the mitogenic pathway. It is remarkable that the CD4+ and CD8+ T-cells at both the HIV+ and AIDS stages generally show the same degree of suppression with all the various activators and coactivators used.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acquired Immunodeficiency Syndrome; Adult; CD28 Antigens; CD4 Lymphocyte Count; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Concanavalin A; Enterotoxins; Hispanic or Latino; HIV Infections; Humans; Interleukin-2; Lymphocyte Activation; Pokeweed Mitogens; Severity of Illness Index; T-Lymphocyte Subsets; Tetradecanoylphorbol Acetate

We find that purified CD4+ T cells from 30 HIV+ individuals have a suppressed Interleukin-4 (IL-4) production compared to normal controls regardless of activator (anti-CD3 or Con A) or co-activator [phorbol ester (PMA or anti-CD28)], generally by 2-4 fold. In every case, the cells producing IL-4 respond more strongly to anti-CD28 co-activation than to PMA, ie, 1150 pg/ml compared to 2070 pg/ml for controls and 398 pg/ml compared to 1250 pg/ml for HIV+ cells, respectively. In contrast, anti-CD3 with PMA gives a more vigorous IL-2 response than with anti-CD28, ie, 37.3 ng/ml compared to 12.3 ng/ml for controls and 28.5 ng/ml versus 15.1 ng/ml for HIV+ cells, respectively. These data are not compatible with the TH1/TH2 switch hypothesis since IL-4 production is decreased, not increased for CD4+ HIV+ T-cells and while IL-2 production is decreased with PMA, it is not decreased significantly with anti-CD28. Interestingly, 5 mM N-acetylcysteine (NAC) acts as an immunoenhancer; mitogenesis was enhanced 2 fold or more in general for control and HIV+ CD4+ T-cells and IL-2 production was enhanced 2-3 fold for anti-CD3 (with PMA or anti-CD28) for both controls and HIV+ CD4+ cells. However, NAC suppressed IL-4 production induced by anti-CD3 and anti-CD28 in both control and HIV+ CD4+ T cells. In the other cases, it produced in general no significant change.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acetylcysteine; Adult; Antibodies, Monoclonal; CD28 Antigens; Concanavalin A; Hispanic or Latino; HIV Infections; Humans; Interleukin-2; Interleukin-4; Lymphocyte Activation; Muromonab-CD3; Tetradecanoylphorbol Acetate; Th1 Cells; Th2 Cells

The neuropeptide substance P (SP) is known to increase cell-mediated immune responses in animal models and healthy subjects. Several studies have suggested an involvement of neuropeptides in the immunopathogenesis of some diseases. The study of the immunomodulatory effects of neuropeptides, namely SP, may represent a model for the analysis of immunoregulatory defects in HIV infection at the level of the interaction between the immune and nervous systems, both of which are known to be affected by the virus. In the present study, we investigate the possibility of a disturbance in the immunomodulatory properties of SP in HIV infection by analysing the effects of SP (10(-10)-10(-6) M) on the lymphocyte proliferative responses to concanavalin A (Con A) and phytohaemagglutinin (PHA) assessed by 3H-thymidine incorporation in peripheral blood lymphocytes from 34 HIV-infected patients (16 asymptomatic (ASY)/persistent generalized lymphadenopathy (PGL); 18 ARC/AIDS) and in 37 healthy subjects. In ASY/PGL HIV-infected patients, SP 10(-7) M was identified as the concentration inducing the maximal increase in the lymphocyte responses to Con A and PHA, similarly to what was observed in healthy subjects. In ARC/AIDS patients, SP appeared to inhibit the mitogenic responses, particularly those induced by Con A, in contrast to the effects found either in healthy subjects or in ASY/PGL patients. These results suggest the existence of an alteration in the in vitro immunomodulatory properties of SP in ARC/AIDS patients compared with healthy subjects and ASY/PGL patients. In conclusion, the unexpected finding of an inhibitory effect of SP on lymphocyte proliferation from ARC/AIDS patients justifies further investigation of the neuropeptide-dependent immunoregulatory systems in HIV infection.

Topics: Acquired Immunodeficiency Syndrome; Adult; Aged; AIDS-Related Complex; CD4-Positive T-Lymphocytes; Concanavalin A; Female; HIV Infections; Humans; In Vitro Techniques; Lymphocyte Activation; Male; Middle Aged; Neuroimmunomodulation; Phytohemagglutinins; Substance P; T-Lymphocyte Subsets

We sought to evaluate the relationship of CD8+ T cell-mediated inhibition of autologous HIV replication in vitro to disease stage in HIV+ individuals. Depletion of CD8+ T cells from peripheral blood lymphocytes of 16 HIV+ subjects increased the percentage of virus-producing cultures from 56% to 81%. CD4+ T cells were purified from 52 HIV+ individuals and cultured alone or in the presence of autologous CD8+ T cells. In 13 (25%) subjects HIV replication was only detected in the absence of CD8+ T cells (inhibition positive); in 26 (50%) viral replication occurred both in the absence and presence of CD8+ cells (inhibition negative). In the remaining 13 (25%) subjects, CD8+ T cell-mediated inhibitory activity could not be evaluated because stimulation of their purified CD4+ T cells did not result in p24 production. In some virus culture-negative individuals, the inability to demonstrate HIV replication was due to the presence of low numbers of CD8+ T cells that co-purified with CD4+ T cells. Detection of inhibitory CD8+ T cells was associated with significantly higher CD4 counts and better clinical status compared with inhibition-negative subjects. These results demonstrate that CD8+ T cell-mediated inhibition of HIV replication correlates with disease stage, and thus may play a role in preventing disease progression. CD8+ T cells did not inhibit autologous HIV replication across a semipermeable membrane. Further, the ability of CD8+ T cells to prevent HIV replication did not correlate with lysis of autologous CD4+ T cells. Thus, CD8+ T cells inhibited autologous HIV replication in vitro through a contact-mediated non-lytic mechanism.

Topics: CD4-Positive T-Lymphocytes; CD8 Antigens; Cell Communication; Concanavalin A; HIV Core Protein p24; HIV Infections; HIV Reverse Transcriptase; HIV-1; Humans; In Vitro Techniques; Leukocyte Count; Lymphocyte Activation; RNA-Directed DNA Polymerase; T-Lymphocyte Subsets; Virus Replication

Activation-induced programmed cell death, or apoptosis, is a physiological cell suicide process involved in the negative thymic selection of the T-cell repertoire. We have proposed that the inappropriate re-emergence in the mature CD4+ T-cell population of such a death program could explain both the early dysfunction and the late depletion of CD4+ T-cells from human immunodeficiency virus (HIV)-infected individuals. We present evidence showing that the selective failure of T-cells from 10 HIV-infected asymptomatic individuals (with normal CD4+ T-cell counts) to proliferate in vitro to pokeweed mitogen and to self-major histocompatibility complex class-II T-cell receptor mobilization by superantigens is due to the induction by these stimuli of CD4+ T-cell death. This death process has characteristic features of apoptosis, including DNA fragmentation into multiples of a 200 base pair unit, and the preventive effect of the protein synthesis inhibitor cycloheximide. These findings suggest that in vivo CD4+ T-cell suicide upon activation might account, independently of any HIV-mediated cytopathic effect, for the progressive depletion of CD4+ T-cells that leads to AIDS.

Topics: CD4-Positive T-Lymphocytes; Cell Division; Cell Survival; Concanavalin A; HIV Infections; HIV Seropositivity; Humans; In Vitro Techniques; Phytohemagglutinins; Pokeweed Mitogens

Superinfection of latently human immunodeficiency virus (HIV)-infected rabbits with either Treponema pallidum or Shope fibroma virus (SFV) activates HIV expression. In addition, HIV-infected rabbits demonstrate prolonged cutaneous lesions (chancres) after intracutaneous challenge with T. pallidum, the causative agent of syphilis. Rabbits were infected by intravenous inoculation of 3 x 10(7) human T-cell lymphotrophic virus type III (HTLV-III)/B10 (HIV-1)-infected H9 (human) cells. Five weeks after initial infection, integrated HIV-1-specific DNA sequences were detected in the DNA of the peripheral blood lymphocytes of only one of eight rabbits using polymerase chain reactions (PCR); human DNA could not be detected at this time. Furthermore HIV infection could not be demonstrated by either seroconversion or PCR during the next 6 months. All HIV-infected rabbits remained clinically healthy and had normal white blood cell counts. Six months after HIV infection, four HIV-infected and two noninfected controls were superinfected with 10(6) T. pallidum in eight skin sites in the shaved skin of the back, and four infected and two control animals were challenged with an intradermal injection with SFV. After infection with either syphilis or SFV, the DNA from the white blood cells of all eight HIV-infected rabbits contained HIV sequences, and HIV sequences were demonstrated in dermal mononuclear cells of the syphilitic lesions by in situ hybridization. The SFV-induced tumors were rejected normally in the HIV-infected rabbits, but four of the four rabbits challenged with T. pallidum had delayed development of cutaneous lesions and three of four demonstrated larger and more prolonged lesions. White blood counts, mitogen responses, and interleukin-2 production remained within normal limits, and seroconversion for HIV was not detected. Three of four rabbits in a second group, challenged with T. pallidum 4 months after HIV-inoculation, also had delayed healing of syphilitic lesions. These results indicate that latent HIV-infection of rabbits may be activated by immunostimulation and that latently HIV-infected rabbits have impaired delayed hypersensitivity reactions. It is hypothesized that true latent HIV-infection in the rabbits is in monocytes and postulated that further immunostimulation may produce infection of lymphocytes and activation of disease.

Topics: Animals; Antigens, Viral; Base Sequence; Biopsy; Blotting, Southern; Cell Differentiation; Concanavalin A; DNA, Viral; Fibroma Virus, Rabbit; HIV Infections; HIV-1; Lymphocytes; Male; Molecular Sequence Data; Nucleic Acid Hybridization; Polymerase Chain Reaction; Rabbits; Superinfection; Syphilis; Treponema pallidum

To assess the value of feline immunodeficiency virus (FIV) infection as a model for human immunodeficiency virus (HIV) infection in man, we studied the impairment of certain immunological functions following natural or experimental FIV infection. Proliferative responses of peripheral blood mononuclear cells (PBMC) from symptomatic and asymptomatic cats after naturally or experimentally acquired FIV infection, induced by activation with the mitogens concanavalin A, pokeweed mitogen, or lipopolysaccharide or by stimulation with human interleukin-2 (IL-2), were significantly lower than the proliferative responses found with PBMC from noninfected control cats. Also IL-2 production levels of mitogen-activated PBMC from naturally infected symptomatic cats were significantly reduced. These data confirm that the pathogenesis of FIV infection in the cat, like HIV infection in man, is characterized by a serious malfunction of the immune system.

Topics: Animals; Cats; Concanavalin A; Disease Models, Animal; Feline Acquired Immunodeficiency Syndrome; HIV Infections; Humans; Immunodeficiency Virus, Feline; Interleukin-2; Leukocytes, Mononuclear; Lipopolysaccharides; Lymphocyte Activation; Lymphopenia; Pokeweed Mitogens

Immune responses in resting T cells are initiated by the presentation of antigen by bone marrow-derived dendritic cells (DC). Normal DC are susceptible to infection with human immunodeficiency virus (HIV) in vitro (Patterson & Knight, 1987) and this blocks their capacity to stimulate T-cell responses to other antigens (Macatonia, Patterson & Knight, 1989a). To study the relationship between HIV and DC in patients and its relevance to the pathogenesis of disease, DC have been isolated from the blood of individuals in the different clinical categories, counted, examined for the presence of virus genome and their antigen-presenting capacity measured. Infection, depletion and impaired function of DC occur in early HIV infection. HIV seropositive patients who were asymptomatic and those with symptoms of disease had significantly reduced numbers of DC, but patients with persistent generalized lymphadenopathy had normal numbers. Between 3% and 21% of DC, identified as large low-density cells not bearing monocyte, lymphocyte or natural killer cell markers, were infected with HIV, as indicated by in situ hybridization. Less than 0.12% of the lymphocytes or monocytes were infected. The DC from infected individuals were poor at enhancing responses to the mitogen concanavalin A (Con A). They also caused low levels of stimulation in allogeneic lymphocytes in mixed leucocyte cultures. By contrast, T cells from asymptomatic patients gave normal T-cell responses to uninfected allogeneic DC, although those from acquired immunodeficiency syndrome (AIDS) patients did show reduced responsiveness. Defects in DC thus precede both the appearance of symptoms and changes in T cells and may be instrumental in the development of AIDS. Furthermore, since DC numbers and function differ at different stages of disease, monitoring these may contribute to clinical assessment and lead to new therapeutic approaches.

Topics: Cell Count; Concanavalin A; Dendritic Cells; HIV; HIV Infections; Humans; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Male