concanavalin-a and Orthomyxoviridae-Infections

Previously, we showed that mice fed white button mushrooms (WBM) had enhanced immune functions known to help the body's antiviral defence. In the present study, we tested whether WBM conferred protection against viral infection. Young (4-month-old) and old (22-month-old) C57BL/6 mice were fed a diet containing 0, 2 or 10 % WBM powder for 8 weeks. Mice were then infected with influenza Puerto Rico/8/34 (H1N1), and killed at day 0 (uninfected), 2, 5 or 7 post-infection. The primary outcomes of the study were viral titre and body weight. Secondary outcomes were natural killer (NK) cell activity, lymphocyte proliferation and cytokine production. The results showed that WBM did not affect viral titre, nor did it prevent infection-induced weight loss. WBM supplementation was found to enhance NK cell activity in old mice and to increase interferon (IFN)-γ production in young and old mice under naive (uninfected) conditions, but it had no such effect after infection. The lack of a mushroom supplementation effect on NK activity and concanavalin A-stimulated IFN-γ production after infection may explain the immune system's failure to reduce viral load and weight loss in mice after influenza infection. WBM supplementation, however, did induce changes in other aspects of the immune response: it significantly increased the production of T-helper type 2 cytokines IL-4 and IL-10 in uninfected mice and pro-inflammatory cytokines IL-1β and TNF-α in infected mice. These mushroom-induced systemic changes, however, were not adequate to confer a protective effect against influenza infection.

Topics: Agaricales; Animals; Concanavalin A; Diet; Disease Resistance; Food, Preserved; Influenza A Virus, H1N1 Subtype; Interferons; Killer Cells, Natural; Lung; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Orthomyxoviridae Infections; Viral Load; Weight Loss

Traditionally, the in vitro activation of virus-specific memory cytotoxic T lymphocytes (CTLs) has been achieved by stimulating the CTLs with antigen-presenting cells (APCs) infected with an appropriate virus or pulsed with virus-specific antigenic peptides. Here, we describe the utilization of the polyclonal activator Concanavalin A (ConA) for in vitro restimulation of memory CTLs from virus-primed mice. Using this simple method, the activation of splenocytes with ConA for 3 days (i) eliminates the need to stimulate with virus-pulsed APCs and (ii) generates CD8+ CTLs that exhibit virus specificity and MHC-restricted lytic activity similar to CTLs obtained by conventional viral restimulation. In vitro ConA stimulation of splenocytes from BALB/c mice primed with the A/Texas/77 or A/Japanese/57 strain of influenza virus and from C57L/J mice infected with the A/Texas strain, generated CTLs with specific lytic activity. Hence reactivation of memory CTLs by this method is a general phenomenon rather than a mouse or viral strain-specific one. The ConA stimulation method used here had a recall of long-term (1 year) memory CTLs that effectively lysed virally infected targets. Further ConA-stimulated effector lymphocytes from virally primed animals have been shown to recognize and subsequently lyse target cells pulsed with virus or virus-derived peptides. The ConA reactivation of specific anti-viral CTLs may facilitate (i) studying anti-viral CTL responses and (ii) identifying of viral epitopes when unknown or when appropriate viral stimulation is impossible.

Topics: Animals; Chick Embryo; Concanavalin A; Immunologic Memory; Influenza A virus; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Orthomyxoviridae Infections; T-Lymphocyte Subsets; T-Lymphocytes, Cytotoxic

The course of influenza and tuberculosis infections under the conditions of disturbances in the immune response of experimental animals has been studied. As revealed in the survival test, the induction of secondary T- and B-cell-mediated immunodeficiency in mice leads to an increase in the sensitivity of the body to influenza virus, especially in cases of T-cell-mediated immunodeficiency. The injection of BCG in combination with cyclophosphamide into mice induces tolerance to this antigen in the animals; this tolerance has a "split" character, i.e. it affects only T-cell-mediated, but not humoral immunity. The induction of T-cell-mediated immunodeficiency or tolerance to BCG in mice has been shown (in the survival test) to lead to the development of the sensitivity of the animals to experimental tuberculosis infection. B-cell-mediated immunodeficiency did not influence the animal survival rate.

Topics: Animals; B-Lymphocytes; BCG Vaccine; Concanavalin A; Cyclophosphamide; Immune Tolerance; Immunologic Deficiency Syndromes; Influenza A virus; Lipopolysaccharides; Male; Mice; Orthomyxoviridae Infections; Serratia marcescens; T-Lymphocytes; Tuberculosis

Topics: Animals; Concanavalin A; Immunity, Cellular; Immunity, Innate; In Vitro Techniques; Interleukin-2; Killer Cells, Natural; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Orthomyxoviridae Infections; Spleen; T-Lymphocytes; T-Lymphocytes, Regulatory

We have studied the release of immune interferon (IFN-gamma) by influenza-specific cytotoxic T-cell (Tc) clones. IFN-gamma release is entirely dependent on specific antigen recognition or mitogen treatment and correlates inversely with the growth rate of the clone, while no differences in cytotoxic activity can be discerned at the different stages of Tc maturation. Although the mitogen Con A provides a more powerful stimulus for IFN release by Tc clones, specific antigen leads to a more rapid secretion, starting within 2 hr of contact with Tc clones and their specific targets. This may be of significance in an infection, providing a quick, but localized, mechanism to prevent viral spread. We also examined whether ligand interactions with T-cell surface glycoproteins Lyt-2 or LFA-1, important in Tc recognition, affected IFN release. Monoclonal antibodies to both Lyt-2 and LFA-1 block specific target cell lysis of Tc clone BA4, but do not affect Tc clone T9/5. This latter finding adds LFA-1 to the list of T-cell surface components which are not always essential for target cell recognition. Antibody to Lyt-2 blocked antigen-induced IFN-gamma release by all Tc clones studied, whilst two monoclonal antibodies to LFA-1 had little or no effect. Thus, the Lyt-2 molecule plays a role in the regulation of IFN secretion.

Topics: Animals; Antigen-Antibody Reactions; Antigens, Surface; Clone Cells; Concanavalin A; Cytotoxicity, Immunologic; Epitopes; Interferon-gamma; Isoantibodies; Kinetics; Lymphocyte Function-Associated Antigen-1; Mice; Mice, Inbred BALB C; Orthomyxoviridae Infections; T-Lymphocytes, Cytotoxic

The levels of serum thymic activity (STA), the Thy-1.2 positivity of spleen "spontaneous" rosette-forming cells (SSRFCs) (measured in terms of Az sensitivity), as well as the blastogenic response to specific mitogens for T-lymphocytes, were studied in Balb/C mice after intranasal infection with A/PR/8/34 (HON1) influenza virus. As early as 12 hours, and more drastically, 24 hours the levels of STA were profoundly decreased after virus infection. Spleen Az sensitivity and blastogenic response of thymocytes and splenocytes to stimulation with Concanavalin A and Phytohemagglutinin, respectively, were depressed only later (day 2 or 3). These changes remain evident for about 1 week and later revert to normal values. All of the effects described are dose-dependent and appear to be virus related. Thence the PR8 virus infection initially induces a decrease of STA levels and secondly a impairment of thymus-derived immune functions.

Topics: Animals; Antigens, Surface; Azathioprine; Cell Division; Concanavalin A; Dose-Response Relationship, Drug; Influenza A virus; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Orthomyxoviridae Infections; Phytohemagglutinins; Rosette Formation; Spleen; T-Lymphocytes; Thy-1 Antigens; Thymic Factor, Circulating; Thymus Hormones; Time Factors

This study reports the examination of in vivo and in vitro properties of an antigen-dependent murine cytotoxic T cell (Tc) clone T5/5 specific for type A influenza virus. This clone differs morphologically and in its migratory pattern and biological properties from a previously examined anti-influenza Tc clone L4 which grew in T cell growth factor independently of antigen. Unlike Tc clone L4, T5/5 cells do not release significant amounts of immune interferon on contact with influenza-infected target cells nor do they limit virus replication in vivo, although they efficiently lyse influenza-infected target cells and can release interferon in the presence of concanavalin A. Thus individual Tc clones vary in function and further work is required to establish the properties of Tc that are associated with host protection against virus infection.

Topics: Animals; Cell Movement; Clone Cells; Concanavalin A; Cytotoxicity, Immunologic; Influenza A virus; Interferon-gamma; Lung; Mice; Mice, Inbred BALB C; Organoids; Orthomyxoviridae Infections; T-Lymphocytes, Cytotoxic; Virus Replication

Aged mice of the CBA/Ca strain, 15 months of age, and A/J mice, 17 months of age, exhibited impaired lymphoblastogenic response to concanavalin A but not to lipopolysaccharide. This defective cellular responsiveness was not accompanied by decreased antibody response to protein antigen or decreased ability to develop delayed hypersensitivity to picryl chloride. An increased susceptibility to influenza virus infection given intranasally was noted in the aged mice as compared with young animals. Such virus infection also impaired the lymphoblastogenic response to mitogens. Surprisingly, the virus infection in aged animals was less lethal after a subsequent infection with a small inoculum of Listeria bacteria.

Topics: Administration, Intranasal; Aging; Animals; Antibody-Producing Cells; Concanavalin A; Cytotoxicity, Immunologic; Female; Immunologic Deficiency Syndromes; Injections, Intraperitoneal; Listeriosis; Lymphocyte Activation; Mice; Mice, Inbred A; Mice, Inbred CBA; Orthomyxoviridae Infections

Test of Con A induced cell agglutination, method of binding cells to Con A coated nylon fibres and modified procedure of cell-to-cell binding were used in the investigation of architectural surface changes in normal and polyoma virus transformed hamster cells infected with influenza virus. In both cell types influenza virus infection caused 1) increase in fixation resistant Con A agglutination, 2) decrease in the level of surface membrane fluidity and cell plasticity. It has postulated that influenza virus infection results in stabilization of the cell surface architecture. These changes are amplified by polyoma virus transformation. Con A acts in this system, as an indicator rather than as a modifier of architectural changes.

Topics: Agglutination; Animals; Cell Membrane; Cell Transformation, Viral; Cells, Cultured; Concanavalin A; Cricetinae; Cricetulus; Erythrocytes; Humans; Lung; Orthomyxoviridae Infections; Polyomavirus