ovalbumin and Arterivirus-Infections

Lactate dehydrogenase-elevating virus (LDV) is an apparently innocuous and persistent virus that can modify mouse immune reactions. We have shown that LDV-infected mice immunized with human growth hormone (hGH) showed a deep modification of the specificity of the anti-hGH antibodies (Ab) in CBA/Ht mice but not BALB/c animals. The aim of this work was to extend the previous observations to another mouse strain, C57BL/6, as well as to an antigen unrelated to hGH, ovalbumin (OVA), and to explore at the same time the production of various cytokines at serum and cellular levels. The amount of Ab directed to hGH or OVA native antigenic determinants versus the concentration of Ab to cryptic epitopes was evaluated by ELISA competition experiments. Results indicated that LDV infection affected Ab specificity solely in CBA/Ht mice. In CBA/Ht the virus infection was associated with a reduction of the Ab titers to hGH native epitopes and with a decrease of IL-13 and IL-17 serum levels, but Ab to native OVA epitopes were increased with a simultaneous increase of IL-17. Accordingly, only lymph node cells from infected CBA/Ht mice immunized with OVA were found to produce INF-γ, IL-13 and IL-17. Thus, a correlation of cytokine production with a change in Ab specificity after a viral infection was found, although this phenomenon was restricted to a given antigen and to the genetic background of immunized animals. These observations suggest that an apparent harmless virus can affect some immunological mechanisms, which could lead, for example, to inflammatory or autoimmune disorders.

Topics: Animals; Antibodies, Viral; Antibody Specificity; Arterivirus Infections; Cytokines; Growth Hormone; Humans; Immunodominant Epitopes; Lactate dehydrogenase-elevating virus; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred CBA; Ovalbumin; Species Specificity

The present study was conducted to determine whether lactate dehydrogenase-elevating virus (LDV) infection at the sensitization and challenge phases affect the development of delayed allergic eosinophilic rhinitis induced by ovalbumin (OVA) in BALB/c mice (DAR group). Compared to the DAR group, LDV infection at the priming (DAR/LDVs group) and immunizing (DAR/LDVc group) phases reduced the induction of eosinophils in the bone marrow (BM) and/or blood. However, the number of eosinophils in the BM was not affected in the DAR/LDVc group. In addition, total blood IgE values were reduced in the DAR/LDVs but not the DAR/LDVc groups. Compared to the production of cytokines from splenic cells and blood IgE values in the DAR group, OVA-specific IL-4 and IFN-gamma productions and IgE values were reduced in the DAR/LDVs, whereas OVA-specific IFN-gamma and IL-4 productions were increased and decreased, respectively in the DAR/LDVc,but not the DAR/LDVs groups. Both DAR/LDVs and DAR/LDVc groups reduced the development of eosinophilic rhinitis associated with reduced VCAM-1 expression on endothelium in blood vessels and ICAM-1 expression on nasal respiratory epithelium at inflamed areas. The present study suggests that LDV infection at the sensitization phase may reduce the development of T helper (Th) 1 and Th2 responses, whereas LDV infection at the challenge phase may inhibit the development of Th2 response by shifting to Th1 response. These may be responsible for the reduction of the development of DAR by LDV infection.

Topics: Animals; Arterivirus Infections; Bronchial Provocation Tests; Disease Models, Animal; Eosinophilia; Female; Immunization; Immunoglobulin E; Immunologic Factors; Interferon-gamma; Lactate dehydrogenase-elevating virus; Mice; Mice, Inbred BALB C; Nasal Mucosa; Ovalbumin; Rhinitis, Allergic, Perennial; Species Specificity; Specific Pathogen-Free Organisms; Th1 Cells; Th2 Cells

The effects of interferon (IFN)-gamma induced by virus infection on eosinophil reaction in allergic airway inflammation are not yet clear. We investigated the effects of lactic dehydrogenase virus (LDV) infection, which increases IFN -gamma production with no viral infection or replication in respiratory epithelium, on allergic airway hypersensitivity. LDV infection suppressed antigen-induced eosinophil recruitment into the airway in sensitized mice. IL -5 gene expression in bronchoalveolar lavage (BAL) cells was significantly suppressed in LDV -infected mice compared with uninfected controls. The numbers of total T cells and CD 4+ T cells were significantly reduced in LDV -infected mice compared with controls. The present results suggested that the increase in production of IFN -gamma by viral infection suppresses the eosinophil reaction, and this suppressive effect may be mediated by inhibition of the recruitment of CD 4+ T cell and IL -5 production.

Topics: Allergens; Animals; Arterivirus Infections; Base Sequence; Bronchoalveolar Lavage; CD4-Positive T-Lymphocytes; Eosinophils; Gene Expression Regulation; Hypersensitivity; Interferon-gamma; Interleukin-5; Lactate dehydrogenase-elevating virus; Male; Mice; Ovalbumin; Respiratory System; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Rodent Diseases

Enzyme-linked immunosorbant assays (ELISAs) were developed for the detection of antibodies against the major envelope glycoprotein (G(L)) of equine arteritis virus (EAV). A 6-Histidine tagged recombinant protein expressing the complete G(L) ectodomain (G(L)-6His), a glutathione-S-transferase recombinant protein expressing amino acids 55-98 of G(L) (G(L)-GST) and an ovalbumin-conjugated synthetic peptide representing amino acids 81-106 of G(L) (G(L)-OVA) were used as diagnostic antigens. An ELISA procedure was developed and optimised for each antigen. The G(L)-OVA and G(L)-6His assays showed the greatest specificity while the G(L)-GST assay was slightly more sensitive that the G(L)-OVA and G(L)-6His assays; results based on the analysis of 50 virus neutralisation positive and 50 virus neutralisation negative sera. The G(L)-OVA ELISA was selected for further evaluation since it was simpler to use than ELISAs based on recombinant antigens and did not suffer from background reactivity. The final sensitivity and specificity of the G(L)-OVA ELISA were 96.75 and 95.6%, respectively, results based on the analysis of 400 virus neutralisation positive and 400 virus neutralisation negative sera. It also detected EAV antibody (100% efficiency) in seropositive shedding stallions and, in ponies infected experimentally with the UK93 isolate of EAV, the appearance of virus neutralising antibodies and G(L)-OVA ELISA-specific immunoglobulins coincided.

Topics: Animals; Antibodies, Viral; Antigens, Viral; Arterivirus Infections; Enzyme-Linked Immunosorbent Assay; Equartevirus; Glutathione Transferase; Histidine; Horse Diseases; Horses; Ovalbumin; Recombinant Fusion Proteins; Sensitivity and Specificity; United Kingdom; Viral Envelope Proteins

The effects of lactic dehydrogenase virus (LDV) infection on allergic immunoglobulin (Ig)E production and interleukin (IL)-4 gene expression were studied. LDV infection suppressed antigen-induced IgE production in sensitized mice. The elevations of IL-4 gene expression in spleen and mesenteric lymph nodes 3 and 7 days after ovalbumin challenge were suppressed significantly in LDV-infected mice compared with control mice. The expression of the interferon (IFN)-gamma gene of mesenteric lymph nodes was significantly increased in LDV-infected mice. These results suggest that LDV infection suppressed antigen-induced IgE production by decreasing IL-4 production, and that suppression of IL-4 gene expression may be mediated by a mutual inhibition mechanism between T helper (Th)1 and Th2 cells.

Topics: Allergens; Animals; Arterivirus Infections; Gene Expression; Immunoglobulin E; Interferon-gamma; Interleukin-4; Lactate dehydrogenase-elevating virus; Male; Mice; Mice, Inbred BALB C; Ovalbumin

The effects of lactic dehydrogenase virus (LDV) infection on allergic eosinophil reaction and IL-5 gene expression were studied. LDV infection suppressed antigen-induced eosinophil recruitment into the peritoneal cavity in sensitized mice. The elevation of IL-5 gene expression in the spleen and mesenteric lymph nodes 6 h after ovalbumin challenge was significantly suppressed in LDV-infected mice compared with uninfected (control) mice. The expression of the interferon-gamma and IL-2 genes in the spleen, but not in mesenteric lymph nodes, was significantly suppressed in LDV-infected mice compared with control mice. The present results suggest, that suppression of IL-5 gene expression by LDV infection may not be mediated by a mutual inhibitory mechanism between Th1 and Th2 cells.

Topics: Animals; Antigens; Arterivirus Infections; Base Sequence; DNA Primers; Eosinophils; Gene Expression; Hypersensitivity; Interferon-gamma; Interleukin-2; Interleukin-5; Lactate dehydrogenase-elevating virus; Lymph Nodes; Male; Mice; Mice, Inbred BALB C; Ovalbumin; Peritoneal Cavity; Spleen; Th1 Cells; Th2 Cells