Cell-mediated immunity to porcine reproductive and respiratory syndrome virus in swine.
Cell-mediated immunity has been demonstrated to be a necessary component of immunity against viral infection. Methods to detect T-cell mediated immune responses to porcine reproductive and respiratory syndrome virus (PRRSV) infection were established both in vitro as lymphocyte proliferation and in vivo as delayed-type hypersensitivity response (DTH). Optimal conditions for detection of lymphocyte proliferation were determined by testing different antigen concentrations and various stimulation periods. The proliferation response to PRRSV was antigen-specific and dose-dependent. The kinetics of the T-cell proliferation response to PRRSV were analyzed after primary and secondary exposure to virus. Lymphocyte proliferation was first detected at four weeks post-infection (PI), peaked at 7 weeks PI, and declined after 11 weeks PI. The secondary response increased in magnitude. Experiments with blocking antibodies to porcine leukocyte antigens demonstrated that CD4+ T-cells were the major effector cells in the proliferation response. The in vivo response to PRRSV was shown by detection of a dose-dependent DTH reaction in infected pigs after intradermal challenge with UV-inactivated virus. These results demonstrate that pigs generate specific T-cell responses on PRRSV infection and provide a foundation for studying their role in protection.
Bautista
E M
EM
Department of Clinical and Population Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, USA.
Molitor
T W
TW
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D006968:Hypersensitivity, Delayed / Q000276:immunology / Q000662:veterinary / Q000821:virology; D007114:Immunization; D007117:Immunization, Secondary; D008213:Lymphocyte Activation; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D013552:Swine; D013601:T-Lymphocytes / Q000276:immunology / Q000821:virology