Gradual development of the interferon-gamma response of swine to porcine reproductive and respiratory syndrome virus infection or vaccination.
Infection of swine with virulent porcine reproductive and respiratory syndrome (PRRS) virus induced a rapid, robust antibody response that comprised predominantly nonneutralizing antibodies and waned after approximately 3 months. In contrast, the initial onset of virus-specific interferon (IFN)-gamma-secreting cells (SC) in the pig lymphocyte population remained at a fairly low level during this period and then increased gradually in frequency, plateauing at 6 months postinfection. A similar polarization of the host humoral and cellular immune responses was also observed in pigs immunized with a PRRS-modified live virus (MLV) vaccine. Even coadministration of an adjuvant that enhanced the immune response to a pseudorabies (PR) MLV vaccine failed to alter the induction of PRRS virus-specific IFN-gamma SC (comprising predominantly CD4/CD8 alpha double positive memory T cells with a minority being typical CD4(-)/CD8 alpha beta(+) T cells) and the generation of neutralizing antibodies. Moreover, unlike inactivated PR virus, nonviable PRRS virus did not elicit virus-neutralizing antibody production. Presumably, an intrinsic property of this pathogen delays the development of the host IFN-gamma response and preferentially stimulates the synthesis of antibodies incapable of neutralization.
Department of Veterinary Pathobiology, University of Illinois, Urbana, IL 61802-617, USA.
William A
WA
Meier
Judy
J
Galeota
Fernando A
FA
Osorio
Robert J
RJ
Husmann
William M
WM
Schnitzlein
Federico A
FA
Zuckermann
D000818:Animals; D000917:Antibody Formation; D001483:Base Sequence; D007371:Interferon-gamma / Q000276:immunology*; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology; D016366:Open Reading Frames; D019318:Porcine Reproductive and Respiratory Syndrome / Q000188:drug therapy / Q000276:immunology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000187:drug effects*; D013552:Swine; D013997:Time Factors; D014765:Viral Vaccines
D014765:Viral Vaccines; D007371:Interferon-gamma