A TRANSMISSIBLE GASTROENTERITIS CORONAVIRUS NUCLEOPROTEIN EPITOPE ELICITS T-HELPER CELLS THAT COLLABORATE IN THE IN-VITRO ANTIBODY-SYNTHESIS TO THE 3 MAJOR STRUCTURAL VIRAL-PROTEINS

Four strong T cell epitopes have been identified studying the blastogenic response of lymphocytes from haplotype-defined transmissible gastroenteritis virus (TGEV) immune miniswine to sixty-one 15-mer synthetic peptides. Three of these epitopes are located on the nucleoprotein (N-46, amino acids 46 to 60; N-272, amino acids 272 to 286; and N-321, amino acids 321 to 335), and one on the membrane protein (M(196), amino acids 196 to 210). N-321, peptide induced the highest T cell response and was recognized by immune miniswine lymphocytes with haplotypes dd, aa, and cc, T lymphocytes from peptide N321(-) immune miniswine reconstituted the in vitro synthesis of TGEV-specific antibodies by complementing CD4(-) TGEV-immune cells. This response was directed at least against the three major structural proteins. The synthesized antibodies specific for S protein preferentially recognized discontinous epitopes and neutralized TGEV infectivity. These results show that peptide N-321 defines a functional T helper epitope eliciting T cells capable of collaborating with B cells specific for different proteins of TGEV. (C) 1995 Academic Press, Inc.