Mapping the cytotoxic T-lymphocyte epitopes of Pichinde virus.

Abstract

One of the aims of this study was to determine whether the glycoproteins of Pichinde virus harbour any cytotoxic T-lymphocyte (CTL) epitopes on the murine haplotypes, H-2$\sp{\rm b}$ and H-2$\sp{\rm d}$ since, on neither of these MHC backgrounds are there any CTL epitopes on the nucleoprotein of this virus. Using a vaccinia virus recombinant, vvGPC, which expresses the full-length glycoprotein precursor (GPC) of Pichinde virus, standard chromium release CTL assays were performed. Three independent assays are shown for each of the haplotypes. In each of these assays for both of the haplotypes, it was observed that CTL derived against Pichinde virus did not recognize vvGPC-infected target cells nor did CTL derived against vvGPc recognize Pichinde-infected target cells. This indicates that no CTL were generated with either virus that might recognize the glycoproteins of Pichinde virus and, therefore, that the glycoproteins do not contain CTL epitopes on these murine MHC backgrounds. A second aim of this work was to compare the CTL epitopes of Pichinde wild-type virus with two temperature sensitive mutants derived from it. Both these mutants have been shown to be defective in their glycoprotein processing. The H-2$\sp{\rm d}$-restricted epitopes appear to be disrupted in TS13 as it is not recognized by Pichinde-specific CTL derived on this background. TS908 is not recognized by Pichinde-specific CTL on either haplotype suggesting that the wild-type virus' epitopes were probably disrupted during the derivation of this mutant. (Abstract shortened by UMI.)