A porcine CD8+ T cell clone with heterotypic specificity for foot-and-mouth disease virus.

Foot-and-mouth disease virus (FMDV)-specific T cell lines and clones have been obtained from a swine lymphocyte antigen (SLA) inbred miniature pig vaccinated with chemically inactivated virus. One of the clones obtained, CE3, showed a specific and heterotypic proliferation against infectious but not inactivated FMDV in the presence of syngeneic peripheral blood mononuclear cells (PBMC). Adherent cells from PBMC were sufficient to support specific activation of the clone and the proliferation was abolished when the contact between CE3 and adherent cells was prevented. Phenotypic characterization of CE3 cells revealed expression of CD2, CD25 (interleukin-2 receptor), SLA class I and SLA class II. Furthermore, the cells were highly CD8 positive but showed low expression of CD4. The expression of T cell receptor (TCR) alpha and beta genes confirmed their T cell nature. Consistent with the CD8 phenotype, the proliferative response of CE3 was inhibited with MAbs to SLA class I and CD8. Altogether, these results indicate that CE3 is a porcine SLA class I-restricted CD8+ T cell clone, that recognizes a heterotypic FMDV antigen.