FUNCTIONAL EXPRESSION OF A CATTLE MHC CLASS-II DR-LIKE ANTIGEN ON MOUSE L-CELLS

Cattle DRA and DRB genes, cloned by reverse-transcription polymerase c hain reaction, were transfected into mouse L cells. The cattle DR-expr essing L-cell transfectant generated was analyzed serologically, bioch emically, and functionally. Sequence analysis of the transfected DRB g ene clearly showed showed that it was DRB3 allele DRB30101, which cor responds to the 1D-IEF-determined allele DRBF3. 1D-IEF analysis of the transfectant confirmed that the expressed DR product was DRBF3. Funct ional integrity of the transfected gene products was demonstrated by t he ability of the transfectant cell line to present two antigens (the foot-and-mouth disease virus-derived peptide FMDV15, and ovalbumin) to antigen-specific CD4+ T cells from both the original animal used to o btain the genes, and also from an unrelated DRBF3+ heterozygous animal . Such transfectants will be invaluable tools, allowing us to dissect the precise contributions each locus product makes to the overall immu ne response in heterozygous animals, information essential for rationa l vaccine design.