IN-VITRO ANALYSIS OF A PRIMARY, MAJOR HISTOCOMPATIBILITY COMPLEX (MHC)-RESTRICTED, CYTOTOXIC T-LYMPHOCYTE RESPONSE TO AVIAN-LEUKOSIS VIRUS (ALV), USING TARGET-CELLS EXPRESSING MHC CLASS-I CDNA INSERTED INTO A RECOMBINANT ALV VECTOR

The interaction between the major histocompatibility complex (MHC) and cytotoxic T lymphocytes (CTLs) is an important component of the host' s resistance to viral infections and tumor formation. In this study, a n avian leukosis virus (ALV) vector system, RCASBP, expressing MHC chi cken class I (B-F) cDNA was used to develop target cells expressing th e chicken class I glycoproteins complexed with ALV antigens on the cel l surface. Peripheral blood from chickens inoculated with ALV was show n to contain antigen-specific, MHC-restricted, CD8(+) effector CTLs, u sing a Cr-51 release assay utilizing the RCASBP B-F target cells. The stimulated effector cells were also predominantly alpha beta T-cell re ceptor-positive (TCR2) T cells. The CTL response varied between two ha plotypes of chickens which differed in their response to Rous sarcoma virus (RSV)-induced tumors. Chickens with the B-21 haplotype which reg ress RSV-induced tumors showed maximal cytolytic activity, while chick ens with the B-13 haplotype which do not regress RSV-induced tumors ha d minimal to no cytolytic activity. In addition to assessing the CTL r esponse to ALV, the creation of MHC-specific immortal target cell line s will be extremely useful in evaluating CTL responses to other viral disease in chickens.