Allospecific cytotoxic T cells generated from beta 2m-/- mice in primary MLC: analysis of activation requirements, specificity, and phenotype.

It has been demonstrated by several investigators that beta 2m-/- knockout mice are deficient in the expression of MHC Class I molecules but can nevertheless generate CD8(+) allospecific cytotoxic T cells following vigorous in vivo priming. We demonstrate here that in vivo priming is not necessary to generate MHC Class I allospecific CTL from beta 2m-/- mice. When splenocytes from naive unprimed beta 2m-/- mice were provided exogenous cytokines in MHC Class I disparate primary MLC, allospecific cytolytic effectors were generated. beta 2m-/- MHC Class I allospecific CTL that were CD3+ and Thy1.2+ were otherwise heterogeneous in phenotype, including CD8+, CD4+, CD8-CD4-, TCR alpha beta+, and TCR gamma delta+ T cells. This phenotypic variability of beta 2m-/- CTL generated in primary MLC reveals the diversity of CTL precursors that develop in vivo in the absence of MHC Class I.