A human CD4 transgene rescues CD4-CD8+ cells in beta 2-microglobulin-deficient mice

The specificity of the alpha beta T cell receptor for class I or class II major histocompatibility complex (MHC) molecules determines whether a mature T cell will be of the CD4-CD8+ or CD4+CD8- phenotype, respectively. We show here that a human CD4 transgene can rescue a significant fraction of CD4-CD8+ T cells in beta 2-microglobulin-deficient mice. Cells with this phenotype could be induced to become potent killers of targets expressing allogeneic MHC antigens, indicating that lineage commitment can precede the rescue of developing cells by the T cell receptor for antigen and the CD4 coreceptor.