Priming potency of the products of individual regions of the H-2 complex and their role in the restimulation in secondary MLC.

Genetic analysis of the determinants causing an early proliferation in MLC after priming with allogeneic cells in vivo was performed. The active determinants were localized in the I-A subregion of the H-2 complex by using appropriate recombinant mouse strains. Upon priming with antigens coded by the whole H-2 complex, the lymphocytes gave a strong MLC response only to the priming stimulator cells and cells sharing the I-A subregion determinants of the latter. The response to third party stimulator cells and cells not sharing I-A subregion determinants was low. Upon priming with various H-2 region products, only lymphocytes primed against I-A subregion products gave an early proliferative MLC response to the priming stimulator cells, whereas lymphocytes primed against other H-2 region products gave none.