Decreased Syngeneic Mixed Lymphocyte Reaction in Autoimmune Susceptible Mice

The syngeneic mixed lymphocyte reaction (SMLR) is a proliferative response mediated by murine splenic thymus‐derived (T) lymphocytes after stimulation by syngeneic non‐T cells. Several murine strains genetically susceptible to autoimmune diseases have decreased SMLR compared with normal strains. This diminished SMLR occurs before the onset of clinical disease and is most pronounced in those autoimmune mice that express a severe form of the disease. For example, in NZB/NZW F1 hybrid (B/W) mice, the SMLR is lower at 7 than at 2 months of age. The SMLR is lower in BXSB males, which develop more accelerated autoimmune disease, than in BXSB females. The defect in these autoimmune strains resides within the responding Lyt 1+, 2, 3− T‐cell population. These results suggest the presence of a common T‐cell defect in several murine strains that spontaneously develop autoimmunity.