Modification of helper and suppressor/cytotoxic lymphocyte subsets in mice with motor end-plate disease.

Motor end-plate disease (Med) in mice is associated with complex immunological abnormalities which are shared by the heterozygous +/MedJ mice, which exhibit no or mild clinical manifestations, and by MedJ/MedJ mice which die from this neuromuscular disorder. In the present paper we extend our immunological data with the study of splenic lymphocyte subsets with Lyt monoclonal antibodies. Both MedJ/MedJ and +/MedJ 14-18 day old mice have high Lyt1+/Lyt2+ ratios, with higher Lyt1+ and reduced Lyt2+ lymphocyte pools as compared to normal mice. This correlates with the low suppressive function previously described, but is unexpected in view of the low helper function as measured by the response to SRBC immunization. Adult +/MedJ mice recovered normal T lymphocyte subset levels, while the small group of MedJ/MedJ mice that escapes death but continues to suffer from the neuromuscular illness maintains high Lyt1+/Lyt2+ ratios.