Primary in vitro cell-mediated lympholysis reaction of NZB mice against unmodified targets syngeneic at the major histocompatibility complex.

Abstract

T[thymus-derived]-cell cytotoxicity of NZB mice was tested after in vitro sensitization against a group of H-2 identical strains (BALB/c, B10.D2, DBA/2, HW19). A highly significant and unexpected unidirectional cell-mediated lympholysis (CML) reaction by the sensitized NZB effector cells on these targets was found. After sensitization in vitro with stimulator cells of one H-2d strain, NZB effector cells (H-2d) lysed all other H-2d targets and to a lesser degree, some non-H-2d targets (C57BL/10, DBA/1, B10.Q, CBA, B10.S, A.SW). NZB targets were not lysed. Differences in the major histocompatibility region between NZB and other H-2d strains could be excluded as a possible explanation for the observed reaction of NZB (H-2d) against other H-2d strains. These results consequently represent the 1st description of a primary in vitro CML directed against determinants not coded for in the major histocompatibility complex. The responsible effector cells are T cells. The CML of NZB against H-2 identical targets appears best explained by a reaction against minor histocompatibility antigens. The cytotoxic T-cell system in NZB mice is probably not subjected to restrictions found in all normal mouse strains tested until now under similar conditions. This hyperreactivity is probably related to the autoimmune responsiveness of the NZB strain.