A MOUSE B-CELL ALLOANTIGEN DETERMINED BY GENE(S) LINKED TO THE MAJOR HISTOCOMPATIBILITY COMPLEX

The humoral response to transplantation across species includes the production of antibodies specific for the major histocompatibility alloantigens of the donor animal (1-3). In particular, rats immunized with mouse tissues have been shown to produce antibodies reactive against a number of individual H-2 specificities (1). One possible advantage of this method of production of cytotoxic antisera is the possibility that rats may respond to histocompatibility alloantigens not detected by other mice, thus providing new genetic markers. In the course of analyzing antisera from a series of cross-species immunizations, and unexpected cytotoxic reaction with C57Bl/10 lymph node cells was observed with an antiserum which, according to the current H-2 chart, should have contained only specificity for H-2.31. The results of additional studies indicate: (a) that immunizations between appropriate congenic mouse strains produce alloimmune antisera which likewise detect this new specificity, (b) that these cytotoxic antisera (hereafter called anti-"beta") detect a cell-surface antigens(s) (hereafter called "beta") expressed preferentially on B cells, and (c) that tests of recombinant strains indicate that the gene(s) determining beta are linked to the K-end of the H-2 complex; i.e., in or to the left of the Ir-1 region.