Immunohistochemical characterization of B cells and T cells in musk shrew (Suncus murinus) lymphoid tissues using monoclonal antibodies.

We have developed and characterized three monoclonal antibodies (mAbs), which recognize the surface antigens of musk shrew B cells and T cells. About 30% of all lymph node cells reacted with the mAb ST1. Staining of frozen sections showed that ST1-positive cells were located in the primary lymphoid follicles of lymph nodes, and were absent in the thymus. mAbs ST4 and ST2 were also surface-reactive. The ST1-negative (about 60% of the total) lymph node cells reacted positively with ST4, and about 30% of these ST4-positive cells were recognized by ST2. The distribution of ST4-positive cells was shown by staining of lymph node sections to be identical to that of T cells reported in other species. Western blot analysis showed that the apparent molecular weights of the antigens recognized by ST1 and ST4 were 70000 and 74000, and 60000 and 64000, respectively. These findings suggest that the antigens detected by ST1, ST4, and ST2 are the musk shrew homologues of pan-B cells, pan-T cells, and T cell subsets, respectively. The three mABs may facilitate immunohistochemical analysis of the cellular immune response in this species.