Lymphoid cells from the rodent Praomys (Mastomys) natalensis express antigenic determinants present on mouse and rat lymphocytes.

Recent studies have suggested that Praomys (Mastomys) natalensis might be a suitable model for analyzing the underlying mechanisms of autoimmunity, since a high incidence of autoantibodies to a wide variety of specificities occurs in this rodent which is intermediate in size between the mouse and the rat. Mastomys, also called the "multimammate mouse" or "multimammate rat", more closely resembles the rat than the mouse as regards some anatomical traits, and differs from both common rodents as to others. Because of controversies many years ago, Mastomys was never phylogenetically classified as a genus, but remains a subgenus, designated Praomys (Mastomys) natalensis. We have attempted to determine whether immunological markers differentiated on mouse or rat lymphocytes are present on Mastomys lymphoid cells. It was demonstrated that Mastomys cells (thymus, spleen, lymph node, bone marrow) bear theta determinants of both mouse and rat, express mouse membrane Ig, and bind with anti rat Ia antigens (which cross-react with mouse specificities). Functional markers (helper or suppressor/cytotoxic functions of the mouse or rat) were never found on Mastomys lymphoid cells.