Precursors of B-lymphocytes with surface IgM and their possible migration from bone marrow to peripheral lymphatic tissues

Abstract

The lymphocytes with surface immunoglobulins (sIg) represent precursors of B-lymphocytes and were studied in ontogeny of pigs by autoradiography using iodinated monospecific anti-mu, anti-gamma or anti-alpha antibodies. The earliest detection of sIgM+ small lymphocytes was at 44 days of gestation in liver, followed at 51 days in spleen and at 60 days in bone marrow, the thymocytes being sIg-negative. The first circulating small lymphocytes were detected at 38--40 days and are most probably thymus-derived.