Direct evidence for immunoglobulins on the surface of thymus lymphocytes of amphibian larvae

Immunoglobulins associated with the membrane of amphibian lymphocytes are easily detectable by immunofluorescence and behave very much like membrane immunoglobulins on mammalian lymphocytes. Ontogenic studies of the thymus and spleen in larvae show a sharp increase (from less than 1 % to 80 %) in the level of lymphocytes carrying immunoglobulins in the thymus at very early stages of their development. This level remains constant during the entire larval and early adult life, and is significantly higher than that in the thymus of older adults (9 %). Splenic lymphocytes having immunoglobulins on their membrane remain at a constant level (40–60 %).