Surface immunoglobulin on lymphocytes of the tortoise Agrionemys horsfieldii.

Surface immunoglobulin bearing (sIg+) cells were identified in the tortoise Agrionemys horsfieldii by indirect immunofluorescence by using class-specific antisera to tortoise IgM and IgY produced in mice. With this technique 13-23% of blood lymphocytes were found to bear surface IgM and 5-8% IgY. Spleen lymphocytes show a higher percentage of sIg+ cells: 25-52% sIgM+ and 5-20% sIgY+ lymphocytes. There is strong indication that tortoise sIgY+ lymphocytes of blood and spleen also express IgM on their surface.