Five types of lymphocytes (Ig-theta-, Ig-theta+weak, Ig-theta+strong, Ig+theta- and Ig+theta+) characterized by double immunofluorescence and electrophoretic mobility. Organ distribution in normal and nude mice.

The simultaneous detection of Ig and theta on the surface of mouse lymphocytes permits the detection of four cell types (Ig-theta-, Ig-theta+, Ig+theta-, and Ig+theta+) which also have distinct electrophoretic profiles. All types are present in variable proportions in all lymphoid organs studied. Results obtained in congenitally athymic nude mice and in T-deprived mice define a new type of lymphocyte, the Ig-theta+weak. This cell is non-recirculating, Ig-, with a low density of theta and a slow electrophoretic mobility. It is a candidate for a T-committed prethymic cell.