Studies on non-H-2 linked lymphocyte activating determinants. I. Description of the cell type bearing the Mls product

The non-H-2 linked, lymphocyte activating determinants (LADs), which are coded by the minor (histocompatibility) lymphocyte stimulating locus (Mls), were detected on B lymphocytes, but not on immunoglobuin (Ig) negative or on theta positive T lymphocytes. These determinants, like the complement receptor and surface IgD, develop late in neonatal life. Thus, the Mls coded LADs mark a population of B lymphocytes which are not present in the spleens of newborn to 2-week-old mice. Studies of B lymphocytes derived from the spleens of adult mice indicated that the cells bear the Mls coded LADs have a high density of surface Ig and possess the complement receptor.