Peanut agglutinin. II. Characterization of the Thy‐1, Tla and Ig phenotype of peanut agglutinin‐positive cells in adult, embryonic and nude mice using double immunofluorescence

The Thy‐1, Tla and Ig phenotype of peanut agglutinin (PNA)‐binding cells was characterized in various strains of mice. In the thymus, PNA was found to bind principally but not exclusively to the Thy‐1+ Tla+ Ig− steroid‐sensitive cortical thymocytes. Thy‐1+ Tla− Tg− steroid‐resistant cells are not labeled with PNA. In other lymphoid organs, PNA bound to a minority of T or null cells but generally not to B cells. During ontogeny, PNA+ and PNA− T lineage cells appear simultaneously in the liver at day 10 of gestation, in the thymus at day 11 and in the spleen at day 18. No evidence was found for a maturation from PNA+ to PNA− cells. Prethymocytes present in nude mice were also divided into a PNA+ and PNA− population. The findings possibly support the proposition that cortical and medullary thymocytes develop independently. Moreover, they suggest that both populations might arise from distinct precursors and give rise to distinct functional peripheral T cells.