Hidden Thy-1 antigen in a subpopulation of mouse bone marrow cells

Immunofluorescence and cytolysis studies using antisera against the xeno- and alloantigenic components of the Thy-1 molecule have shown that in adult mouse bone marrow more cells bear the xeno than the alloantigen. Allo+ cells form a subset of a larger, xeno+ population. Xeno+ allo- 'prothymocytes' can be induced to express the alloantigen in vitro; this could result from the unmasking of cryptic antigen, the presence of which is demonstrated, rather than de novo antigen synthesis. Some xeno+ allo- cells are involved in splenic haemopoiesis, either as a subpopulation of precursors, or as accessory helper cells.