Mouse LFA-3 studied with chimeric soluble CD2 shows preferential expression on lymphoid cells.
Here we have used a soluble, polyvalent form of mouse CD2, i.e. CD2-hC mu, to detect its ligand LFA-3. Mouse LFA-3 is preferentially expressed on lymphoid cells unlike human LFA-3 which shows a wide tissue distribution. Mouse LFA-3 is one of the early surface molecules expressed on developing thymocytes appearing on the surface of fetal thymocytes on day 13 of gestation. Like human LFA-3, the mouse homolog could be shown to be a phosphatidyl inositol-linked membrane protein. Since mouse LFA-3 is preferentially expressed on lymphoid cells and since CD2 is expressed by both T and B lymphocytes, we would favor the view that the CD2/LFA-3 adhesion system in the mouse may play a role in interactions between lymphocytes (T-T and/or T-B) rather than in cell interactions between lymphocytes and non-lymphoid cells in the thymic, bone marrow or spleen microenvironments.