Blood lymphocytes, monocytes and NK cells modulate their expression of CD44, ICAM-1, LFA-1 and MHC class II after arrival into lymphoid organs

Adhesion molecules expressed on surface membranes of lymphocytes and other leukocytes enable their entry into the lymphoid and other tissues. However, little,is known about molecules that govern the transit of leukocytes through the parenchyma of lymphoid organs proper. We show that in comparison to blood leukocytes, the corresponding cells isolated from lymphoid organs, i.e., lymph nodes and spleen, have a significantly augmented expression of certain surface molecules. The helper and cytotoxic subsets of T cells, as well as B cells, display the increased expression of CD44, ICAM-1 and LFA-1, whereas B cells additionally show the augmented expression of MHC class H. In comparison with blood monocytes, splenic monocytes show the increased expression of 1CAM-1 and MHC class 11 molecules. When compared with blood NK cells, splenic NK cells only show the increased expression.