Lymphocytes become adherent and aggregate after stimulation with phorbol esters such as PMA. Time-lapse video showed that aggregating cells were motile and exhibited vigorous pseudopodial movements. Adhesion sites were initiated between pseudopodia of neighboring cells, and then moved to the uropod. PMA-stimulated aggregation by EBV-transformed B cell lines, SKW-3 (a T cell line), differentiated U937 (a monocytic line), and blood lymphocytes was inhibited by mAbs to LFA-1. A number of different mAb to the LFA-1 alpha and beta subunits and F(ab')2 and Fab' fragments inhibited aggregation. Furthermore, lymphoblasts from normal individuals, but not from LFA-1-deficient patients, aggregated in response to PMA. These findings suggest LFA-1 is critically involved in stimulated lymphocyte adhesion. LFA-1 expression was not increased by PMA stimulation, showing that other mechanisms regulate LFA-1-dependent adherence. LFA-1-deficient patient cells were able to coaggregate with LFA-1+ cells, showing that aggregation is not mediated by like-like interactions between LFA-1 molecules on opposite cells. Aggregation was Mg+2-dependent, inhibited by cytochalasin B, and was reversed when LFA-1 mAb was added to preformed aggregates. Previous findings suggesting that LFA-1 is important in a wide variety of leukocyte functions are elucidated by this work, which shows that LFA-1 is a general leukocyte cell adhesion molecule, the activity of which is regulated by cell activation.
Publications
The requirement for lymphocyte function-associated antigen 1 in homotypic leukocyte adhesion stimulated by phorbol ester. J. Exp. Med. 163, 5, 1132-1149 (1986).Abstract
Defective membrane expression of the LFA-1 complex may be secondary to the absence of the β chain in a child with recurrent bacterial infection. Eur. J. Immunol. 16, 2, 205-208 (1986).Abstract
A partial genomic DNA clone for the α subunit of the mouse complement receptor type 3 and cellular adhesion molecule Mac-1. Proc Natl Acad Sci USA 83, 15, 5644-5648 (1986).Abstract
Macrophages. Handbook of experimental immunology Vol.IV: Applications of immunological methods in biomedical sciences, 118 (1986).
The Ly-15 alloantigenic system: A genetically determined polymorphism of the murine lymphocyte function-associated antigen-1 molecule. Proc Natl Acad Sci USA 82, 2, 526-530 (1985).Abstract
Leukocyte LFA-1, OKM1, p150,95 deficiency syndrome: functional and biosynthetic studies in three kindreds. Fed. Proc. 44, 10, 2671-2677 (1985).Abstract
The importance of the Mac-1, LFA-1 glycoprotein family in adherence-dependent inflammatory functions: Insights from an experiment of nature. Infection and Malignancy (RES Symposium) (1985).Abstract
The LFA-1, Mac-1 leukocyte adhesion glycoprotein family and its deficiency in a heritable human disease. Biochem. Soc. Trans. 13, 3-6 (1985).
The function of LFA-1 in cell-mediated killing and adhesion: Studies on heritable LFA-1, Mac-1 deficiency and on lymphoid cell self-aggregation. Mechanisms of Cell-Mediated Cytotoxicity II 311-322 (1985).
Sequence homology of the LFA-1 and Mac-1 leukocyte adhesion glycoproteins and unexpected relation to leukocyte interferon. Nature 314, 6011, 540-542 (1985).Abstract
Functional and structural interrelationships among the Mac-1, LFA-1 family of leukocyte adhesion glycoproteins, and their deficiency in a novel, heritable disease. Hybridoma Technology in the Biosciences and Medicine 191-206 (1985).
The LFA-1, Mac-1 glycoprotein family and its deficiency in an inherited disease. Fed. Proc. 44, 10, 2660-2663 (1985).Abstract
Human cytolytic T-lymphocyte clones and their function-associated cell surface molecules. Hybridoma Technology in the Biosciences and Medicine 559-573 (1985).