The Journal of Immunology, Vol 158, Issue 1 273-279, Copyright © 1997 by American Association of Immunologists

ARTICLES

Characterization of lymphocyte function-associated antigen 1 (LFA-1)- deficient T cell lines: the alphaL and beta2 subunits are interdependent for cell surface expression

KS Weber, MR York, TA Springer and LB Klickstein
Division of Rheumatology and Immunology, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.

The leukocyte, or beta2, integrins are heterodimeric cell surface molecules that share a common beta subunit, and have unique alpha subunits. LFA-1 is the predominant beta2 integrin on lymphocytes, and plays an important role in many lymphocyte functions; however, most studies of the cytoplasmic regions of LFA-1 have been performed in transfected epithelial cells, such as COS, in part because no lymphoid cell lines deficient in the LFA-1 alpha subunit have been described. To address structure-function studies of beta2 integrins in relevant cell types, two T lymphoblastoid cell clones that completely lack cell surface LFA-1, J-(beta2).7 and SK-(beta2).7, derived from Jurkat and SKW3, respectively, were prepared by chemical mutagenesis and selection. Biosynthetic labeling and immunoprecipitation showed that the J-(beta2).7 clone did not translate any LFA-1 alpha subunit protein, while the SK-(beta2).7 cells did not synthesize any beta2 subunit protein. Northern blot analysis of poly(A+) RNA from these cells revealed an absence of the corresponding mRNA in each case. By transfection analysis, only the alpha subunit reconstituted LFA-1 expression in the J-(beta2).7 cells, while only the beta subunit restored cell surface LFA-1 expression in the SK-(beta2).7 cells. Functional studies with the parental cell lines, the J-(beta2).7 and SK- (beta2).7 cells, and the transfectants showed that all binding of Jurkat and SKW3 cells to purified ICAM-1 is mediated by LFA-1, and the reconstituted LFA-1 expressed by the J-(beta2).7 and SK-(beta2).7 transfected cells is regulated normally.