Characterization of lymphocyte function-associated antigen 1 (LFA-1)-deficient T cell lines: the alphaL and beta2 subunits are interdependent for cell surface expression.
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.
Weber
K S
KS
Division of Rheumatology and Immunology, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.
York
M R
MR
Springer
T A
TA
Klickstein
L B
LB
D018821:CD18 Antigens / Q000032:analysis* / Q000502:physiology*; D002460:Cell Line; D006801:Humans; D016023:Integrins / Q000032:analysis / Q000502:physiology; D019169:Jurkat Cells; D016169:Lymphocyte Function-Associated Antigen-1 / Q000032:analysis* / Q000096:biosynthesis* / Q000276:immunology; D008565:Membrane Proteins / Q000032:analysis* / Q000096:biosynthesis*; D010446:Peptide Fragments / Q000032:analysis* / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*
D018821:CD18 Antigens; D016023:Integrins; D016169:Lymphocyte Function-Associated Antigen-1; D008565:Membrane Proteins; D010446:Peptide Fragments