Induction of strong homotypic adhesion in human T cell lines positive with human T-cell leukemia virus type 1 by monoclonal antibodies to MHC class I and beta 2-microglobulin.
To identify the cellular receptors and other cell surface molecules playing essential roles in the transmission of human T-cell leukemia virus type 1 (HTLV-1), we have been isolating monoclonal antibodies (mAbs) that are capable of inhibiting HTLV-1-induced syncytium formation. In the present study, we isolated two mAbs, H11 (IgM) and H14 (IgG1), inhibitory to syncytium formation in the coculture of TOM-1 or C91/PL (both HTLV-1-positive human T-cell lines) and MOLT-4/8 (HTLV-1-negative human T-cell line) by immunizing the membrane fraction of human osteosarcoma line HOS. By immunoprecipitation and immunoblotting, H11 and H14 were found to be specific for MHC class I heavy chain and beta 2-microglobulin (beta 2 M), respectively. Among the four commercially obtained mAbs, two mAbs for MHC class I antigen and two mAbs to beta 2 M, one mAb to MHC class I antigen and one mAb to beta 2 M were also found to be inhibitory to the syncytium formation. The functional comparison of these mAbs revealed that the syncytium-inhibitory mAbs induced strong homotypic cell adhesion particularly in the HTLV-1-positive T-cell lines. This cell adhesion was dependent on temperature, energy metabolism, and microfilament function but not on the activity of protein kinase C or divalent cations. These results suggest a novel type of LFA-1-independent cell adhesion induced by signal transduction via MHC class I antigen.
Furuse
M
M
Shionogi Institute for Medical Science, Osaka, Japan.
Fukudome
K
K
Imai
T
T
Uwabe
K
K
Hinuma
Y
Y
Yoshie
O
O
D000911:Antibodies, Monoclonal / Q000276:immunology; D002448:Cell Adhesion; D002449:Cell Aggregation; D002459:Cell Fusion; D000939:Epitopes; D015490:HTLV-I Infections / Q000635:transmission*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D066298:In Vitro Techniques; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000382:microbiology*; D001613:beta 2-Microglobulin / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D015395:Histocompatibility Antigens Class I; D001613:beta 2-Microglobulin