Association of human lymph node homing receptor (Leu 8) with the TCR/CD3 complex.
Cross-linking of the human homologue of the murine MEL-14 lymph node homing receptor (Selectin-1, LECAM-1, Leu 8) on both T and B cells results in modification of cell function. To investigate this phenomenon, we performed studies to determine if the Leu 8 molecule influences T cell activation via the TCR/CD3 complex. In initial studies, we treated T cells with immobilized anti-CD3 (OKT3 mAb) in the presence or absence of immobilized Leu 8 mAb. We found that although Leu 8 mAb alone had no effect on T cell proliferation, this antibody markedly augmented immobilized OKT3 mAb-induced proliferation. In further studies, we immunoprecipitated surface radioiodinated T cell lysates with OKT3 and Leu 8 mAb to determine if molecules in the TCR/CD3 complex associate with Leu 8 molecules. Although Leu 8 mAb immunoprecipitated only a single protein of approximately 80 kDa from T cell lysates treated with Nonidet P-40 under reducing condition, it coimmunoprecipitated additional proteins of 48, 42, 28, 24, and 22 kDa from T cell lysates treated with 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate. These additional proteins were identified as the alpha-, beta-, gamma-, delta-, and epsilon-chains of the TCR/CD3 complex by one-dimensional and two-dimensional diagonal SDS-PAGE. Densitometric scanning showed that, on average, 18% of the TCR/CD3 complex associates with Leu 8. In a final study, we showed by immunoblotting analysis using anti-zeta peptide antibody that Leu 8 mAb coimmunoprecipitates the zeta-chain of CD3. These results indicate that the human lymph node homing receptor homologue (Leu 8) participates in the activation of T cells, probably via its association with the TCR/CD3 complex.
Murakawa
Y
Y
Mucosal Immunity Section, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892.
Minami
Y
Y
Strober
W
W
James
S P
SP
D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism*; D017252:CD3 Complex; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D019041:L-Selectin; D008198:Lymph Nodes / Q000166:cytology; D008213:Lymphocyte Activation; D046911:Macromolecular Substances; D011940:Receptor Aggregation; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D016201:Receptors, Lymphocyte Homing / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000502:physiology* / Q000648:ultrastructure
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D015815:Cell Adhesion Molecules; D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell; D016201:Receptors, Lymphocyte Homing; D019041:L-Selectin