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The L‐selectin (Leu8) molecule is associated with the TcR/CD3 receptor; fluorescence energy transfer measurements on live cells
Author(s) -
SZABO GABOR,
PINE P. SCOTT,
WEAVER JAMES L.,
RAO PATRICIA E.,
ASZALOS ADORJAN
Publication year - 1994
Publication title -
immunology and cell biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0818-9641
DOI - 10.1038/icb.1994.48
Subject(s) - t cell receptor , epitope , cd3 , monoclonal antibody , antibody , microbiology and biotechnology , flow cytometry , biology , t cell , receptor , lymphocyte homing receptor , antigen , chemistry , cell , biochemistry , immunology , cell adhesion , cd8 , immune system
Summary Several accessory molecules were shown to play important roles in T cell functions and be in dose proximity to the T cell receptor (TcRyCD3). The L‐selectin molecule (Leu8, LAM 1‐1, LECAM1) also plays an important role in lymphocyte homing and proliferation. We were interested in determining the proximity of this molecule to the TcR/CD3 complex on live peripheral human T cells. Using a fluorescence energy transfer method, designed to study individual cells, we could show that L‐selectin is within 170 Å of the TcR/CD3 complex. Monoclonal antibody directed against the LAMl‐l (Leu8) epitope of the L‐selectin molecule suppressed the mitogenic activity of antibodies specific for various CD3 epitopes in vitro. Intracellular Ca 2+ mobilization obtained with wt31 followed by cross‐linking antibody or with anti‐CD3 was not influenced by anti‐Leu8 antibody. Also antibody directed against the LAMl‐1 epitope did not influence the binding of the mitogenic antibodies, as shown by fluorescence‐based flow cytometry. Therefore, we suggest that binding of TcR/CD3 bound mitogenic antibodies to accessory cell Fc receptors may be hindered by antibodies bound to the close proximity L‐selectin molecules.