title: Coclustering of CD4 (L3T4) molecule with the T-cell receptor is induced by specific direct interaction of helper T cells and antigen-presenting cells.
abstract: Blocking studies with monoclonal antibodies have suggested that helper T cell recognition and triggering involve the CD4 (L3T4) accessory molecule as well as the T-cell receptor (TCR) that is linked to the T3 complex. We have investigated the surface distribution of L3T4 and TCR during the direct interaction of a cloned murine helper T-cell line with an antigen-presenting B-cell line. Using immunofluorescence microscopy, we show that in 1:1 cell couples formed between the two cells, in which a specific interaction can be demonstrated, the L3T4 and the TCR become redistributed on the T-cell surface so that they are concentrated in the cell-cell contact region. This coclustering of L3T4 with TCR occurs only when the relevant antigen and appropriate major histocompatibility class II molecules are presented to the T cell, and it therefore requires the specific interaction of the TCR with its complex ligand on the antigen-presenting cell.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D007152:Immunologic Capping; D051379:Mice; D011948:Receptors, Antigen, T-Cell / Q000032:analysis*; D006377:T-Lymphocytes, Helper-Inducer / Q000648:ultrastructure*
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D011948:Receptors, Antigen, T-Cell