T-cell antigen receptor assembly and cell surface expression is not affected by treatment with T-cell antigen receptor-alpha chain transmembrane Peptide

A synthetic peptide termed core peptide (CP), which corresponds to a specific sequence of the TCR-alpha chain transmembrane domain, is known to inhibit IL-2 production in antigen stimulated T-cells. The molecular mechanism of the TCR inhibition is not known. This study examined the effects of CP on TCR subunit assembly and TCR cell surface expression in vitro. Co-transfection experiments between TCR-alpha and CD3-delta using COS-7 cells, and the interaction between TCR-alpha and the CD3 proteins in a T-cell line (2B4) were analysed after incubation with CP or its conjugates. Results indicate that CP co-precipitates with CD3-delta and CD3-epsilon in vitro, without any effect on TCR-alpha/CD3-delta dimerisation or TCR multisubunit assembly and cell surface expression.