The CD4 and CD8 T Cell Surface Antigens are Associated with the Internal Membrane Tyrosine-Protein Kinase p56(lck) (Reprinted from Cell, vol 77, pg 301-308, 1994)

The CD4 and CD8 T cell antigens are thought to transduce an independent signal during the process of T cell activation. We report our evaluation of the possible involvement of the lymphocyte-specific tyrosine kinase p56(lck) in these transduction pathways. Our data demonstrate that p56(lck) is specifically modulated with either CD4 or CD8 following antibody-mediated cross-linking of these molecules and that a large fraction of the total cellular lck protein can be coimmunoprecipitated with these surface glycoproteins. These results suggest that p56(lck) is functionally and physically associated with CD4/CD8 in normal murine T lymphocytes and support the concept that an independent signal is transduced by the interaction of these surface molecules with major histocompatibility complex determinants.