CHARACTERIZATION OF A MONOCLONAL-ANTIBODY DIRECTED AGAINST THE PHOSPHOTYROSINE KINASE P56LCK, IN HUMAN T-CELLS

A monoclonal antibody (anti-p56lck) was generated against a fusion protein containing the residues 145-509 of the human p56lck, a lymphocyte-specific membrane-associated protein tyrosine kinase. The involvement of this enzyme in T-cell transmembrane signalling seems to be an early and crucial event during T-cell receptor-mediated activation. We have produced a monoclonal antibody which recognizes p56lck in free form and when associated with CD4. It functions in western blot analysis and is capable of selectively blocking auto-phosphorylation of this kinase. This monoclonal antibody should be useful for investigating the role of p56lck in T-cell activation.