Mobility of HLA Class I antigen is influenced by anti-CD-4 monoclonal antibody in lymphocyte membranes. A flow cytometric energy transfer, fluorescence photobleaching recovery and rotational relaxation study

摘要

Fluctuations, mobility of receptor proteins and lipids in the plane and perpendicular to the plasma membrane and their proximity (assembly and dissociation properties) have enormous biological importance. CD-4 antigen (a cell surface receptor expressed mostly on helper T lymphocytes) is known to be a target of the Acquired Immune Deficiency Syndrome virus (AIDS-virus). Cells carrying this antigen are the major targets of the virus. The eventual damage of such cells, like helper T lymphocytes, results in a critical decrease in the cellular immunity, finally leading to the development of the AIDS disease. The obvious importance of this receptor protein motivated us to study its biophysical parameters. Human peripheral lymphocytes and cell-lines showing positivity for anti-CD-4 monoclonal antibodies display a relatively low density of the CD-4 antigen. This fact renders it difficult to investigate physical parameters, like mobility and association of CD-4 antigen to other cell surface elements. Thus the indirect investigation seemed to be a tool to obtain information of the above properties of CD-4 antigen. Similar, indirect investigations helped us to confirm the non-random association of the interleukin-2 binding receptor to a that time only putative new receptor subunit. Data gained from these types of experiment may have significant consequences even in the field of target oriented drug design.