Fate of antibodies bound to lymphocyte surface. II.--Degradation and release of immune complexes.
The fate of horse anti-human lymphocyte globulins, rabbit anti-human beta2 microglobulin antibodies and anti-HL-A alloantibodies radiolabelled with 125I and complexed to their corresponding lymphocyte surface antigens, was investigated. During prolonged incubation at 37 degrees C, part of these antibodies were actively released into the surrounding medium after enzymatic degradation occuring either intracellularly or at the cell surface. Metabolism of the antibodies was temperature-dependent and involved only antibodies able to react with antigens on the cell surface. Sephadex G200 filtration of the small percentage of non dialysable radioactive products in the supernatant revealed that all the 125I-anti-human lymphocyte globulin was recovered as a macromolecular structure in the void volume. Similar experiments were performed with 51Cr labelled lymphocytes coated with anti-lymphocyte globulins: treatment with anti-horse immunoglobulin precipitated part of 51Cr activity in the void volume which was therefore associated with anti-human lymphocyte globulin as an immune complex. The same protocol applied to the other two antibodies studied showed that anti-beta2 microglobulin antibodies were recovered both as macromolecular and 7 S immune complexes, whereas anti-HL-A antibodies were recovered as macromolecular, 7 S and still smaller immune complexes.
D000906:Antibodies / Q000378:metabolism; D000936:Antigen-Antibody Complex; D000961:Antilymphocyte Serum; D002462:Cell Membrane / Q000276:immunology; D006680:HLA Antigens; D006801:Humans; D007074:Immunoglobulin G; D008214:Lymphocytes / Q000276:immunology*; D011947:Receptors, Antigen, B-Cell
D000906:Antibodies; D000936:Antigen-Antibody Complex; D000961:Antilymphocyte Serum; D006680:HLA Antigens; D007074:Immunoglobulin G; D011947:Receptors, Antigen, B-Cell