Internalization and processing of antibodies to surface antigens on human B cells. Monoclonal anti-IgM antibodies are processed differently than monoclonal antibodies towards non-Ig surface receptors.
The internalization and intracellular processing of monoclonal antibody to immunoglobulin mu heavy chain (Mamu) have been investigated in two human Burkitt lymphoma cell lines (Ramos and Raji), in a human B cell lymphoma and in normal human peripheral blood B cells. In addition to the degradation of 125I-labeled Mamu to trichloroacetic acid (TCA) soluble material, a distinct pattern of larger 125I-Mamu fragments was detected in all sources of B cells tested. The particular fragmentation pattern, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis, involved the cleavage of both peptide bonds and disulfide bridges. This type of antibody fragmentation appeared to be a selective mechanism associated with sIgM, as no other degradation than that leading to TCA-soluble material could be detected after the internalization and degradation of radiolabeled monoclonal antibodies towards a variety of non-Ig B cell surface receptors. Three fragments of 125I-Mamu degradation were also detected in the supernatant of Ramos cells, implying that the recycling and exocytosis of certain 125I-Mamu fragments also took place.
Ruud
E
E
Blomhoff
H K
HK
Funderud
S
S
Godal
T
T
D000911:Antibodies, Monoclonal / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology*; D001402:B-Lymphocytes / Q000378:metabolism*; D002051:Burkitt Lymphoma; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D005089:Exocytosis; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D007148:Immunoglobulin mu-Chains / Q000276:immunology; D008223:Lymphoma
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D007075:Immunoglobulin M; D007148:Immunoglobulin mu-Chains; C033027:secretory IgM