Binding of natural human IgM auto-antibodies to human tumor cell lines and stimulated normal T lymphocytes.
In a recent publication we described the binding of natural IgM antibodies derived from the human fetal B cell repertoire to the cell surface of some human tumor cells including colon carcinoma, small-cell lung cancer and B lymphoma lines [1]. Further analyses showed that a similar molecule was bound by the respective monoclonal human antibodies on the cell surface of polyclonally stimulated human CD3+ T cells, but is absent from unstimulated MNC. Both CD4+ and CD8+ stimulated cells were recognized. The molecule was found to be expressed together with lymphocyte activation markers (4F2, CD72, CD25). The membrane antigen expressed on both the activated T lymphocytes and tumor cells was characterized in a 2-D electrophoresis system: molecular weight 55-60 kDa, pI-approximately 6.0. Whereas the proliferation capacity of tumor cells was detected to be decreased significantly in the presence of the binding antibodies, no influence on [3H]thymidine uptake into stimulated T cells was found, suggesting different functional consequences of binding the respective antigen on malignant and normal cells. An interesting finding is the enhanced expression of major histocompatibility complex class I molecules on tumor cells incubated with human natural antibodies.
Bohn
J
J
Institute for Medical Immunology, Medical Faculty (Charité), Humboldt-University Berlin, Germany.
Roggenbuck
D
D
Settmacher
U
U
Döcke
W
W
Volk
H D
HD
Von Baehr
R
R
Jahn
S
S
D000954:Antigens, Surface / Q000032:analysis; D001323:Autoantibodies / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D003602:Cytotoxicity, Immunologic; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D007075:Immunoglobulin M / Q000378:metabolism*; D008213:Lymphocyte Activation; D008970:Molecular Weight; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism*; D014407:Tumor Cells, Cultured / Q000276:immunology / Q000378:metabolism
D000954:Antigens, Surface; D001323:Autoantibodies; D007075:Immunoglobulin M