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Detection and biochemical characterization of antigens in human leukemic sera that cross-react with primate C-type
Abstract:
Antigens have been detected in 35 to 40% of sera from patients with leukemia that cross-react with the Mr 30,000 core proteins (p30) of baboon endogenous virus (BaEV) and/or of simian sarcoma-simian sarcoma-associated virus (SiSV) in a solid-phase enzyme immunoassay using anti-SiSV p30 and anti-BaEV p30 antisera. These antigens could not be found in sera from nonleukemic persons. Fetal calf serum; normal chicken, goat, rabbit, and rhesus sera; and normal human serum components like albumin, immunoglobulins, and transferrin did not react with the anti-SiSV p30 and anti-BaEV p30 antisera. The reactivity in the leukemic sera was abolished by treatment with protease, but not with glycosidases. The antigens purified by immunoaffinity chromatography showed essentially one band with an apparent molecular weight of 70,000 on sodium dodecyl sulfate: polyacrylamide gel electrophoresis. In competition enzyme-linked immunosorbent assays the leukemia-associated antigens competed out SiSV p30 in the anti-SiSV p30 system. Peptide mapping experiments with antigens from sera of two different leukemic patients showed that the two antigens were identical concerning numbers of peptides and their position. Eleven of 21 major peptides of SiSV p30 and 10 of 20 major peptides of BaEV p30 (50 to 60% of major peptides) showed mobilities identical with those of the major peptides of the human antigens. The data suggest the presence in human sera of retroviral antigens closely associated with leukemia.
Insights
Retroviral antigens, closely resembling baboon endogenous virus (BaEV) and simian sarcoma-associated virus (SiSV) core proteins (p30), were identified in leukemia patient sera. These novel leukemia-associated antigens were absent in healthy individuals, suggesting a potential link to human leukemia.
Area of Science:
- Oncology
- Virology
- Immunology
Background:
- Retroviruses, such as baboon endogenous virus (BaEV) and simian sarcoma-associated virus (SiSV), possess core proteins (p30) that are targets for antibody recognition.
- Previous research has explored potential links between viral components and human malignancies, including leukemia.
Purpose of the Study:
- To investigate the presence of retroviral antigens in the sera of leukemia patients.
- To characterize these antigens and compare them to known viral p30 proteins.
Main Methods:
- Solid-phase enzyme immunoassay using antisera against SiSV p30 and BaEV p30.
- Protease and glycosidase treatment to assess antigen composition.
- Immunoaffinity chromatography and SDS-PAGE for antigen purification and molecular weight determination.
- Competition enzyme-linked immunosorbent assays and peptide mapping for antigen comparison.
Main Results:
- Antigens cross-reacting with BaEV and SiSV p30 were detected in 35-40% of leukemia patient sera, but not in non-leukemic individuals.
- The reactivity was abolished by protease treatment, indicating a protein nature, and showed similarities to viral p30 peptides.
- Purified antigens had an apparent molecular weight of 70,000 and competed with SiSV p30 in immunoassays.
Conclusions:
- The study suggests the presence of novel retroviral antigens in human leukemia sera.
- These antigens share significant structural similarities with the core proteins of BaEV and SiSV.
- The findings imply a potential association between these retroviral antigens and human leukemia.