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Redistribution and modulation of Gross murine leukemia virus antigens induced by specific antibodies
Abstract:
Gross murine leukemia virus (G-MuLV)-induced rat leukemia cells in tissue culture replicate G-MuLV, express strong virus-associated membrane antigenicity, and are consistently killed by specific antibodies and complement in cytotoxicity tests. To explore the effect of specific antibodies, rat anti-G-MuLV antisera were added to the cultures of leukemia cells for variable periods of time. Redistribution of virus particles as well as of membrane virus antigens in the form of polar patches and caps was observed by electron microscopy, indirect immunofluorescence, and immunoelectron microscopy. Substantial decreases in cytotoxicity indexes accompanied these changes. The antigen modulation induced by anti-G-MuLV antibodies in vitro paralleled similar changes obtained in vivo by transplanttion of leukemia cells in rats with high anti-G-MuLV antibody titers. The importance of antigen modulation in this system resides in its direct relationship with the malignant potential of the leukemia cells.
Insights
Antigen modulation in Gross murine leukemia virus (G-MuLV)-induced rat leukemia cells reduces their susceptibility to antibody-mediated killing. This phenomenon, observed both in vitro and in vivo, is linked to the malignant potential of leukemia cells.
Area of Science:
- Virology
- Immunology
- Oncology
Background:
- Gross murine leukemia virus (G-MuLV) induces rat leukemia.
- Leukemia cells express G-MuLV antigens and are susceptible to antibody-mediated cytotoxicity.
- Antigen modulation is a known phenomenon in immunology.
Purpose of the Study:
- To investigate the effect of specific antibodies on G-MuLV-induced rat leukemia cells in vitro.
- To explore the relationship between antigen modulation and the malignant potential of leukemia cells.
Main Methods:
- Exposure of G-MuLV-induced rat leukemia cells to rat anti-G-MuLV antisera in tissue culture.
- Observation of virus particle and antigen redistribution using electron microscopy, indirect immunofluorescence, and immunoelectron microscopy.
- Assessment of cytotoxicity indexes before and after antibody treatment.
Main Results:
- Antibody treatment induced redistribution of G-MuLV particles and membrane antigens into polar patches and caps.
- Significant decreases in cytotoxicity indexes were observed following antigen modulation.
- In vitro antigen modulation mirrored changes seen in vivo in rats with high anti-G-MuLV antibody titers.
Conclusions:
- Antigen modulation by specific antibodies reduces the susceptibility of G-MuLV-induced leukemia cells to antibody-mediated killing.
- Antigen modulation is directly related to the malignant potential of these leukemia cells.
- This study highlights the importance of antigen modulation in the context of viral oncogenesis and immune evasion.