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Anti-DNA autoantibodies reveal toxicity to tumor cell lines
A V Kozyr1, L P Sashchenko, A V Kolesnikov
1Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya st., 16/10, Moscow, Russia.
Abstract:
Cytotoxicity of anti-DNA autoantibodies from sera of SLE and CLL patients was assayed on permanent cell lines L929, HL-60, Raji, and K562. L929 cells appeared to be the most sensitive to antibody treatment. DNA-hydrolyzing properties of the same autoantibody preparations were analyzed in parallel. The data obtained outlined the correlation between cytotoxicity and DNA-hydrolyzing properties of these autoantibodies. It was shown that treatment of the cells with cytotoxic anti-DNA autoantibodies induced internucleosomal DNA fragmentation and Annexin V binding to the cell surface characteristic of apoptotic pathway of cell death. A time-dependent profile of antibody-mediated toxicity to L929 cells suggested recruitment of at least two distinct mechanisms of cell death. The first peak of cell death observed in 3 h of incubation was completely inhibited by preincubation of cells with caspase inhibitor YVAD-CHO, while the second increase in cell mortality (18-30 h) persisted. Possible mechanisms for anti-DNA autoantibody cytotoxicity are discussed.
Insights
Anti-DNA autoantibodies from SLE and CLL patients show cytotoxicity, damaging cells via DNA hydrolysis and apoptosis. L929 cells are most sensitive, with dual mechanisms of cell death observed.
Area of Science:
- Immunology
- Cell Biology
- Autoimmunity
Background:
- Systemic Lupus Erythematosus (SLE) and Chronic Lymphocytic Leukemia (CLL) are associated with autoantibodies.
- Anti-DNA autoantibodies are implicated in autoimmune diseases but their cytotoxic mechanisms require further elucidation.
Purpose of the Study:
- To investigate the cytotoxicity of anti-DNA autoantibodies from SLE and CLL patients.
- To correlate antibody-mediated cytotoxicity with DNA-hydrolyzing properties.
- To characterize the mechanisms of cell death induced by these autoantibodies.
Main Methods:
- Assay of anti-DNA autoantibody cytotoxicity on permanent cell lines (L929, HL-60, Raji, K562).
- Analysis of DNA-hydrolyzing properties of autoantibody preparations.
- Assessment of internucleosomal DNA fragmentation and Annexin V binding.
- Time-dependent toxicity profiling and caspase inhibition studies.
Main Results:
- L929 cells exhibited the highest sensitivity to anti-DNA autoantibody treatment.
- A correlation was found between cytotoxicity and DNA-hydrolyzing activity of the autoantibodies.
- Cytotoxic antibodies induced apoptosis, characterized by DNA fragmentation and Annexin V binding.
- A time-dependent profile revealed at least two distinct cell death mechanisms, one caspase-dependent and another persistent.
Conclusions:
- Anti-DNA autoantibodies from SLE and CLL patients possess cytotoxic potential.
- Cytotoxicity is linked to DNA-hydrolyzing activity and induces apoptotic cell death.
- Multiple mechanisms contribute to antibody-mediated cell death, suggesting complex pathological roles.