Target antigens for antibodies and complement at the cell surface of RSV-transformed fibroblasts

Area of Science:

• Virology
• Immunology
• Cell Biology

Background:

• Rous sarcoma virus (RSV) is an RNA tumor virus with a fully characterized genome and structure.
• Understanding virus-induced surface antigens is crucial for studying viral pathogenesis and immune responses.
• Identifying targets for antibody and complement-mediated lysis helps elucidate immune evasion mechanisms.

Purpose of the Study:

• To investigate which virus-induced surface antigens on RSV-transformed cells can be targeted by antibodies and complement.
• To differentiate between viral structural proteins and transformation-specific antigens as mediators of immune lysis.
• To determine the role of specific viral antigens, such as gp85, in immune-mediated cell killing.

Main Methods:

• Utilized Rous sarcoma virus (RSV)-transformed cells for experimental analysis.
• Employed the 51Cr-release assay to measure immune-mediated cell lysis.
• Investigated the involvement of various viral proteins, including envelope antigen gp85, core proteins, and reverse transcriptase.

Main Results:

• The envelope antigen gp85 was identified as a mediator of immune lysis, while core proteins and reverse transcriptase were not.
• Group-specific antigenic determinants of gp85 were found to be primarily involved in the lysis.
• A distinct virus-induced cell surface antigen (VCSA), specific for transformation, was also effective in mediating lysis.
• Differential expression of these antigens on various cell types was observed.

Conclusions:

• The RSV envelope antigen gp85 and the transformation-specific VCSA are key targets for antibody and complement-mediated immune lysis.
• The findings support the non-identity of virus structural antigens and VCSA, suggesting distinct roles in viral transformation and immune recognition.
• This research provides insights into the specific molecular targets involved in the immune response against RSV-transformed cells.