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Papain solubilization of the Epstein-Barr virus-induced membrane antigen
Abstract:
The Epstein-Barr virus (EBV)-induced membrane antigen (MA) was successfully solubilized from the membranes of viable EBV-infected Raji cells by treatment with papain (5 to 6 U per 1 X 10(7) to 2 X 10(7) cells). The loss of MA from viable cells was monitored by membrane immunofluorescence and antibody-dependent cellular cytotoxicity. Soluble MA was demonstrated in papain digests through inhibition of antibody-dependent cellular cytotoxicity and by inhibition of the binding of anti-MA antibodies to cells as detected by use of 125I-labeled staphylococcal protein A. Approximately 75% of the MA activity in the extracts was not sedimentable at 100,000 X g,, indicating that the majority of EBV MA activity that was released by this procedure was associated with small-molecular-weight material. Antiserum prepared from an owl monkey immunized with these papain extracts contained antibody to MA and neutralizing antibodies, but lacked detectable antibodies against viral capsid antigens and EBV-induced early antigens.
Insights
Researchers solubilized Epstein-Barr virus (EBV)-induced membrane antigen (MA) from infected cells using papain. This soluble MA was characterized, showing potential for further study of EBV-associated immune responses.
Area of Science:
- Virology
- Immunology
- Cell Biology
Background:
- Epstein-Barr virus (EBV) is a human herpesvirus associated with various cancers.
- EBV-induced membrane antigen (MA) plays a role in viral pathogenesis and immune evasion.
- Understanding EBV MA's properties is crucial for developing diagnostic and therapeutic strategies.
Purpose of the Study:
- To solubilize and characterize the EBV-induced membrane antigen (MA) from infected cells.
- To investigate the properties of soluble MA and its potential immunogenicity.
Main Methods:
- Solubilization of MA from viable EBV-infected Raji cells using papain.
- Monitoring MA loss via membrane immunofluorescence and antibody-dependent cellular cytotoxicity (ADCC).
- Characterization of soluble MA in papain digests using ADCC inhibition and 125I-labeled staphylococcal protein A binding assays.
Main Results:
- Papain treatment successfully solubilized EBV MA from viable infected cells.
- Soluble MA inhibited ADCC and antibody binding, confirming its identity.
- Approximately 75% of solubilized MA activity was associated with small-molecular-weight material, indicating it was not highly aggregated.
- Antiserum against papain extracts contained antibodies to MA and neutralizing antibodies, but not to viral capsid or early antigens.
Conclusions:
- Papain is effective for solubilizing EBV MA from infected cell membranes.
- The solubilized EBV MA is immunologically active and contains neutralizing epitopes.
- This method provides a means to study EBV MA and develop related diagnostic or therapeutic tools.