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Primate retroviruses: immunological cross-reactivity between major structural proteins of new and old world primate
Abstract:
The major 35,000-molecular-weight internal antigen (p35) of the squirrel monkey retrovirus (SMRV) was isolated and partially characterized. Immunological analysis of SMRV p35 led to the demonstration of antigenic determinants common to SMRV and the Mason-Pfizer monkey virus (MPMV). A broadly reactive competition immunoassay was developed utilizing antiserum to MPMV to precipitate 125I-labeled SMRV p35. Although the major structural proteins of MPMV and SMRV competed with equal efficiency in this assay, type B and type C oncornavirus proteins lacked detectable reactivity. Antibodies reactive with the major structural proteins of both MPMV and SMRV were observed in sera of several normal rhesus monkeys with known prior exposure to MPMV-infected animals. These findings demonstrate the ability of sera from naturally immunized primates to recognize broadly reactive interspecies antigenic determinants shared by the major structural proteins of type D oncornaviruses, and they suggest possible horizontal transmission of MPMV among rhesus monkeys. Although sera from a number of squirrel monkeys contained antibody to SMRV p35, the possibility that this latter reactivity was due to endogenous virus activation rather than horizontal transmission cannot be ruled out.
Insights
Researchers identified common antigens between squirrel monkey retrovirus (SMRV) and Mason-Pfizer monkey virus (MPMV). This suggests potential horizontal transmission of MPMV in rhesus monkeys, highlighting shared viral determinants in type D oncornaviruses.
Area of Science:
- Virology
- Immunology
- Primate Retroviruses
Background:
- Squirrel monkey retrovirus (SMRV) and Mason-Pfizer monkey virus (MPMV) are type D oncornaviruses.
- Internal antigens play crucial roles in viral structure and host immune responses.
Purpose of the Study:
- To isolate and characterize the major internal antigen (p35) of SMRV.
- To investigate immunological cross-reactivity between SMRV and MPMV.
- To explore potential horizontal transmission of MPMV.
Main Methods:
- Isolation and partial characterization of SMRV p35.
- Development of a competition immunoassay using anti-MPMV antiserum.
- Analysis of protein reactivity using radioiodinated SMRV p35.
Main Results:
- SMRV p35 shares antigenic determinants with MPMV.
- MPMV and SMRV structural proteins competed equally in the immunoassay.
- Antibodies against MPMV and SMRV were found in rhesus monkeys exposed to MPMV-infected animals.
- Type B and C oncornavirus proteins showed no reactivity.
Conclusions:
- Naturally immunized primates possess antibodies recognizing interspecies antigenic determinants of type D oncornaviruses.
- Findings suggest possible horizontal transmission of MPMV among rhesus monkeys.
- Reactivity in squirrel monkeys to SMRV p35 may involve endogenous virus activation or horizontal transmission.