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Primate retroviruses: envelope glycoproteins of endogenous type C and type D viruses possess common interspecies
Abstract:
The major 70,000- to 80,000-molecular-weight envelope glycoproteins of the squirrel monkey retrovirus, Mason-Pfizer monkey virus, and M7 baboon virus and the related endogenous feline virus, RD114, were isolated and immunologically characterized. Immunoprecipitation and competition immunoassay analysis revealed these viral envelope glycoproteins to possess several distinct classes of immunological determinants. These include species-specific determinants, group-specific antigenic determinants unique to endogenous primate type C viruses, and group-specific determinants for type D viruses such as Mason-Pfizer monkey virus and squirrel monkey retrovirus. In addition, a class of broadly reactive antigenic determinants shared by envelope glycoproteins of both type C viruses of the baboon/RD114 group and type D viruses of the Mason-Pfizer monkey virus/squirrel monkey virus group are described. Other mammalian oncornaviruses tested, including isolates of nonprimate origin and representative type B viruses, lacked these determinants. The demonstration of antigenic determinants specific to envelope glycoproteins of type C and type D primate viruses indicates either that these viruses are evolutionarily related or that genetic recombination occurred between their progenitors. Alternatively, endogenous type D oncornaviruses may be replication defective, and acquisition of endogenous type C viral genetic sequences coding for envelope glycoprotein determinants may be necessary for their isolation as infectious virus.
Insights
Researchers characterized retroviral envelope glycoproteins from primate viruses. They found shared and distinct antigenic determinants, suggesting evolutionary links or genetic recombination between type C and type D primate retroviruses.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- Primate retroviruses, including type C and type D, possess distinct envelope glycoproteins.
- Understanding the immunological properties of these glycoproteins is crucial for viral classification and evolutionary studies.
Purpose of the Study:
- To isolate and immunologically characterize the envelope glycoproteins of squirrel monkey retrovirus, Mason-Pfizer monkey virus, M7 baboon virus, and RD114 virus.
- To identify and compare antigenic determinants across different primate retrovirus groups.
Main Methods:
- Isolation of 70,000- to 80,000-molecular-weight envelope glycoproteins.
- Immunoprecipitation and competition immunoassay analysis to characterize immunological determinants.
Main Results:
- Identified species-specific, group-specific (type C and type D), and broadly reactive antigenic determinants on viral envelope glycoproteins.
- Demonstrated shared determinants between type C (baboon/RD114) and type D (Mason-Pfizer monkey virus/squirrel monkey virus) primate viruses.
- Other mammalian oncornaviruses lacked these specific determinants.
Conclusions:
- The presence of shared antigenic determinants suggests an evolutionary relationship or genetic recombination between type C and type D primate retroviruses.
- An alternative hypothesis suggests endogenous type D oncornaviruses might require genetic sequences from type C viruses for infectious isolation.