Possible viral interactions in the acquired immunodeficiency syndrome (AIDS)

Abstract

Viral interactions may occur whenever a host is infected simultaneously with two viruses. Persons at high risk for acquired immunodeficiency syndrome (AIDS) may provide a substrate for such interactions. These could include complementary immunosuppression, potentiation of infection by altered receptors or genetic complementation, phenotypic mixing, or genetic recombination. The possibility of such interactions should be considered in the pathogenesis of AIDS.

PIP: Interactions among viruses may be significant to the pathogenesis of the profound immunologic defects observed in acquired immunodeficiency syndrome (AIDS). Such interactions could include complementary immunosuppression, potentiation of infection by altered receptors or genetic complementation, phenotypic mixing, or genetic recombination. The abnormalities induced by simultaneous infection with cytomegalovirus of Epstein-Barr virus, for example, may be synergistic and suppression induced by 1 virus may permit replication of another virus to high titer. Given the alterations in cell-surface components during the course of a viral infection, it is possible that AIDS infection modifies the expression of histocompatibility antigens on lymphocyte membranes or viral receptors not normally available on a given cell become expressed during infection with a 2nd virus. An alternative, viral potentiation, occurs when 1 virus codes for a gene product required for growth of another, resulting in a greater virus yield that would be expected from either virus alone. Phenotypic mixing occurs when 2 enveloped viruses infect the same cell, and the genome of 1 becomes incorporated in an envelope composed of glycoproteins from the other. In genetic recombination, actual exchange of genetic information between viruses allows for the emergence of new viruses with altered biologic characteristics. Such recombination occurs with high frequency in the human retroviruses, probably during a phase of replication involving reverse transcriptase to viral DNA. To learn more about such interactions, viruses isolated from the blood and semen of AIDS patients should be analyzed for cell tropism, neutralization kinetics, and hybridization.