Viruses and Immunosuppression

Abstract

The recognition that viruses are able to compromise immunity dates back to the observation by von Pirquet in 1908 that measles infection resulted in a reduced delayed hypersensitivity response in patients who would normally respond to tubercle bacillus antigens. Thus, von Pirquet was the first to suggest an immunologic explanation for the increased susceptibility to superinfection observed in patients with viral diseases. This was followed a decade later by a report in 1919 that influenza virus could also suppress tuberculin reactivity. The investigation of viruses and their effects on immunity then went unre-ported for 40 years. Beginning about 1960, oncogenic viruses were given serious consideration as immunosuppressive agents. This was first alluded to by Old and colleagues, and a few years later, Good and co-workers presented the first systematic evaluation of suppression of antibody responses by murine leukemia viruses.^(1,2) During the late 1960s and early 1970s, there was a flurry of activity in this field. Numerous reports supported the concept that oncogenic viruses suppress immunity. Both humoral and cellular immunity were shown to be depressed. Concomitant to studies with oncogenic viruses, similar studies with many nononcogenic viruses also resulted in findings of immunosuppressive activity^(3,4) Many investigators considered virus-induced immunosuppression important to the establishment of persistent infections that lead to chronic diseases or tumor formation. However, during the mid-1970s, the emphasis in virus biology moved away from this field and the number of studies in this area decreased.