EFFECT OF CYCLOPHOSPHAMIDE TREATMENT ON EXPERIMENTAL ARBOVIRUS INFECTIONS

Thind, I. S. and W. H. Price (Johns Hopkins Univ. School of Hygiene and Public Health, Baltimore, Md. 21205). The effect of cyclophosphamide treatment on experimental arbovirus infections. Amer. J. Epid., 1969, 90; 62-68.-Cyclophosphamide (60 mg/kg), given intraperitoneally 24 hours before and after intra-peritoneal viral inoculation, increased the LD50 of 7 of 10 Group A and Group B arboviruses tested. The enhancing effect on mortality was observed only with viruses which titered at least 102.3 LD50 per 0.3 ml intraperitoneally in normal mice. When mice were inoculated intraperitoneally with concentrations of the virulent parent Langat M4 virus or the attenuated Langat E5 virus, so that nearly equal levels of virus were found in the brain during the first 3 days following inoculation, both the increase in viral multiplication in the brain and mortality were similar on administration of cyclophosphamide for the two viruses. Three doses of cyclophosphamide given with an attenuated virus or a virus of moderate peripheral virulence led to an increased mortality compared to that observed with two doses of cyclophosphamide. These results suggest, as did the authors' previously reported findings, that the overall primary immune response played a major role in the recovery from primary infection. © 1969, by THE JOHNS HOPKINS UNIVERSITY.