The Effects of Pretreatment with X-Rays on the Pathogenesis of Lymphocytic Choriomeningitis in Mice

Abstract

Summary: The protective effect of x-ray pretreatment on mice infected with LCM virus was quantitatively compared using two different virus and mouse strains. The x-ray dose effect was host controlled, and under optimal conditions 500 r protected for 4 to 8 days; this period coincided with severe leukopenia. X-irradiation caused a slight increase in virus titer in brain and blood, while eliminating signs of disease and mortality. The conclusion is made that infection with the virus used is intrinsically harmless, and the protective effect of x-rays is due to a suppression of the disease-producing immune response of the host resulting in a state of tolerant immunity similar to immunological paralysis.