Increased Susceptibility of Mice to Malarial Infection Following UV-B Irradiation
1999 年 9 巻 6sup 号 p. 93-96
詳細
1999 年 9 巻 6sup 号 p. 93-96
Using a mouse model, we examined whether UV-B was a risk factor for malarial infection. Two mouse strains, susceptible (BALB/c) and resistant (C57BL/10) to murine malaria (Plasmodium chabaudi), were UV-preirradiated and infected with a sub-lethal dose of malaria parasite (104 and 105, respectively). Parasite growth was assayed with tail-blood smears counting parasitized red blood cells. Mice resistant to malaria were bled by heart puncture and the plasma cytokines were determined. Our results showed that UV-B irradiation worsened the malarial infection and 100% of the malaria-resistant mice strains died due to a usual infection at sub-lethal dose following UV-B irradiation. In the resistant mice strain infected with the parasite, the plasma IFN-^Q production was inhibited by UV-B irradiation and the maximum titer was about one-fifth of the non-irradiated mice. Furthermore, activation of macrophages from UV-irradiated mice also decreased compared with that of non-irradiated mice. IFN-^Q administration prevented the death of UV-B irradiated resistant mice and the cure ratio was 60%. In conclusion, UV-B increased the susceptibility of both strains of mice and impaired IFN-γ production in the malaria-resistant mice strain. J Epidemiol, 1999 ; 9 : S93-S96.
