High ambient temperatures dampen immune responses in mice infected with viral pathogens, according to a study. Climate change may expand the geographical distribution of vector-borne diseases and put half of the world's population at risk for a food crisis. However, the effects of environmental temperature and nutritional status on host defense to viral infection are unclear. Miyu Moriyama and Takeshi Ichinohe compared the immune responses of mice kept at 22?C and 36?C beginning seven days prior to infection with the influenza virus. Compared with mice kept at room temperature, heat-exposed mice reduced their food intake and showed a 10% reduction in body weight, a decrease in lung T cells, and impaired antibody and T cell responses. Heat exposure also impaired immune responses in mice infected with either Zika virus or a pathogenic tick-borne virus that causes severe fever with thrombocytopenia syndrome. Injection with either glucose or short-chain fatty acids--metabolites produced by gut microbes--enhanced the secretion of T cells and antibody responses in heat-exposed mice. The findings suggest that outside temperature and nutritional status may be critical determinants of vaccine efficacy in tropical or developing countries. Moreover, the clinical management of emerging infectious diseases in these countries may require nutritional supplementation in addition to antiviral therapy.
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Article #18-15029: "High ambient temperature dampens adaptive immune responses to influenza A virus infection," by Miyu Moriyama and Takeshi Ichinohe.
MEDIA CONTACT: Takeshi Ichinohe, The University of Tokyo, JAPAN; tel: +81-364092125; e-mail: ichinohe@ims.u-tokyo.ac.jp
Journal
Proceedings of the National Academy of Sciences