1. Deletion of Card9 eliminates the detrimental facets of mycobacterial adjuvants
- Author
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Hideo Mitsuyama, Ei'ichi Iizasa, Akiko Kukita, Shuji Toda, Hiroki Yoshida, Hiromasa Inoue, and Hiromitsu Hara
- Subjects
Card9 ,Mycobacteria ,Adjuvant ,Vaccine ,Autoimmunity ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
Although mycobacterial adjuvants are capable of eliciting a strong adaptive humoral and cellular immunity, they also sometimes provoke detrimental outcomes, including autoimmune/inflammatory syndromes. Here, we show that the deletion of caspase recruitment domain family member 9 (Card9), a signaling adaptor of a set of innate immune receptors, can eliminate the detrimental effects of mycobacterial adjuvants. Long-lasting tissue-destructive skin inflammation at the site of complete Freund's adjuvant (CFA) injection, lung granuloma formation induced by intratracheal Mycobacterium bovis Bacillus Calmette-Guérin infection, and the incidence and severity of experimental autoimmune encephalomyelitis and collagen-induced arthritis induced by autoantigen immunization with CFA were considerably attenuated in Card9-deficient (Card9−/−) mice compared to control wild-type mice. Card9−/− mice showed impaired development of Th17, but not Th1, in the early phase after autoimmune induction, due to the impaired development of IL-6-producing Sirpαhigh dendritic cells, which are essential for priming pathigenic Th17, in the draining lymph nodes. However, Card9 deletion did not affect overall adaptive antibody production or delayed-type hypersensitivity following immunization with CFA, indicating that humoral and type 1 immune responses remained intact. These results suggest that avoiding the activation of Card9 signaling during vaccination with mycobacteria-containing vaccines may mitigate the risk of detrimental type 3 immune responses, while preserving type 1 immune responses that are effective against intracellular pathogens and cancers.
- Published
- 2024
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