Secretory intestinal IgA can protect from re-infection with rotavirus (RV), but very little is known about the mechanisms that induce IgA production during intestinal virus infections. Classical dendritic cells (cDCs) in the intestine can facilitate both T cell-dependent and -independent secretory IgA. Here, we show that BATF3-dependent cDC1, but not cDC2, are critical for the optimal induction of RV-specific IgA responses in the mesenteric lymph nodes. This depends on the selective expression of the TGFβ-activating integrin αvβ8 by cDC1. In contrast, αvβ8 on cDC1 is dispensible for steady state immune homeostasis. Given that cDC2 are crucial in driving IgA during steady state but are dispensable for RV-specific IgA responses, we propose that the capacity of DC subsets to induce intestinal IgA responses reflects the context, as opposed to an intrinsic property of individual DC subsets.

分泌性肠道 IgA 可以防止再次感染轮状病毒 (RV)，但对于在肠道病毒感染期间诱导 IgA 产生的机制知之甚少。肠道中的经典树突状细胞 (cDC) 可以促进 T 细胞依赖性和非依赖性分泌 IgA。在这里，我们表明 BATF3 依赖性 cDC1 而不是 cDC2 对于肠系膜淋巴结中 RV 特异性 IgA 反应的最佳诱导至关重要。这取决于 cDC1 对 TGFβ 激活整合素 αvβ8 的选择性表达。相反，cDC1 上的 αvβ8 对于稳态免疫稳态是可有可无的。鉴于 cDC2 在稳态期间对驱动 IgA 至关重要，但对于 RV 特异性 IgA 反应是可有可无的，我们建议 DC 亚群诱导肠道 IgA 反应的能力反映了背景，