The conduit system exports locally secreted IgM from lymph nodes

• DOI: 10.1084/jem.20180344
• Publication Date: 2018-11-14T14:25:46Z
• Authors: Guilhem R. Thierry; Mirela Kuka; Marco De Giovanni; Isabelle Mondor; Nicolas Brouilly; Matteo Iannacone; Marc Bajénoff
• Keywords: Electrical conduit; Immunoglobulin M; Parenchyma; Reticular cell

Immunoglobulin M (IgM) is the first type of antibody produced during acute infections and thus provides an early line specific defense against pathogens. Being in secondary lymphoid organs, IgM must rapidly be exported to blood circulation. However, it currently unknown how such large pentameric molecules are released from lymph nodes (LNs). Here, we show that upon immunization, transiently gains access luminal side conduit system, a reticular infrastructure enabling fast delivery tissue-derived soluble substances LN parenchyma. Using microinjections purified IgM, demonstrate conduit-associated delivered by neither afferent nor blood, but locally conveyed conduits. Exploiting vivo models, further activated, antigen-specific B cells migrating T cell zone. Thus, our study reveals system coopted export secreted out LNs.