Association between segmented filamentous bacteria (SFB) colonization and TNFR1 deficiency in the immune response of gut-joint axis

DISTEL MATÍAS NICOLÁS; JAVIER ELIÇABE; JUAN EDUARDO SILVA ; MARÍA SILVIA DI GENARO

San Luis

Congreso; LXXI Reunión Anual de la Sociedad Argentina de Inmunología; 2023

Sociedad Argentina de Inmunología

Segmented filamentous bacteria (SFB) are potent microbial stimuli of the gutmucosal immune system, including IgA and IL-17 production. In the ileum of mice,SFB appear shortly after weaning, and then quickly decreases. TNF receptor 1deficient (TNFR1-/- ) mice develop reactive arthritis (ReA) after oral infection withYersinia enterocolitica (Ye) serotype O:3. The aim was to analyze at normal steadystate whether TNFR1 deficiency impacts on joint and gut immune response duringand after SFB colonization. First, SFB presence was analyzed by Gram staining inthe ileum lavage of male 21 to 34 day-old (weaning time) and 8 to12 week-old(adult) C57BL/6 wild-type (WT) and TNFR1-/- mice. Then, IgA and IL-17 levels weredetermined in the intestinal lumen by ELISA, and the number of IgA-producing cellsin lamina propria by immunofluorescence. Finally, lymphocytes, neutrophils,macrophages and CX3CR1 macrophages were evaluated in mesenteric lymphnodes (MLN) and regional lymph nodes of the joint (RLN) by flow cytometry. Highnumber of SFB was found in both WT and TNFR1-/- mice around weaning time.Although almost no IgA positive-cells were detected in lamina propria in 21 to 34day-old WT and TNFR1-/- mice, IgA levels in luminal intestinal were increased atweaning time, suggesting similar passively acquired maternal IgA. However, asignificant decrease of neutrophils and macrophages was detected in RLN of 21 to34 day-old TNFR1-/- compared with WT mice (p