NEUTROPHILS RECRUITMENT MODULATES T CELL RESPONSE IN LYMPH NODES

CASTELL, SOFÍA D; HARMAN, MARÍA F; GORLINO, CAROLINA V; MORÓN, VICTOR G; MALETTO, BELKYS A; PISTORESI, MARÍA C

Buenos Aires

Congreso; IV LASID Meeting-LXIII Argentinean Soociety for Immunology Meeting-II French- Argentinean Immunology Meeting; 2015

Previously we demonstrated that when mice were immunized with OVAemulsified in Freund?s complete adjuvant on day 0, boosted with OVA emulsifiedin Freund?s incomplete adjuvant on day 15, and 10 days after injected with OVA-FITC in the footpad, the mainOVA-FITC+ cells recruited in draining popliteal lymph nodes (D-poLNs)were neutrophils whereas these cells were undetectable on control popliteallymph nodes (ND-poLNs) corresponding to the footpad injected with salinesolution (D-poLNs 9,9±2% vs. ND-poLNs 0,3±0,1%; p<0.001).This influx was dependent on an antigen-specific response, since the formationof OVA/anti-OVA immunocomplex (IC) is required.In the present study we evaluate the influence of the presence ofneutrophils activated with IC on T-cell response. In order to perform in vitroproliferation assays, CD4+ T-cells purified from OTII mice were co-culturedwith cells from D and ND-poLNs obtained from immunized mice 6 h after footpadinjection. These cells were stimulated with OVA for 72 h and proliferation wasdetermined by CFSE dilution. We observed that in the presence of neutrophils(D-poLNs) the T-cell proliferative response was reduced compared to ND-poLNs(p<0.01). Cytokines levels weremeasured in these culture supernatants andhigher levels of IL-17 were found in D-poLNs respect to ND-poLNs (p<0.01). Besides,we observed that in presence of neutrophils, T-cells from immunized mice24 h after footpad injection upregulate CD25and CD69 molecules (p<0.01). These results suggest that neutrophilrecruitment in draining popliteal lymph nodes could be modulating the T cellresponse.