NEUTROPHILS ACTIVATED BY IMMUNOCOMPLEXES MODULATE T CELL RESPONSE IN LYMPH NODES

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

Congreso; LXIV reunión de la Sociedad Argentina de Inmunología; 2016

NEUTROPHILS ACTIVATED BY IMMUNOCOMPLEXES MODULATE T CELL RESPONSE IN LYMPH NODESCastell, Sofía D1; Harman, María F1; Morón, Victor G1; Maletto, Belkys A1; Pistoresi, María C11CIBICI- CONICET- Facultad de Ciencias Químicas- UNC- Córdoba- Argentina Previously we demonstrated that immunocomplexes (IC) generated by injecting OVA in the footpad of immunized mice that have anti-OVA antibodies, induce the migration of neutrophil OVA+ to draining popliteal lymph nodes (D-poLNs). In the present study we evaluate the influence of neutrophils activated by IC on T-cell response in lymph nodes.C57BL/6 mice were immunized with OVA emulsified in Freund?s complete adjuvant and 15 days later boosted with OVA emulsified in Freund?s incomplete adjuvant. Ten days after last immunization they were injected with OVA-FITC in the footpad and D-poLNs were obteined at different times (between 3 and 48 h); saline solution was injected on footpad corresponding to control non-draining popliteal lymph nodes (ND-poLNs). The different cell populations in the lymph nodes were characterized by flow cytometry.3 h after footpad inyection, an increased number of neutrophils OVA-FITC+ was observed in D-poLNs compared to ND-poLNs (p<0.05). The highest levels of neutrophils OVA-FITC+ were detected 6 h after OVA inyecction (p<0.001), at 12 h neutrophils decreased to basal levels. However, total number of D-poLN cells increase after 24 h of OVA inyection (p<0.01). At 24 h we observed an increase of dendritc cells CD11c+ in D-poLNs compared to ND-poLNs (p<0.01). At 48 h we observed an icrease of CD4 T cells (p<0.01), particulally effector CD4 T-cells CD44+ CD62L- (p<0.01) with respect to ND-poLNs. Besides, we observed higher percentage of Ki67+ CD4 T-cells in immunized mice 24 h after OVA injection (p<0.001), indicating that CD4 T-cells have higher levels of proliferation after migration of neutrophils activated by IC. These results suggest that neutrophil recruitment in draining popliteal lymph nodes could be modulating the T cell response.