NEUTROPHILS RECRUITMENT IMPACT ON T CELL RESPONSE IN LYMPH NODES

SOFÍA CASTELL; FLORENCIA HARMAN; CAROLINA GORLINO; G MORON; BELKYS A. MALETTO; MARÍA C. PISTORESI-PALENCIA

Mar del Plata

Congreso; LXII Reunión de la Sociedad Argentina de Inmunología. Mar del Plata; 2014

Sociedad Argentina de Inmunología

Previously we demonstrated that when mice were immunized with OVA emulsified in Freund?s complete adjuvant (OVA/CFA) at days 0, 15, 30, and ten days after the last immunization were injected with OVA-FITC in the footpad, the main OVA-FITC+ cells recruited in draining popliteal lymph nodes were neutrophils, this influx was dependent on an antigen-specific response (Maletto et al, Blood, 2006; Gorlino et al, Journal of Immunology, 2014). In order to reduce CFA potentially harmful effects, in the present study we performed only two immunizations, for this, mice were immunized with OVA/CFA and 15 days after boosted with OVA/IFA; IFA is Freund?s adjuvant incomplete form that lacks the mycobacterial components. Ten days after the last immunization, mice were injected with OVA-FITC in the footpad and we still found neutrophils migration in draining popliteal lymph nodes (p<0.05). Next we evaluated whether neutrophils recruitment impact in T cell response. We analyzed CD25 and CD69 molecules in T lymphocytes of draining popliteal lymph nodes compared with the not draining. Interestingly, we observed that in presence of neutrophils, T cells upregulate those activation markers (p<0,001). Cytokines levels were measured in culture supernatants of popliteal lymph nodes cells after 72h of OVA stimulation. Importantly, higher levels of IL-17 were found in draining popliteal lymph nodes compared to not draining (p<0.05). In conclusion, these results suggest that in the less harmful model of immunization we also found neutrophil recruitment in draining popliteal lymph nodes and these cells could be modulating the T cell response.