CHARACTERIZATION OF CYTOTOXIC CD8+ T LYMPHOCYTE EFFECTOR AND MEMORY RESPONSE INDUCED BY A NOVEL FORMULATION STRATEGY FOR THE CPG-ODN ADJUVANT USING A NANOSTRUCTURE PLATFORM

ANA LAURA CHIODETTI; FERNANDA SÁNCHEZ VALLECILLO; MARÍA INÉS CRESPO; VIRGINIA AGUIRRE; SANTIAGO PALMA; DANIEL ALLEMANDI; MA. CRISTINA PISTORESI-PALENCIA; GABRIEL MORÓN; BELKYS A. MALETTO

Buenos Aires

Congreso; IV LASID Meeting. LXIII Argentinean Immunology Society Meeting. II French-Argentinean Immunology Meeting; 2015

Background: Previously, we have shown that CpG-ODN formulated with a nanostructure of 6-O-ascorbyl palmitate (Coa-ASC16) has the capacity to enhance a specific humoral and cellular (CTL and Th1) immune response in compare to the CpG-ODN solution alone using OVA as an antigen model. In addition, Coa-ASC16 alone elicited IL-6 production. Here, we farther characterized the CTL response and the possible signals involved on its development.Methods: To study effector characteristics of CD8+ T lymphocytes, mice were subcutaneously immunized on day 0 with OVA/CpG-ODN/Coa-ASC16 or OVA/CpG-ODN. Seven days after immunization, spleen cell suspensions were cultured with medium or OVA257-264 (1 µg/ml) for intracellular staining. To test an effector memory CTL response, we performed an in vivo cytotoxicity assay 30 days after immunization with OVA/CpG/Coa-ASC16. To seek if the CTL response was IL-6 dependent we repeat the assay in Il-6-/- mice.Results: Mice immunized with OVA/CpG-ODN/Coa-ASC16 presented a higher frequency of CD8+ T lymphocytes producing pro-inflamatory cytokines IFN-γ (0.53±0.11 vs 0.05±0.02; p<0.01) and TNF-α (0.25±0.03 vs 0.04±0.03; p<0.01), and expressing LAMP-2 cell surface protein (0.54±0.01 vs 0.11±0.11; p<0.05) after stimulation with OVA257-264 peptide than splenocytes from mice immunized with OVA/CpG-ODN. The CTL response persisted for at least 30 days after immunization with OVA/CpG/Coa-ASC16 (% specific killing: 63±26). Il6-/- mice showed CTL response as efficiently as in WT mice.Conclusions: OVA/CpG-ODN/Coa-ASC16 exhibited a robust capacity to induce a specific-antigen CTL response that is IL-6 independent. This adjuvant strategy represents an attractive approach for the design of effective vaccines against intracellular pathogens.