POLY(I:C) IMPROVED THE IMMUNE RESPONSE INDUCED BY A NUCLEOPROTEIN BASED ANTICOVID VACCINE

ALARCÓN, VALENTINA; PEREZ ELIZALDE,JULIETA; VALERIO-CHAVEZ, MARITZA; ESPUL,CARLOS; MACKERN-OBERTI, JUAN PABLO; SANCHEZ, MARIA VICTORIA

Congreso; XL REUNIÓN ANUAL DE LA SOCIEDAD DE BIOLOGIA DE CUYO; 2022

Sociedad Biología de Cuyo

COVID-19 has a major impact on public health worldwide. Although novel vaccines are currently used to prevent disease, there is still a need to develop more effective vaccines that can provide not only antibody responses but also robust cellular responses. The combination of conserved antigens capable of inducing T cell responses with novel adjuvants may be a valuable strategy for the development of a universal vaccine capable of protecting against antigenic viral variants.The aim of this study was to explore the TLR 3 adjuvant, Poly(I C), combined with the conserved nucleoprotein antigen ( to elicit enhanced humoral and cellular immune responses NP adjuvanted and unadjuvanted vaccines were administered in C57BL 6 mice intramuscularly in a two dose regimen (day 1 and 21 and humoral and cellular immune responses were determined bydifferent immunological techniques Regarding humoral immune responses, it was observed that the adjuvanted formulation induced a significant increase in specific IgG NP titers compared to the unadjuvanted formulation Analysis of IgG subclasses showed enhanced and balanced IgG 1 and IgG 2 a titers.Regarding T cellular responses, the Poly (I C) formulation induced good cellularimmune responses evidenced by antigen specific IFN γ secreting T cells measured by ELISPOT and significant IL 6 secretion determined by ELISA.Moreover, the adjuvanted formulation also showed an enhanced T cell memory, T effector and T central memory response, measured by flow cytometry. The findings presented here have important implications for understanding the role of Poly (I C) adjuvant and NP antigen in mounting functional immune responses for COVID 19 prevention.