DEVELOPMENT AND CHARACTERIZATION OF NEW VACCINES EXPRESSING THE RV2626C PROTEIN TO PREVENT LATENT MYCOBACTERIUM TUBERCULOSIS INFECTION

MARIA PAULA MORELLI; DEL MEDICO PAULA; AMIANO NICOLAS; NANCY L. TATEOSIÁN; CANDELA MARTIN; CALAMANTE GABRIELA; GARCÍA VERÓNICA

Congreso; Reunión conjunta SAIC-SAI-AAFE-NANOMER.AR 2021; 2021

DEVELOPMENT AND CHARACTERIZATION OF NEW VACCINES EXPRESSING THE RV2626C PROTEIN TO PREVENT LATENT MYCOBACTERIUM TUBERCULOSIS INFECTION.María Paula Morelli1,2, María Paula Del Medico Zajac3, Nicolás Oscar Amiano1,2, Nancy Tateosian1,2, Candela Martin1,2, Gabriela Calamante3, Verónica García1,2.1 IQUIBICEN, UBA-CONICET, Buenos Aires, Argentina. 2 Departamento de Química Biológica, FCEN, UBA, Buenos Aires, Argentina. 3IABIMO, INTA-CONICET, Buenos Aires, Argentina.Tuberculosis (TB) has not been eliminated from any country until now.Moreover, almost 2 billion persons are latently infected with Mycobacterium tuberculosis (Mtb) and at risk of disease reactivation. Thus, new effective vaccines that might prevent TB infection are required. Hence, multi-state vaccines including early secretory antigens plus latency associated antigens from Mtb were proposed. Here, Rv2626c latency antigen was evaluated as a new candidate vaccine by combining a recombinant Modified Vaccinia virus Ankara (MVA) expressing the Rv2626c (MVA2626c) with Rv2626c DNA (DNA vaccine -pCI). Accordingly, Rv2626c DNA was amplified by PCR and ligated into a pCR-TOPO vector. Then, Rv2626c gene was sub-cloned into pCI vector for DNA vaccine (pCI-Rv2626c) or into a transference vector VT (VT-Rv2626c). VT also contains the expression cassette for the β-glucuronidasa enzyme and the flanking sequences of the MVA086R gene (which codifies for the thymidine kinase enzyme). Moreover, VT-Rv2626c was then transfected into CEFs previously infected with wtMVA and recombinant viral clones were subsequently isolated. Then, to evaluate the immunogenicity of these preparations, Balb/c mice were immunized with pCI-Rv2626c/pCI-IL12 (two doses every 14 days). After two weeks, a boost of MVA2626c was administered. Eight days later, splenocytes were obtained and in vitro stimulated with Rv2626c protein. After three days, IFN-γ production and plasma IgG levels were determined by ELISA. Our findings showed that pCI-Rv2626c /MVA2626c induced specific IgG and IFN-γ responses against Rv2626c as compared to non-immunized animals. Furthermore, we observed a significantly increase in IFN-γ (p