Evaluation of the protective capacity of an immunogenic formulation for the control of infections caused by Chlamydia trachomatis

RUSSI ROMINA CECILIA; DEL BALZO DIEGO; LUJAN AGUSTIN ; FLOR NOELIA; REIDEL IVANA; GARCIA MARIA INES; DAMIANI MARIA TERESA; VEAUTE CAROLINA

Congreso; Reunión Conjunta de Sociedades de Biociencias (SAI, SAIC, SAFIS); 2020

Sociedad Argentina de Inmunología

Chlamydia trachomatis (Ct) is the most frequent sexually transmitted bacteria worldwide, therefore, a vaccine development is strongly needed. Our aim was to evaluate the ability to induce a protective immune response of a vaccine composed of a fragment of polymorphic membrane protein D (PmpD) in a murine model of genital infection by Ct. A fragment of PmpD was expressed in Escherichia coli (rPmpD). The sequence was subcloned in a eukaryotic expression vector (pVAX1). Female C57BL/6 (n=5) mice were immunized with a first intradermal dose of plasmid DNA and three rPmpD boosters, every three weeks, by intranasal and subcutaneous route, simultaneously. Twenty days after the last dose, the immunized mice and not immunized mice (control group, n=4) were vaginally infected with 1.5x105 inclusion forming units (UFIs) of Ct-GFP. Anti-rPmpD antibodies in sera (IgG, IgG1, IgG2c) and vaginal washing (IgG, IgA) were measured by indirect ELISA. Infectious bacterial progeny released in cervical secretion was quantified by UFIs assay and fluorescence microscopy. Fourteen days post infection the uterine horns were dissected for morphological analysis. The immunized mice produced a significant systemic IgG2c humoral immune response, indicating PmpD immunogenicity (two-way ANOVA, post-test Bonferroni; p 0.05). The immune sera from vaccinated animals decreased the percentage of Ct infected HeLa cells when evaluating their protective ability (Mann-Whitney; p0.05). The uterine horns of vaccinated mice did not show morphological alterations as did those from unvaccinated mice. The PmpD fragment is a potential vaccine candidate to develop a prophylactic strategy to the control of the most common sexually transmitted bacteria.Resumen en pagina 172.