Immunogenicity of an Adenoviral Vector Vaccine (rAd‐MOMP‐CpG) Against Chlamydia Trachomatis

Abstract

Chlamydia trachomatis (C. trachomatis) infection is categorized as an important causes of sexually transmitted diseases in humans. Currently, there is no approved vaccine against C. trachomatis. This study was conducted to develop and evaluate the immunogenicity of a recombinant adenovirus (rAd‐MOMP‐CpG) vaccine against C. trachomatis in mice. The vaccine was constructed using adenovirus type 5 based on the major outer membrane protein (MOMP) antigen of C. trachomatis. Sixty mice were divided into 4 groups. In group 1, mice received rAd‐MOMP‐CpG (5×108 PFU) intranasal, 3 times at 2‐weeks intervals. Mice in groups 2, 3 and 4 received equivalent volume of adenovirus vector, CpG 1826, and PBS, respectively. Splenic cytokine levels and mRNA expression levels of IFNg and IL‐4 were determined by ELISA and qPCR, respectively. Furthermore, serum specific murine anti‐MOMP IgG levels were determined by quantitative ELISA. The constructed rAd‐MOMP‐CpG vaccine provoked a Chlamydia‐specific T helper type 1 response. There was a significant (P = 0.047) splenic IFNg stimulation in vaccinated group in comparison to the vector‐control group. The splenic IL‐4 expression remained at minimal stimulation levels across time points. In addition, the vaccine induced significant increase (P = 0.006) of delayed humoral anti‐MOMP IgG response compared to control groups. A recombinant adenovirus vaccine against C. trachomatis could provide important clues toward a vaccine development for C. trachomatis serovar protection in humans. However, further in vitro and in vivo studies are warranted to determine the most effective dosage, vaccine efficacy and safety.Support or Funding InformationJordan University of Science and Technology, Deanship of Research (grant number: 20140275).