Immunological evaluation of two novel engineered Plasmodium vivax circumsporozoite proteins formulated with different human-compatible vaccine adjuvants in C57BL/6 mice

In this study, in vivo immunological evaluation of two novel engineered proteins ofP. vivax circumsporozoite (PvCS127 and PvCS712) with two different arrangements of the repeat sequences of VK210 and VK247 was assessed. The immunological properties of theEscherichia coli-expressed chimeric proteins were evaluated by the immunization of C57BL/6 mice administered in NLX, CpG-ODNs, and QS21, alone or in combination as adjuvants. A significant increase in anti-rPvCS127 and -rPvCS712 IgG antibodies was observed in all the vaccine groups after the first boost, and the predominant isotypes were high-avidity cytophilic antibodies, IgG2b, and IgG2c. The highest ratio of IgG2b/IgG1 (2.74) and IgG2c/IgG1 (2.1) levels was detected in mouse groups immunized with rPvCS712  + NLX-CpG-QS21. The lowest level of IFN-γ (mean: 441 and 588 pg/mL, respectively) was produced by the mouse group, which received both antigens without any adjuvant, while significant levels of IFN-γ were detected in the mouse groups immunized with rPvCS127- or rPvCS712-NLX-CpG-QS21 formulat ion (mean: 1200 and 3092 pg/mL, respectively). The current results indicated that in C57BL/6 mice, both recombinant antigens were efficient immunogens and could induce humoral and cellular immune responses and their combination with three Th1 potent adjuvants had an impact on the magnitude and the quality of humoral responses (specific antibody subclasses, titer, and high avidity). Although the overall response was marginally...
Source: Medical Microbiology and Immunology - Category: Microbiology Source Type: research