| Toxoplasma gondii, the etiological agent of toxoplasmosis, can cause severe or lethal damages in both animals and
man. So, tends to develop a more effective vaccine to prevent this disease is extremely needed and would be so
prominent. The novel dense granule antigen 14 (GRA14) has been identified as a potential vaccine candidate
against T. gondii infection. The aim of this study was evaluation of protective immunity induced by prime/boost
vaccination strategy of GRA14 antigen with calcium phosphate (CaPNs) or Aluminum hydroxide (Alum) nanoadjuvants
in BALB/c mice. The finding showed that immunization with the prime-boost strategy using plasmid
DNA (pcGRA14) and recombinant protein (rGRA14) with nano-adjuvants significantly elicited levels of specific
IgG antibodies and cytokines against T. gondii infection. Given that, there were the high levels of total IgG,
IgG2a, IFN-γ in mice of rGRA14-CaPNs and pcGRA14 + rGRA14-CaPNs groups, which indicating a Th-1 type
response. While immunization of mice with Alum based rGRA14 and pcGRA14 + rGRA14 elicited specific IgG1
and IL-4 levels, which was confirmed a Th-2 type response. Mice immunized with DNA prime-protein boost
vaccine with nano-adjuvants produce more vigorous specific lymphoproliferative responses than mice immunized
with other antigen formulations. In addition, the CaPNs-based prime-boost vaccine of
pcGRA14 + rGRA14 showed the longest survival time in mice and the lowest parasitic load in their brain tissue
compared to the other groups. The results obtained in this study show that the use of GRA14 based DNA prime–
protein boost vaccination regime with CaPNs can dramatically enhanced both humoral and cellular immune
responses. Therefore, this strategy can provide a promising approach to the development of an effective vaccine
against T. gondii infection in the future. |