Background:
One of the main challenges in protein-based vaccines is the poor
immunogenicity of antigens, which can be solved by the use of adjuvants.
Advax is a novel microparticle polysaccharide adjuvant that in
combination with antigens can induce both cellular and humoral immunity
based on the intrinsic features of the antigen. It has been shown that
poly(I:C) can be a suitable adjuvant for the PfMSP-142-based malaria
vaccine. Advax is a suitable co-adjuvant for poly(I:C) to increase its
half-life and reduce dose-dependent toxicity.
Objectives:
To investigate whether advax alone or advax /poly(I:C) combination
can enhance the immunogenicity with increased parasite inhibitory
anti-PfMSP-142 antibodies in comparison to poly(I:C).
Methods:
Mice groups were inoculated with rPfMSP-142 alone or formulated in
poly(I:C), poly(I:C)/advax, or advax. Then, humoral and cellular immune
responses, the ratio of Th1/Th2 and growth inhibitory activity of
induced antibodies were analyzed.
Results:
Poly(I:C)/advax formulated PfMSP-142 induced higher levels of
anti-PfMSP-142 IgG, IgG2a, and IgG2b antibodies relative to
poly(I:C)-formulated PfMSP-142. The maximum ratio of IFN-?/IL-4 (50.13)
and IgG2a/IgG1 (2.65), was induced in mice receivedadvax-formulated
PfMSP-142. Besides, poly(I:C)/advax formulated PfMSP-142 induced a
higher ratio of IFN-?/IL-4 (25.33) and IgG2a/IgG1 (1.89) when compared
with poly(I:C) alone. Strong growth inhibitory activity was observed in
antibodies induced in mice received poly(I:C)/advax-formulated
PfMSP-142.
Conclusion:
These findings indicate that advax is a favorable adjuvant to be
combined with poly(I:C), and this combination of adjuvants could induce
Th1 immune responses and growth inhibitory antibodies against
rPfMSP-142.