engleski

The limitation of mice model for the effectiveness of strong adjuvants assessment

The effectiveness of any novel adjuvant formulation should be preliminary assessed in an animal model. It is generally recommended and widely accepted to use mice, guinea pig or rabbit model. Mice model is usually chosen for preliminary adjuvant assessment, primarily due to availability of reagents required for the assays of induced immune response (subclass analyses, cytokine profiles). The aim of this study was to investigate and compare the effectiveness of two novel adjuvant formulations on humoral immune response using different animal models (mouse and rabbit). The novel formulations were oil-based Montanide ISA adjuvants, ISA 720 and ISA 206, respectively, containing the experimental immunomodulator of bacterial origin peptidoglycan monomer (PGM). Humoral immune response was followed by determination of antigen-specific IgG. Novel adjuvant formulations were tested in several separate experiments with different antigen types (protein antigens, peptide antigens and snake venom as a mixture of antigens). In each experiment respective antigen specific IgG was quantified by appropriate ELISA assay and compared to control groups of mice treated with: a) antigen without adjuvant as negative control, b) antigen and oil adjuvant and c) antigen and CFA/IFA as positive control. Here we report on limitations of mice model when strong adjuvants are investigated. There was no difference in IgG levels in groups treated with adjuvant formulations containing PGM in comparison to the groups treated with respective oil-based adjuvants only. These results could mislead to conclusion that PGM incorporation into oil-based adjuvants didn't improve the effectiveness of resulting adjuvant formulations. Interestingly, the use of CFA/IFA induced equally high level of antigen-specific IgGs as the use of all oil-based adjuvants. On contrary, in rabbits, the experimental adjuvant formulations containing PGM induced statistically significant increase in antigen-specific IgG levels compared to IgG levels in respective oil-only treated groups. Accordingly, it could be concluded that strong adjuvants completely recruit all mice immune capacities for mounting the increased immune response and because of such limitation no differences or improvements could be further observed.

peptidoglycan monomer; mouse; rabbit; adjuvant

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