Comparison of mouse and rabbit model for the assessment of strong PGM-containing oil-based adjuvants.

Peptidoglycan monomer (PGM) is an adjuvant active molecule with potential for use in human and veterinary vaccine. PGM's action is short-lived in mammals hence its effects might be limited. Novel PGM-containing oil-based formulations have been developed recently by incorporation of PGM into Montanide ISA720 and ISA206 adjuvants with the aim to prolong and improve immunostimulating activities of PGM. In the present work we studied the efficacy of such novel adjuvant formulations using two different antigens, ovalbumin and snake venom, respectively. Novel formulations were also tested in two experimental models, mice and rabbits. In rabbits the incorporation of PGM into oil-based adjuvants led to overall improvement of antigen-specific IgG response. However, in the mouse model, under experimental conditions used, it was not possible to distinguish differences in antigen-specific IgG response among several strong oil-based adjuvant formulations.

Effectiveness of novel PGM-containing incomplete Seppic adjuvants in rabbits.

Peptidoglycan monomer (PGM) is adjuvant active molecule in experimental mice, although its adjuvanticity is much lower in comparison to potent adjuvants. The novel adjuvant formulations were developed by incorporation of PGM into Montanide ISA 206 and Montanide ISA 720 adjuvants, with the aim to enhance its adjuvanticity by protecting it from the fast degradation and metabolic clearance. Adjuvanticity of the novel adjuvant formulations was tested in rabbits for induction of protein-specific antibodies. Both novel adjuvants ISA206(PGM) and ISA720(PGM) were significantly stronger than Montanide adjuvants themselves, and also significantly more potent than Complete Freund Adjuvant. Montanide ISA 720 was shown as much better carrier of PGM, since the novel ISA720(PGM) adjuvant was significantly stronger adjuvant than the ISA206(PGM).