Mode of action of immunological adjuvants: some physicochemical factors influencing the effectivity of polyacrylic adjuvants.

The adjuvant effects of different polyacrylic products and monomers were tested. Influenza vaccine was used as a model antigen. Addition of monomers resulted in a decrease in the antibody response, though adjuvant activity of the monomers should be expected according to some theories on adjuvant action. The particle size of the polymer adjuvants proved to be a very important parameter for adjuvant activity. Particles of 0.1 to 0.2 micron yielded a good adjuvant effect, whereas conglomerates or particles bigger than 0.5 micron yielded only poor or no adjuvant effects. The adjuvant effect of 0.1- to 0.2-micron particles was much more reproducible than rat of Al(OH)3. Attention is drawn to the importance of using physiochemically reproducible materials, such as polymer particles, for experimental work.