Study of the effect of polybutylcyanoacrylate nanoparticles and their metabolites on the primary immune response in mice to sheep red blood cells

Polybutylcyanoacrylate nanoparticles (PBCN) and their metabolites (polycyanoacrylic acid—PCAA, and n-butanol) were compared with respect to their effects on the primary immune response of mice to sheep red blood cells (SRBC). PCAA was synthetized via a Knoevenagel reaction. Antibody production (hemagglutinins) and E-rosette-forming cells (E-RFC) were used to document the induction of antigen-specific immune response to SRBC in all immunized mice. PBCN showed a time- and dose-dependent effect on the immune response, both humoral and cellular. The inductive phase of immune response was affected preferably. The high dose of PBCN (200 mg kg-1) tended to suppress the immune response. This was expressed more in mice treated before antigenic stimulation. Lower dose (10 mg kg-1) stimulated the immune response. A significant difference was found in the effects of PBCN and their metabolites on the immune response. PCAA and n-butanol administered at doses equivalent (after lysosomal hydrolysis) to the doses applied of intact PBCN did not impair significantly the immune response. A clear time dependence and dose dependence were not observed. The study led to the hypothesis that the greater suppressive effect of PBCN, relative to either PCAA or n-butanol, or a mixture of them, is probably due to the blocking of the immunopresenting function of macrophages instead of some toxicity towards the immunocompetent cells.