The adjuvant effect of particles - Importance of genetic background and pre-sensitisation

Background: We have previously reported that simple and well-characterised particles, such as polystyrene particles (PSP), have an IgE adjuvant effect in mice. The purpose of this study was to explore the importance of geneti c background concerning the adjuvant effect of PSP in different strains of mice. Methods: Inbred NIH/Ola, BALB/c and C3H/HeJ mice were given two intra peritoneal injections with either PSP plus OVA or OVA alone, and then an in traperitoneal challenge with OVA alone. NIH/Ola mice were also pre-sensitis ed to develop a weak or strong IgE response to OVA, and then given an intra peritoneal challenge with PSP plus OVA or OVA alone. Serum levels of total and allergen-specific IgE and IgG2a were measured. Results: PSP had a speci fic IgE and IgG2a adjuvant effect in NIH/Ola mice but not in C3H/HeJ and BA LB/c mice. Weakly pre-sensitised NIH/Ola mice showed the same response patt ern as the naive NIH/Ola mice. In contrast, strongly pre-sensitised mice sh owed an antibody response pattern similar to that of high-responder BALB/c mice. Conclusion: Our results indicate that the allergen responder status, either genetic or induced, is of importance for the adjuvant effect from pa rticles. The IgE and IgG2a adjuvant effect may depend on the genetically de termined susceptibility of an individual to be influenced by exposure to th e adjuvant. Therefore, the allergy-enhancing effect from particle pollution may differ between individuals. Copyright (C) 2000 S. Karger AG. Basel.