In vivo monitoring of the immune response to mIgG conjugated to iron oxide nanoparticles using the pulp (dermis) of growing feathers as a test-tissue in chickens, (IRC8P.495)

Abstract

Abstract Biomedical applications of nanoparticles (NPs) are growing. Data on the biological activities of NPs are, however, limited. We are evaluating the growing feather (GF) in chickens as a test-site (US-Patent 8,216,551; GF Erf) to monitor in vivo activities of NPs. In this study, the immune response to mouse (m) IgG initiated with different antigen-adjuvant combinations was examined. Specifically, 8-week-old male chickens were immunized i.m. with 0.1 mL of mIgG alone, a mixture of Alum adjuvant & mIgG, or mIgG conjugated to iron oxide NP (IONP-mIgG, 10 nm) (n=6 birds/treatment). To monitor the immune response, 0.01 mL mIgG was injected into the pulp (dermis) of 20 GF/bird ten days post-immunization. GF were collected before (0 h) and at 0.25, 1, 2, 3, 5, and 7 d post-GF-injection for flow cytometry, mRNA and histological analysis. Flow-cytometric cell-population analysis of pulp cell suspensions revealed higher levels (%, P<0.001) of lymphocyte infiltration [due to B cells (P<0.001), alpha-beta TCR+ T cells (P<0.005) and CD4+ T cells (P<0.05)] in birds immunized with IONP-mIgG compared to Alum & mIgG or mIgG. These data demonstrate the effectiveness of GF as a test-site to monitor qualitative and quantitative aspects of immune activities in vivo and the usefulness of this minimally invasive procedure as a window into biological activities of NP. Moreover, the results suggest effective adjuvant activities of IONP in stimulating a primary immune response to protein antigen.