Simultaneous monitoring of in vivo humoral and cellular immune responses in the avian model (VAC5P.1123)

Abstract

Abstract Using the dermis (pulp) of growing feathers (GF) as a test-tissue together with blood sampling, we monitored cellular and humoral immune responses in chickens immunized with 3 different formulations of mouse IgG test-antigen (T-Ag). Test-antigen (26 μg) was injected i.m. in 2 groups of chickens either alone, mixed with Alum adjuvant or conjugated to iron-oxide nanoparticles (10 nm). Group 1 was immunized at 7 weeks and Group 2 at 7 and 11 weeks (n = 18 chickens/group). Antibody production (IgM, IgG) to T-Ag was monitored for 4 weeks following both the primary and secondary i.m. immunizations. To examine the local effector response to T-Ag, T-Ag was injected into 20 GF per bird (10 μL/GF) on Day 10 (Group 1) or Day 5 (Group 2) post-primary or secondary immunization, respectively, and GF collected 0.25, 1, 2, 3, 4, 5, & 7 days post-injection. Analysis of GF pulp cell suspensions by flow cytometry revealed temporal, qualitative and quantitative differences (P < 0.05) in leukocyte-infiltration between immunization treatments and primary/memory effector-responses. Cytokine expression analysis (qRT-PCR) is in progress. ELISA also revealed temporal, qualitative, and quantitative differences (P < 0.05) in the humoral responses to T-Ag following the different primary/secondary i.m. immunizations. Minimally invasive, non-terminal procedures such as sampling of injected GF and blood provides unique insight into cellular and humoral immune activities in the same individual over time.