Analysis of T and B cell phenotype and effector memory T cell response in a mouse model of tree nut allergy (125.10)

Abstract

Abstract Tree nuts cause potentially fatal anaphylactic reactions for reasons that are not well understood. We previously reported an adjuvant free mouse model of hazelnut allergy. Here we analyzed the T & B cell phenotype and effector memory responses. Balb/c mice were transdermally sensitized with hazelnut. Hazelnut allergy was confirmed by measuring hazelnut specific IgE antibodies and systemic anaphylaxis (hypothermia) upon challenge. Using flow cytometry T cell and B cell phenotypes were studied. Hazelnut allergic mice exhibited a significant increase in the number of CD4+ CD62L - T cells in the bone marrow and the spleen. Among B cells, there was increase in CD80+ cells in BM, spleen and MLN and CD62L- cells in BM and spleen of allergic mice. Among CD80+ B cells a significant proportion were CD73- in the MLN of allergic mice. Effector memory Type-2 cytokine responses were analyzed using spleen cell cultures. Allergic mice exhibited a robust IL-4, IL-5 and IL-13 response that was blocked by anti-CD4 mAb. The STAT6 KO mice exhibited IL-5 and IL-13 but not IL-4 memory response. These data demonstrate that hazelnut elicits: (i) significant expansion of CD4+CD62L- T cells in both the BM and the periphery; (ii) a modest increase in CD80+ and CD62L- B cells in BM and the periphery; and a significant down regulation of CD73 expression on a subset of CD80+ B cells in the MLN; and (iii) STAT6 and CD4 dependent IL-4 memory; and STAT6 independent, CD4 dependent IL-5/IL-13 memory.