IgG from atopic individuals can mediate non-atopic infant thymic and adult peripheral CD8+ TC2 skewing without influence on TC17 or TC22 cells.

Summary: The potential of IgG antibodies as allergy regulators has been discussed for decades and was brought to light that anti-allergen IgG is related to allergy inhibition in children during the first years of life and that IgG repertoire can differ between atopic and non-atopic individuals. Here, we aimed to evaluate in vitro the differential effects of purified IgG from atopic and non-atopic individuals on the production of IL-4, IL-17, and IL-22 by human intra-thymic and mature peripheral CD8+ T cells respectively termed as TC2, TC17, and TC22 cells. We additionally evaluated the IFN-􀁊 production by CD8+ T cells. Thereupon we used infants thymic tissues from non-atopic mothers and blood samples from individuals clinically classified as non-atopic. Thymocytes or PBMCs were cultured with IgG from atopic or non-atopic individuals. As controls, we used commercial IgG (Intravenous immunoglobulin - IVIg) or mock condition. The phenotype and intracellular cytokine production were evaluated using flow cytometry. IgG from atopic individuals could increase the frequency of TC2 cells in non-atopic infant thymic and adult peripheral cell cultures compared to all control conditions. Due to the TC2 cell's potential to collaborate with pathology and severity of asthma in humans, this evidence can cooperate with the understanding of the development of an atopic state.