Non-Atopic Individuals Exhibit a Distinct Immune Reactivity Patterns in Response to Timothy Grass Pollen in and out-of-Season
Monday, March 7, 2016
South Exhibit Hall H (Convention Center)
Denise Hinz, Gregory Seumois, Jason Greenbaum, Brandie White, Veronique M. Schulten, David H. Broide, MB ChB FAAAAI, John Sidney, Carla Oseroff, Erik R. Wambre, PhD MBE, Eddie A. James, PhD, William W. Kwok, PhD, Pandurangan Vijayanand, Bjoern Peters, PhD, Alessandro Sette, Dr. Biol. Sci.
Rationale: Timothy grass (TG) pollen is one of the most frequent aero-allergens causing symptoms ranging from mild rhinitis to severe asthma in allergic individuals.

In this study, we were interested in assessing and characterizing changes in seasonal TG-specific T cell responses.

Methods: Peripheral blood mononuclear cells (PBMC) from allergic and non-allergic donors were obtained either during or out of TG pollen season. Cells were stimulated either with TG extract or a pool of previously identified Phl p-derived immunodominant T cell epitopes.

Results: T cell responses from in-season allergic subjects were found to be associated with higher levels of IL-5 and IL-10 compared to out-of-season donors. Strikingly, non-atopic donors exhibited an opposing pattern in immune reactivity compared to allergic patients, with immune responses being significantly lower in-season compared to out-of-season. Transcriptomic analysis of allergen-specific T cells defined genes modulated in concomitance with allergen exposure and inhibition of responses in non-allergic donors.

Conclusions: Magnitude and functionality of T-helper cell responses are differentially regulated in-season versus out-of-season in allergic and non-allergic subjects. Cohort-specific and opposing modulation of immune responses can be observed in atopic versus non-atopic individuals following antigenic stimulation during the pollen season. Seasonal immune-downregulation in non-allergic donors indicates that healthy individuals react with an active suppression of responses following antigenic stimulation during the pollen season. This differential seasonal modulation may reflect the enactment of specific molecular programs associated with health and allergic disease.