Androgens protect against development of immune responses to peanut

About This Grant

PROJECT SUMMARY/ABSTRACT Sex differences exist in food allergies. Females report significantly more food allergies than males, mirroring what is seen in asthma following puberty. Recent epidemiological data shows that females, starting in childhood and maintained into adulthood, are twice as likely to develop peanut (PN) allergy than males. The prevalence of PN allergy continues to increase. The reasons behind both the increase in PN allergy and the biological sex differences observed in disease prevalence remain unclear. Recent clinical trials have shown that eating PN early in life is important to promote tolerance, where the immune system ignores ingested PN. Without eating PN early in life, exposure to PN found in household dust via non-oral routes such as skin or airways likely promotes the development of PN allergy. In fact, mice exposed to PN on their skin or airways develop PN allergy, and the mice even undergo clinical signs of anaphylaxis. While almost two decades (2000- 2017) of recommending parents to avoid feeding PN to children for the first few years of life explains, at least in part, the increase in PN allergy, our knowledge about how the immune system responds to non-oral PN exposure remains incomplete. Even less is known about the biological mechanisms underlying sex differences in susceptibility to food allergies. Our long-term goal is to dissect the immunological pathways responsible for immune sensitization to PN and these discoveries will allow us to better understand how sex hormones modulate immune responses to PN. The objective of this grant is to characterize how androgens negatively regulate the development of PN allergy. The central hypothesis is that androgens weaken innate immune responses to PN leading to a decrease downstream in PN-specific adaptive immune responses. Our rationale is that androgens, specifically testosterone, has been shown to decrease airway inflammation in mice. Recently, we showed that female and androgen receptor-deficient mice mount stronger allergic responses to PN than males. Our specific aims will test the following hypotheses: (Aim 1) Androgens, working through the androgen receptor (AR), weaken the responses of ILC2s, DCs, and mast cells to PN; (Aim 2) T cells and B cells activated against inhaled PN are suppressed in their ability to respond by androgens. In Aim 1, we will utilize our three-day PN inhalation mouse model in wildtype (WT) male, female, and androgen receptor deficient (ARTfm) male mice to study how androgens exert negative regulatory control on innate responses against PN. We will use an 11-day inhalation mouse model in WT and ARTfm mice to study the impact of androgens on T and B cell responses to PN in Aim 2. Upon conclusion, we will better understand how androgens exert their control on PN-responsive immune cells to establish sex differences in PN allergies. This contribution is significant since it will be the first comprehensive study to pinpoint how androgens regulate the development of allergic immune reactions to PN. The proposed research is innovative because it will give us crucial insight into the biological mechanisms underlying sex differences in PN allergy. Such knowledge will prove useful in examining other food allergies.