B cells and food allergy

Lycopene alleviates food allergy by modulating the PI3K/AKT pathway in peanut-sensitized BALB/c mice

Food allergies, which lead to life-threatening acute symptoms, are considered an important public health problem. Therefore, it is essential to develop efficient preventive and treatment measures. We developed a crude peanut protein extract (PPE)-induced allergy mouse model to investigate the effects of lycopene on peanut allergy. Mice were divided into four groups: 5 mg/kg lycopene, 20 mg/kg lycopene, no treatment, and control groups. Serum inflammatory factors were detected using enzyme-linked immunosorbent assay. In addition, pathology and immunohistochemistry analyses were used to examine the small intestine of mice. We found that lycopene decreased PPE-specific immunoglobulin E (IgE) and IL-13 levels in the serum, relieved small intestine inflammation, attenuated the production of histamine and mouse mast cell protease-1, and downregulated PI3K and AKT1 expression in the small intestine tissues of mice allergic to peanuts. Our results suggest that lycopene can ameliorate allergy by attenuating the PI3K/AKT pathway and the anaphylactic reactions mediated by PPE-specific IgE.

Trained innate immunity, epigenetics, and food allergy

In recent years the increased incidence of food allergy in Western culture has been associated with environmental factors and an inappropriate immune phenotype. While the adaptive immune changes in food allergy development and progression have been well-characterized, an increase in innate cell frequency and activation status has also recently received greater attention. Early in prenatal and neonatal development of human immunity there is a reliance on epigenetic and metabolic changes that stem from environmental factors, which are critical in training the immune outcomes. In the present review, we discuss how trained immunity is regulated by epigenetic, microbial and metabolic factors, and how these factors and their impact on innate immunity have been linked to the development of food allergy. We further summarize current efforts to use probiotics as a potential therapeutic approach to reverse the epigenetic and metabolic signatures and prevent the development of severe anaphylactic food allergy, as well as the potential use of trained immunity as a diagnostic and management strategy. Finally, trained immunity is presented as one of the mechanisms of action of allergen-specific immunotherapy to promote tolerogenic responses in allergic individuals.

Broad responses to chemical adducts shape the natural antibody repertoire in early infancy

Natural antibodies are an integral part of innate humoral immunity yet their development and polyreactive nature are still enigmatic. Here, we show that characteristic monoclonal natural antibodies recognize common chemical moieties or adducts, supporting the view that polyreactive antibodies may often correspond to anti-adduct antibodies. We next examined the development of immunoglobulin M (IgM) and IgG to 81 ubiquitous adducts from birth to old age. Newborn IgM only reacted to a limited number of consensus determinants. This highly restricted neonatal repertoire abruptly diversified around 6 months of age through the development of antibodies to environmental antigens and age-driven epigenetic modifications. In contrast, the IgG repertoire was diverse across the entire life span. Our studies reveal an unrecognized component of humoral immunity directed to common adducts. These findings set the ground for further investigations into the role of anti-adduct B cell responses in homeostatic functions and pathological conditions.