Macrophages alter T helper cell balance and attenuate mast cell degranulation in tropomyosin-induced food allergy.

Food allergy is a complex immune-mediated disorder involving multiple immune cell populations. Macrophages play an important role in both innate and adaptive immune responses. However, their contribution to food allergy remains incompletely understood. In this study, murine models of macrophage depletion and adoptive transfer were established in vivo, along with an in vitro co-culture system of macrophages and mast cells. The effects of macrophages on T helper cell balance and mast cell degranulation were systematically evaluated by these models. It was found that macrophage depletion exacerbated allergic symptoms and intestinal inflammation in mice. During food allergy, the M1/M2 macrophage ratio in mesenteric lymph nodes decreases, and macrophage depletion disrupts T-cell balance by reducing Th1 differentiation and promoting Th17 polarization. Moreover, macrophages attenuated mast cell degranulation, potentially through FcεRII-mediated IgE binding and cytokine-dependent signals. These findings provide new insights into the immunoregulatory role of macrophages in food allergy.