TSP1-producing B cells show immune regulatory property and suppress allergy-related mucosal inflammation.

Specific immunotherapy (SIT) is the only specific remedy for the treatment of allergic diseases currently. B cells are important immune cells in the immunity. The role of B cells in immune regulatory activities has not been fully understood yet. This study aims to elucidate the role of the thrombospondin (TSP)1-producing B cells in the immune regulatory role of SIT. The results showed that after SIT, the frequency of CD35(+) B cells was increased in the intestine of mice with food allergy. The CD35(+) B cells expressed TSP1 after exposure to specific antigens. Co-culture with the TSP1-producing CD35(+) B cells decreased the levels of CD80/CD86 in dendritic cells; the cells convert naïve CD4(+) T cells to regulatory T cells to inhibit allergic inflammation in the intestine.