The role of b cells in shaping the antitumor immune response

Abstract

Although many experimental tumor models have demonstrated the importance of CTL, Th1 response, and NK cells in antitumor immunity, relatively little is known about the role of B cells in tumor immunity. The ability and mechanism of B cell-mediated regulation of cellular immune responses and infl ammation have only recently been described and remain incompletely understood. Although B cells are recognized as a signifi cant proportion of tumor-infi ltrating lymphocytes in both mouse models and human tumors, relatively little mechanistic information is available describing how these cells infl uence antitumor immunity and immunosurveillance. Recently, studies in several murine models have found an association indicating that reduced number of tumor-infi ltrating B cells is associated with improved CD8+ T cell and NK cell infi ltration into the tumor bed and decreased tumor growth. Multiple mechanisms have been implicated in B cell-mediated suppression of antitumor immunity including (1) preferential polarization of immune responses to Th2; (2) direct suppression of tumor immunity by immunosuppressive regulatory B cells (Breg), and (3) coordination of regulatory T cell (Treg) recruitment and suppression within the tumor microenvironment. Because B cells are readily targeted in the clinic with monoclonal antibodies, understanding of how these cells infl uence tumor immunity may lead to rapidly translatable approaches to enhancing therapeutic immunity for both solid and hematological malignancy.