B cell-regulated immune responses in tumor models and cancer patients

Abstract

The essential role played by T cells in anticancer immunity is widely accepted. The immunosuppressive functions of regulatory T cells are central for tumor progression and have been endowed with a robust predictive value. Increasing evidence indicates that also B cells have a crucial part in the regulation of T-cell responses against tumors. Although experiments reporting the production of natural antitumor antibodies and the induction of cytotoxic immune responses have revealed a tumor-protective function for B cells, other findings suggest that B cells may also exert tumor-promoting functions, resulting in a controversial picture. Here, we review recent evidence on the interactions between B and T cells in murine models and cancer patients and their implications for cancer immunology.

Clinically feasible approaches to potentiating cancer cell-based immunotherapies

“…B cells exogenously pulsed with an antigen can present MHC class II epitopes independently of their B-cell receptor specificity, and also are able to promote MHC class I cross-presentation. 15 Classical (ab) T cells recognize small peptides presented by MHC molecules on the surface of antigen-presenting cells (APCs). Intracellular antigens are subjected to proteolysis, antigenic peptides are bound within the peptide-binding groove of the MHC molecule, and peptide-MHC complexes are transportd to the cell surface for subsequent T cell recognition.…”

“…IDO expression in DCs is considered to be an important mechanism of immune tolerance. 15 Alternatively activated macrophages (M2s) are generated from circulating monocytes upon IL-4 stimulation. M2s facilitate tumor angiogenesis and promote tumor invasion and metastasis.…”

“…21 Regulatory B cells (Bregs) secrete IL-10 and TGF-b shifting the balance of tumor-specific immune responses toward immunosuppression, thus sustaining tumor progression. 15 A Th1/Th2 imbalance is often established during tumor development, with the predominance of anti-inflammatory (Th2) cytokines. 29 This imbalance could reduce Th1-mediated immune anti-tumor responses.…”

The correlation of CD19 + CD24 + CD38 + B cells and other clinicopathological variables with the proportion of circulating Tregs in breast cancer patients

“…In addition to Tregs, there is also a subset of B cells described with regulatory capacity, confirmed as regulatory B cells [16,17]. The identification of Bregs in human is controversial.…”

“…T cells [18,19]. Further evidences suggested that these Bregs play an essential role in pathogenesis of autoimmune diseases [16]. Although Bregs have been extensively studied in these diseases, there is a little known about their role in human cancer.…”