B cells inhibits the antitumor immunity against an established murine fibrosarcoma.

MAGLIOCO ANDREA; MACHUCA DAMIAN; N BADANO; NANNINI P; CAMERANO GABRIELA; COSTA H; RP MEISS; RUGGIERO RAÚL; GIORDANO MIRTA; DRAN GRACIELA

Oncology Letters

Spandidos Publications UK LTD

Año: 2017

Despite B cell classicrole in favouring immune response, an inhibitory role for B lymphocytes intumor immunity has been recently turned into focus. In the mouse fibrosarcomaMCC, the loss of immunogenicity and the establishment of tolerance areparalleled by systemic immune suppression and the appearance of IL-10-producing B cells in the tumor- draining lymph nodes. The aim of this paper wasto study the role of B cells in the immune evasion and tolerance exhibited byMCC by means of depleting these cells in tumor bearing mice. We found that Bcell depletion, once the tumor is established resulted in lower tumor growthand delayed onset of tolerance. Additionally, B cell absence exacerbated T celldependent- tumor rejection, reduced the regulatory T cell population andincreased cytotoxic CD8+ T cells both in the lymph node and tumor tissue. More,T cell dependent- tumor rejection was increased in B cell- absence. Contrarilyto these signs of immune activation, B cell depletion performed before tumorimplantation resulted in enhanced tumor progression[C1]  suggesting theinhibition of the immune antitumor response. In vitro analysis showed a directeffect of B cells upon T cell proliferation partially mediated by IL-10 secretion.These results suggest that B cells contribute to the immunological tolerance ofMCC tumor and that B cell depletion would unmask a pre- existing antitumorresponse. The present findings draw attention to the convenience of modulatingB cells in the development of future and more effective immunotherapies againstcancer.