Impaired Cytokine Production of Tumor Infiltrating Lymphocytes in a Model of Primary Intraocular B-Cell Lymphoma

Abstract

Purpose:: Primary intraocular lymphoma (PIOL) is a high grade non-Hodgkin lymphoma which pathogenesis is still unclear. Microenvironment is known to be crucial in controlling tumor growth and maintenance. In order to study the immune microenvironment in intraocular lymphoma and to characterize the cytokine polarization of infiltrating T-lymphocytes (TIL), a murine model of intraocular B-cell lymphoma was developed in immunocompetent mice.

Methods:: Immunocompetent adult mice were injected intravitreally with a syngeneic lymphomatous B-cell line. Clinical, histological and flow cytometric analysis were performed in order to characterize tumoral invasion and the immune infiltration. Cytokine production of ocular cells was investigated by RT-PCR and fluorescent immunoassay with or without stimulation by anti-CD3 plus anti-CD28 antibodies.

Results:: Intraocular lymphoma developed in all eyes injected by lymphomatous B-cells. At day 19, the retina and the vitreous cavity were infiltrated by tumor cells. Up to 15% of living cells were T-lymphocytes. Cytokine profile analysis of the supernatant of ocular cells cultured ex vivo demonstrated the presence of IL10, IL6, IFN-γ, and TNF-α. Stimulation of ocular cells with anti-CD3 plus anti-CD28 antibodies increased the IFN-γ level, and led to the induction of IL2 production, completing the type 1 (Th1/Tc1-like) pattern of cytokine expression. IL6 and IL10 levels were not modified. IL12p70 and IL4, potent Th1 or Th2 differenciating factors, were undetectable even after stimulation.

Conclusions:: Our results suggest that TIL from intraocular B-lymphoma are characterized by a Th1/Tc1 like profile that could be partially inhibited in vivo. These data raise the possibility of an in situ T-cell immunostimulation in order to reactivate the Th1/Tc1 lymphocytes and to improve the intraocular anti-tumoral immunity.

Keywords: tumors • cytokines/chemokines • immunomodulation/immunoregulation