Dados do Trabalho

Título

CHARACTERIZATION AND FUNCTIONAL ANALYSIS OF B CELLS FROM PATIENTS WITH CUTANEOUS LEISHMANIASIS CAUSED BY Leishmania braziliensis

Introdução

Cutaneous leishmaniasis (CL) caused by Leishmania braziliensis is characterized by strong activation of specific CD4 T cells and a potent inflammatory response. While it is known that both CD4+ and CD8+ T lymphocytes contribute to the inflammatory response in CL, the role of B cells in the pathogenesis of CL still poorly understood.

Objetivo (s)

To investigate the contribution of B cell on cytokine production and their participation in the immunopathology observed in CL patients.

Material e Métodos

Peripheral blood mononuclear (PBMC) cells were obtained from healthy controls and CL patients for staining with CD19, CD38, CD24 and CD3 surface markers, and intracellular staining for IL-10 and TNF after culture with soluble Leishmania antigens (SLA). PBMC and biopsies from the CL lesions were obtained for B cells depletion and levels of cytokines and chemokines in response to SLA were determined by ELISA.

Resultados e Conclusão

We observed that T cells from CL patients produce more TNF, while B cells predominantly produce IL-10. Indeed, increased levels of IL-10 were observed in supernatants of purified human B cells after stimulation with SLA. We also identified three sub-populations of B cells: mature B cells (CD19+CD38-CD24-), transitional B cells (CD19+CD38hiCD24hi) and memory B cells (CD19+CD38-CD24hi). The frequency of mature B cells (CD19+CD38-CD24-) is increased in PBMC from CL patients when compared to healthy controls. Although IL-10 is produced by all subpopulations of B cells, the transitional B cells (CD19+CD38hiCD24hi) were the main source of this cytokine. Additionally, depleting B cells significantly reduced IL-10 levels in PBMC and in CL lesions. Conclusion: Our results pointed out that B Lymphocytes are an important source of IL-10, possibly favoring L. braziliensis replication and establishment.

Palavras-chave

Cutaneous leishmaniasis, Cytokines, B cells, Interleucin-10

Agradecimentos

INCT-DT, CAPES