Artículos de revistas
IFN-beta, IFN-gamma, and TNF-alpha decrease erythrophagocytosis by human monocytes independent of SIRP-alpha or SHP-1 expression
Registro en:
Immunopharmacology And Immunotoxicology. Informa Healthcare, v. 34, n. 6, n. 1054, n. 1059, 2012.
0892-3973
WOS:000310314800024
10.3109/08923973.2012.697470
Autor
de Almeida, AC
Barbosa, SM
Barjas-Castro, MDR
Olalla-Saad, ST
Condino-Neto, A
Institución
Resumen
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Background: Many cases of autoimmune hemolytic anemia have been reported after viral infection. Phagocyte activation and accompanying erythrophagocytosis are thought to result from proinflammatory cytokines released during viral infection. SIRP-alpha (signal regulatory protein-alpha), a receptor expressed on phagocytes, inhibits phagocytosis when bound to CD47 on the erythrocyte membrane. Ligation with CD47 results in SHP-1 recruitment to SIRP-alpha and dephosphorylation of specific downstream substrates involved in phagocytosis. SIRP-alpha ligation by CD47 may be inhibited by proinflammatory cytokines. Objectives: The aim of this work was to evaluate the effect of IFN-beta, IFN-gamma, and TNF-alpha on erythrophagocytosis and assess the effect on expression of SIRP-alpha and SHP-1 in human monocytes. Materials and methods: Monocytes were cultured ex vivo with IFN-beta or IFN-gamma/TNF-alpha. Erythrophagocytosis was determined by flow cytometry. SIRP-alpha and SHP-1 gene expression was determined by real time-PCR, while SIRP-alpha and SHP-1 protein expression was determined by western blot. Results: Erythrophagocytosis by monocytes significantly decreased after treatment with either IFN-beta or IFN-gamma/TNF-alpha. Monocytes cultured with IFN-gamma/TNF-alpha showed increased SIRP-alpha gene and protein expression and SHP-1 gene expression. Monocytes cultured with IFN-beta did not show any alteration in SIRP-alpha or SHP-1 expression. Conclusion: We conclude that IFN-beta and IFN-gamma/TNF-alpha decrease erythrophagocytosis by human monocytes in vitro, and this effect does not apparently require an increase in SIRP-alpha or SHP-1 expression. 34 6 1054 1059 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)