Effects of protoscoleces and AgB from Echinococcus granulosus on human neutrophils: possible implications on the parasite's immune evasion mechanisms.
The factors affecting the innate susceptibility to Echinococcus granulosus infections are largely unknown. We assessed the interaction of healthy human neutrophils with protoscoleces (PSC) and antigen B (AgB) of E. granulosus by analysis of CD11b upregulation and H(2)O(2) production by flow cytometry. PSC induced neutrophil activation, but their viability was not affected. In contrast, no effects were observed with AgB in both assays. Neutrophil-enriched fractions were also incubated with PSC or AgB, and interleukin 8 (IL-8) production was measured by ELISA. Significant increment in IL-8 production was detected only in supernatants from neutrophil-enriched fractions cultured with PSC. The possible effect of a prior incubation with AgB on the phorbol myristate acetate-induced activation was also evaluated. No changes were observed in CD11b expression, but the H(2)O(2) production was significantly reduced in platelet-activating factor (PAF)-primed neutrophils. These results suggest a possible AgB-mediated mechanism of evasion of the host immune response, which would operate upon events of spillage of the fertile hydatid cyst content.
Virginio
Veridiana Gomes
VG
Laboratório de Biologia Molecular de Cestódeos, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Taroco
Lorena
L
Ramos
Ana Lía
AL
Ferreira
Ana Maria
AM
Zaha
Arnaldo
A
Ferreira
Henrique Bunselmeyer
HB
Hernández
Ana
A
D000328:Adult; D000818:Animals; D039481:CD11b Antigen / Q000096:biosynthesis; D002478:Cells, Cultured; D015536:Down-Regulation; D048209:Echinococcus granulosus / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D015801:Helminth Proteins / Q000276:immunology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D016209:Interleukin-8 / Q000096:biosynthesis; D008074:Lipoproteins / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology* / Q000469:parasitology*
D039481:CD11b Antigen; D015801:Helminth Proteins; C509295:ITGAM protein, human; D016209:Interleukin-8; D008074:Lipoproteins; C089273:antigen B, Echinococcus; D006861:Hydrogen Peroxide