A novel neutrophil-activating factor released by Trichomonas vaginalis

Abstract

We have investigated the effects of a novel neutrophil-activating factor released by Trichomonas vaginalis (TV-NAF) on neutrophil chemotaxis. TV-NAF was present in the supernatant from 107 T. vaginalis (STV) cultured in 1 ml of serum-free Hanks' balanced salt solution (HBSS) at 37°C for 30 min. With a multichamber chemotactic assay, we found that there were 112 + 15 migrated neutrophils (mean ± standard deviation, n = 7) for STV and 11 ± 4 for HBSS per high-power field (x400). STV was also able to induce neutrophil actin assembly (increased 1.5-fold), enhance expression of complement receptor type 3 (increased 5-fold), and promote intracellular calcium mobilization (increased 2.5-fold). There was no chemotactic activity in the preparation of STV from killed trichomonads. The fact that heating up to 100°C or deproteinization by treatment with proteinase K at 65°C for 1 h did not abolish its chemotactic activity suggests that the TV-NAF involved was not a protein. The chemotactic activity of TV-NAF was associated with the fraction containing small molecules of less than 3,000 Da. Therefore, the possibility that eicosanoid production by trichomonads is responsible for neutrophil activation was investigated. Leukotriene B4 (LTB4; 500 pg/ml) but not thromboxane B2 (<20 pg/mi) or prostaglandin E2 (<8 pg/ml) was found in the STV by radioimmunoassay. Production ofLTB4 by trichomonads was time dependent and increased twofold when arachidonic acid (100 ,uM) was added but was not decreased when eicosanoid inhibitors were present. Evidence for the presence of LTB4 in STV was further provided by the fact that rabbit anti-LTB4 antiserum could abolish the chemotactic activity of STV. These studies suggest that the spontaneous release of TV-NAF, which is most likely LTB4, may activate neutrophils, presumably through a different arachidonate metabolic pathway than that in mammalian cells. * Corresponding author. cellular calcium mobilization. The results from these studies provide more information about the inflammatory response induced by T. vaginalis. MATERIALS AND METHODSOrganism. Seven local isolates, axenically cultivated, were maintained in a modified medium identical to the TYI-S-33 medium of Diamond et al. (7), except that 0.5% Panmede (Paines & Byrne Limited, Greenford, England) was added. The number of organisms per culture was determined with a Coulter counter (model D industrial; Coulter Electronics, Inc., Hialeah, Fla.) with a 70-,um aperture tube.Preparation of STV. Each isolate of T. vaginalis grown at 37°C in 15-ml tubes containing TYI-S-33 medium was harvested during the logarithmic growth phase after 36 h of cultivation. They were centrifugally washed three times in HBSS (GIBCO, Grand Island, N.Y.), and then viable cells were counted in a hemacytometer with trypan blue-saline. HBSS without phenol red was used as the wash buffer and diluent throughout this study. The medium-free flagellates (107) were incubated in 1 ml of HBSS at 37°C for 30 min. Motile flagellates were then removed by gentle centrifugation (500 ...

Generation of interleukin-8 from human monocytes in response to Trichomonas vaginalis stimulation

“…Chemotaxis was assessed in a 48-well microchemotaxis chamber (Neuro Probe, Inc., Cabin John, Md.) by a method described previously (33). Various concentrations of STVCM, MTVCM, WTVCM, and CCM were tested for the chemotactic activity by neutrophils.…”

“…We have found high levels of interleukin-8 (IL-8) and leukotriene B 4 (LTB 4 ) in vaginal discharges from patients with symptomatic trichomoniasis (31,34). The presence of LTB 4 in vaginal discharges from patients with trichomoniasis could be due to the spontaneous release of LTB 4 from T. vaginalis (33) and/or from neutrophils induced by the interaction of trichomonads and humoral immunity (32). Recent studies have indicated that IL-8, a novel chemotactic and activating cytokine with high selectivity for neutrophils (5), enhances the antimicrobial activities of neutrophils by inducing neutrophil degranulation, respiratory burst, and 5-lipoxygenase activity (14,23,26,28).…”

Eicosapentaenoic Acid Modulates Trichomonas vaginalis Activity

“…, ; Shaio et al. ). It is possible that oxAA interferes with this pathway, leading to the observation in our study that oxAA is more detrimental to T. vaginalis survival than native AA.…”

“…; Shaio et al. ) but, to date, there are no reports examining the effects of EPA on this parasite. Notably, uptake of AA by T. vaginalis leads to an increased production of leukotriene B 4 , indicating that T. vaginalis has the ability to metabolize AA (Nam et al.…”

Immunity in urogenital protozoa

“…In vitro experiments conducted with cervical, VECs and immune cell types exhibited T. vaginalis‐ stimulated IL‐8, leucotrienes (LT) and RNI in leucocyte culture . The parasite produces leucotrienes that are capable of activating the host cells , implying that the activation of the complement pathway is critical for the amplification of T. vaginalis host‐defence mechanisms. Therefore, humoral immunity may encourage the mutual interactions between T. vaginalis and neutrophils, resulting in the enhancement of the inflammatory response through increased LT B4 production.…”