Histamine and leukotriene concentrations in duodenal tissue and mucus of lambs selected for high and low responsiveness to vaccination and challenge with Trichostrongylus colubriformis

Kinetics of Serum and Local Leukotriene B<sub>4</sub> Response in Experimental Intravaginal Trichomoniasis by <i>T. vaginalis</i> Isolates from Symptomatic and Asymptomatic Women

“…On other hand, LTB 4 down-regulate IL-12, and up-regulate IL-10 by dendritic cells leading to immune tolerance [48]. These results also correlated well with the earlier reports conducted in experimental animals whereby Increase in LTB 4 in intestine has been demonstrated in other nematode-infected animals [49] [50] and other protozoan parasite as Entamoeba histolytica [51]. Experimental studies conducted on Strongyloides venezuelensis indicated greater LTB 4 release in the lungs, duodena and serum than that seen in the tissue of uninfected animals.…”

Relationship of intestinal histology with the resistance to Trichostrongylus colubriformis infection in three breeds of sheep

“…At 3 days post challenge, histamine concentration was higher in high responder lambs than in low responder lambs. Jones et al (1990) found a significant negative correlation coefficient (r = -0.46; P<0.05) between tissue histamine concentration and FEC at 28 days post challenge, while coefficients between histamine levels and EPG 21 days post challenge and worm counts (-0.35 and -0.28, respectively) did not reach significant levels. In the present study, these coefficients between histamine x worm burden (r = -0.164) and histamine x FEC (r = -0.300) were also negative and not significant.…”

“…Similarly, in a herd of young grazing sheep, blood histamine levels and intestinal content fluid were similar in sheep with high and low egg counts and higher during maximum challenge by larval nematodes of several species (Douch et al 1984). According to Jones et al (1990), duodenal tissue histamine concentrations in lambs bred selectively for high responsiveness or low responsiveness to vaccination with irradiated T. colubriforimis were lower at 3 days than at 28 days post challenge. At 3 days post challenge, histamine concentration was higher in high responder lambs than in low responder lambs.…”

Leukotrienes Play a Role in the Control of Parasite Burden in Murine Strongyloidiasis

“…In addition, we detected an increase in LTB 4 levels in duodena of infected-only mice, at the same time that worms are detected in this tissue. Increase in leukotrienes in intestine has been demonstrated in other nematode-infected animals (27)(28)(29). Impairment of leukotriene synthesis, by either pharmacologic or genetic means, clearly resulted in increased numbers of worms and eggs recovered from infected animals, reflecting increased larvae survival during their passage through the lung and duodena.…”

“…The importance of leukotrienes in controlling helminth parasite burdens is still unknown, and very little information is available on the subject. It has been shown that levels of leukotriene B 4 (LTB 4 ) and leukotriene C 4 (LTC 4 ) are elevated in the intestinal mucosa of lambs infected with Trichostrongylus colubriformis (27)(28)(29). The authors suggested that these lipid mediators are associated with larval rejection and exclusion.…”