, 2010). However, no differences between infected and control groups were observed for these cells in the present trial ( Fig. 1). This might be due to the short period of infection, only 7 days. In cattle infected with O. ostertagi it is known that cells accumulate after adult worms are present for 1 or 2 days in the abomasum ( Scott et al., 1998 and Simpson, 2000). In the present work, infection was caused by larvae and abomasums were obtained 7 days after infection, a period when most of the larvae should be in L4 stage, which marks the beginning of the hematophagous phase and is expected to stimulate host protective response. From our results, it was demonstrated that, in
animals that had not been exposed to H. placei beforehand, this period of time was not enough to deflagrate local response in the mucosa. For the other genes evaluated (IL-2, IL-8, IL-12, IFN-γ and MCP-1), as well as PDGFR inhibitor for pepsinogen and lysozyme no difference in mRNA profile was observed in any of the tissues studied.
As in this work, infections with H. placei, Cooperia spp. and Ostertagia spp. were found not to be associated with changes in the levels of IL-8 ( Li et al., 2007, Bricarello et al., 2008 and Zaros et al., 2010). Nevertheless, variations were reported for some of these genes, mTOR inhibitor as in the work by Li et al. (2007), which concluded that IL-2, IFN-γ and IL-12 were responsible for conferring resistance to Angus heifers infected with O. ostertagi. Other evidence for the involvement of these genes in response to parasite has been found in Nellore cattle infected with H. placei, where a strong Th2 profile was detected in resistant
animals ( Zaros et al., 2010). In conclusion, we suggest that IL-4 and IL-13 initiate the immune response in the abomasal lymph nodes and abomasal mucosa in the first infection of naïve Nellore calves with H. placei, evidencing a possible initial Th2 polarization. It may be possible that TNF-α helps in this polarization and that this cytokine is modulated by the parasite. In contrast, no significant increase in eosinophils and mast cells was detected, indicating that the local inflammatory response to H. placei occurs later during the infection of Bos indicus Nellore calves. We thank Dr. Ivo Bianchin, most of the Embrapa Beef Cattle Research Center, for providing the larvae and Dr. Rogério Taveira Barbosa and Dr. Rui Machado for taking care of calves. This work was financially supported by Prodetab and Embrapa. We thank CAPES for providing scholarships to AMGI and LCN and CNPq for fellowships to LLC and LCAR. “
“Species of Trichuris Roederer, 1791 (Nematoda: Trichuridae) have worldwide distribution ( Cafrune et al., 1999). The genus Trichuris comprises parasites of medical and veterinary importance ( Bundy and Cooper, 1989 and Grencis et al., 1993) because it can parasitize different species, among them humans, primates, pigs, dogs, sheep, goats, cattle and rodents.