, 1993). IL-4 and IL-13 are frequently studied because they may be the first genes to have increased DNA Damage inhibitor levels in response to extracellular
parasites, leading to Th2 polarization (Else and Finkelman, 1998) and resistance to animals (Zaros et al., 2010). In this study, the IL-4 mRNA levels in the abomasal lymph node of the infected group were up-regulated 14-fold in comparison to the control group (Fig. 2). Similar results were obtained by (Canals et al., 1997), who observed a significant up-regulation of IL-4 abomasal lymph node of Bos taurus cattle infected with O. ostertagi on the fourth day post primary infection, increasing gradually until the 28th day of infection. Claerebout et al. (2005) observed an increase in the expression of IL-4 and IL-10 in lymph nodes of immunized calves also infected with O. ostertagi, after 3 weeks of infection. In contrast, in the present study we found no difference in this interleukin in the abomasal mucosa, corroborating the results obtained by www.selleckchem.com/products/bgj398-nvp-bgj398.html ( Li et al., 2007) and contrasting with those of Lacroux et al. (2006), studying sheep (which are more sensitive to this nematode infection). IL-13 acts in parasitic infections to promote allergic response, mast cell increase and IgE production, among other reactions. In the present work, severe induction of IL-13 mRNA in abomasal lymph node was observed,
about 30 times higher in the infected than Mephenoxalone in the control group (Fig. 2). In the abomasal mucosa, IL-13 expressed the same pattern, with a fivefold increase in the infected group compared with the control group (Fig. 3). Bancroft et al. (1998), studying knockout mice for IL-13, observed susceptibility to T. muris infection as well as a decrease in the response of other Th2 cytokines, inhibiting the expulsion
of the parasites. An increase of IL-13 was also observed in sheep immunized and infected primarily with H. contortus ( Lacroux et al., 2006), showing this cytokine is essential in the protection against gastrointestinal nematode infection. In fact, some IL-4 and IL-13 functions are redundant, conferring protective response, resistance and expulsion of the parasites (Else and Finkelman, 1998). We showed that IL-13 had a strong up-regulation, in both tissues, indicating this cytokine could be a precursor of IL-4, stimulating its increase and probably the protective response in the early infection stage in Nellore cattle. This is possible because it has been found that IL-4 starts to increase in the fourth day post-infection of calves with O. ostertagi ( Canals et al., 1997). There is little data about this polarization in zebu cattle, but it is clear that both cytokines are expressed synergistically and are essential to control this infection.