TH1 and TH2 cytokines mRNA levels in Brazilian Somalis crossbreed sheep resistant and suceptible to Trichostrongylus colubriformis infection.
2019
ZAROS, L. G. | COUTINHO, L. L. | NAVARRO, A. M. C. | NEVES, M. R. N. | BENVENUTI, C. L. | SIDER, L. H. | VIEIRA, L. da S.
Cytokines are proteins that play a central role in immune mechanisms involved in defense against gastrointestinal nematodes infections. The present study used the real-time PCR methodology to quantify Brazilian Somalis crossbreed sheep cytokines (IL-4, IL-13, TNF-? and IFN-?) in two groups: one resistant and other susceptible to Trichostrongylus colubriformis infection. From a Somalis sheep herd, 75 young animals were kept together on pasture without anthelmintic treatment for 4 months. The eight most resistant and the eight most susceptible animals were chosen based on the mean of fecal egg counts and slaughtered for recover the parasites and small intestine tissue samples collection. RT-PCR was performed using the LightCycler PCR and SYBR Green I dye. SDHA (succinate dehydrogenase complex subunit A) was used for normalization and the relative quantifi cation of genes was calculated by REST software. Resistant animals presented lower EPG counts than susceptible animals (1312,5 and 5081,6, respectively; P<0.0001) and 3 fold less specimens of Trichostrongylus colubriformis (P<0.05). Only IL-13 was up-regulated in resistant animals (P<0.02) and the other three genes analyzed, IL-4, TNF-? and IFN-? were down-regulated in this group, although not signifi cantly (P>0.05). IL-13 is a cytokine that stimulates the TH2 response, leading the host to quickly and effi ciently respond to the infection and contributes to the parasite expulsion. Although IL-4 acts together with IL-13 in this process, IL-13 is independent to eliminate the parasite for itself. It can be inferred that in the resistant animals a bias of TH2 type response was activated.
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