Quantification and expression studies of IL-13 gene in response to experimental infection with Haemonchus contortus...

To evaluate the role of IL-13 gene in Garole/Sahabadi sheep against resistant/susceptibility to Haemonchus contortus five Garole sheep (Group I) with consistently showing low egg per gram of faeces (EPG) (≤150) and another five Garole sheep (Group II) with high EPG (≥500) were selected and fed orally with active H. contortus third stage (L₃) larvae at the dose rate of 500 larvae/kg body weight. Five Sahabadi sheep (Gr-III) known susceptible to H. contortus were also challenged with the same dose as the previous groups. Blood was collected from each group on day 0, 7 and 14days post infection (dpi). The serum level of IL-13 cytokine was evaluated by ELISA at different days of post infection. The ovine IL-13 was partially isolated and the RNAm level of IL-13 expression was studied by real-time PCR at different days post infection. In the resistant Garole sheep (Gr-I) the concentration of IL-13 cytokine increased significantly (P≤0.05) 14days PI compared to susceptible Garole (Gr-II)/Sahabadi (Group-III). In similar way the relative expression of IL-13 in group I (Gr-I) was found more than seven fold higher than Gr-II and Gr-III on 14 dpi. The Th₂ type immune response to H. contortus characterized by higher serum level of IL-13 cytokine and IL-13 gene expression indicated that IL-13 gene plays a vital role for the reduced establishment and/or survival of established H. contortus in resistant Garole sheep.