Role of IFN-γ and IL-10 cytokines and associated genes on Haemonchus contortus infection in resistant and susceptible Garole sheep.

Role of IFN-γ and IL-10 cytokines and associated genes (IFN-γ and IL-10) on Haemonchus contortus resistance was studied in experimentally infected resistant and susceptible Garole sheep. Nine resistant and nine susceptible Garole sheep were selected based on faecal egg counts (FEC) and divided into 3 groups; uninfected control (n = 6), infected resistant (n = 6) and infected susceptible (n = 6). Sheep of infected groups were orally challenged with 500 H. contortus infective larvae per kg body weight of experimental sheep. Faecal egg counts were measured from 18 days post infection (DPI) at 3 days intervals for nine occasions, and plasma cytokines (IFN-γ and IL-10) concentration and expressions of cytokine genes (IFN-γ and IL-10) expressions were measured from 0 DPI to 40 DPI at 10 days intervals. Resistant sheep had significantly (P < 0.001) lower FEC from 27 DPI onwards compared to susceptible sheep and subsequently no eggs were found in resistant sheep from 33 DPI onwards. In resistant sheep, significantly higher concentration of IFN-γ cytokine and expression of IFN-γ gene were observed at early stage (10-20 DPI), and IL-10 cytokine production and IL-10 gene expression upregulated at later stage of infection (20-30 DPI) after which there was significant reduction of egg output in faeces of resistant group of sheep. Hence in Garole sheep both the IFN-γ and IL-10 cytokines and their associated genes might be linked with H. contortus resistance with IL-10 cytokine gene playing comparatively more active role in development of resistance to H. contortus.