Parasitological and immunological response to Haemonchus contortus infection: Comparison between resistant Garole and susceptible Sahabadi sheep.

Parasitological and immunological responses to the experimentally induced Haemonchus contortus infection were compared between Garole and Sahabadi breeds of sheep. The experiment was conducted in a 2 (breed) × 2 (infection status) factorial arrangement with a completely randomised design. Two breeds of sheep were divided into infected (n = 10) and control (n = 6) groups, and the infected groups were orally infected with H. contortus (500 stage 3 larvae per kilogram of body weight). Faecal egg counts (FEC) were determined from 18 days post infection (DPI) at 3-day intervals until 42 DPI. Average daily body weight gain, packed cell volume (PCV), concentrations of serum immunoglobulin (Ig) G1, IgG2, IgE and peripheral eosinophil count were measured at 14-day intervals from 0 to 42 DPI. Lymphocyte proliferation in response to somatic antigen of H. contortus was determined by in vitro lymphoproliferation assay, and concentrations of interferon gama (IFN-γ) and interleukin 4 (IL-4) in lymphocyte culture supernatant were measured at 14-day intervals until 42 DPI. Variables were analysed using the repeated measures mixed model procedure over DPI. Faecal egg count was significantly (p < 0.01) lower in Garole sheep than Sahabadi sheep and no faecal eggs were detected in the infected Garole sheep on 30 DPI. Infected Garole sheep had significantly (p < 0.05) higher body weight gain and PCV% than the infected Sahabadi sheep. In the infected Garole sheep, serum Ig except IgE increased significantly (p < 0.05) compared to infected Sahabadi sheep. On 28 DPI, peripheral eosinophil number, in vitro lymphoproliferation as well as concentrations of IFN-γ and IL-4 in culture supernatant were significantly (p < 0.05) higher in the infected Garole sheep than in the infected Sahabadi sheep. Parasitological observations indicated that Garole sheep were resistant to H. contortus and they exhibited greater cellular as well as humoral immune responses compared to Sahabadi sheep.

Antigenic Cross-reactivity among Haemonchus contortus, Oesophagostomum columbianum and Trichuris ovis of Goat.

BACKGROUND: Cross antigenicity is the major problem in developing a reliable tool for immunodiagnosis and immunoprophylaxis of parasitic diseases. Mixed infection due to different types of gastrointestinal parasites is more common than single species infection under field condition. METHODS: The present study was undertaken to detect antigenic cross-reactivity among Haemonchus contortus, Oesophagostomum columbianum and Trichuris ovis of goats by SDS-PAGE and western blot analysis using hyperimmune sera (HIS) rose in rabbit separately against the antigens of the three nematode species. RESULTS: Thirteen, 16 and 14 polypeptides in crude somatic antigen (CSAg) of H. contortus (CSAg-Hc), O. columbianum (CSAg-Oc) and T. ovis (CSAg-To), respectively, were resolved in SDS PAGE analyses. It was revealed that 54 kDa peptide was shared by H.contortus and O. columbianum, whereas 47 kDa peptide was shared by O. columbianum and T. ovis. Western blot analyses revealed that three immunogenic polypeptides (MW 54, 49 and 42 kDa) in CSAg-Hc, five in CSAg-Oc (54, 47, 44, 38 and 35.5 kDa) and CSAg-To and five polypeptides (90, 51, 47, 39.5 and 31 kDa) in CSAg-To cross-reacted with the heterologous HIS. Four species-specific immunoreactive polypeptides (92, 85, 65 and 39 kDa) of H. contortus and two (72 & 26 kDa) in O. columbianum were also identified in the study. CONCLUSION: The shared polypeptides and species-specific polypeptides might be evaluated as protective antigen and subsequently exploitation for developing immunodiagnostic and for immunoprophylactic tools of for these common nematode species.