Semester

Spring

Date of Graduation

2024

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Division of Animal and Nutritional Sciences

Committee Chair

Scott Bowdridge

Committee Member

Jianbo Yao

Committee Member

Scott Greiner

Abstract

An excretory/secretory (E/S) product, common to many helminths, is neutrophil inhibitory factor (NIF) which negatively affects neutrophil migration and activity. Due to differences in neutrophil accumulation between parasite resistant St. Croix STC and parasite susceptible Suffolk (SUF) sheep, we hypothesized that Hc-NIF may inhibit migration of SUF and not STC neutrophils. Previous studies have demonstrated that Hc produces NIF but is not commercially available. To test our hypothesis, neutrophils were cultured from STC and SUF sheep in the presence of Ancylostoma caninum-derived NIF (Ac-NIF) and measure chemotaxis to Interleukin-8 (IL-8), HcLA or H. contortus third-stage excretory/secretory (E/S) products. Neutrophils were isolated then incubated with Ac-NIF (0.125μg/ml) or complete media for 1 hour. Neutrophils (1 x 106 cell/mL) were applied to cell migration inserts and placed into a reservoir containing HcLA (20μg/ml), HcL3E/S (20μg/ml), IL-8 (50ng/ml), or complete media. Migration plates were incubated (37°C, 5% CO2 ) for 24 hours, after which, migrating cells were quantified using fluorescence. AcNIF-incubated neutrophils inhibited migration towards IL-8 compared to untreated neutrophils (8.2% and 44.9%, respectively) (P = 0.0025) In response to HcLA, 64% of STC neutrophils migrated, versus 40.9% of SUF neutrophils (P

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