Submitted to: National Animal Disease Center Virtual Conference
Publication Type: Abstract Only
Publication Acceptance Date: May 28, 1997
Publication Date: N/A
Technical Abstract: The mucosal immune system is the first line of immunological defence against Ostertagia ostertagi (Oo), a gastric nematode responsible for considerable economic losses in cattle, but data on gastric mucosal populations are very limited. Characterization of surface marker phenotypes of gastric lamina propria lymphocytes (LPL) and analysis of the cytokine pattern developed in cattle experimentally infected with Oo were the focus of this study. Cell surface phenotype of LPL from control animals (non infected calves) and animals after a non-protective primary infection with Oo were analyzed by indirect immunofluorescence staining. Quantification of mRNA levels of several T cell cytokines (IL2, IL4, IL10 and IFN- gamma) was analyzed by competitive reverse transcriptase polymerase chain reaction (competitive RT-PCR). Within 10 days of infection, previously naive calves showed a rapid increase in the percentage of gamma delta-T cells (WC1+), B cells (IgM+) and activated cells (IL2R+). Analysis of RNA from the same animals, showed message for IL4 and IFN-gamma were elevated. However, by 60 days after infection, the percentage of cells bearing surface markers was comparable to preinfection levels, and mRNA's for IL4, IFN-gamma and IL10 were increased. These results suggest that in the first days of infection, fourth-stage larvae, in the gastric glands, induce important changes in cell surface phenotype and cytokine gene expression of mucosal lymphocytes. Within two months of infection, the induction of the anti-inflammatory cytokine IL10 may have a role in the return to a normal mucosal lymphocyte profile.