Date of Graduation

12-2016

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor

Gisela F. Erf

Committee Member

Nicholas B. Anthony

Second Committee Member

Charles F. Rosenkrans

Keywords

Biological sciences; Health and environmental sciences; Cell-mediated immunity; Chickens; Phytohemagglutinin

Abstract

Phytohemagglutinin (PHA) is commonly used to gain insight into an individual’s cellular immuno-competence. PHA is typically injected intradermally (i.d.) into the skin (e.g. wing web) and the tissue swelling response is then monitored, whereby the extent of the swelling positively relates to the individual’s cellular immune system capabilities. Although i.d. injected PHA was shown to stimulate mononuclear cell- and basophil-infiltration to the site of injection, reports on temporal, qualitative and quantitative aspects of the local PHA response are limited. The objective of this study was to use the growing feather (GF) as a cutaneous test-site to assess and monitor the type and relative amounts of leukocytes present in the pulp of GFs following i.d. injection of PHA. Two studies were conducted: Study I was carried out in non-vaccinated chickens in the Poultry Health Laboratory; Study II in vaccinated chickens reared at the Poultry Research Farm. For both studies, the pulp of 21 GFs per chicken were injected with 10 µL of either diluent (PBS) or 300 µg/mL PHA-P (10 chickens/Study). GFs were collected from each chicken before- (0) and at 0.25, 1, 2, 3, 4, 5, and 7 d post-injection. At each time-point, one GF was used for immunofluorescent staining of pulp cell suspensions and leukocyte population analysis by flow cytometry, and another GF for histological analysis (Study I). Both studies revealed predominant infiltration of CD4+ T cells and αβ T cells in PHA-injected GFs, with elevated levels observed within 6 h and throughout the 7 d post-injection. B cells and γδ T cells also infiltrated in response to PHA although at lower levels than CD4+ T cells. This is the first report describing time-course and phenotype of leukocytes, especially CD4+ T cells, participating in the PHA response and further affirms this polyclonal response as an indicator of cell-mediated immunoresponsiveness.

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