Identifier

etd-04022014-111815

Degree

Master of Science (MS)

Department

Biomedical and Veterinary Medical Sciences - Veterinary Clinical Sciences

Document Type

Thesis

Abstract

ABSTRACT Objectives – To characterize the response of horse skin following intradermal injection of polyclonal rabbit anti-canine IgE (anti-IgE) and rabbit immunoglobulin G (IgG) in an attempt to develop a model of equine allergic skin disease. Study design - In vivo study. Animals – 10 Adult Thoroughbred horses. Methods –Horses were injected intradermally with one of two different concentrations of anti-IgE and rabbit immunoglobulin G (IgG). Wheal measurements and injection site biopsies were obtained before and 20 min, 6 hr, 24 hr, and 48 hr after injection. Tissue sections were stained with Hematoxylin and Eosin, Luna, and Toluidine Blue. Immunohistochemistry for CD3+, CD4+, and CD8+ cells was performed. Cells were counted in 1 mm2 of dermis and divided over four depths for standard stains: superficial dermal, superficial follicular, deep follicular, and deep follicular to adnexal. The superficial dermis was evaluated in immunohistochemistry sections. Results – Lower concentrations of anti-IgE produced suboptimal responses, so the higher concentration injections were evaluated. Anti-IgE wheals were significantly larger than IgG wheals at 20 min, 6 hr, and 24 hr after injection. Anti-IgE injected skin had significantly more degranulated mast cells than IgG injected skin and there were significantly more inflammatory cells (6 hr, 24 hr), eosinophils (6hr, 24hr, 48hr), and neutrophils (6 hr). Eosinophil counts significantly increased in anti-IgE samples in the deeper but not superficial dermis when compared to IgG samples. There were more eosinophils in the deeper dermis of anti-IgE injected skin. There were no significant differences between anti-IgE and IgG injected skin for CD3+, CD4+, or CD8+ cells. Conclusion - Injection of anti-IgE antibodies at a higher concentration was associated with the development of gross and microscopic inflammation that was characterized by mast cell degranulation and accumulation of inflammatory cells, particularly eosinophils and neutrophils. This pattern was similar to that seen in horses with spontaneous allergic skin disease, although lymphocytes were not increased. Clinical Relevance - This study documents the response to intradermal anti-IgE injection in horses and demonstrates the potential use of this model for studying equine allergic skin disease.

Date

2014

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Andrews, Frank M

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