Effects of T-2 toxin on vaccinal immunity against Marek's disease and on the immune system of white ...

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" Effects of T-2 toxin on vaccinal immunity against Marek's disease and on the immune system of white leghorn chickens "
E. Kufuor-Mensah

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1113194
Doc. No	:	TLpq304257352
Main Entry	:	E. Kufuor-Mensah
Title & Author	:	Effects of T-2 toxin on vaccinal immunity against Marek's disease and on the immune system of white leghorn chickens\ E. Kufuor-Mensah
College	:	Michigan State University
Date	:	1996
student score	:	1996
Degree	:	Ph.D.
Page No	:	184
Abstract	:	Four trials were conducted to determine the effects of T-2 toxin on vaccinal immunity against Marek's disease (MD). Day-old, RPRL line 15I5 x usd7\sb1usd chicks were treated daily for seven days via crop gavage with T-2 toxin at a subclinical dose of 1.25 mg/kg body weight. Treated and untreated chicks were vaccinated with herpesvirus of turkeys (HVT) at hatch and challenged with JM strain of MD virus (MDV) at 8 days of age. Chickens were tested for HVT and MDV viremia and were observed for the development of MD lesions within 8 weeks of age. T-2 toxin significantly reduced body weight by 7 days after treatment. T-2 toxin shortened the incubation period for the development of MD lesions and mortality, but only in unvaccinated, challenged chickens. T-2 toxin also significantly reduced titres of HVT viremia within 7 days post-vaccination. However, the percent protection from MD in T-2 toxin-treated, HVT-vaccinated chickens ranged from 82%-95% and was comparable to that in untreated chickens (89%-100%). In a second experiment, the effect of T-2 toxin on peripheral blood and splenic B- and T-lymphocyte subpopulations was evaluated using flow cytometry. Day-old, 15I5 x usd7\sb1usd chicks were treated daily for 7 days via crop gavage with T-2 toxin at a subclinical dose of 1.25 mg/kg body weight. Peripheral blood and splenic lymphocytes from T-2 toxin-treated and untreated control chicks were analysed for phenotypic expression of CD4, CD8, CD3 and IgM cell surface markers at 8-9, and 21-22 days of age. The percentages of both peripheral blood and splenic B-lymphocytes in T-2 toxin-treated chickens were significantly lower than that in untreated chickens but only at 8-9 days of age. However, at 21-22 days of age the percentages of B- and T-lymphocytes were comparable to untreated chickens. The data suggest that exposure of chickens to T-2 toxin may influence the development of (a) HVT viremia; and (b) MD lesions and mortality, but only in unvaccinated chickens. The data also suggest that T-2 toxin may severely deplete B-lymphocytes and relatively increase CD4 and CD3 T-lymphocytes.
Subject	:	Animal diseases
	:	Biological sciences
	:	Health and environmental sciences
	:	Immunology
	:	Pathology
	:	Toxicology