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Sheep lymphocyte antigens and scrapie.
Journal of Comparative Pathology
|July 1, 1984
Summary
Lymphocyte antigen frequencies in sheep were analyzed for scrapie resistance. No significant associations were found between specific antigens and scrapie susceptibility or resistance in the studied flocks.
Area of Science:
- Immunogenetics
- Veterinary Medicine
- Scrapie Research
Background:
- Scrapie is a transmissible spongiform encephalopathy affecting sheep.
- Genetic factors, including lymphocyte antigens, are investigated for their role in scrapie susceptibility.
- Two experimental flocks of Herdwick sheep, one bred for resistance (Blue Flock) and one for susceptibility (Red Flock) to scrapie, were utilized.
Purpose of the Study:
- To determine the frequencies of 15 lymphocyte antigens in two experimental sheep flocks.
- To investigate potential associations between lymphocyte antigen frequencies and scrapie resistance or susceptibility.
- To examine the Major Histocompatibility Complex (MHC) linkage with scrapie.
Main Methods:
- Lymphocyte antigen typing was performed on 158 sheep from the Red Flock and 51 sheep from the Blue Flock.
- Antigen frequencies were compared between the two flocks and within the Red Flock (scrapie-affected vs. healthy, experimentally infected vs. non-infected).
- Haplotype segregation analysis was conducted using Red Flock pedigrees.
Main Results:
- Marked frequency differences in lymphocyte antigens were observed between the Red and Blue flocks, attributed to genetic drift.
- No significant antigen frequency differences were found between sheep that developed natural scrapie and their healthy flockmates within the Red Flock.
- Experimental scrapie inoculation in Red Flock lambs showed no difference in antigen frequency between those that developed scrapie and those that did not.
- Analysis of antigen haplotypes provided no evidence of MHC linkage with either natural or experimental scrapie.
Conclusions:
- The studied lymphocyte antigens do not appear to be directly linked to scrapie susceptibility or resistance in this Herdwick sheep model.
- Genetic drift is a more likely explanation for observed antigen frequency differences between the experimental flocks.
- Further research may be needed to identify other genetic markers associated with scrapie in sheep.