| Sign In to gain access to subscriptions and/or personal tools. |
The Incidence of Thymic B Lymphoid Follicles in Healthy Beagle DogsDepartment of Toxicology and Drug Disposition, NV Organon, Oss, The Netherlands, Jan-peter.ploemen{at}organon.com
Department of Toxicology and Drug Disposition, NV Organon, Oss, The Netherlands
Department of Toxicology and Drug Disposition, NV Organon, Oss, The Netherlands
The incidence of thymic B cell lymphoid follicles was retrospectively studied in 62 male and 58 female healthy control beagle dogs (age 11.3 ± 4.8, range 6 to 23 months). The animals were selected from toxicological studies performed in the period 1990—2001 at the Organon labs. The animals had received vehicle treatment. Thorough microscopic examination of the thymus in hematoxylin & eosin (H&E)-stained sections resulted in an unexpectedly high overall incidence of 70% of medullary lymphoid follicles. Occasionally, these lymphoid follicles contained germinal centers. With the use of a T- and B cell marker (respectively CD3 and CD79
Key Words: Thymus • canine • lymphoid follicles • germinal center • B lymphocyte • immunohistochemistry.
Toxicologic Pathology, Vol. 31, No. 2,
214-219 (2003) |
|
||
 |
|
|
 |
|
Sign In to gain access to subscriptions and/or personal tools.
) we confirmed that the lymphoid follicles exclusively contained large numbers of B lymphocytes. Moreover, with the use of the B cell marker, almost all animals (97%) prove to have B cell rich medullary areas. The study also confirmed that the dog thymus underwent progressive involution during the period from 6 to 23 months of age. As a consequence of the involution, B cell areas and lymphoid follicles may be obscured in some H&E sections. Results of this study indicated that dense B lymphocyte aggregates and/or B lymphoid follicles are a normal constituent of the canine thymus.