IQI/Jic mice have thymic B cells.
The thymus of IQI/Jic mice aged 3 to 15 months was studied chronologically by flow cytometry and immunohistochemistry. Thymic B cells (Thy B) expressing the surface marker B220+IgM+ were detected in both sexes, but were more prominent in females. Thy B appeared as early as 4 months of age in female mice, and the incidence of Thy B-positive mice and average Thy B ratio in thymocytes increased with age, reaching over 90% and 15%, respectively, after 9 months of age. In males, Thy B-positive animals appeared around 9 months of age and its incidence and average ratio increased gradually to 53% and 5%, respectively, at 15 months. The Thy B-rich thymus was thickened with cortical atrophy and medullary hyperplasia. Small- to medium-sized Thy B crowded and often formed follicle-like structures in the medulla. When mice of various ages were injected with mercuric chloride to induce antinucleolar antibody, many Thy B-rich animals could not develop the antibody, implying that these animals are immunologically impaired. IQI/Jic can be a novel strain to elucidate the relationship between the presence of Thy B and disorders of the immune system.
Laboratory of Experimental Toxicology, National Institute of Industrial Health, Kawasaki, Japan.
J
J
Saegusa
A
A
Yasuda
H
H
Kubota
D000375:Aging; D000818:Animals; D000974:Antibodies, Antinuclear; D001402:B-Lymphocytes / Q000737:chemistry / Q000166:cytology*; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D007150:Immunohistochemistry / Q000379:methods; D018655:Lymphocyte Count; D008297:Male; D008627:Mercuric Chloride; D051379:Mice; D012727:Sex Characteristics; D013950:Thymus Gland / Q000737:chemistry / Q000166:cytology* / Q000254:growth & development
D000974:Antibodies, Antinuclear; D008627:Mercuric Chloride