title: Age Difference in Morphology and Immunohistology inthe Thymus and Spleen in Crl:CD (SD) Rats.
abstract: We investigated chronological changes in immunohistochemical phenotyping in the thymus and spleen in Crl:CD rats up to the age of about one year. In the thymus, T cells increased markedly from 3 to 4 weeks of age. Proliferating cells also increased markedly at these points. B cells tended towards an increase with age. In the spleen, white pulp increased until 9 weeks of age and remained fairly stable thereafter. In the periarteriolar lymphoid sheath and marginal zone, T cells gradually increased until 9 weeks of age and became almost flat thereafter. In the lymph follicle, T cells increased with age. B cells tended towards an increase with age in all areas of the spleen. It was concluded that development of the thymus was most marked from 3 to 4 weeks of age and that both the thymus and spleen had matured by 9 weeks of age.
authors.affiliation: Drug Safety Research Laboratories, Shin Nippon Biomedical Laboratories, Ltd., 2438 Miyanoura, Kagoshima 891-1394, Japan.
authors.forename: Rinya
authors.initials: R
authors.lastname: Kodama
authors.forename: Takanobu
authors.initials: T
authors.lastname: Okazaki
authors.forename: Tamio
authors.initials: T
authors.lastname: Sato
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Iwashige
authors.forename: Yohei
authors.initials: Y
authors.lastname: Tanigawa
authors.forename: Junko
authors.initials: J
authors.lastname: Fujishima
authors.forename: Akiko
authors.initials: A
authors.lastname: Moriyama
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Yamashita
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kamimura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maeda