Summer Research Fellow, National Institutes of Health Medical Student Training Grant.
Marginal zone and germinal center development in the spleens of neonatally thymectomized and nonthymectomized young rats†
Version of Record online: 3 FEB 2005
Copyright © 1968 Wiley-Liss, Inc.
American Journal of Anatomy
Volume 123, Issue 3, pages 489–499, November 1968
How to Cite
Pettersen, J. C. and Rose, R. J. (1968), Marginal zone and germinal center development in the spleens of neonatally thymectomized and nonthymectomized young rats. Am. J. Anat., 123: 489–499. doi: 10.1002/aja.1001230306
This project received support from a General Research Support grant to the University of Wisconsin Medical School from the National Institutes of Health, Division of Research Facilities and Resources.
- Issue online: 3 FEB 2005
- Version of Record online: 3 FEB 2005
Spleens from neonatally thymectomized and nonthymectomized young rats were studied histologically and histochemically to elucidate the development of the splenic immune system with and without thymus.
In intact animals primitive germinal center activity could be elicited with antigen as early as 13 days of age. More definitive germinal centers lacking tingible body macrophages were observed at 18 days of age. Germinal centers containing tingible body macrophages did not develop until 35 days of age in response to antigenic stimulation. This coincided with maximal development of the marginal zone of medium-sized lymphocytes and the mature development of nodular macrophages possessing strong acid phosphatase activity.
Neonatally thymectomized rats developed marginal zones and germinal centers similar to control littermates when the young animals were maintained on tetracycline. Thymectomized animals not given tetracycline showed disturbances in splenic development. These are discussed.
The results suggest that the thymus may be critical to the immune system in rats from birth to about 30 days of age but is not essential to its function beyond this period. Marginal zone lymphocytes and germinal center cells proliferate normally and mature to the plasma cell stage in the absence of a thymus if the animals are maintained on tetracycline beyond this critical age.