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The effect of cortisone acetate on specific cell mediated immunity in mice was investigated using contact sensitivity to oxazolone. A long-acting cortisone acetate preparation was found to be much more effective than a soluble preparation in suppressing temporarily the recall response to oxazolone. The long-acting preparation was also effective in inhibiting the induction of sensitivity when injected before (but not after) oxazolone. Removal of the thymus either before or after sensitization did not significantly enhance the effects of cortisone acetate, and it is therefore suggested that cortisone acetate acts independently of the thymus-derived lymphocyte population. [ABSTRACT FROM AUTHOR]

Normal, 'deprived' (thymectomized, irradiated, bone marrow injected) and 'reconstituted' (thymectomized, irradiated, bone marrow injected, thymus grafted) CBA mice have been tested for their ability to respond to the contact sensitizing agent, oxazolone. The test involved painting the ear of a previously sensitized animal and subsequently measuring alterations in ear thickness. .A sensitized condition could be detected in the normal and reconstituted mice after either one or two sensitizing contacts with oxazolone but in the deprived animal little or no sensitivity could be detected. It is concluded, that the thymus influences the development of contact sensitivity probably by provision of a population of reactive cells. [ABSTRACT FROM AUTHOR]

Thymus was labelled in vivo by injecting newborn C3H/Bi mice with three or four doses of 2 μc of [3H]thymidine. The labelled thymus was grafted into the kidney capsule of 22-25-day-old intact and thymectomized syngeneic recipients which were killed 18, 41 or 42 days later. The grafts and lymphoid tissue were sectioned and examined by autoradiography after exposure times of up to 26 weeks. Small and medium labelled lymphocytes were seen in the thymus-dependent areas of the lymph nodes and spleen of all recipients provided the sections were exposed for a sufficiently long period. More labelled cells were seen in recipients killed at 18 days than at 41 or 42 days after grafting. It was concluded that these cells were the direct descendants of those cells labelled in the graft. There was no evidence of re-utilization of the isotope label. Most of the cells originally labelled in the graft either lost their label by multiple divisions or were replaced by unlabelled cells; although the epithelial-reticular cells remained heavily labelled. The importance of this last finding is discussed. [ABSTRACT FROM AUTHOR]

The article presents a study, where comparing the effects of neonatal thymectomy on New Zealand Black (NZB) mice, he possible role of thymus in autoimmune disease was discovered. The neonutally thymectomized NZB mice, in common with those of other strains, showed lethal wasting, a lymphocyte deficit in their lymphoid organs and blood, their packed cell volume was reduced and some had liver lesions associated with the hepatotrophic virus MHV-l. Although germinal centers develop and plasma cells occur in the lymphoid organs of most thymectomized mice, the striking feature of the NZB mice was the large number, size and activity of the germinal centers that persisted after thymectomy.