The role of the thymus in the enhancement of humoral immunity by estrogen

Previous investigators have observed that estrogen enhances humoral immune responsiveness. The goal of this thesis has been to establish a physiological in vivo model in which to study this phenomenon and to characterize the role of the thymus as its mediator. An immunizing dose of 0.25 mg fluorescein conjugated to keyhole limpet hemocyanin was found to distinguish between the anti-fluorescein responses of ovariectomized adult Lewis rats with and without estrogen replacement. This dose of immunogen was then administered to adult ovariectomized rats given physiological estrogen replacement by means of chronic subcutaneous implant and of subcutaneous injections every four days, in a factorial fashion. The four-day injection regimen of estradiol exposure, which replicates the levels and profile of serum estradiol of the rat estrous cycle, exerted a greater immunoenhancing influence than the chronic estradiol implant treatment. The cyclic regimen of estrogen replacement was used to test by factorial design the effect of thymectomy against estradiol administration in enhancing anti-fluorescein titers. It was determined that an intact thymus is required for the enhancement of in vivo humoral immune responsiveness to be observed, although receptors for estrogen in thymic tissue, when sought, could not be found. It was then determined by replacing factorially estradiol and thymosin fraction 5 (1 mg/Kg) in ovariectomized-thymectomized adult rats that estrogen increased anti-fluorescein titers only in animals given thymosin injections. These studies conclude that the thymus does not directly mediate enhanced humoral immune responsiveness by estrogen, but permits this effect of estrogen by the provision of a constitutive factor which is a component of thymosin fraction 5.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Molecular and Integrative Physiology

Grantor

University of Illinois at Urbana-Champaign

Date dc:date

10000-01-01

Author dc:creator

• Erbach, Gregory Thomas

Contributors dc:contributor

• Bahr, Janice M.

• Biology, Animal Physiology
• Health Sciences, Immunology

Statement dc:rights

• Copyright 1989 Erbach, Gregory Thomas

Language dc:language

eng

Identifier

AAI9010853
(UMI)AAI9010853

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/19826