Influence of stage of the reproductive cycle and estradiol on thymus cell antigen presentation

Charles R Wira1, John V Fahey, Vikki M Abrahams

  • 1Department of Physiology, Dartmouth Medical School, Lebanon, NH 03756, USA. charles.r.wira@dartmouth.edu

The objective of this study was to determine whether thymus cells present antigen and if endocrine balance influences antigen presentation. We report here that antigen presenting cells (APC) from the thymus glands of male and female rats, when incubated with ovalbumin (OVA)-specific T cells and OVA, are functionally able to present antigen via MHC class II. To determine whether antigen presentation in the thymus is under hormonal control, tissues from female rats at different stages of the estrous cycle were analyzed. Antigen presentation was higher at estrus and proestrus than that seen at diestrus when estradiol levels are low. Estradiol given to ovariectomized animals for 3 days stimulated antigen presentation by adherent thymus cells compared to saline controls. Flow cytometry studies indicated that the adherent thymus cell preparations consisted of DC, T cells, B cells and cells of the myeloid lineage all of which expressed MHC class II, as did a small population of non-leukocytes. Antibody neutralization studies indicated that thymus cell antigen presentation involves the expression of transmembrane proteins B7.1 and B7.2. These studies demonstrate that sex hormones play a central role in regulating antigen presentation in the thymus.

Related Concept Videos

T Cell Activation and Clonal Selection01:22

T Cell Activation and Clonal Selection

T cells are integral to our adaptive immune system, recognizing and effectively responding to foreign antigens. T cell activation and clonal selection are pivotal in orchestrating this immune response. This article elucidates these mechanisms, detailing the roles of cluster of differentiation (CD) markers, major histocompatibility complex (MHC) molecules, costimulatory signals, and the process of clonal selection.
Naive T cells that have not yet encountered an antigen express two primary CD...
Development of Immunocompetence01:22

Development of Immunocompetence

The initiation of cell-mediated immunity can be observed as early as the third month of fetal growth, with active antibody-mediated immunity following approximately one month later.
The initial cells that migrate from the fetal thymus settle within the skin and epithelial tissues lining the mouth, digestive tract, and in females, the uterus and vagina. These cells, including skin-based dendritic cells, serve as antigen-presenting cells, playing a key role in T cell activation.
Subsequent T...
B Cell Activation and Differentiation01:24

B Cell Activation and Differentiation

The adaptive immune response, a sophisticated defense mechanism, relies on the activation and differentiation of B lymphocytes, or B cells. These processes enable our bodies to mount a tailored response against specific pathogens such as bacteria, free virus particles, toxins, and parasites.
When naive B cells encounter a specific antigen that can bind to the B cell receptor (BCR) on their surface, they undergo sensitization to respond to the antigen's presence. Sensitization begins with...
Cells of the Adaptive Immune Response01:23

Cells of the Adaptive Immune Response

The T and B lymphocytes of the adaptive immune system develop from common lymphoid progenitor cells in the bone marrow. These progenitors give rise to precursors that eventually develop into both T and B lymphocytes. As these precursors mature, they gain the ability to detect and respond to foreign antigens in the body, a process known as immunocompetence. Additionally, these precursors acquire self-tolerance, a process that ensures they do not react to self-antigens. This intricate system...
Antigen Presenting Cells01:22

Antigen Presenting Cells

The immune system is a complex network of cells and molecules that protects the body from foreign invaders. T cells, a type of white blood cell, play a crucial role in this process. They recognize and attack foreign substances, such as pathogens, that enter the body.
T cells require the help of antigen-presenting cells (APCs), which process foreign antigens into smaller fragments that can be recognized by T cells. These APCs are highly specialized cells that efficiently internalize antigens...