Related Experiment Video

Updated: Aug 8, 2026

Ex vivo Expansion of Tumor-reactive T Cells by Means of Bryostatin 1/Ionomycin and the Common Gamma Chain Cytokines Formulation
07:20

Ex vivo Expansion of Tumor-reactive T Cells by Means of Bryostatin 1/Ionomycin and the Common Gamma Chain Cytokines Formulation

Published on: January 15, 2011

CD81 expressed on human thymocytes mediates integrin activation and interleukin 2-dependent proliferation

S C Todd1, S G Lipps, L Crisa

  • 1Department of Biology and Molecular Biology Institute, San Diego State University, California 92182-4614, USA.

The Journal of Experimental Medicine
|November 1, 1996
PubMed

Insights

CD81, or target of antiproliferative antigen (TAPA)-1, associates with T cell coreceptors in human thymocytes. This interaction promotes cell adhesion and costimulates T cell activation, suggesting a regulatory role in thymocyte development.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Biology

Background:

  • T cell receptor (TCR) and coreceptor signaling regulate lymphocyte adhesion and function.
  • CD81 (target of antiproliferative antigen [TAPA]-1) is a cell surface protein with known roles in cell proliferation and adhesion.

Purpose of the Study:

  • To investigate the expression and function of CD81 in human thymocytes.
  • To determine the association of CD81 with T cell coreceptors (CD4 and CD8).
  • To elucidate the role of CD81 in regulating thymocyte adhesion and activation.

Main Methods:

  • Immunohistochemistry to detect CD81 expression on human thymocytes.
  • Co-immunoprecipitation to assess the physical association of CD81 with CD4 and CD8 coreceptors.
  • Flow cytometry to measure integrin-mediated cell-cell adhesion (LFA-1) and T cell proliferation following CD81 ligation.

Main Results:

  • CD81 is expressed on human thymocytes and physically associates with CD4 and CD8 coreceptors.
  • Antibody-mediated ligation of CD81 rapidly induces integrin-mediated cell-cell adhesion via LFA-1.
  • Cross-linking CD81 acts as a costimulatory signal with TCR/CD3, leading to interleukin-2-dependent thymocyte proliferation.

Conclusions:

  • CD81 plays a significant role in regulating human thymocyte adhesion and activation.
  • A CD81-mediated signaling pathway contributes to the control of cell adhesion and immune cell activation during thymocyte development.

More Related Videos

Assessment of the Synaptic Interface of Primary Human T Cells from Peripheral Blood and Lymphoid Tissue06:27

Assessment of the Synaptic Interface of Primary Human T Cells from Peripheral Blood and Lymphoid Tissue

Published on: July 30, 2018

Evaluation of T Follicular Helper Cells and Germinal Center Response During Influenza A Virus Infection in Mice07:07

Evaluation of T Follicular Helper Cells and Germinal Center Response During Influenza A Virus Infection in Mice

Published on: June 27, 2020

Related Concept Videos

The JAK-STAT Signaling Pathway01:20

The JAK-STAT Signaling Pathway

Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as  SH2...
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
Immunoglobulin-like Cell Adhesion Molecules01:31

Immunoglobulin-like Cell Adhesion Molecules

Immunoglobulin-like cell adhesion molecules or Ig-CAMs are a versatile group of cell surface glycoproteins belonging to the immunoglobulin protein superfamily. Ig-CAMs possess the characteristic immunoglobulin protein domains and other domains such as the fibronectin type III domain. The Ig domains are glycosylated to varying degrees in different Ig-CAMs.
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
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...
T Cell Types and Functions01:24

T Cell Types and Functions

When T cells with CD4 markers are activated, they give rise to two types of effector cells: helper T cells and regulatory T cells. Meanwhile, T cells with CD8 markers differentiate into effector cytotoxic T cells. The differentiation of CD4 T cells into helper T cell subsets, such as Th1, Th2, and Th17 cells, is dependent on the antigen type, antigen-presenting cell, and regulatory cytokines.
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
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...