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Updated: Aug 9, 2026
Killer Artificial Antigen Presenting Cells (KaAPC) for Efficient In Vitro Depletion of Human Antigen-specific T Cells
Published on: August 12, 2014
T cell antigen receptor engagement abrogates CD4-mediated T cell deletion in vivo
Z Q Wang1, A Dudhane, T Orlikowsky
1Department of Microbiology and Immunology, New York Medical College, Valhalla 10595, USA.
Abstract:
We have previously shown that the engagement of CD4 by specific antibody in the mouse initiates a T cell apoptosis response with the following features: spleen and lymph node CD4+ T cells migrate into the bloodstream within minutes of anti-CD4 administration where they exhibit the phenotype of null cells. If they are capable of expressing functional Fas protein on their surface they degrade their DNA and disintegrate rapidly. We show here that the engagement of the T cell antigen receptor blocks the CD4-mediated deletion process in mouse. Anti-CD4-reactive T cells avoid the exodus into the bloodstream when their TCR is engaged by anti-CD3 or by a superantigen, do not modulate surface receptors and are not deleted. In contrast to the apoptosis-inducing CD4-specific antibody which causes migration of lymphocytes from lymphoid organs into the blood stream, the T cell-activating CD3-specific antibody causes lymphoid cell redistribution in the opposite direction, from the bloodstream to lymphoid organs. The TCR-mediated protection of T cells against CD4-mediated deletion lasts for several hours but ceases before the T cells become blasts.
Insights
Engaging the T cell receptor (TCR) prevents CD4-mediated T cell deletion in mice. This TCR engagement blocks T cell migration and apoptosis, offering protection against immune system deletion.
Area of Science:
- Immunology
- Cell Biology
Background:
- Antibody engagement of CD4 in mice triggers T cell apoptosis.
- This process involves T cell migration to the bloodstream and DNA degradation via Fas protein.
Purpose of the Study:
- To investigate whether T cell receptor (TCR) engagement influences CD4-mediated T cell deletion.
- To understand the mechanisms of T cell protection against apoptosis.
Main Methods:
- Mice were administered anti-CD4 antibodies to induce T cell apoptosis.
- T cell responses were analyzed following co-engagement of TCR with anti-CD3 or superantigen.
- Lymphocyte migration patterns and surface receptor modulation were assessed.
Main Results:
- TCR engagement by anti-CD3 or superantigen prevented CD4-mediated T cell deletion.
- Anti-CD4-reactive T cells undergoing TCR engagement did not migrate to the bloodstream or undergo apoptosis.
- CD3-specific antibodies induced lymphocyte redistribution from blood to lymphoid organs, contrasting with anti-CD4 antibody effects.
Conclusions:
- TCR engagement provides a protective mechanism against CD4-mediated T cell deletion.
- This protection is transient, lasting several hours before T cells mature.
- The findings elucidate a novel regulatory pathway in T cell homeostasis and survival.
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