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Updated: Aug 12, 2026
Isolation of Murine Lymph Node Stromal Cells
Published on: August 19, 2014
Close encounters of the first and second kind: T-DC and T-B interactions in the lymph node
Michael D Cahalan1, Ian Parker
1Department of Physiology and Biophysics and Center for Immunology, University of California, Irvine, CA 92697-4561, USA. mcahalan@uci.edu
Insights
Cellular interactions in lymphoid organs are key to immune responses. This review details T cell, B cell, and dendritic cell "close encounters" that drive immune activation and antibody production.
Area of Science:
- Immunology
- Cell Biology
- Microscopy
Background:
- Lymphoid organs orchestrate immune responses through cellular interactions.
- T lymphocytes, B lymphocytes, and dendritic cells (DCs) engage in dynamic
- close encounters
- within lymph nodes.
- Understanding these interactions is crucial for deciphering immune activation.
Purpose of the Study:
- To compare the activation choreography of CD4+ T cells.
- To elucidate the sequential interactions of CD4+ T cells with dendritic cells and B cells.
- To provide insights into the initiation of the humoral immune response.
Main Methods:
- Two-photon microscopy in lymph nodes.
- Observation of T cell, B cell, and DC motility and interactions.
- Analysis of cellular activation stages, from transient interactions to stable clusters and proliferation.
Main Results:
- The first
- close encounter
- : T cells interact with antigen-bearing DCs, initiating T cell activation (CD4+ and CD8+).
- Activation progresses through stages: transient interactions, stable clusters, dissociation, and clonal expansion.
- The second
- close encounter
- : Antigen-engaged B cells migrate to the follicle edge, interacting with T cells.
- Helper T cells provide signals for B cell differentiation into plasma cells.
Conclusions:
- CD4+ T cell activation involves distinct sequential interactions with DCs and B cells.
- This choreography is fundamental to initiating the humoral immune response.
- The study highlights the dynamic nature of cellular interactions in adaptive immunity.
Abstract:
Cellular interactions in lymphoid organs initiate the immune response and determine its outcome. Using two-photon microscopy in the lymph node, several groups have begun to investigate the motility characteristics and interactions among T lymphocytes, B lymphocytes, and dendritic cells (DC) in lymphoid organs. In the first "close encounter", T cells of a particular antigen specificity interact with antigen-bearing dendritic cells and begin to activate. Activation of both CD4+ and CD8+ T cells evolves through several stages; from transient interactions to stable clusters and later to dissociation and proliferation of T cells (clonal expansion). The second "close encounter" requires that antigen-engaged B cells become accessible to T cells by directed migration to the edge of the follicle. T cells and B cells then pair up and waltz together for an extended period, while helper T cells provide signals for B cells to differentiate into plasma cells. In this topical review, we compare the activation choreography of CD4+ T cells interacting first with dendritic cells, and then with B cells, during initiation of the humoral immune response.
