The microanatomy of T‐cell responses

Abstract

The priming of a T cell results from its physical interaction with a dendritic cell (DC) that presents the cognate antigenic peptide. The success rate of such interactions is extremely low, because the precursor frequency of a naive T cell recognizing a specific antigen is in the range of 1:10(5)-10(6). To make this principle practicable, encounter frequencies between DCs and T cells are maximized within lymph nodes (LNs) that are compact immunological projections of the peripheral tissue they drain. But LNs are more than passive meeting places for DCs that immigrated from the tissue and lymphocytes that recirculated via the blood. The microanatomy of the LN stroma actively organizes the cellular encounters by providing preformed migration tracks that create dynamic but highly ordered movement patterns. LN architecture further acts as a sophisticated filtration system that sieves the incoming interstitial fluid at different levels and guarantees that immunologically relevant antigens are loaded on DCs or B cells while inert substances are channeled back into the blood circulation. This review focuses on the non-hematopoietic infrastructure of the lymph node. We describe the association between fibroblastic reticular cell, conduit, DC, and T cell as the essential functional unit of the T-cell cortex.

Materials engineering for immunomodulation

“…Dendritic cells and B cells reside in the lymph nodes, and T cells traffic through the paracortical region, the architecture of which is optimized for rapid cell trafficking to help naive T cells to make contact with thousands of dendritic cells to find their APC partners 9 . Immature dendritic cells patrol peripheral tissues and then migrate to the lymph nodes after they take up antigen, but the lymph nodes also contain many immature dendritic cells that constantly sample antigens carried through the lymph nodes by lymph drained from the peripheral tissues; the latter population of dendritic cells may function mainly for the purpose of maintaining tolerance 4 .…”

Effects of autotransplanted lymph node fragments on the lymphatic system in the pig model

“…Studies with LN transplantation alone and in combination with growth factor therapy showed an improvement of lymphedema after lymphadenectomy in mice [18]. These results are not unexpected, since a role of LN in the regulation of peripheral fluid homeostasis is obvious [19]. The preventive effects of residual LN was shown recently and was obvious since the biopsy of the sentinel lymph node only reduced the occurrence of lymphedema [20].…”

Reaction-Diffusion Modelling of Interferon Distribution in Secondary Lymphoid Organs

“…However, the secondary lymphoid organs have an elaborated architecture. The details of their structural organization allow to suggest that an intensity of the transport processes, in particular, the diffusion, mediating the spread of soluble factors, in particular, IFNα, differs essentially depending on the location in the specific anatomical SLO compartments [16]. To examine the diffusion effect on the spatial distribution of IFNα we consider the concentration of the interferon I at time t to be also dependent on position x ∈ Ω ⊂ R 3 , where Ω represents the spatial region occupied by the lymphoid organ.…”

“…The microanatomy of a paradigmatic SLO can be essentially reduced to three zones: the subcapsular zone, which is an APC-rich area, the B-cell activation zone (B-cell follicle) and T-cell activation zone [12]. Although direct measurements of the hydraulic conductivity within the T-cell zone are missing, it is considered that both diffusion and convection are extremely low [16]. Therefore, the spatial distribution of IFN in SLO deserves further investigation.…”