What is Trogocytosis and what is its purpose?
Trogocytosis corresponds to an active transfer phenomenon that is triggered specifically by antigen receptor signaling. It occurs within minutes of conjugate formation between two live cells and therefore cannot be the result of phagocytosis of apoptotic bodies2,3,4.
What is the function of immature dendritic cells?
For bacterial and viral infections, the immature dendritic cells (iDCs) derived from the bone marrow and residing in peripheral tissues are recruited to the inflamed site by pathogen signals. They capture foreign antigens and undergo maturation and migration to secondary lymphoid organs such as lymph nodes (LNs) [3].
Why are follicular dendritic cells important?
Follicular dendritic cells (FDCs) are stromal cells residing in primary follicles and in germinal centers of secondary and tertiary lymphoid organs (SLOs and TLOs). There, they play a crucial role in B-cell activation and affinity maturation of antibodies.
What are marginal zone B cells?
Marginal zone (MZ) B cells are strategically located at the interface between the circulation and the white pulp of the spleen, where they provide a first line of defence by rapidly producing IgM and class-switched IgG antibodies in response to infections by blood-borne viruses and encapsulated bacteria.
What are CD5 cells?
CD5 is a signal transducing molecule involved in tyrosine phosphorylation of intracellular proteins [5, 51]. It modulates signaling through the antigen-specific receptor complexes TCR and B-cell receptor (BCR) [5, 52]. CD5 is expressed at low density on thymocytes and at high density on all mature T-lymphocytes.
What is the major difference between immature and mature dendritic cells?
Immature DCs have a round and smooth surface, while mature DCs have a rough surface with multiple pseudopodia. In the immature state, DCs express lower levels of costimulatory molecules, such as CD80, CD86, CD83, and MHC II and secrete lower levels of immunostimulatory cytokines, such as IL-12, IL-10, and TNF.
What are the three types of dendritic cells?
Three types of DCs have been defined in human blood: the CD1c+ myeloid DCs, the CD141+ myeloid DCs and the CD303+ plasmacytoid DCs.
What is the functional difference between dendritic cells and follicular dendritic cells?
Follicular dendritic cells (FDCs) have a dendritic morphology but are completely unrelated to DCs and pDCs in lineage and function. While DCs are critical for T cell responses, FDCs are important for B cell responses and are abundant in the secondary lymphoid organs where B cell activation occurs (see Ch. 5).
How do follicular dendritic cells work?
The FDC function is to bind and retain antigens by linking to complement and immune complexes and then present these antigens to germinal center B cells that start the secondary immune response.
What are germinal center B cells?
The germinal center (GC) is a specialized microstructure that forms in secondary lymphoid tissues, producing long-lived antibody secreting plasma cells and memory B cells, which can provide protection against reinfection.
What is CD5 and CD10?
CD5, CD10, and CD23 are cell surface antigens used to distinguish B-cell disorders. The expression of these antigens and their clinical significance in Waldenström’s macroglobulinemia (WM), an uncommon B-cell disorder, remains to be clarified.
Why are dendrites important to neural function?
Nerve cells (neurons) have extensive processes called dendrites. These occupy a large surface area of a neuron. They receive many signals from other neurons and contain specialized proteins that receive, process, and transfer these to the cell body.
What cytokines do dendritic cells secrete?
Through the cytokines they secrete, e.g.: IL-12, IL-23 or IL-10 as well as the surface molecules they express, e.g.: OX40-L [33] or ICOS-l [34] DCs can polarize naïve T cells into Th1, Th2, Treg or Th17.
How do dendritic cells capture antigens?
Mature dendritic cells use endocytic receptors to capture and present antigens.
What is trogocytosis?
This phenomenon, which we have called ‘trogocytosis’ 1 (from the ancient Greek trogo, meaning ‘gnaw’), involves the transfer of plasma membrane fragments from the presenting cell to the lymphocyte. Trogocytosis has been documented in T, B and natural killer cells both in vitro and in vivo.
What triggers trogocytosis in T cells?
On T cells and B cells, trogocytosis is triggered when the T cell receptor (TCR) on T cells or B cell receptor (BCR) on B cells interacts with the antigen recognized on antigen-presenting cells.
What are the physiological consequences of transgenic trogocytosis?
Trogocytosis can have physiological consequences in two ways: either because “recipient” cells acquire and make use of molecules they do not usually express or because «donor» cells are stripped of molecules, which may alter their interaction with cellular partners.
What do lymphocytes inherit during trogocytosis?
During trogocytosis, lymphocytes inherit many different molecules from conjugating cells. Some of these molecules, which are not transcribed by lymphocytes, may directly or indirectly influence the phenotype and function of the lymphocytes.