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Lecture

B Cell T-Dependent Activation: Response and Signaling

In course

BIO-310: Immunology

Ce cours décrit le fonctionnement du système immunitaire humain et les bases immunologiques de la vaccination, de la transplantation, de l'immunothérapie, et de l'allergie. Il présente aussi le rôle des cellules souches dans la formation des tissus, notamm ...

Description

This lecture covers the activation of B cells in response to T-dependent antigens, including affinity maturation, class switching, and germinal center reactions. It explains the signal transduction pathways downstream of the B cell receptor and the role of co-receptors in informing B cells of the antigen environment. The process of antigen recognition, interaction between B and T cells, and antigen presentation to T cells are also discussed, along with the consequences of B cell activation by signal 1 and 2.

In MOOC

Introduction to immunology (part 1)

Instructors (2)

Bruno Lemaitre

David Michael Suter

Official source

Quiz

Ontological neighbourhood

Health sciences

Immunology: Immune system

Related concepts (32)

Antigen-presenting cell

An antigen-presenting cell (APC) or accessory cell is a cell that displays antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation. T cells may recognize these complexes using their T cell receptors (TCRs). APCs process antigens and present them to T-cells. Almost all cell types can present antigens in some way. They are found in a variety of tissue types.

Antigen presentation

Antigen presentation is a vital immune process that is essential for T cell immune response triggering. Because T cells recognize only fragmented antigens displayed on cell surfaces, antigen processing must occur before the antigen fragment, now bound to the major histocompatibility complex (MHC), is transported to the surface of the cell, a process known as presentation, where it can be recognized by a T-cell receptor. If there has been an infection with viruses or bacteria, the cell will present an endogenous or exogenous peptide fragment derived from the antigen by MHC molecules.

Antigen

In immunology, an antigen (Ag) is a molecule, moiety, foreign particulate matter, or an allergen, such as pollen, that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. Antigens can be proteins, peptides (amino acid chains), polysaccharides (chains of simple sugars), lipids, or nucleic acids. Antigens exist on normal cells, cancer cells, parasites, viruses, fungi, and bacteria. Antigens are recognized by antigen receptors, including antibodies and T-cell receptors.

B cell

B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or inserted into the plasma membrane where they serve as a part of B-cell receptors. When a naïve or memory B cell is activated by an antigen, it proliferates and differentiates into an antibody-secreting effector cell, known as a plasmablast or plasma cell.

Signal transduction

Signal transduction is the process by which a chemical or physical signal is transmitted through a cell as a series of molecular events. Most commonly, protein phosphorylation is catalyzed by protein kinases, ultimately resulting in a cellular response. Proteins responsible for detecting stimuli are generally termed receptors, although in some cases the term sensor is used. The changes elicited by ligand binding (or signal sensing) in a receptor give rise to a biochemical cascade, which is a chain of biochemical events known as a signaling pathway.

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