Unlocking the Immune Response: Antigen Uptake by Dendritic Cells, Macrophages, and B cells

Antigen recognition by T cells: Antigen uptake

~ Incorporation ofantigen (via phagocytosis, pinocytosis, or endocytosis).

Antigen uptake is the process of taking up an antigen by antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells. Antigen uptake by APCs is a crucial step in the initiation of an immune response.

Dendritic cells are the most efficient APCs for antigen uptake. They have long, branched dendrites that protrude from their surface, which they use to capture antigens from the environment. Dendritic cells can take up antigens through several mechanisms, including phagocytosis, receptor-mediated endocytosis, and macropinocytosis.

Macrophages can also phagocytize antigens and present them to T cells. B cells, on the other hand, can recognize antigens directly through their B-cell receptors (BCRs), which bind to specific regions of the antigen called epitopes. The B-cell internalizes the antigen through receptor-mediated endocytosis.

Once antigens are taken up by APCs, they are processed and presented to T cells. The antigens are broken down into smaller peptides and loaded onto major histocompatibility complex (MHC) molecules. MHC molecules then present the antigenic peptides to T cells, allowing them to recognize and respond to the antigen. The interaction between the T-cell receptor (TCR) and the MHC-peptide complex triggers T-cell activation and initiates an immune response.

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