ANTIGEN PRESENTING CELLS

ANTIGEN PRESENTING CELLS - best APC is, in fact, the B-cell...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
ANTIGEN PRESENTING CELLS (APCs) Induction of the humoral immune response begins with the recognition of antigen. Through a process of clonal selection , specific B-cells are stimulated to proliferate and differentiate. However, this process requires the intervention of specific T-cells that are themselves stimulated to produce lymphokines that are responsible for activation of the antigen-induced B-cells. In other words, B cells recognize antigen via immunoglobulin receptors on their surface but are unable to proliferate and differentiate unless prompted by the action of T-cell lymphokines. In order for the T-cells to become stimulated to release lymphokines, they must also recognize specific antigen. However, while T-cells recognize antigen via their T-cell receptors, they can only do so in the context of the MHC molecules. This "antigen-presentation" is the responsibility of the antigen-presenting cells (APCs). Several types of cells may serve the APC function. Perhaps the
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: best APC is, in fact, the B-cell itself. When B-cells bind antigen, the antigen becomes internalized, processed and expressed on the surface of the B-cell. Expression occurs within the class II MHC molecule, which can then be recognized by T-helper cells (CD4 + ). Click the image to animate. Other types of antigen-presenting cells include the macrophage and dendritic cells. These cells either actively phagocytose or pinocytose foreign antigens. The antigens are then processed in a manner similar to that observed for the B-cells. Next, specific antigen epitopes are expressed on the macrophage or dendritic cell surface. Again, this expression occurs within the class II MHC molecule, where T-cell recognition occurs. The stimulated T-cells then release lymphokines that act upon "primed" B-cells (B-cells that have already encountered antigen), inducing B-cell proliferation and differentiation. Click the image to animate....
View Full Document

This note was uploaded on 11/05/2011 for the course BIOLOGY MCB2010 taught by Professor Jessicadigirolamo during the Fall '10 term at Broward College.

Page1 / 2

ANTIGEN PRESENTING CELLS - best APC is, in fact, the B-cell...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online