Definition of
APC: Any cell that can process and present antigenic peptides in association
with class II MHC molecules and deliver a co-stimulatory signal necessary for T
cell activation. This interaction enhances immune response.
B cell as Antigen presenting cell
Step 1: B cell
activation=Antigen binding to Naïve B cell receptor followed by Antigen
degradation inside B cell
Step 2: B cell
acts as antigen presenting cells (APCs). Degrades antigenic peptides are
displayed on MHC Class II recetor.
-T cell receptor (TCR) of Th cell
binds to MHC class II bound antigenic peptide
-TCR activates B cells by secreting
chemokines such as interleukins
Step 3: Clonal
selection and Differentiation: That activated B cell divide continuously forming clone of B cells
with that specificity
Late these B cells differentiate into
Plasma cells and memory B cells
Watch this video for better concept clarity
Watch this video for better concept clarity
Step 4: Plasma
cells produce antibodies and are released into the blood stream that binds to
the antigen and neutralize it. Thus preventing further infection
-Memory B cells produced are
responsible for immunologic memory. (when the same antigen attacks the body for
the second time, memory B cells recognizes it quickly and trigger an enhanced
immune response, thus preventing further infection).