Video Transcript
Fill in the blank. A B cell will internalize the
antigens present on the surface of a pathogen and blank. (A) Incorporate them into its own
genetic material. (B) Display them on its
surface. (C) Destroy them by lysis. Or (D) neutralize them to release
them back to the blood to act as antibodies.
When a B cell, like the one shown
here, recognizes an extracellular pathogen such as a bacterium using its B cell
receptor, the B cell engulfs the pathogen by phagocytosis. Once the pathogen has been
engulfed, it is then digested inside the B cell using enzymes. A specialized molecule called a
major histocompatibility complex, MHC for short, is then assembled around a fragment
of the digested pathogen. And together, they are transported
to the cell surface membrane of the B cell. This pathogen fragment is known as
an antigen.
Once the B cell has antigens bound
to MHCs on its cell surface, it is said to be displaying or presenting antigen. A displayed antigen can be
recognized by a T helper cell, which will then release cytokines to fully activate
the B cell.
We have therefore determined that
the correct answer is (B). A B cell will internalize the
antigens present on the surface of a pathogen and display them on its surface.
