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  • B cell activation When antigens enter tissues B cells are called

  • into the infected region. There the B cell interacts with the antigen. B cells specific

  • for the antigen will use their B cell receptors the BCR to bind to the antigen.

  • Once bound to the antigen the B cell internalizes the BCR with antigen and enzymes within the

  • B cell degrade the antigen down. The B cell then loads the piece of antigen onto an MHC

  • Class II molecule for presentation. Now the B cell is ready for full activation.

  • This requires the help of a helper T cell. The helper T cell will bind to the B Cell

  • if it recognizes both the MHC and piece of antigen.

  • AS you see here the T cell uses its CD4 marker to recognize the MHC on the B cell. The T cell

  • uses its TCR, the antigen receptor, to recognize the piece of antigen being presented.

  • Once the T cell binds to the B cell it will release interleukins which will activate the

  • B cell to proliferate. The B cell will then produce Memory Cells

  • and Plasma Cells.

  • Memory cells will go back to the secondary lymphoid tissue for future infections.

  • The Plasma cells will actively secrete antibody, These antibodies are used to help clear the

  • pathogen. Antibodies do this by binding to the antigen and tagging it for opsonization

  • by phagocytes, neutralizing it from binding to target tissue, and in some cases it will

  • cause the antigen to agglutinate and finally some antibodies will activate the classical

  • path of complement.

B cell activation When antigens enter tissues B cells are called

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