ANTIBODY MEDIATED RESPONSE

what is antibody mediated response?

provides resistance to pathogens before they enter the cells of the body

what is the first step in antibody mediated response?

ANTIGEN PRESENTING CELLS

antigen presenting cells present the antigens to:

1. specific B cells in lymphoid tissue

2. helper T cells which release cytokines

   • cytokines cause helper T cells clone themselves

   • begin releasing different T cells which activate more B cells

What are cytokines?

proteins released by cells to act as messengers in the immune response

what is the second step in antibody mediated response?

B CELLS

activated B cells enlarge and divide into a group of cells called a clone and:

1. most become plasma cells

• plasma cells secrete specific antibodies into the blood, lymph and extracellular fluid

• these antibodies can attach to the antigen’s active site

2. remaining B cells become memory cells

• memory cells spread to all tissues of the body

• allow the response to occur more rapidly if second exposure to antigen occurs

what occurs in the primary response?

• immune system responds fairly slowly

• takes several days

• because time needed for B cells to multiply and differentiate into plasma cells before secreting antibodies

• once level of antibodies peak, begins to decline

• now have ‘memory’ of the antigen due to the creation of memory B cells

what occurs in the secondary response?

• occurs during subsequent exposures to the same antigen

• response is much faster as memory B cells recognise the non- self antigen

• plasma cells produces very quickly, bein to secrete antibodies

• antibody levels within the blood: rise faster (to a higher level), last longer

• response often so quick that the antigen has little time to produce an effect on the body= no illness results