12 humoral response

what b lymphocytes?

white blood cells involved in a specific immune response

where are all lymphocytes made?

the bone marrow and b cells mature there too

what’s the humoral response?

the response involving b cells and antibodies

are antibodies soluble and where do they transport?

yes they’re soluble and transport in bodily fluids

approximately how many b cells are there?

10 million b cells which have antibodies on their surface complementary to 10 million different antigens

how do b cells work?

• antigens in the blood collide with their complementary antibody on a b cell

• this b cell takes in the antigen by endocytosis and then presents it on it’s cell surface membrane

• when this b cell collides with a helper t cell receptor, this activates the b cell to go through clonal expansion and differentiation (clonal selection)

• b cells undergo mitosis to make large numbers of cells, these differentiate into plasma cells or memory b cells

what do plasma cells do?

make antibodies

what do b memory cells do?

can divide rapidly into plasma cells when reinfected with the same pathogen to make large numbers of antibodies rapidly

how long can memory b cells and plasma cells live for?

memory b cells - decades

plasma cells - short lived

what’s active immunity?

memory b cells dividing rapidly by mitosis to make plasma cells, resulting in a large number of antibodies to be produced so rapidly that the pathogen is destroyed before any symptoms can occur

what’s an antibody?

quaternary structure protein (4 polypeptide chains)

what’s antibody agglutination?

antibodies are flexible and can bind to multiple antigens to clump them together to create an antigen-antibody complex. this makes it easier for phagocytes to locate and destroy pathogens

what part of the antibody is number 1?

light chain

what part of the antibody is number 2?

heavy chain

what part of the antibody is number 3 (shown in red)?

constant region

what part of the antibody is number 4 (shown in purple)?

variable region

what part of the antibody is number 5?

antigen binding sites

what’s the variable region?

the part that changes shape to bind to an antigen

what’s the primary response?

when an antigen enters the body for the first time and activates the immune system. antigens won’t be produced as quickly but after the infection is fought off, there’ll be a store of memory b cells

what’s the secondary response?

if the same pathogen enters the body again, the immune system will produce a quicker and stronger immune response. the store of memory b cells will divide into plasma cells to produce the correct antibody