b lymphocytes and humoral immunity 5.4

Describe the steps in the humoral response?

1)Surface antigens of pathogens taken in by B cell .by endocytosis

2)B cells process the antigens and present antigens on its surface.

3)T helper cells attached to processed antigen + activates B cell to go through (clonal selection).

4)B cells divide via mitosis to produce plasma cells.

5)Plasma cells produce and secrete specific antibodies that are complementary to the antigen.

6)the antibody attaches to antigens on the pathogen and destroys them.















7)Some B cells develop into memory cells → circulate the blood, secondary response

B Cells can mature into 2 types of cells. State their names and functions.

Plasma cells → secrete antibodies into blood plasma..
-these cells can only survive a few days but make 2000 antibodies during its lifespan.
These antibodies destroy antigens
-the plasma cells are responsible for the primary immune response (the production of antibodies and memory cells)


Memory cells → responsible for secondary immune response
-live longer than plasma cells.
-do not produce antibodies directly, but circulate in blood

How do memory cells work?

-when they encounter the same antigen again ,they divide rapidly and develop into plasma cells and more memory cells.

The plasma cells produce antibodies needed to destroy the pathogen ,while the new memory cells circulate to prepare for future infection.

Memory cells therefore provide long term immunity against the original infection

an increased quantity of antibodies is secreted at a faster rate, rather than the primary immune response .
it ensures infection is immediately destroyed before it causes harm.

Describe the secondary immune response?

Second exposure to the same pathogen -> a lot quicker
Memory cells in blood divide to form a large population of B cells
Produce clones that can make antibodies

State adaptations of a stimulated B cell

mitochondria provide (more) ATP / energy;
(more) RER / ribosomes synthesise proteins;
(more) Golgi body secretes / modifies or packages proteins /
produces glycoproteins;
(B lymphocytes) produces antibodies;

In what cases may reinfection of the same pathogen occur?

Different strains of the same pathogens
Different antigen (antigenic variability)
Memory cells aren't useful, produce an incorrectly shaped antibody
Primary immune response initiated = reinfection

what is humoral immunity?

Immunity involving antibodies that are present in body fluids or ''humour'' such as blood plasma .

Humoral immunity uses specific antibodies to combat infection