3.2.4.4 Humoral Immunity

Question 1

What is meant by “humoural immunity”?

Answer 1

An immune response that involves the destruction of pathogens using antibodies

Question 2

How many different types of B lymphocytes exist in the body

Answer 2

10 million approx - each one has different shaped receptors that bind to specific antiges

Question 3

B lymphocytes can develop into which type of cells after an immune repsonse?

Answer 3

Plasma cells

Memory cells

Question 4

Plasma cells develop from B lymphocytes. What is their function?

Answer 4

They produce antibodies to destroy pathogens

Question 5

Memory cells can develop from B lymphocytes. What is their function?

Answer 5

They are responsible for the secondary immune response.

If they encounter the same pathogen again, they multiply rapidly and develop into plasma cells, which produce antibodies

Question 6

Describe the process of humoural immunity

Answer 6

1. Foreign antigen enters blood, initiating an immune response
2. A specific B lymphocyte engulfs foreign antigen via endocytosis and presents foreign antigens on its cell surface membrane
3. T helper cell binds to and stimulates specific B lymphocyte to undergo mitosis (clonal selection)
4. Cloned B lymphocytes develop into plasma cells that produce monoclonal antibodies (primary response)
5. Some B lymphocytes become memory cells that circulate blood ready to develop into plasma cells upon a recurring infection (secondary response)

Question 7

Describe how the presentation of a viral antigen leads to the secretion of antibody against viral antigens

Answer 7

T cells bind to the antigen (on APC)

T cells are activated into T helper cells

T helper cells stimulate specific B cells

B cells stimulated to divide by mitosis (clonal selection)

Forms plasma cells which release antibodies

Question 8

What makes all antibodies unique?

Answer 8

Specific tertiary structure

Variable region will only bind / complementary to one antigen

Only forms antigen - antibody specific complexes with specific antigens

Question 9

How is a secondary immune response differ to a primary response

Answer 9

Secondary is..

Faster
Greater concentration in antibodies produced
No lag/delay in antibody production

Question 10

How is passive immunity different to active immunity

Answer 10

Passive is…

Quicker
No memory cells produced