Primary & Secondary Immune Response

Primary & secondary immune response

1. Initial exposure

2. Primary immune response produces a small concentration of antibodies

3. Secondary exposure

4. Secondary immune response produces a high concentration of antibodies

Why is there a time delay between initial exposure and the primary immune response?

• The clonal selection and expansion of specific T cells and B cells

• The synthesis of antibodies

What do B cells do in the primary immune response?

Some B cells differentiate during clonal expansion to become plasma cells and memory cells

What is the secondary immune response?

The response to the secondary exposure to the pathogen or antigen or disease

What happens in the secondary immune response?

• During the primary response, there are no memory cells.

• After the immune response, there are now T and B memory cells that have been produced during cell mediated and humoral response

• If the same foreign antigen re-enters, B memory cells recognise the antigen.

• B memory cells divide quickly and differentiate into plasma cells to produce antibodies and more memory cells.

Is the secondary immune response quick?

Yes

Why is the secondary immune response quicker?

Because memory B-cells and Memory T-cells can recognise the antigen and produce the correct antibodies quicker.

Mention these key terms in an answer:

Clonal selection

Clonal expansion

Plasma cells & antibody concentration

How do T memory cells play a part in the secondary immune response?

T-lymphocytes differentiate into memory cells, producing:

• Memory T helper cells

• Memory T killer cells

What will T memory cells do?

Like B memory cells, they remain in the body for a long time and provide long term immunity