Plasma & Memory Cells (AQA A Level Biology) : Revision Note

Lára Marie McIvor

Written by: Lára Marie McIvor

Reviewed by: Lucy Kirkham

Updated on

Plasma & Memory Cells

  • During an immune response B-lymphocytes give rise to:

    • plasma cells, which produce antibodies

    • memory cells, which form the basis of immunological memory

  • Plasma cells and memory cells are involved in two different levels of immune response:

    • primary immune response to a newly encountered antigen

    • secondary immune response to a previously encountered antigen

Primary immune response

  • After clonal selection and mitosis the B-lymphocytes that have become plasma cells secrete specific antibodies into the blood

    • These plasma cells are short-lived and antibody numbers gradually decrease over time after the response has ended

  • Some B-lymphocytes develop into memory cells that remain in the blood for a long time

  • The primary response to a newly encountered pathogen is relatively slow, due to:

    • time taken to find lymphocytes with complementary receptors (clonal selection)

    • time taken for mitosis to occur

    • time taken for antibody production to begin

Secondary immune response

  • If the same antigen is encountered a second time the memory cells recognise the antigen, divide very quickly and differentiate into plasma cells to produce antibodies

  • This response is very quick, meaning that the infection can be destroyed and removed before the pathogen population increases too much and symptoms of the disease develop

The function of B-lymphocytes during a primary and secondary immune response (1)_1, downloadable AS & A Level Biology revision notes
Diagram illustrating the secondary immune response, showing memory cells creating plasma cells and antibodies upon a second antigen entry.
During a secondary immune response memory cells divide very quickly into plasma cells, resulting in fast production of many antibodies

Examiner Tips and Tricks

Immunological memory is the reason why catching some diseases twice is so unlikely. Some infections however, such as the common cold and influenza, are caused by viruses that constantly mutate and that show antigenic variability. As each strain has different antigens the primary immune response must be carried out each time before immunity can be achieved.

You've read 0 of your 5 free revision notes this week

Sign up now. It’s free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Lára Marie McIvor

Author: Lára Marie McIvor

Expertise: Biology Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.

Lucy Kirkham

Reviewer: Lucy Kirkham

Expertise: Head of STEM

Lucy has been a passionate Maths teacher for over 12 years, teaching maths across the UK and abroad helping to engage, interest and develop confidence in the subject at all levels.Working as a Head of Department and then Director of Maths, Lucy has advised schools and academy trusts in both Scotland and the East Midlands, where her role was to support and coach teachers to improve Maths teaching for all.

Download notes on Plasma & Memory Cells