In the secondary immune response, do memory B cells need activation?

Question

The primary immune response requires IL-4 and IL-5 for B cells to grow and differentiate into plasma and memory. Upon subsequent exposure to Ag, are the interleukins required again, or will a memory cell differentiate into plasma cells as soon as it encounters Ag again?

Also, are macrophages still involved in the secondary response?

Answer 1

I'm a RN who has taught Nursing for over 25 years and in addition I have a specific Immunology problem due to a block at the Interleukin 5-6 level. As a result I have a definite interest in Immunology, have several Immunology medical textbooks, and have had long discussions with my Immunologist who lives in Canada while I live in the southern USA. You end up turning to where the answers are. After saying all of that, I found your questions interesting as well as challeging. According to my understanding of the medical literature, IL-2, IL-4, IL-10, and IL-21 are required along with antigen stimulation in order to interrupt memory B cell expansion and induce differentiation into plasma cells in the secondary response. Compared to the primary response, antibody production during the secondary response is much more rapid. Maximum antibody concentrations in the blood are reached in less than two hours and are maintained for a longer time than in the primary response. This rapid rise in antibody production is usually sufficient to prevent the disease. Before stimulation by a particular antigen, the B cells that make the appropriate antibodies produce mainly IgM antibodies. These IgM antibodies therefore account for a high proportion of the antibodies made during the primary response. In contrast, most antibodies made during the secondary response are in the IgG subclass. Memory cells are stimulated to secrete antibodies during the secondary response. It is the secondary response that provides active immunity against the specific pathogens. Hope this helps. Good luck to you.

Answer 2

Memory B Cell Activation

Answer 3

When your immune system is exposed to antigen (Ag) for 2nd time and more times after, you already have that memoryB-cells for that antigen. plasma B cell would come across that antigen and that signals it to turn into plasma B cell which makes antibodies for that antigen. Interleukens aren't needed to activate memory B cells to turn into plasma B cells.

It's only when you come across a new antigen for the first time then interleukens are required. That's because T-cells are activated and they secrete IL 4 and IL5 to get B cells to differentiate into plasma B cells for that antigen and also memory B cells so when they come across antigen again they will be ready to make antibodies to fight that antigen. That way 2nd immune ressponse to that same antigen is more faster.

Answer 4

Try looking at this web site, it may help

http://focosi.immunesig.org/immuneresponses.html#naive%20B%20cells%20activation