Question

Explain the difference between the primary and secondary immune responses.

Answer 1

PRIMARY IMMUNE RESPONSE	SECONDARY IMMUNE RESPONSE
1. This generally is produced as a result of first time(primary) contact with an antigen.	1.This generally occurs as a result of second or subsequent contact with the particular antigen.
2. The response initiated is mainly due to B cells and T cells.	2. The response initiated is mainly due to the action of memory cell.
3. The primary immune response takes relatively longer time to provide immunity.	3. Due to previous exposure, the secondary immune response take much less time to provide immunity.
4. The first antibody produced is IgM, along with small amounts of IgG.	4. The first antibody produced is IgG along with IgM later, even IgE and IgA are produced in case of allergy.
5.Primary immune response mainly appears in the regions of lymph nodes and spleen.	5.Secondary immune response mainly happens in the bone marrow, followed by spleen and region of lymph nodes.
6.The thymus dependent and thymus independent antigen is responsible for primary immune response.	6.Only the thymus -dependent antigen helps to deliver the secondary immune response.
7.The level of antibody produced is generally lower and reaches peak in 7-10 days.	7. The level of antibody produced is much higher in comparison and reaches peak in 3-5 days.