Question

What's the key difference between the first and second run of the immune system simulation? How does this simulate the function of the human immune system?

Answer 1

The first run of the immune system or the primary immune response occurs when an antigen comes in contact to the immune system for the first time. During this time the immune system has to learn to recognize antigen and how to make antibody against it and eventually produce memory lymphocytes.

The second run of the immune system or the secondary immune response occurs when the second time (3rd, 4th, etc.) the person is exposed to the same antigen.

The key difference between these two types of immune responses is the responding cells involved in the immune response. In primary immune response, the responding cells are naïve B-cell and T-cell, while in secondary immune response, the responding cells are memory cells.

This arrangement of immune system is crucial to stimulating its function, since at the time of secondary immune response, immunological memory has been established and the immune system can start making antibodies immediately. Also, in the second run, lag phase is shorter (1-4 days) due to the presence of memory cell and level of antibody reaches peak in 3 to 5 days, thus taking shorter time to establish immunity.