IMMUNOLOGY

Detailed explanation-1: -The primary immune response to antigen occurs on the first occasion it is encountered. This response can take up to 14 days to resolve and leads to the generation of memory cells with a high specificity for the inducing antigen.

Detailed explanation-2: -Level of antibody reaches peak in 3 to 5 days. It takes longer time to establish immunity. Takes shorter time to establish immunity. First antibody produced is mainly IgM.

Detailed explanation-3: -Whereas in a primary encounter, antibodies are not generated for several days, during a memory response antibodies appear in just a few days.

Detailed explanation-4: -Step 1: A macrophage engulfs the pathogen. Step 2: The macrophage then digests the bacterium and presents the pathogen’s antigens. Step 3: A T helper cell binds to the macrophage and becomes an activated T helper cell. Step 4: The activated T helper cell binds to a B cell in order to activate the B cell.

Detailed explanation-5: -The immune system has special cells (known as B cells) that make the antibodies. It takes time for your body’s immune system to recognise the pathogens that can make you ill. This could take a week, or sometimes as long as 3 weeks.