Question

Following are some statements regarding the primary and secondary antibody response in humans. All the statements are correct except

• A. lag period (time between the introduction of antigen and appearance of antibodies in blood) in primary response is longer than that in secondary response
• B. predominant isotype produced in primary response is $IgM$ while that in secondary response is $IgG$
• C. primary antibodies have a higher affinity for antigen as compared to secondary antibodies
• D. primary immune response is more quicker and intense than secondary immune response

Answer 1

Answer: (D)

The reaction of the body's immune system to the first attack of microbes (antigens) is called primary immune response. It takes much longer time to develop because of the requirement of suitable receptor development. This response is feeble and declines rapidly. This however produces both receptors and memory cells. The reaction of the body's immune system to any subsequent infection of the same microbe is termed secondary immune response. This response is quicker and more intense than the primary immune response. This is so because the memory $B$ cells are present to quickly deal with the invading microbes by forming antibodies. Body "remembers" that it has previously encountered certain type of infection.