Immunity
Read the following passage carefully and answer the given questions.
On daily basis, large number of pathogens are entering our body from the air we breathe in or the food we eat but we are not falling ill daily. It is because of the reason that our body can fight with most of these pathogens entering our body and kill them. Immunity is of two types - acquired or innate immunity. Innate immunity is non specific type of defence which is present from the birth. It is provided by four kinds of barriers - physical, physiological, cellular and cytokine barrier. It is a non specific type of defence. Acquired immunity is acquired when pathogen enters the body. It is pathogen specific and is characterised by memory of the immune system. Acquired immunity is carried out by two special type of lymphocytes called as B-cells and T-cells. B-cells produce antibodies and are responsible for humoral response whereas T-cells produce cell-mediated immune response.
The colostrum secreted by the mother during initial days of lactation is important for the infant as it provides:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Passive immunity
When ready-made antibodies are given to a body, the immunity is passive. When the body makes its own antibodies after meeting an antigen, it is active.
(1) Physiological barrier for the pathogen — Incorrect. Physiological barriers, such as acid in the stomach, saliva and tears, belong to innate immunity. Colostrum does not work as a barrier.
(2) Passive immunity — Correct. Colostrum, the yellowish fluid secreted in the first days of lactation, has abundant antibodies (IgA). The infant receives these ready-made.
(3) Active immunity — Incorrect. The infant does not make these antibodies. It receives them from the mother, and active immunity is slow to develop.
(4) Cell mediated immunity — Incorrect. This is carried out by T-lymphocytes. Colostrum supplies antibodies, which belong to the humoral response.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Active and Passive Immunity –
