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.
A person has been bitten by a snake, doctor immediately gives him an injection which consists of:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Preparation containing preformed antibodies against the venom
Snake venom acts fast, so the body cannot wait to make its own antibodies. Passive immunisation gives ready-made antibodies directly. The injection for a snakebite is of this kind.
(1) Preparation containing preformed antibodies against the venom — Correct. The antibodies neutralise the venom at once.
(2) Preparation of antigenic proteins of the pathogen — Incorrect. This is how a vaccine is made. It makes the body produce its own antibodies, which is a slow response, and venom is not a pathogen.
(3) Inactivated/weakened pathogen — Incorrect. This is also a vaccine. It trains the body in advance and does not give quick protection after a bite.
(4) Activated antigen — Incorrect. An antigen starts the body’s own, slower, response. It does not give ready-made antibodies.
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:
Vaccination and Immunisation – “If a person is infected with some deadly microbes to which quick immune response is required as in tetanus, we need to directly inject the preformed antibodies, or antitoxin (a preparation containing antibodies to the toxin). Even in cases of snakebites, the injection which is given to the patients, contain preformed antibodies against the snake venom. This type of immunisation is called passive immunisation.”