Question

The given flow chart shows classification of acquired immunity. What types of immunity will be developed by the persons $X$ and $Y?$

$X:$ A person who has recovered from an attack of measles.
$Y:$ A person who is given anti-tetanus serum.

• A.

  X	Y
  $A(i)$	$B(i)$

• B.

  X	Y
  $B(i)$	$A(ii)$

• C.

  X	Y
  $B(ii)$	$A(ii)$

• D.

  X	Y
  $A(i)$	$A(ii)$

Answer 1

Answer: (B)

Acquired immunity is immunity that we develop over our lifetime. It can come from a vaccine, exposure to an infection or disease, another person’s antibodies. Adaptive immunity creates memory after an initial response to a specific pathogen, and leads to an enhanced response to future encounters with that pathogen.
Acquired immunity is different from innate immunity, which is present since birth. Our innate immune system doesn’t fight specific germs.
The acquired immunity is divided into two types of immunity named as active and passive immunity.
Active immunity: It occurs when the antibodies against an antigen are formed, on getting exposed to the pathogen, by the body cells of a person. It takes a long time in its action and it develops memory.
Passive immunity: When antibodies developed in other organism are injected into the human body at the time of the need. It has a quick response but is not long-lasting.
The person (X) who has recovered from measles, must have developed memory of the infectious antigen and have created antibodies against it. Hence, it comes under natural acquired immunity. The body must have also taken some time period to identify the pathogen in first encounter and create antibodies against it.
The person (Y) who is injected with the anti-tetanus serum develops artificial passive immunity.