Acquired immunity is characterised by memory. Identify the sequence in which it happens :

(A) Subsequent encounter of the body with same pathogen
(B) Primary response is produced when the body encounter pathogens for the first time
(C) T-lymphocytes help B-lymphocytes to produce an army of proteins
(D) Body exhibits highly intensified anamnestic response

Choose the correct answer from the options given below:

(B), (C), (A), (D)

The correct answer is Option (2) → (B), (C), (A), (D)

(B) Primary response is produced when the body encounter pathogens for the first time

(C) T-lymphocytes help B-lymphocytes to produce an army of proteins

(A) Subsequent encounter of the body with same pathogen

(D) Body exhibits highly intensified anamnestic response

Acquired immunity is pathogen specific. It is characterised by memory. This means when our body encounters a pathogen for the first time it produces a response called primary response which is of low intensity. Subsequent encounter with the same pathogen elicits a highly intensified secondary or anamnestic response. This is ascribed to the fact that our body appears to have memory of the first encounter. The primary and secondary immune responses are carried out with the help of two special types of lymphocytes present in our blood, i.e., B-lymphocytes and T-lymphocytes. The B-lymphocytes produce an army of proteins in response to pathogens into our blood to fight with them. These proteins are called antibodies. The T-cells themselves do not secrete antibodies but help B cells to produce them. Each antibody molecule has four peptide chains, two small called light chains and two longer called heavy chains.