Question

Which of the following is responsible for the production of antibodies specific to an infecting agent?
A) B cell
B) Fibrinogen
C) Pathogen
D) Phagocyte
E) T cell

Answer 1

Hint:Antibodies are produced by a certain type of B-cell present with the blood plasma. During an infectious attack, the T-cells recognize the pathogen and send signals to the B-cells to produce an array of antibodies. The B-cells possess special genetic tools to produce antibodies of different specificities and shapes.

Complete answer:During the event of an infection, all immune cells get activated and play a specific role in trying to eliminate the antigen/pathogen. Complex organisms fight infections primarily by producing antibodies targeted to that specific antigen.
There are two types of B-cells, namely plasma B-cell and memory B-cell. The main function of the plasma B-cell is to produce antibodies and the memory B-cell is capable of storing the information of antibodies produced in case of further attack or during a secondary immune response.

B-cells possess a specific mechanism known as class switching, where it can rearrange the genetic code of their genetic material. By doing so, each antibody produced is unique and specific. During infection of an unknown pathogen, the T-cells identify the threat and signal the B-cells to produce a different type of antibodies.
The B-cell produces the different types of antibodies, to find the one specific antibody that can bind to the pathogen. Once the specific antibody is found, other immune cells such as the phagocytes digest the pathogen and send signals to the B-cell. Now the B-cell divides and produces only that specific antibody in large amounts to fight the infection.
Once the infectious pathogen has been eliminated, the activated B-cells stop dividing and become memory cells. If the same pathogen attacks in the future, these cells immediately produce the specific antibody and prevent the attack even before it begins. This is known as acquired immunity.
Therefore, the correct option is A, B-cell.

Note:B-cells produce specific antibodies against pathogens.
They initially produce different types of antibodies through altering their genetic material until they find the antibody capable of affecting the pathogen.
Fibrinogen is a compound involved in blood clotting and does not play a key role in immune function.
A pathogen is an infectious microorganism against which antibodies are produced.