Question

Student to attempt either option (A) or (B):
(A) Explain how the immunity of a person is affected if there is atrophy (degeneration) of the thymus gland at an early stage of life. 
OR
(B) (i) What are interferons? Explain their role in providing immunity to a person. 
(ii) Which category of innate immunity defence barrier can interferons be classified into?

Hint:

The thymus is vital for T-cell maturation; early atrophy leads to compromised cell-mediated immunity. Interferons are antiviral proteins and form part of innate physiological barriers.

Answer 1

(A) Step 1: The thymus gland is a primary lymphoid organ responsible for the maturation of T-lymphocytes (T-cells), which play a central role in cell-mediated immunity.
Step 2: If thymus undergoes atrophy at an early stage of life, it results in reduced T-cell production. 
Step 3: This weakens the body's immune response, making the person more susceptible to infections and immune-related disorders. 
OR  
(B) (i) Step 1: Interferons are proteins released by virus-infected cells. 
Step 2: They inhibit viral replication in surrounding uninfected cells by activating antiviral enzymes, thus preventing the spread of infection. 
Step 3: They also stimulate the immune cells such as natural killer cells and macrophages. 
(ii) Step 1: Interferons are classified under the physiological barriers of innate immunity. 
Step 2: These barriers include antimicrobial substances produced in the body that inhibit the growth of pathogens.