Question

Given below are two statements:
Statement (I): The animals infected with Theileria annulata are cross-protected against Theileria parva infection.
Statement (II): Protective immunity in Theileria parva is conferred by cytotoxic T lymphocytes which cause lysis of parasites by osmotic alteration in target cells leading to swelling and disruption of the cells.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Humoral antibodies play a negligible role in protecting against the intracellular schizont stage of *Theileria parva*.
Protective immunity is almost entirely mediated by CD8+ Cytotoxic T Lymphocytes (CTLs).

Answer 1

The Correct Option is D