Chapter 34, Problem 1SA

________trigger(s) immune responses.

a. Cytokines	d. Antigens
b. Lysozyme	e. Histamines
c. Antibodies	f. $\text{MHC}$ markers

Summary Introduction

Introduction:

An organism’s capacity to resist and combat against various foreign invaders (pathogens) like bacteria, virus and many others is known as the immunity of the body. The immunity of an individual is depicted by its immune system. The study of immunity is known as immunology.

Answer to Problem 1SA

Correct answer:

An immune response is triggered by antigens. Hence, the correct answer is option d.

Explanation of Solution

Reason for correct answer:

Option d. is given as “antigens.”

An antigen represents the foreign particle which invades an individual’s body. It is responsible for the generation of the immune response by the immune system. The body clearly differentiates between self-cells and non-self (antigen) cells. So, when an invader enters the body, the immune response is generated and responds against the pathogen.

Reason for incorrect answer:

Option a. is given as, “cytokines.”

The cytokines are responsible for enhancing the ability of the immune system. These are produced by the white blood cells when the invasion of the pathogen is detected. Hence, option a. is incorrect.

Option b. is given as, “lysozyme.”

Lysozyme is found in tears, sweat, and saliva. It is a part of innate immunity and causes the lysis of non-self cells. Hence, option b. is incorrect.

Option c. is given as, “antibodies.”

The antibodies are specific in nature and are generated according to the invading antigen. These are produced from the activated B-cells of adaptive immunity. Hence, option c. is incorrect.

Option e. is given as, “histamines.”

When an invader enters the body of an individual, histamines are released from the white blood cells and mast cells. Histamines are responsible for the inflammatory responses at the injured part resulting in swollen and red condition due to excess secretion of interstitial fluid. Hence, option e. is incorrect.

Option f. is given as, “MHC markers.”

The MHC markers are the type of proteins which are present on the cell surface. These markers are responsible for the identification of pathogens during an immune response. Hence, option f. is incorrect.

Hence, the options a., b., c., e., and f. are incorrect.

Conclusion

The immune responses are generated against foreign antigens. Thus, the correct option is d.