Immunity & Cancer
Read the following passage carefully and answer the given questions.
If the pathogens succeed in gaining entry to our body, specific antibodies and cells serve to kill these pathogens. The B-lymphocytes produce an army of proteins in response to pathogens into our blood to fight with them. The T-cells themselves do not secrete antibodies but help B cells to produce them. The principle of immunisation or vaccination is based on the property of ‘memory’ of the immune system. In vaccination, a preparation of antigenic proteins of pathogen or inactivated/weakened pathogen (vaccine) are introduced into the body. The antibodies produced in the body against these antigens would neutralise the pathogenic agents during actual infection. The exaggerated response of the immune system to certain antigens present in the environment is called allergy. The human immune system consists of lymphoid organs, tissues, cells and soluble molecules like antibodies. Cancer causing viruses called oncogenic viruses have genes called viral oncogenes. Furthermore, several genes called cellular oncogenes (c-onc) or proto oncogenes have been identified in normal cells which, when activated under certain conditions, could lead to oncogenic transformation of the cells.
Allergens are responsible for the production of:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → IgE
(1) IgA — Incorrect. IgA is found in body secretions. It is plentiful in colostrum, the first milk of the mother, and protects the newborn.
(2) IgM — Incorrect. IgM is the first antibody made when the body meets an antigen for the first time. It is not the allergy antibody.
(3) IgE — Correct. The passage calls allergy the exaggerated response of the immune system to certain antigens in the environment. These antigens are called allergens, such as dust mites, pollen and animal dander. The antibodies produced against them are of the IgE type. They make mast cells release histamine and serotonin, which cause sneezing and watery eyes.
(4) IgG — Incorrect. IgG is the most common antibody in the blood. It is not the one produced against allergens.
Note: This passage is taken from NCERT as it is. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Allergies –
