Natural killer cells (NK-cells) kill virus-infected cells and tumor cells by all of the following methods, except
Important Questions on Human Health and Disease
Read the following statements and identify the wrong ones among them:
(i) Peyer’s patches are also called 'abdominal tonsils'.
(ii) Immunoglobulins are chemically lipoproteins.
(iii) Spleen is a large bean-shaped organ which mainly contains lymphocytes and phagocytes.
(iv) All lymphocytes are phagocytic and engulf pathogens.
Read the following statements:
(i) No vaccine is available for the prevention from chicken pox.
(ii) Bursa of Fabricius is a lymphoid organ found in birds.
(iii) IgM is present as pentamer.
(iv) Interferons constitute the cytokine barrier of immunity.
(v) B – and T – lymphocytes forms the cellular barrier.
Which of the following are incorrect?
Read the following statements and identify true (T) and false (F) amongst them:
(i) T–lymphocytes mediate the humoral immune response.
(ii) Mucus coating of the epithelium lining the respiratory and urogenital tract forms a physical barrier to specific immunity.
(iii) Bacteria–infected cells secrete proteins called interferons which protect non–infected cells from further infection.
(iv) An activated exotoxin called toxoid is used to induce active immunity to a toxin–causing disease.
