IMMUNOLOGY

Detailed explanation-1: -These specialized cells and parts of the immune system offer the body protection against disease. This protection is called immunity. Humans have three types of immunity-innate, adaptive, and passive: Innate immunity: Everyone is born with innate (or natural) immunity, a type of general protection.

Detailed explanation-2: -Immune system response The damaged DNA in cancer cells frequently directs the mutated cell to produce abnormal proteins known as tumour antigens. These abnormal tumour proteins mark cancer cells as ‘non-self’. The immune system likely encounters and eliminates cancer cells on a daily basis.

Detailed explanation-3: -Antibodies help the body to fight microbes or the toxins (poisons) they produce. They do this by recognising substances called antigens on the surface of the microbe, or in the chemicals they produce, which mark the microbe or toxin as being foreign. The antibodies then mark these antigens for destruction.

Detailed explanation-4: -Adaptive immune responses are carried out by white blood cells called lymphocytes. There are two broad classes of such responses-antibody responses and cell-mediated immune responses, and they are carried out by different classes of lymphocytes, called B cells and T cells, respectively.

Detailed explanation-5: -Antigens are substances (usually proteins) on the surface of cells, viruses, fungi, or bacteria. Nonliving substances such as toxins, chemicals, drugs, and foreign particles (such as a splinter) can also be antigens. The immune system recognizes and destroys, or tries to destroy, substances that contain antigens.