IMMUNOLOGY

Detailed explanation-1: -The immune system refers to a collection of cells, chemicals and processes that function to protect the skin, respiratory passages, intestinal tract and other areas from foreign antigens, such as microbes (organisms such as bacteria, fungi, and parasites), viruses, cancer cells, and toxins.

Detailed explanation-2: -The innate immune system is the body’s first line of defense against germs entering the body. It responds in the same way to all germs and foreign substances, which is why it is sometimes referred to as the “nonspecific” immune system.

Detailed explanation-3: -Antibodies act against viruses primarily by binding to and neutralizing virions and by directing the lysis of infected cells by complement or killer leukocytes.

Detailed explanation-4: -The immune system is a complex network of organs, cells and proteins that defends the body against infection, whilst protecting the body’s own cells. The immune system keeps a record of every germ (microbe) it has ever defeated so it can recognise and destroy the microbe quickly if it enters the body again.

Detailed explanation-5: -Antibody. The specific immune response to parasites leads to the production of antibody. Infection by protozoan parasites is associated with the production of IgG and IgM.