IMMUNOLOGY

Detailed explanation-1: -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-2: -Keratinocytes. Keratinocytes are the predominant cells in the epidermis. They act as the first line of innate immune defence against infection. They express Toll-like receptors (TLRs), which are pattern-recognition receptors (PRRs) that detect conserved molecules on pathogens and trigger an inflammatory response.

Detailed explanation-3: -The first line of defense against infection are the surface barriers that prevent the entry of pathogens into the body. The second line of defense are the non-specific phagocytes and other internal mechanisms that comprise innate immunity.