Mucosal surfaces, constantly exposed to foreign antigens, have developed the ability to protect the host from potentially harmful organisms by means of innate and acquired immune responses.
In the primary humoral immune response, a single class IgM in monomeric form is initially secreted. The secondary response induced by a subsequent exposure to the same antigen will be mainly characterized by the production of IgG isotype but at higher titre and affinity.
Specific humoral immunity is mediated by glycoproteins called antibodies or immunoglobulins.
The main mechanism of defense against intracellular infections, particularly virus.
The role of each player in the innate immunity response: Type 1 Interferons and pro-inflammatory cytokines, complement, acute phase proteins, antimicrobial proteins, phagocytes, NK cells, γ/δ T lymphocytes,...
Recognition of the pathogen is the first step of defensive immune response; both innate and specific immunity have mechanism to recognize the pathogen.