Microbial antigens: pathogen-associated molecular patterns, list the types
The teams that we play against include bacteria, viruses, fungi, protozoans, and worms. These microbes have components that are necessary for them to survive and replicate and most importantly, these components are not typically found in the host. These essential components are often shared among a group of related organisms; for example, peptidoglycan is found in the cell wall of most bacteria, zymosan is a polysaccharide or glucan found in yeasts and fungi, and ssRNA, dsRNA, and unmethylated DNA are found in viruses. Microbes cannot alter these components without damaging their ability to survive. These essential components are called pathogen-associated molecular patterns or PAMPS for short. PAMPS are recognized by the innate immune system as danger signals.
Pathogen recognition receptors (PRRs), innate vs adaptive
PRRs adaptive vs innate
The antigen receptors on innate immune cells that recognize PAMPS and DAMPS are called pathogen recognition receptors or PRRs. PRRs differ from antigen receptors expressed on lymphocytes of the adaptive immune system in that they recognize microbial structures shared among a group of organisms. PRRs are also germline encoded with limited diversity whereas lymphocytes that develop in the bone marrow or thymus have unique antigen receptors that are assembled from gene segments. PRRs are also nonclonally expressed in all cells of a given type but each clone of lymphocytes express a unique antigen receptor. However, both PRRs and antigen receptors on lymphocytes can discriminate between self and non-self.