Innate Immunity Overview

Peptidoglycan, mannans, zymosan, and nucleic acid are all bacterial structures recognized by TLRs on macrophages. TLRs are pattern recognition receptors that recognize PAMPs (pathogen-associated molecular patterns) on pathogens.

Toll-like receptors (TLRs) are transmembrane glycoproteins that recognize pathogen-associated molecular patterns (PAMPs). They play a critical role in innate immunity by triggering signaling pathways that activate immune responses.

Opsonins are molecules that enhance phagocytosis by coating pathogens and making them more attractive to phagocytic cells like macrophages. Examples include antibodies and complement proteins.

Macrophages are phagocytic cells that engulf and destroy pathogens. They play a vital role in innate immunity and are also involved in adaptive immunity.

Viral PAMPs are molecular patterns that are unique to viruses and are recognized by the immune system. Nucleic acids (DNA or RNA) are common viral PAMPs.

The alternative pathway of complement is a part of the innate immune system. It involves a cascade of proteins that leads to the lysis of pathogens and enhances phagocytosis.

Non-specific defense mechanisms are part of innate immunity. They are broadly effective against a wide range of pathogens and do not require prior exposure. Examples include proteolytic enzymes of the small intestine.

Defensins are antimicrobial peptides that create pores in bacterial membranes, disrupting their integrity and killing them. They are a key part of the innate immune system.

Lactoferrin is a protein that binds to iron, depriving microbes of this essential nutrient. Iron is crucial for bacterial growth and survival.

Natural killer cells are cytotoxic lymphocytes that kill infected cells and tumor cells without previous antigen sensitization. They recognize infected or abnormal cells based on changes in cell surface markers. They are key players in innate immunity and are involved in antibody-dependent cell-mediated cytotoxicity (ADCC).