Immunology Lec 2 Flashcards
Lecture 2:
Name the main types of phagocytic cells involved in innate immunity.
Monocytes/macrophages and neutrophils.
What are the three types of epithelial barriers involved in innate protection?
Mechanical barriers (flow of air or fluid, movements of mucus), chemical barriers (fatty acids in skin, lysozyme in saliva and tears, pepsin in the gut), and microbiological barriers (commensal bacteria).
What is the importance of Mucosal-Associated Lymphoid Tissue (MALT)?
It is the principal site for infections and allergic reactions, serves as an absorptive surface for food and oxygen, acts as a barrier against antigen penetration, and responds to antigens.
What role do commensal bacteria play in innate immunity?
They prevent adherence and penetration into the mucosa and are the main immune stimuli for neonates from microbial signals.
Define opsonization and name two types of opsonins.
Opsonization is the process by which pathogens are marked for ingestion and destruction by phagocytes. Two types of opsonins are immunoglobulins and complement protein fragments.
What are Pattern Recognition Receptors (PRRs) and what do they recognize?
PRRs are receptors that recognize pathogen-associated molecular patterns (PAMPs).
Name the types of PRRs and give one example of each.
Cellular: Scavenger receptors
Humoral: Collectins
Intracellular/Cytosolic: NOD-like receptors
Surface: Toll-like receptors (TLRs)
What are the functions of Toll-like Receptors (TLRs)?
TLRs bind to PAMPs, triggering immune responses such as cytokine production and inflammation.
List four examples of antimicrobial factors and their functions.
Salivary Peroxidase: Bactericidal effects
Lysozyme: Digests bacterial cell walls
Lactoferrin: Iron-binding to block bacterial growth
Histatins: Anti-fungal agents
What are antimicrobial peptides, and what is their mechanism of action?
Antimicrobial peptides are amphipathic cationic molecules that interact with membrane phospholipids to form pores in pathogens’ membranes.
What are the key functions of Natural Killer (NK) cells in innate immunity?
NK cells defend against viruses and tumors, produce interferon-gamma (IFN-γ), and contain perforin and granzymes for cell-mediated cytotoxicity.
Summarize the main characteristics of innate immunity.
Innate immunity is the first line of defense, versatile despite limited diversity, does not react against host cells, is activated only on microbial surfaces, and lacks immunological memory.
What are the main components of innate immunity?
Barriers (prevent microbial entry), circulating cells (neutrophils, macrophages, NK cells), and soluble factors (complement, mannose-binding lectin, C-reactive protein, cytokines).
