20: Immunology Flashcards
opportunistic pathogen
pathogen that only causes disease in at risk individuals
What are some features of the innate immune system?
genetically encoded, present at birth
physical barrier to infection (skin and mucous membrane)
specialized cellular defenders
nonspecific response to destroy invading cells(indescrimininently)
What are some features of the adaptive immune system?
adaptive through organisms life
specialized cellular defenders
specific antigen rxn
What is an antigen?
any chemical compound or structure foreign to the body that elicits immune response
What are some characteristics of physical barriers?
exposed to the external environment
colonized with microbes
invasion barrier
What is a prime example of a physical barrier?
mucus membranes exposed to the environment with tight junctions
What is the physical defense system of the skin?
Sheds dead skin cells and regenerates epithelial cells
What are the chemical defense systems of the skin?
acidic, dry, salty, can lyse bacterial cells
salt can increase osmotic stress
sebum and keratin
antimicrobial peptides
What is sebum?
Oil secreted by the skin that lowers the pH to target acid sensitive organisms
What is keratin?
material that repels water and decreases H2O availability
What are antimicrobial peptides(defensins)?
small, antimicrobial cationic peptides that are hydrophobic and attract negative charge to create pores
What are the two classes of defensins?
alpha defensins: stored in cytoplasmic granules
beta defensins: not stored on granules, released on skin
What is the mucous membrane?
A single layer of cells that has tight junctions that act as a physical barrier between cells. Membranes are covered in secretion and have movement systems in place
What are some chemical defenses ?
acidic, nutrient deprived, lyses cells,
stomach acid, antimicrobial peptide, lysozyme
What is lactoferrin?
Chemical defense that sequesters iron by binding iron tightly to prevent bacteria from taking it up. If no iron present, bacteria are forced to ferment which limits bacteria
What is the respiratory epithelium?
cilia that push mucus out of lungs into throat
What are the interior defenses of the cell?
MAMPS,PRR,TLR, NLR
What are MAMPS?
membrane associate molecular patterns that mark a microbe as foreign.
Attached to techie acids, LPS, PG, flagellum. F-met peptides
What are TLRs?
Type of PRR, toll like receptors are located on the cell surface and can bind flagella, technic acids, flagellin, LPS to signal cytokine synthesis
What are NLRs?
Type of PRR in the cytosol of a cell, recognize intracellular pathogens, bind MAMP, trigger cytokine and inflammasome synthesis
What is a PRR?
a pattern recognition receptor is an alarm system that is activated when intruders sensed
sense MAMPS
What is a cytokine?
triggered by a PRR, they are the alarm that recruit phagocytes to the infection site to activate phagocytes.
What are the main types of phagocytes?
macrophages, neutrophils, phagolysozomes
What is a macrophage?
a monocyte that is present in the body and always ready. Can phagocytose the cell
What is a neutrophil
short lived, and only recruited to wound site
contain granules with defensin, protease and lactoferrin
engulf microbe by phagocytosis
What is NETosis
neutrophil spews neutrophil lactic work to trap and kill microbes in intermediate area with antimicrobial peptides
after infection
What is a phagolysozome?
has ROS that kill bacteria
filled with digestive enzymes (protease, lysozyme, defensin)
generate RS that kill organism
What are the innate origins?
CGAS PRR and STING
