Lecture 2 8/29/23 Flashcards
What are the functions of memory cells?
-rapid recognition
-stronger adaptive response
-long-term protection
How does the immune system determine which type of memory cell will persist following an infection?
-whichever type of adaptive response worked better, that type of memory cell will persist
-cell-mediated worked better: memory T cells persist
-humoral worked better: memory B cells persist
Why do memory cells of only the best-working type of adaptive response persist following an infection?
body can save resources/energy by only stimulating this type of response during next exposure instead of both responses
How can pathogens bypass physical barriers?
-skin abrasions
-having large #s that overcome barrier
-burns
-mosquito/tick bites
-vitamin and/or mineral deficiency
What cells are produced via the myeloid pathway?
-erythrocytes
-platelets
-granulocytes
-macrophages/monocytes
What cells are produced via the lymphoid pathway?
-NK cells
-innate lymphoid cells
-adaptive immune response cells
What cells fall under the granulocyte category?
-neutrophils
-mast cells
-basophils
-eosinophils
-macrophages
What are the characteristics of granulocytes?
-most common WBC
-contain enzymes and granules in cytoplasm
Which granulocyte is the most abundant?
neutrophils (40-60%)
What are the characteristics of neutrophils?
-phagocytic cells that attack and destroy
-move rapidly but lack stamina
-can cause collateral damage
-rapidly mobilized
How do neutrophils kill?
-hydrogen peroxide
-hypochlorite ions
-bactericidal granules
-lactoferrin
-enzymes
How can neutrophils be identified microscopically?
they have irregular, sausage-like/segmented nuclei
How do neutrophils behave in the bloodstream?
-normally circulate and bounce off vessel walls
-vessel walls become “sticky” in inflamed tissues and neutrophils stick to them
What is the role of selectins?
to slow down neutrophils as they roll along vessels
Which selectin is present on neutrophils?
L-selectin
Which selectin is present on vessel walls?
P-selectin
What is the role of integrins?
cause neutrophil to strongly adhere to vessel walls
Which integrin is present on neutrophils?
LFA-1
Which integrin is present on vessel walls?
ICAM-1
What is diapedesis?
the movement of neutrophils through a vessel wall and into inflamed tissues
What are the stages of phagocytosis?
-phagosome
-phagolysosome
-intracellular destruction
What is a phagosome?
stage that occurs when the cell membrane fuses around a microorganism
What is a phagolysosome?
stage that occurs when phagosome fuses with a lysosome (filled with bactericidal granules)
How are microorganisms killed in phagocytosis?
-hydrogen peroxide
-hypochloride
What happens if a microorganism is too large for a neutrophil to phagocytose?
they will deploy netosis
What is netosis?
-release of a neutrophil extracellular trap
-trap is formed from sticky DNA containing antibacterial molecules
-net captures and kills microorganisms
When are mast cells present?
-parasitic infections
-allergies
When are basophils present?
-tick infestations
-allergies
When are eosinophils present?
-worm infestations
-allergies
What are the characteristics of macrophages?
-move slowly but are more powerful phagocytes
-kill bacteria that defeat neutrophils
-located in tissues and blood stream
What other names are used for macrophages?
-microglia (brain)
-Kupffer cells (liver)
-histiocytes (liver)
-monocytes (blood)
-alveolar macrophages (lungs)
What can monocytes differentiate into?
-macrophages
-dendritic cells
What is the role of M1 macrophages?
phagocytize microbes and initiate immune response
What is the role of M2 macrophages?
remove dead and dying cells and repair tissues as fast as possible
Which macrophages differentiate in M1 macrophages?
M0 macrophages
Which macrophages differentiate into M2 macrophages?
M0 and M1 macrophages
How do macrophages kill?
-nitric oxide
-reactive oxygen intermediates
What makes innate lymphoid cells “innate?”
-present at all times
-do not need to be induced
-activated through monoclonal receptors
-functional/available before T cell generation
-not specific
-do not form memory
How do natural killer cells kill?
-perforin
-granzymes
What are the characteristics of natural killer cells?
-first line of defense
-do not require activation
-no memory
-not specific
What cells are targeted by NK cells?
-cells with changes in cell surface proteins (associated w/ damage)
-tumor cells and virus-infected cells
