Exam 4 Flashcards
(87 cards)
viral infection
lymphocytes > neutrophils
acute bacterial infection
leukocytosis (elevated WBC) and elevated neutrophils
parasitic infection
elevated eosinophils
Basophils
least common
allergic and helminth responses
release histamine and heparin (decreased clotting and increased blood flow from vasodilation)
Eosinophils
particularly found in GI and respiratory tracts
asthma and allergic reactions
release leukotrienes (airway smooth muscle contraction)
Neutrophils
most abundant "first responders" strongly phagocytic respond to and subsequently release cytokines to amplify immune response release anti-microbial proteins
Mast Cells
basophils that mature in the tissues
release histamine and heparin
massive release of histamine = anaphylaxis and body-wide vasodilation
Monocytes
differentiate into dendritic cells and macrophages when stimulated by pathogens
50% migrate to spleen
Dendritic cells
antigen-presenting cells (APC)
migrate to nearest lymph node once antigen is captured and presents to T and B cells
Langerhans cells = specialized dendritic cell in the skin
Macrophages
APC
large phagocytes
skin, lungs and GI tract
resting, primed and hyper-activated stages
Kupffer cells
specialized macrophages of the liver
destroy bacteria and old RBCs
*chronic activation via EtOH causes overproduction of inflammatory cytokines and chronic inflammation (cirrhosis and CA)
Natural Killer Cells (NK cells)
cytotoxic lymphocytes that do NOT need to recognize pathogen to kill it
killing activity enhanced by cytokines released from macrophages
kill via releasing perforins and proteases that cause cell membrane lysis or trigger apoptosis
opsonization
enhancing phagocytosis of antigens by “marking” them for destruction
membrane attack complex (MAC)
complement cascade resulting in cell lysis via puncturing cell membrane
humoral immunity
type of adaptive immunity
B cells and antibodies
defense against extracellular pathogens (ie. S. pneumonia, M. catarrhalis)
cell-mediated immunity
type of adaptive immunity
T cells and APCs (dendritic cells and macrophages)
defense against intracellular pathogens (ie. virus, fungi, protozoans)
secondary lymphatic organs
spleen
lymph nodes
tonsils
MALT (mucosal associated lymphoid tissue)
MHCII
B cells
dendritic cells
activated macrophages
thymic epithelial cells
T helper cells
T cell receptors and CD4 co-receptors
MHCII molecule presents antigen and has binding site for CD4
activated cells release cytokines to direct immune response
different subtypes activate different cells
T memory cells
recognize antigens from previous exposure
T regulatory (suppressor) cells
prevent immune reactions from getting out of hand
T killer cells (cytotoxic)
activated by T helper cells
CD8 co-receptor
MHCI molecules present antigens
secrete perforin and cytotoxins to cause cell death
primary response
IgM “iMmediate” produced first
IgG follows
B memory cells persist
secondary response
subsequent encounter with same antigen
previously generated B memory cells activated rapidly
IgM formed, but IgG most involved