Exam I part II Flashcards
Which stage of B cell development is antigen drive?
differentiation
What is produced during maturation phase?
mature naive B cell that expresses both IgM and IgD, cannot undergo VDJ rearrangement
major outcomes of differentiation
plasma and memory cells
3 major classes of B cell antigens
T-independent 1, 2 and T dependent
What induces T dependent B cells? T independent?
bacteria (protein), bacteria (LPS)
T-independent B cells
polysaccharide Ag attach BCR -> B-1 cell and marginal zone cell production -> produce IgM and low affinity AB, short lived plasma cells
Importance of somatic hypermutation
can increase (memory cells and isotope switching), decrease or have no effect on Ag binding affinity. modest affinity = plasma cell
Neutralization
blocks toxin, virus or venom from binding to host cell
Ag binding region of Ig? Immune effector function region
variable region, constant (Fc)
L chain isotopes, H chain
L = k and lambda (no functional difference) H = µ, delta, gamma, epsilon and alpha (determine Ig)
Common Ig before isotope switching
IgM
portion of Ag that binds Ab
epitope
ability of organism to harm host
pathogenicity
measurement of level of pathogenicity
virulence
How do phagocytes kill?
via ROS, RNS or oxygen independent mechanisms
targets of intracellular bacteria
epithelial cells, endothelial cells, hepatocytes, macrophages
hyper activated macrophage
macrophages enhanced by Th1 cells to dispose of invaders but can also cause side effects and harm host
cardinal signs of inflammation
heat, redness, swelling, pain and loss of function
two phases of inflammation
vascular = vasodilation, increased vascular permeability cellular = cell trafficking, phagocytosis, killing and degradation
cause of acute inflammation
physical/chemical damage
cause of chronic inflammation
persistent infection
acute immune cells
neutrophils, monocytes/macrophages, mast cells and sometimes eosinophils/basophils
chronic immune cells
monocytes/macrophages, T cells, sometimes neutrophils
foreign body granulomas
response to suture
infectious granuloma
tuberculosis, leprosy, histoplasmosis, cryptococcosis
immune non-infectious granuloma
sarcoidosis, Crohn’s disease
NALT inductive site, effector site
tonsils, lacrimal and nasal glands/salivary glands
two methods of Ag sampling in gut
M cell transcytosis - CCR6+ DCs
direct sampling from lumen by CXCR1 + DCs
location and function of M cells
gut epithelium, Ag sampling
mucosa type in BALT? NALT
type I; Ag sampling by DCs
type II; Ag sampling by M cells and DCs
inductive site in BALT? effector site
bronchial epithelium, bronchial glands and mammary glands
How does Ag exposure induce response at distant effector?
lymph drainage and migration of T and B cells
main constituents in SALT
epidermis = non vascularized basal mem dermis = lymph and blood vessels hypodermis = passive barrier defense
Where are langerhans cells
SALT, epidermis
