Overview of immune system Flashcards
Autoimmunity
when self reacting cells persist and are not destroyed
Most abundant wbc
neutrophils
Mature PMN
multi lobed; segmented
Immature PMN
nonsegmented bands
Which cells are APCs
dendritic cells, macrophages, b cells
MHC is also known as
HLA
MHC I is found on
most cells
MHC II is found on
APCs
Which cells are granulocytes
neutrophils, eosinophils, basophils
Which cells are agranulocytes
monocytes, lymphocytes
Which lymphocytes make up majority
T cells
T cells have which antigens on their surface
CD4 and CD8
CD4 is found on surface of which cells
helper T (make up majority)
CD8 is found on surface of which cells
cytotoxic T cells
What are the two types of helper T cells
TH1 and TH2
Th1 cells produce
IFN gamma and TNF alpha
What role doe IFN gamma and TNF alpha play
activate macrophages during INTRAcellular infection (viruses, bacteria)
Th2 cells produce
IL-4, IL-5, IL-6
What do IL-4/5/6 do
activate B cells
Immunogen
substance that can produce humoral or cellular immune response and react with product of that response
Antigen
substance that reacts with antibody or T cell but may not be able to initially trigger response
Epitope is found on
antigen
Paratope is found on
antibody hypervariable region; recognizes epitope
Pepsin
enzyme that breaks bonds of antibody molecule into 1 FAB and 1 Fc
Papain
enzyme that breaks bonds of antibody into 2 FAB and 1 Fc
Complement fixation occurs at which region of antibody
Fc
Examples of active/acquired immunity
natural- infection/exposure
artificial- vaccination
Examples of passive immunity
- Ig crossing placenta
- breastmilk
- gammaglobulin and antibody injections
Examples of adoptive immunity
- anti cancer treatment
- introduction of NK cells
What does undifferentiated stem cell in bone marrow become
progenitor B cell (pro- B cell)
What does pro B cell have on its membrane
CD45R
What does pro B cell become
pre B cell
What does pre B cell have on its membrane
IL-7 receptor
What does pre B cell become
mature B cell
What stage of B cell maturation does gene rearrangement occur
pro B cell
Variable region of immunoglobulin contains
antigen binding site- Fab
Constant region of immunoglobulin determines
immunoglobulin class
Fab (fragment antibody) contains
antigen binding site and variable region
Fc (fragment crystallizable) contains
constant region
Isotype
unique AA sequence common to all Ig molecules in a given species; differs between Ig classes (IgG, IgM, etc). ** heavy chains
Allotype
minor variation of AA sequence present in some individuals but not others
** constant regions
Idiotype
variable portion is unique to specific antibody molecule, due to differences in heavy and light chains ** variable region
Only Ig that can cross the placenta
IgG
Which Ig activates classical pathway
IgG
IgG is a monomer, T or F
true
Serum IgA is a monomer or tetramer
monomer
Secretory IgA is a monomer or tetramer
tetramer
IgM is a pentamer, T or F
true
Where is IgD found
bound to mature B cells
Classical pathway requires antibody for activation, T or F
true
Alternate pathway does not require antibody for activation, T or F
true
Complement fragments are sensitive to
heat
Three units in classical pathway
recognition, activation, MAC
Components of recognition unit
C1q, C1r, C3
Components of activation unit
C4, C2, C3
Components of MAC
C5-C9
CH50 assay screens for
function of classical pathway
How is CH50 interpreted
indicated by dilution that lyses 50% sheep RBC
- if zero = no complement
- if low= any factor is deficient
AH50 assay screens for
alternate pathway function
If both CH50 and AH50 are abnormal, what complement components are defective
C3 or C5-C9
If only CH50 is abnormal, which components are defective
C1, C4, or C2