L1 Antigens , T/B Cell Antigen Receptors, Clonal Expansion - Hudig Flashcards
What are the four types of pathogens that the immune system must resist?
- Bacteria
- Yeast and Fungi
- Viruses
- Parasites
Are bacteria intra or extra cellular?
both
Extracellular bacteria get coated in (blanks) to allow them to be phagocytized by (blank)
antibodies
neutrophils
What T-cell type initiates the host macrophage response to intracellular bacteria?
TH1
What molecule does TH1 release to stimulate host macrophage killing of intracellular bacteria?
IFN gamma
A (blank) is an Ab that binds to yeast
opsonin
Are yeast and fungi intra or extracellular?
extra
Are viruses intra or extracellular?
intra
Can viruses spread without shedding particles? How?
Yes, by fusing tissues into a syncytium
What CD class is used to target viruses?
CD8
T/F: Ab always prevent viral entry
False, only some of the time
Are parasites intra or extra cellular?
extra
What cell type controls viruses in innate immunity?
NK cells
what cell type controls viruses in adaptive immunity?
CD8 CTLs
What are the three features that distinguish adaptive from innate response?
- SPECIFIC for a unique pathogen
- invloves T and B lymphocytes with specific Ag receptors
- Generates Ag-specific MEMORY
T/F: TCRs can recognize free viral proteins in serum
FALSE
What MHC class does CD4 recognize?
MHC II (4x2=8)
What MHC class does CD8 recognize?
MHC I (8x1=8)
Does innate or adaptive immunity elminate an infection faster?
ADAPTIVE
Are the T and B Ag receptors directly genome encoded?
NO
What cells effect cell-mediated immunity?
T cells
What three things can recognize an antigen?
t cells, b cells, and antibodies
What types of macromolecules can be used as Ags for Abs?
proteins, CHOs, and lipids
Is naked DNA, or single stranded RNA a common antigen?
NO
What type of macromolecule can be used as a T cell Ag?
PEPTIDES only!
What protein must the peptide Ags be bound to to be recognized by the TCR?
MHC
What can used as a B cell antigen?
anything, including antibiotics!!
How many chains make up the TCR receptor? What are their combinations?
Alpha/beta or delta/gamma
T/F: CD3 is on all T cells
True
what is the function of CD3
helps signal that the receptor has bound AG
Can you be both CD4 and CD8?
NO
Do CD proteins bind to the Ag or to the MHC molecule?
MHC
Does the TCR bind to the Ag or to the MHC?
to the Ag
Where does the foreign substance (ag) bind on the B-cells?
Ig receptor
How many light and heavy chains does an Ab have?
2 of each
Are the light chain and heavy chain copies identical, repsectively?
yes
What are the two types of light chains?
Lambda and kappa
T/F: Ag binding requires the interaction of the light chain with the heavy chain
true
What holds the light chains to the heavy chains?
disulfide bridges
How many amino acids or linear sugar molecules can the Ag binding site recognize?
6
What does the constant region of the Ab determine?What chain makes up this region?
Ig class and subclass; the heavy chain
What is the function of the hinge region?
to swivel to optimize binding
What is the Fab? Where is it cleaved? Is it a monomer or dimer?
The antigen binding fragment, cleaved WITHIN the hinge itself, releases two monomers
What is the Fc?
the crystallizable region of the antibody; pure protein with no variation
When cleaved BELOW the hinge, what fragment is created? what makes it special?
F(ab’)2: won’t clear the kidneys as fast and has double the binding capacity because it is a DIMER
How many different TYPES of receptors does each T-cell express?
just one!
Describe clonal proliferation?
- APC presents a peptide Ag to a T helper cell
- T helper divides and produces IL-2
- IL-2 stimulates B-cell differentiation.
What T cell class is necessary to begin the immune response?
T Helper!
What region on the ab holds the Ag in place?
the CDR: complementarity determining region
T/F: Ab to Ag binding is covalent
NO NO NO
IgG1 and IgG3 bind receptors on (blank) cells
neutrophils
Binding of IgG1/3 to neutrophils allows them to do what?
recognize opsonins and eat the fungi and yeast
What is linear determinant for a b cell Ag?
Can bind to the peptide primary sequence; will still bind if denatured
what is conformational determination for b cell ag?
Secondary and tertiary structure dependendant: MAIN binding region is the FOLDED protein, but CAN STILL BIND denatured protein, just not as strongly
What is a neoantigenic determinant for b cell AG?
Any time you cut a protein you get new termini; this new “protein” is recognized as foreign and can stimulate autoimmunity
Can a single Ab recognize linear, conformational, and neoantigenic determinants?
Yes! (with varying binding strength mind you)
What is the first antibody produced in response to infection?
IgM
What antibody allow for antigen memory?
IgG
