Immunology Exam 2

cytochrome c

causes a conformational change in Apaf-1 and forms into an apoptosome

apoptosome

intrinsic pathway, activates caspases

FasL

extrinsic pathway, helps formation of DISC

DISC (death inducing signaling complex)

activates pro-caspases

Pro-caspases

activate downstream caspases

3 types of cytotoxic granules

1. Perforin

2. Granzymes

3. Granulysin

Perforin

creates a pore in the target membrane cell

Granzyme

2 main functions: induces release of cytochrome c and can directly activate caspases

Two types of cytokines that CD8 cells secrete

TNFα and IFNγ

IFNγ function

3 main functions:

1. causes higher expression of MHC1

2. reduces viral replication

3. activates more macrophages = more chemokines = more CD8 cells

TNFα function

binds to TNFR-1 receptor to induce the extrinsic apoptotic pathway

primary foci

activated b cells form this after meeting a t cell, place of early antibody production

germinal center

some activated b cells move into follicles with TFH cells and form an area where b cells undergo somatic hypermutation and affinity maturation

somatic hypermutation

mutations created in the v regions of the B cells on steroids

affinity maturation

the b cells that have BCRs that have higher affinity with the antigen are selected for further proliferation

v region of b cells

antigen specificity

class switching

allows antibodies to turn into other types instead of the og IgM

Ig type is determined by

c region

DNA recombination in the Cμ gene and other C regions causes

production of different antibodies

somatic hypermutation changes the

v region

class switching changes the

c region

different Fc receptors recognize

different antibodies

what are Fc receptors?

they are receptors on immune cells that recognize antibodies. they help determine what happens after the antibody binds its target

Fc receptors are responsible for

allowing phagocytosis of pathogens with polysaccharide capsules (bacteria and fungi)

Cross presentation

peptides from inside the cell are loaded onto MHC 1 by dendritic cells, activating CD8 cells.

Fc portion of the antibody is responsible for

recognizing the antigen

TFH Cell stands for

T follicular helper cell

what is the epitope?

the region on the antigen that is recognized by the antibody

how many heavy and light chains does an antibody have?

2 heavy chains and 2 light chains

how many fab fragments and Fc fragments are on an antibody?

2 fab fragments and 1 Fc fragment

which antibodies can form multimers at their Fc region?

IgM and IgA

IgA is found in

mucosal surfaces

IgM recognizes _____ and is part of the ______ pathway and the ______ system

repetitive structures, classical, complement

this antibody is most abundant in blood and tissue, and can pass through the placenta

IgG

IgD antibodies work with

B cell receptors

IgE is involved in ______

allergies

what are the 3 antigen-presenting cells?

dendritic cells, macrophages, and B cells

what’s special about yS T cells?

they don’t need MHC to recognize antigens

what is the CD3 complex required for?

if the MHCs are responsible for allowing the T cells to recognize the antigen, the CD3 complex is required for the signaling that comes after

What does the CD3 complex work with?

the ITAM proteins, have a total of 10 sequences

PLC-y function

breaks down the membrane lipid into DAG and IP3

IP3 function

increases cytosolic Ca2+

Calmodulin-calcineurin complex function

activates in high Ca2+ levels, dephosphorylates NFAT

NFAT function

helps the T cell start its response

function of RAG1/RAG2

both immunoglobulin and TCR rearrangement, recognize the 12/23 RSS sequences and cleave the DNA

function of TdT

adds random nucleotides to the ends of the cleaved DNA in recombination

CDR1 and CDR2 function in recombination

recognizes the MHC molecules

CDR3 function in recombination

recognizes the peptide loaded in the MHC

where is MHC1 located?

on the rough ER

where is MHC2 located?

on the surface of antigen presenting cells

autophagy

process where a cell breaks down its own organelles and proteins

autophagosome function

picks up antigens and loads them onto the MHC2

proteosome function

degrades proteins in the cytosol through ubiquitination

ubiquitin binding to protein outcomes

1. marked for degradation by proteosome

2. relocation in the cell

3. promotes or prevents interactions with other proteins

TAP1 AND TAP2 Function

forms a heterodimer and delivers peptides that were broken down by the proteosome to the MHC1

Calnexin function

does quality control of the MHC1 folding

PLC stands for

protein loading complex

ERAAP function

trims peptides that are too long for the MHC1

CLIP function

prevents peptides from binding to the MHC2

HLA-DM function

removes CLIP from MHC2 and keeps it in an open conformation, allowing peptide to bind

MHC genes are _____ and _____.

polygenic, polymorphic

bone marrow stromal cells

control lymphocyte proliferation and differentiation

VDJ recombination happens in what stage

pro-b cell stage

Cμ codes for

IgM

what happens when it reaches the pre-b cell stage?

recombination is stopped, proliferation starts, then recombination starts again for the LIGHT CHAIN

if no functional light chain is formed, what happens?

apoptosis

a pre-b cell with a functioning heavy and light chain become a

immature b cell

central tolerance function

testing if the immature b cell reacts to self-antigens

if the immature b cell reacts to self-antigens

RAGs try to rearrange the light chain. go through clonal deletion

if the immature b cell doesn’t react to self-antigens

the immature b cell can migrate to secondary lymph organs

peripheral tolerance function

see if the immature b cell reacts to any other antigens, undergo clonal deletion

clonal deletion

elimination of self-reactive b cells

final b cell maturation occurs in the

spleen

BAFF

a survival signal that immature B cells get in the white pulp to mature

immature b cells will die in ____ days if they don’t receive a survival signal

2-3

mature b cells express high levels of

IgD

Follicular B cells remain in the

bloodstream

Marginal zone B cells remain in the

spleen

B-1 B cells

originate from the fetal liver, not the bone marrow

developing t cells are called

thymocytes

the cortex of the thymus contains mostly

immature thymocytes

all TCRs express ____ on their membrane

CD3

When thymocytes arrive in the thymus, they are

CD3+, CD4- CD8- (double negative)

the medulla of the thymus contains

more mature thymocytes, dendritic cells, B cells, and macrophages

ETP stands for

early thymic progenitor

Notch

how early thymic progenitors interact with the thymic epithelial cells

Notch causes the activation of

GATA3 and TCF1

GATA3 and TCF1 are responsible for expression of

CD3, CD4, CD8, RAG1, RAG2

in TCRs, VDJ rearrangement starts with the ____ chain.

beta

once CD4 and CD8 are expressed on the pre-T cell receptor,

rearrangement of the alpha chain begins

positive selection function

selects thymocytes whose TCRs can recognize self-MHC complexes, determining their CD4/CD8 lineage

Negative selection function

eliminate the thymocytes that interact too strongly with the MHC

AIRE gene function

causes the cells in the medulla to express proteins from all over the body to expose the T cells to them. if they react too strongly to the proteins, they will be eliminated

STATs are a cytokine family that

is involved in class switching

activation of the adaptive immune system takes place in the

lymph nodes

high endothelial venules (HEV)

how T cells and B cells enter the lymph nodes

immunological synapses function

keeps the T cell and antigen presenting cell together

what are the 3 signals antigen presenting cells need to activate a T cell?

recognition, co-stimulation, and soluble mediators

clonal contraction

elimination of t cells after clearing out pathogens

3 waves of TCR signaling

transcription factor activation, inflammatory cytokines activation, clonal contraction