immunology exam 2

surface Ig other name

BCR

Secreted Ig other name

antibody

antigen

anything antibody binds to

somatic recombination

mixing and matching of VDJ segments

RAG1/RAG2

recombination enzyme complex

combinatorial diversity

diversity from V,D,Js

Junctional Diversity

added nucleotides, not from inherited gene, nucleotides, n-nucleotides

p-nucleotides

RAG1/RAG2 adds (junctional diversity)

n-nucleotide

TDT enzyme adds (junctional diversity)

B-cells

what develops in BM

HSC

stromal cell promotes growth of

steps of B-cell development

HSC, pro-B, Large Pre-B, Small Pre-B, immature B

self tolerance

removing or inactivating self-reactive T+B cells

Central self-tolerance purpose

to kill or inactivate self-reactive B-cells

central self tolerance location

during development in BM and thymus is location of what

B-cell doesn’t bind anything

good, can leave BM

Binds antigen on surface of another cell (ex.stromal)

apoptosis or retry LC rearrangement if unsuccessful, undergo apoptosis

BCR binds soluble antigen

anergy, lives but inactivated

peripheral self-tolerance purpose

killing / inactivation after T&B cells are mature and in circulation

TCRs

peptides presented by MHC molecules interact with what

which TCR region rearranges first?

Beta chain (VDJ)

which TCR region rearranges second?

alpha chain (V-J)

CD4

MHCII binds which T-cell

CD8

MHC I binds which T-cell

MHCI

which MHC is found on all cells

on macrophages, dendritic cells

where is MHCII found?

Dendritic cells

bridge between innate and adaptive system, presenting antigens to T cells and activating them, activate adaptive

through phagocytosis and pinocytosis (sample fluid) dendritic

how do DC get peptides?

Dendritic cell

Antigen Presenting Cells (APC) is the job of

combo of MHC and peptide

how do TCR bind?

MHCI

endogenous peptides (here’s what’s inside of me) is presented by

MHCII

exogenous cells (“here’s what I found outside of me") is presented by

MHCI

TAP, proteosome used in which antigen processing

MHCII

lysosome used in which antigen processing

invariant chain

blocks MHCII so no MHCI peptides bind

No

can MHC be on surface without a peptide?

T-cells

thymus is where what develop?

3 steps of t-cell

gene rearrangement, positive selection, negative selection

steps of T-cell -/+

DN, DP, SP

proteins that starts T-cell signal transduction

CD3 - 6 protein cluster

proteins that starts B-cell signal transduction

IG-alpha, IG-beta

cortical epithelial cells

positive selection, MHCI, MHCII on surface, all peptides are self for positive selection

where does positive selection occur?

cortex

where does negative selection occur

medulla

what cells are involved in negative selection?

medullary epithelial cells, MØ, DC

Negative selection

Is TCR self reactive?

Why does T-cell selection need to be so strong?

they activate B-cells

positive selection ideal outcome

interacts with MHCI or MHCII

what do medullar epithelial cells express?

AIRE

AIRE

causes expression of proteins that are normally only in specific tissue

what does AIRE help do

helps eliminate self-reactive T-cells

what happens in an AIRE deficiency?

widespread multi-target autoimmunity

human MHC

HLA: human leukocyte antigen

MHCI varities

HLA-A, HLA-B, HLA-C, coexpressed

MHC varities

HLA-DP, HLA-DQ, HLA-DR, co-expressed

organ donor compatibility is based on what?

HLA compatibility

relationship between HIV and MHC diversity

more diversity = slower onset

HIV impact on cells

kills CD4 T-cells

Mature naive T&B

stage when leave BM, thymus but hasn’t encountered antigen

when are memory cells created?

after activation from encountering an activating pathogen

where do naive cells go?

enter blood, home to 2º lymphoid organs

lymph

clear fluid that drains out of blood and back into lymphatic vessels, moved by bodily movement

high endothelial venue

blood vessel that runs through lymph node, how b and t cells arrive at lymph node

chemokines involved in adhesion process in lymph nodes

CCL19, CCL21

adhesion molecule for naive t and b cells

L-selectin

FDC

follicular dendritic cells

what does FDC do?

secrete CXCL13 to attract B-cells

dendritic are activated…now what

increase MHC, express B7, migrate through lymphatic vessels

chemokine expressed by DC

CCL18

how are T-cells activated

TCR/MHC peptide binding AND B7/CD28 binding

clonal expansion

low affinity IL-2 receptor becomes high affinity upon activation, IL-2 expressed, signals back to itself to divide

why don’t non-activated t-cells clone?

their IL-2 receptors are low affinity, so don’t bind