Chpt.14: T cell activation

T cells recognize soluble antigens directly in lymph

False. TCRs recognize presented antigens via MHC on APCs

Blood is the only fluid that circulates through the spleen

True

B7 proteins are constitutively expressed on all antigen-presenting cells

False. B7 (CD80/86) is only expressed by activated APCs

The marginal zone in the spleen is enriched with T cells

False. It contains phagocytes and marginal zone B cells

Dendritic cells migrate to the paracortex due to CCR7 expression

True

High endothelial venules (HEVs) allow blood entry into lymph nodes

True

T cells that do not receive signal 2 become anergic

True

IL-2 works in a paracrine fashion to stimulate T cell proliferation

False. IL-2 acts autocrinely on the activated T cell that produces it

The cortex of the lymph node is enriched with B cells

True

The cortex of the lymph node is enriched with B cells

False. CD4+ T cells are helpers, not killers

TH1 cells activate macrophages via CD40L and IFN-γ

True

MHC I is only used to activate CD4+ T cells

False. MHC I activates CD8+ T cells, while MHC II activates CD4+

Naïve T cells can enter lymph nodes through afferent lymphatic vessels

False. They enter via HEVs, not afferent lymphatics

The PALS region of the spleen is rich in B cells

False. It is rich in T cells

TH17 cells stimulate neutrophils via IL-17

True

Only professional APCs can activate naïve T cells

True

Tregs promote immune activation

False. They suppress immune responses

CD8+ T cells rely on IL-2 from CD4+ T cells for full activation

True

TFH cells migrate to the paracortex to help B cells

False. They migrate to the cortex, where B cells reside

All antigen-presenting cells have afferent and efferent lymphatic vessels

False. This applies to organs, not cells. The spleen, for instance, lacks afferent vessels

Granzyme release by CD8+ T cells leads to intrinsic apoptosis

True

CD28 is expressed only after T cell activation

False. CD28 is constitutively expressed on T cells

Tregs rely on TGF-β for differentiation

True

IL-4 induces B cell isotype switching to IgE

True

The paracortex of lymph nodes is the outermost layer

False. The cortex is outer; paracortex is deeper

CCR7 guides both dendritic cells and T cells to the paracortex

True

IL-21 is secreted by TH1 cells to activate macrophages

False. IL-21 is secreted by TFH cells to help B cells

Fas ligand on Tc cells delivers an extrinsic apoptosis signal

True

CXCL13 attracts T cells to the paracortex

False. CXCL13 attracts B cells to the cortex

IL-6 is an early cytokine that promotes TFH differentiation

True

The __________ region of the lymph node contains most of the B cells

Cortex

The receptor CCR7 is attracted to __________ and __________

CCL19, CCL21

Signal 1 in T cell activation is the binding of __________ to __________

TCR, antigen-MHC

Signal 2 in T cell activation is the interaction between CD28 and _________

B7

TFH cells secrete __________ and __________ to help B cells

IL-4, IL-21

Tregs are induced by the cytokine __________

TGF-β

The cytokine __________ is critical for TH17 function and neutrophil recruitment

IL-17

CD8+ T cells recognize antigens presented on __________ molecules

MHC I

Activated TH1 cells stimulate macrophages using CD40L and __________

IFN-γ

The __________ sheath in the spleen contains T cells

Periarteriolar lymphocyte (PALS)

The __________ receptor on B cells binds CXCL13 to localize them in the cortex

CXCR5

__________ are professional APCs that bridge innate and adaptive immunity

Dendritic cells

_________ chemokine is important for B cell localization in lymph nodes

CXCL13

The CD4+ T cell subset that helps clear intracellular pathogens is _________

TH1

Tc cells induce apoptosis by secreting perforin and _________

Granzymes

Which of the following is NOT a professional antigen-presenting cell?
A. Macrophage
B. Dendritic cell
C. B cell
D. Neutrophil

D. Neutrophil – Neutrophils are not APCs

Which region of the spleen is most enriched with B cells?
A. Red pulp
B. Marginal zone
C. PALS
D. Paracortex

B. Marginal zone – It has marginal zone B cells

What chemokine draws T cells into the paracortex of lymph nodes?
A. CXCL13
B. CCL2
C. CCL19
D. IL-2

C. CCL19 – Along with CCL21, it attracts CCR7+ cells

Which subset of CD4+ T cells is responsible for activating macrophages?
A. TH2
B. TH17
C. TH1
D. TFH

C. TH1 – TH1 cells help macrophages fight intracellular pathogens

Which of the following cytokines promotes differentiation into Tregs?
A. IL-12
B. IL-6
C. IL-4
D. TGF-β

D. TGF-β – Required for Treg induction.

What is the function of IL-2 in T cell activation?
A. Recruits neutrophils
B. Kills infected cells
C. Promotes T cell proliferation
D. Activates dendritic cells

C. It’s an autocrine growth factor

Which structure in the lymph node is rich in B cells?
A. Paracortex
B. Medullary sinus
C. Cortex
D. HEV

C. Cortex – The follicular zone contains B cells

Which CD4+ subset helps activate B cells via IL-21?
A. TH1
B. TH2
C. TH17
D. TFH

D. TFH

Which interaction prevents T cell anergy during activation?
A. TCR-MHC
B. CD40-CD40L
C. CD28-B7
D. IL-4–IL-5

C. CD28-B7 – Signal 2 is needed to prevent anergy

What do CD8+ T cells recognize on infected cells?
A. IgG
B. MHC II
C. Complement
D. MHC I with antigen

D. MHC I with antigen