Immunology B Cell Activation Quiz

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Which type of antigens can activate B cells independently of THelper cell function?

Thymus-dependent antigens
Thymus-independent antigens (correct)
T-cell dependent antigens
Antigen presenting cells

What is the main function of TI-1 antigens?

Stimulate antibody affinity maturation
Induce clonal expansion of T cells
Cause polyclonal activation of B cells (correct)
Activate only mature B cells

What is the role of the B cell co-receptor complex?

Present antigens to T cells
Produce cytokines for T cell activation
Directly process antigens for MHC presentation
Enhance receptor signaling and activation (correct)

Which antigen class consists of highly repetitive structures that activate B cells by cross-linking BCRs?

TI-2 antigens (B) Signup and view all the answers

What is primarily produced by B cells activated through thymus-independent antigens?

Low-affinity IgM antibodies (B) Signup and view all the answers

What key role does CD21 play in B cell activation?

Facilitates binding of BCR to pathogens (A) Signup and view all the answers

Which group of B cells predominantly responds to thymus-independent antigens?

Marginal zone B cells (A) Signup and view all the answers

What is the primary function of CD40 activation on B cells?

Promotes B cell survival through NFκB activation (C) Signup and view all the answers

Which of the following cytokines is NOT mentioned as a signal provided by TFH cells to activate B cells?

IL-10 (C) Signup and view all the answers

What role do macrophages in the subcapsular sinus (SCS) of lymph nodes play?

They express complement receptors to capture antigens (A) Signup and view all the answers

What type of cells do centroblasts differentiate into within the germinal centre?

Centrocytes (C) Signup and view all the answers

Where are primary foci of activated B cells primarily located?

In the medullary cords of the lymph node (D) Signup and view all the answers

What characterizes plasma cells in terms of their lifespan and function?

Long-lived and migrate to bone marrow for continued antibody production (C) Signup and view all the answers

What is the role of TFH cells in the formation of germinal centres?

They participate with B cells to sustain and enhance B cell proliferation (C) Signup and view all the answers

What migratory change occurs in activated B cells after receiving T cell help?

They downregulate CCR7 and move away from the T cell zone (B) Signup and view all the answers

What is the defining structural component of a germinal centre?

A mantle zone, light zone, and dark zone (C) Signup and view all the answers

What type of antigens activate B cells through polyclonal activation without requiring THelper cell function?

Thymus-independent antigens (A) Signup and view all the answers

Which mechanism is involved in the activation of B cells by TI-2 antigens?

Cross-linking of B cell receptors (C) Signup and view all the answers

What is a characteristic feature of TI-1 antigens in relation to B cell activation?

They cause proliferation of both immature and mature B cells (C) Signup and view all the answers

Which statement accurately describes the role of CD19 in B cell activation?

It amplifies the signal after BCR phosphorylation (C) Signup and view all the answers

Which of the following correctly describes the response of B cells to TI antigens?

They produce predominantly low-affinity IgM antibodies (B) Signup and view all the answers

What type of B cells predominantly respond to thymus-independent antigens?

Marginal zone B cells (B) Signup and view all the answers

To what does the term 'thymus-dependent antigens' refer?

Proteins that require THelper cell interaction for B cell activation (B) Signup and view all the answers

Which of the following signals is crucial for B cell differentiation into plasma cells?

Second signal from THelper cells (C) Signup and view all the answers

What role does IL-21 play in the activation of B cells?

Promotes B cell proliferation and differentiation (B) Signup and view all the answers

Which statement about linked recognition is true?

It necessitates the physical association of the peptide recognized by T cells with the antigen recognized by BCR. (A) Signup and view all the answers

Where do the primary foci of activated B cells develop?

In the medullary cord of the lymph node and red pulp of the spleen (B) Signup and view all the answers

What is the function of centrocytes in the germinal centre?

To reduce their rate of division and reenter the light zone (D) Signup and view all the answers

What distinguishes secondary lymphoid follicles from primary lymphoid follicles?

Existence of germinal centres and their supportive structures (A) Signup and view all the answers

What role do follicular dendritic cells (FDC) play in the immune response?

They express complement receptors and trap immune complexes. (D) Signup and view all the answers

What occurs when activated B cells downregulate CCR7?

They initiate plasmablast formation. (C) Signup and view all the answers

What is a characteristic feature of plasma cells after differentiation?

They migrate to the bone marrow to produce antibodies continuously. (C) Signup and view all the answers

Which cytokine signaling is associated with regulating antibody class-switching?

IL-4 (D) Signup and view all the answers

Which receptor is crucial for the retention of centroblasts in the dark zone of the germinal centre?

CXCR4 (B) Signup and view all the answers

Antigens that require THelper cell function to induce B cell activation are called ______ antigens.

thymus-dependent Signup and view all the answers

Antigens that activate B cells without THelper cell involvement are referred to as ______ antigens.

thymus-independent Signup and view all the answers

TI-1 antigens activate B cells via the ______ receptors.

TLR Signup and view all the answers

The B cell co-receptor complex includes CD19, CD21, and ______.

CD81 Signup and view all the answers

Responses to TI antigens are primarily made by the non-recirculating ______ B cells.

marginal zone Signup and view all the answers

B cells activated through thymus-independent antigens produce low affinity antibodies of the ______ class.

IgM Signup and view all the answers

Binding of CD21 to C3b-opsonized pathogens aids in the binding of the ______ to the same pathogen.

BCR Signup and view all the answers

TI-2 antigens activate B cells by cross-linking a critical number of ______.

BCRs Signup and view all the answers

TFH cells provide several signals that activate B cells and promote their differentiation, including activation of CD40 to induce ______ activation.

NFκB Signup and view all the answers

Naïve B cells express ______ and localize to the follicles while its ligand is produced by FDCs.

CXCR5 Signup and view all the answers

Activated B cells that receive T cell help will downregulate CCR7 and migrate away from the ______ with the T cell zone.

boundary Signup and view all the answers

The process through which T cells recognize the same antigen as the B cells is called ______ recognition.

linked Signup and view all the answers

Primary foci of activated B cells are located within the medullary ______ in the lymph node.

cord Signup and view all the answers

After activation, some B cells can form germinal centres which are sites for sustained B cell ______ and differentiation.

proliferation Signup and view all the answers

Centroblasts in the germinal centre express CXCR4 and CXCR5 and are retained in the dark zone by the chemokine ______.

CXCL12 Signup and view all the answers

Activated B cells in germinal centres differentiate into long-lived ______ cells, which produce antibodies.

plasma Signup and view all the answers

The ______ zone of a germinal centre consists of resting B cells pushed to the periphery by activated cells in the centre.

mantle Signup and view all the answers

Cytokines like IL-21 signaling promote B cell ______ and differentiation into plasma cells.

proliferation Signup and view all the answers

B cell activation signals

B cells need two signals for activation: one from the B cell receptor (BCR) and another involving T helper cells (or microbial antigens).

TD antigens

Antigens that need T helper cells (TFH cells) to activate B cells; mostly protein antigens.

TI antigens

Antigens that activate B cells without T helper cells; generally have repetitive structures.

TI-1 antigens

TI antigens that induce B cell proliferation and differentiation non-specifically (polyclonal activation), often via TLR activation.