30 Questions
What is mandatory for the activation of naïve lymphocytes?
Interaction of MHC/Ag and TCR
Which type of antigens are recognized by T cells in the context of intracellular pathogens?
Cell-associated antigens
What is a crucial role of Antigen Presenting Cells (APCs) in activating T cells?
Expressing co-stimulatory proteins
Why are linear peptides important in activating T cells in the case of extracellular pathogens?
They are more immunogenic
What is the significance of DC licensing by TH cells for APCs?
Activates naive T cells
Which process is necessary to activate an antibody response?
Interaction between B cells and T cells
What initiates the activation of B cells in the humoral immune response?
Antigens recognized by the surface Ig receptors
Which type of B cells are mainly involved in T-dependent antibody responses to protein antigens?
Follicular B cells
What is a characteristic of T-dependent antibody responses?
Production of high-affinity antibodies
What stimulates the proliferation and differentiation of a specific B cell clone in the humoral immune response?
Helper T cells
Which type of antibody response is slower to develop but results in long-lasting antibodies?
T-dependent antibody response
What can progeny of the B cell clone differentiate into in the humoral immune response?
Both plasma cells and memory cells
What is the main difference between the antibodies produced by plasmablasts in primary foci and those produced in the germinal center reaction?
Primary foci antibodies are of the IgM isotype, while germinal center antibodies are more effective in eliminating infections.
What enables the process of affinity maturation in B cells during the germinal center reaction?
Somatic hypermutation
Where do plasma cells primarily migrate to in the case of the primary focus?
Bone marrow
Which cells begin to emerge during the first 4-5 days of an immune response?
Plasmablasts, germinal center B cells, and early memory B cells
What is the role of somatic hypermutation in the germinal center reaction?
Alters the V regions of immunoglobulin genes
Where do plasmablasts migrate to after interacting with activated helper T cells?
Bone marrow
What is the role of Fc receptors in the humoral immune response?
Facilitate phagocytosis of bacteria coated with antibodies
Which molecules bind to the Fc receptors on phagocytes in the humoral immune response?
CR1 and IgG antibody
How do bacteria resist limited phagocytosis by macrophages?
By coating themselves with antibodies and complement
What is the consequence of bacteria being coated with IgG antibody and complement?
They are more readily ingested and degraded by phagocytes
How do Fc receptors and complement receptors synergize in inducing phagocytosis?
By working together to promote bacterial uptake
What happens when macrophage membranes fuse during phagocytosis?
They create a membrane-enclosed vesicle called a phagosome
What is required to drive naïve CD8 T cells to become activated?
Stimulation of APC through CD40
What is a key role of CD4 effector T cells in supporting the activation of CD8 T cells?
Inducing the self production of IL-2 by CD8 T cells
Which molecules increase on antigen-presenting cells following stimulation through CD40 to co-stimulate naïve CD8 T cells?
B7 and 4-1BBL
How do activated dendritic cells prime naïve CD8 T cells for activation?
By inducing the self-production of IL-2 by CD8 T cells
What is the role of IL-2 in the process of activating CD8+ T cells?
Promotes the proliferation and survival of activated T cells
How do cytotoxic CD8+ T cells induce apoptosis in target cells?
Via intrinsic and extrinsic pathways using receptors and perforin
Test your knowledge on the mechanisms involved in antigen presentation and activation of CD4+ T-cells. Learn about the interaction between MHC/Ag and TCR, the roles of ligands, co-receptors, and cytokines in activating naive lymphocytes. Explore the properties of antigens recognized by T cells.
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