221 Questions
What is the primary site of T cell maturation?
Thymus
What are the three critical steps involved in thymic selection?
Development of a functional T-cell receptor, positive selection of thymocytes, and negative selection
What are the three classes of T cells?
Helper T cells, regulatory T cells, and cytotoxic T cells
What is the role of T-cell receptors (TCRs) in the activation process?
Epitope recognition
What is the consequence of T cell activation by superantigens?
All of the above
What is the difference between superantigens and traditional antigens?
Superantigens activate T cells without specific recognition of foreign epitopes, traditional antigens do not
What is the potential consequence of a cytokine storm caused by superantigens?
All of the above
What is the mechanism by which superantigens activate T cells?
Binding to MHC II molecules and the variable region of the TCR β chain
What is the consequence of peripheral tolerance mechanisms?
Protection against autoimmune disease
What is the primary site of T cell maturation?
Thymus
What are the three critical steps involved in thymic selection?
Development of a functional T-cell receptor, positive selection of thymocytes, and negative selection
What are the three classes of T cells?
Helper T cells, regulatory T cells, and cytotoxic T cells
What is the role of T-cell receptors (TCRs) in the activation process?
Epitope recognition
What is the consequence of T cell activation by superantigens?
All of the above
What is the difference between superantigens and traditional antigens?
Superantigens activate T cells without specific recognition of foreign epitopes, traditional antigens do not
What is the potential consequence of a cytokine storm caused by superantigens?
All of the above
What is the mechanism by which superantigens activate T cells?
Binding to MHC II molecules and the variable region of the TCR β chain
What is the consequence of peripheral tolerance mechanisms?
Protection against autoimmune disease
Where are T cells formed?
In the bone marrow
What is the purpose of thymic selection?
To remove self-reactive thymocytes
What are the three classes of T cells?
Helper T cells, regulatory T cells, and cytotoxic T cells
What is the role of T-cell receptors (TCRs)?
To recognize pathogen epitopes
How are helper T cells activated?
By APCs presenting processed foreign epitopes in association with MHC II
What is the result of T cell activation by superantigens?
A cytokine storm
What is a cytokine storm?
An excessive inflammatory response in the body
What can cause cytokine storms?
Superantigens
What is the difference between superantigens and traditional antigens?
Superantigens do not require processing by APCs
What is the primary role of T cells in the immune system?
Cellular immunity
Where do immature T cells differentiate into small lymphocytes?
Bone marrow
What are the three critical steps involved in thymic selection?
Development of a functional T-cell receptor, positive selection of thymocytes that interact appropriately with MHC molecules, negative selection to remove self-reactive thymocytes
What are peripheral tolerance mechanisms?
Mechanisms that protect against autoimmune disease caused by self-reactive T cells that escape the thymus
What are the three classes of T cells?
Helper T cells, regulatory T cells, and cytotoxic T cells
What is the role of T-cell receptors (TCRs) in the activation process?
They recognize foreign epitopes presented by APCs
What provides the genetic diversity required to produce millions of TCRs with unique epitope-specific variable regions?
Genetic rearrangement during thymic selection
What type of cells can only be activated by antigen-presenting cells (APCs) presenting processed foreign epitopes in association with MHC II?
Helper T cells
What type of cells are activated by APCs presenting antigens with MHC I?
Cytotoxic T cells
What are superantigens?
Antigens that activate T cells without specific recognition of foreign epitopes
What is the consequence of a cytokine storm caused by superantigens?
Decreased blood pressure
What can be caused by superantigens?
Diseases such as toxic shock syndrome and staphylococcal food poisoning
What is the primary function of T cells?
Cellular immunity
Where do immature T cells differentiate into small lymphocytes?
Bone marrow
What is the purpose of peripheral tolerance mechanisms?
To protect against autoimmune disease caused by self-reactive T cells that escape the thymus
What are the three critical steps involved in thymic selection?
Development of a functional T-cell receptor, positive selection of thymocytes that interact appropriately with MHC molecules, and negative selection to remove self-reactive thymocytes
What are the three classes of T cells?
Helper T cells, regulatory T cells, and cytotoxic T cells
What is the role of T-cell receptors (TCRs) in the activation process?
They recognize and bind to foreign antigens
What is the consequence of peripheral tolerance mechanisms?
Protection against autoimmune disease caused by self-reactive T cells that escape the thymus
What is the consequence of T cell activation by superantigens?
A cytokine storm
What is the mechanism by which superantigens activate T cells?
By binding to MHC II molecules
What is the consequence of a cytokine storm caused by superantigens?
Shock, multi-organ failure, and potentially death
What is the primary site of T cell maturation?
Bone marrow
What type of T cells can only be activated by antigen-presenting cells (APCs) presenting processed foreign epitopes in association with MHC II?
Helper T cells
What is the consequence of T cell activation by superantigens compared to traditional antigens?
A more severe immune response
What is the primary function of T cells?
Cellular immunity
Where do immature T cells differentiate into small lymphocytes?
Bone marrow
What are the three critical steps involved in thymic selection?
Development of a functional T-cell receptor, positive selection of thymocytes that interact appropriately with MHC molecules, negative selection to remove self-reactive thymocytes
What mechanism protects against autoimmune disease caused by self-reactive T cells that escape the thymus?
Anergy
What are the three classes of T cells based on their surface molecules, mode of activation, and functional roles?
Helper T cells, Regulatory T cells, and Cytotoxic T cells
What is the role of T-cell receptors (TCRs) in the activation process?
They recognize antigens presented by antigen-presenting cells
What provides the genetic diversity required to produce millions of TCRs with unique epitope-specific variable regions?
Genetic rearrangement during thymic selection
What is required for the activation of helper T cells?
Antigens presented by MHC II
What do activated helper T cells differentiate into?
TH1 cells, TH2 cells, TH17 cells, and Memory helper T cells
What type of antigens do cytotoxic T cells recognize?
Antigens presented by MHC I
What is the consequence of T cell activation by superantigens?
An excessive and uncontrolled release of cytokines
What is the difference between superantigens and traditional antigens?
Superantigens do not require processing by APCs
What is the primary role of T cells in the immune system?
Cellular immunity
What is the purpose of thymic selection in T cell maturation?
To remove self-reactive thymocytes
What are peripheral tolerance mechanisms?
Mechanisms that protect against autoimmune disease caused by self-reactive T cells
What is the function of T-cell receptors (TCRs) in the activation process?
To recognize foreign epitopes during the activation process
What is the difference between helper T cells and cytotoxic T cells?
Helper T cells can only be activated by antigen-presenting cells (APCs) presenting processed foreign epitopes in association with MHC II, while cytotoxic T cells are activated by APCs presenting antigens with MHC I
What is the consequence of T cell activation by superantigens?
An excessive and uncontrolled release of cytokines
What is a cytokine storm?
The excessive release of cytokines caused by T cell activation by superantigens
What is the primary source of superantigens?
All of the above
What is the difference between superantigens and traditional antigens?
Superantigens activate T cells by binding simultaneously to MHC II molecules of APCs and the variable region of the TCR β chain, while traditional antigens do not
What is the potential consequence of a cytokine storm caused by T cell activation by superantigens?
All of the above
What is the mechanism by which superantigens activate T cells?
By binding simultaneously to MHC II molecules of APCs and the variable region of the TCR β chain
What is the role of genetic rearrangement during thymic selection?
To produce millions of TCRs with unique epitope-specific variable regions
What is the primary role of T cells in the immune system?
To directly attack and kill pathogens
What is the function of peripheral tolerance mechanisms in relation to T cells?
To remove self-reactive thymocytes
What is the consequence of unregulated T cell activation by superantigens?
A decrease in blood pressure
What is the role of cytokines in a cytokine storm?
To stimulate an excessive inflammatory response
What is the difference between TH1 and TH2 helper T cells?
TH1 cells secrete IFN-γ, while TH2 cells secrete IL-4
What is the consequence of negative selection during thymic selection?
Removal of self-reactive thymocytes
How are T cells activated by traditional antigens?
By binding to MHC I molecules of APCs
What is the consequence of genetic rearrangement during thymic selection?
Production of millions of TCRs with unique epitope-specific variable regions
What is the consequence of T cell activation by superantigens?
Excessive and uncontrolled release of cytokines
What is the function of regulatory T cells?
To inhibit the immune response
How do TH17 cells differ from other helper T cells?
They secrete IL-17
What is the consequence of positive selection during thymic selection?
Selection of thymocytes that interact appropriately with MHC molecules
Where do immature T cells differentiate into small lymphocytes?
Bone marrow
What is the function of peripheral tolerance mechanisms?
To protect against autoimmune disease caused by self-reactive T cells that escape the thymus
What is the role of T-cell receptors (TCRs) in the activation process?
They recognize foreign epitopes during the activation process
What is the genetic rearrangement during thymic selection responsible for?
Producing millions of T cells with unique epitope-specific variable regions
What is the mode of activation for helper T cells?
APCs presenting processed foreign epitopes in association with MHC II
What are the different types of helper T cells?
TH1, TH2, TH17, TH20
What is the mode of activation for cytotoxic T cells?
APCs presenting antigens with MHC I
What can trigger unregulated activation of T cells, potentially leading to a life-threatening condition?
Superantigens
What is the result of T cell activation by superantigens?
Excessive and uncontrolled release of cytokines
What is a cytokine storm?
An excessive inflammatory response in the body
What diseases can be caused by superantigens?
Toxic shock syndrome, staphylococcal food poisoning, and streptococcal toxic shock-like syndrome
What is the difference between superantigens and traditional antigens?
Superantigens do not require specific recognition of foreign epitopes, while traditional antigens do
What is the primary function of T cells?
Cellular immunity
Where do immature T cells differentiate into small lymphocytes?
Thymus
What is the purpose of thymic selection?
To develop a functional T-cell receptor
What are peripheral tolerance mechanisms?
Mechanisms that protect against autoimmune disease caused by self-reactive T cells
What are the three classes of T cells based on their surface molecules, mode of activation, and functional roles?
Helper T cells, regulatory T cells, and cytotoxic T cells
What is the role of T-cell receptors (TCRs) in the activation process?
They are involved in the first step of pathogen epitope recognition
What provides the genetic diversity required to produce millions of TCRs with unique epitope-specific variable regions?
Genetic recombination during thymic selection
What is required to activate helper T cells?
Antigen-presenting cells (APCs) presenting processed foreign epitopes in association with MHC II
What can activated helper T cells differentiate into depending on the cytokines secreted by APCs?
TH1 cells, TH2 cells, TH17 cells, or memory helper T cells
What activates cytotoxic T cells?
APCs presenting antigens with MHC I
What can trigger unregulated activation of T cells, which can be life-threatening?
Superantigens
What is the consequence of a cytokine storm caused by superantigens?
Decrease in blood pressure
What is the difference between humoral and cellular immunity?
Humoral immunity fights pathogens in extracellular spaces while cellular immunity targets intracellular pathogens through T cells.
Where do T cells mature?
In the thymus
What is thymic selection?
The process of eliminating defective TCRs and self-reactive T cells
What is the function of peripheral tolerance mechanisms?
To prevent self-reactive T cells from causing autoimmune disease
How are helper and regulatory T cells activated?
By APCs presenting antigens associated with MHC II
What is the role of helper T cells in adaptive immunity?
To serve as the central orchestrators for both humoral and cellular immunity
How do cytotoxic T cells recognize antigens?
Through antigen presentation of pathogen-specific epitopes associated with MHC I
What is the consequence of T cell activation by superantigens?
Release of cytokines
What is the mechanism by which superantigens activate T cells?
By binding to both MHC II molecules and TCR β chains
What is the consequence of a cytokine storm caused by superantigens?
Stimulation of an excessive inflammatory response
What is the primary effector cell for cellular immunity?
Cytotoxic T cells
What is the consequence of genetic rearrangement in the thymus?
Production of TCRs with unique epitope-specific variable regions
What is the primary difference between humoral immunity and cellular immunity?
Humoral immunity fights pathogens in extracellular spaces while cellular immunity targets intracellular pathogens through T cells.
Where are T cells formed and where do they mature?
T cells are formed in the thymus and mature in the bone marrow.
What is thymic selection and what is its purpose?
It is the process of selecting T cells instead of B cells. It eliminates defective TCRs and self-reactive T cells.
What is the purpose of peripheral tolerance mechanisms?
To prevent self-reactive T cells from causing autoimmune disease.
How are T cells categorized and what determines their functional roles?
T cells are categorized based on their functional roles and their surface molecules.
What activates helper and regulatory T cells?
Antigens associated with MHC II
What activates cytotoxic T cells?
Antigens associated with MHC I
What is the role of helper T cells in adaptive immunity?
They serve as the central orchestrators for both humoral and cellular immunity.
What is the role of regulatory T cells in adaptive immunity?
They prevent undesirable immune responses.
What is the role of cytotoxic T cells in adaptive immunity?
They are the primary effector cells for cellular immunity.
What is the consequence of T-cell receptor (TCR) recognition during the activation process?
It activates T cells.
What is the purpose of genetic rearrangement in the thymus?
To produce millions of TCRs with unique epitope-specific variable regions.
What is the consequence of superantigen binding to MHC II molecules and TCR β chains?
It results in the production of cytokines.
Which of the following is true about T cells?
They can target both extracellular and intracellular pathogens
What is the function of regulatory T cells?
To prevent undesirable immune responses
Which of the following is required for the production of millions of TCRs with unique epitope-specific variable regions?
Genetic rearrangement in the thymus
Which of the following is true about helper T cells?
They serve as the central orchestrators for both humoral and cellular immunity
What is the consequence of superantigen binding to MHC II molecules and TCR β chains?
Activation of a cytokine storm
Which of the following is true about cytotoxic T cells?
They recognize and kill cells infected with intracellular pathogens
What is the role of TH1 cells?
To kill cells infected with intracellular pathogens
Which of the following is a potential consequence of superantigens?
Decrease in blood pressure
What is the function of memory helper T cells?
To provide long-term immunity
Which of the following is true about peripheral tolerance mechanisms?
They prevent self-reactive T cells from causing autoimmune disease
What is the consequence of an unregulated and excessive T cell response triggered by superantigens?
Activation of a cytokine storm
Which of the following is true about regulatory T cells?
They prevent undesirable immune responses
What is the primary difference between humoral and cellular immunity?
Humoral immunity fights pathogens in extracellular spaces while cellular immunity targets intracellular pathogens through T cells.
What is the role of helper T cells in adaptive immunity?
They serve as the central orchestrators for both humoral and cellular immunity.
What is the function of regulatory T cells in adaptive immunity?
They prevent undesirable immune responses.
What is the consequence of peripheral tolerance mechanisms?
They prevent self-reactive T cells from causing autoimmune disease.
What is the function of cytotoxic T cells in adaptive immunity?
They serve as the primary effector cells for cellular immunity.
What is the consequence of T cell activation by superantigens?
An excessive, uncontrolled release of cytokines.
What is the role of MHC II molecules in T cell activation?
They recognize specific foreign epitopes presented within the MHC II antigen-binding cleft during the activation process.
What is the consequence of T cell activation by traditional antigens?
A decrease in inflammation.
What is the function of TH1 cells?
They serve as the primary effector cells for cellular immunity.
What is the function of TH2 cells?
They serve as the central orchestrators for both humoral and cellular immunity.
What is the consequence of a decrease in blood pressure caused by superantigens?
Multi-organ failure.
What is the consequence of cytotoxic T cell recognition of cells infected with intracellular pathogens?
The infected cells are destroyed through antigen presentation of pathogen-specific epitopes associated with MHC I.
What is the primary function of T cells in adaptive immunity?
To target intracellular pathogens
What is the role of regulatory T cells in adaptive immunity?
To prevent autoimmune disease
What is the difference between helper T cells and cytotoxic T cells?
Helper T cells recognize specific foreign epitopes presented within the MHC, while cytotoxic T cells are activated by recognition of an antigen presented with MHC I
What is the purpose of peripheral tolerance mechanisms in adaptive immunity?
To prevent autoimmune disease
What is the consequence of genetic rearrangement in T cells?
Production of millions of T cell receptors
What is the result of superantigen binding to MHC II molecules and TCR β chains?
Excessive, uncontrolled release of cytokines
What is a cytokine storm?
An excessive inflammatory response
What is the potential consequence of superantigens in bioterrorism?
A decrease in blood pressure
What is the role of TH1, TH2, or TH17 cells in adaptive immunity?
To differentiate into helper T cells
What is the primary effector cell for cellular immunity?
Cytotoxic T cells
What is the consequence of thymic selection in T cell maturation?
Elimination of self-reacting thymocytes to prevent autoimmune disease
What is the role of perforin and granzymes in cellular immunity?
To destroy infected cells
Which of the following is true about T cells?
They recognize specific foreign epitopes presented within the MHC II antigen-binding cleft during the activation process.
What is the role of regulatory T cells?
To prevent autoimmune diseases.
What is the difference between the activation of helper T cells and cytotoxic T cells?
Helper T cells are activated by APCs presenting antigens associated with MHC II while cytotoxic T cells recognize antigens presented in association with MHC I.
What is the function of TH2 cells?
To produce cytokines that stimulate B cells to produce antibodies.
What is the consequence of superantigen binding to MHC II molecules and TCR β chains?
The result is an excessive, uncontrolled release of cytokines.
What is the potential consequence of a cytokine storm caused by superantigens?
It can lead to a dangerous decrease in blood pressure.
What is the role of peripheral tolerance mechanisms?
To prevent self-reactive T cells from causing autoimmune disease.
What is the function of memory helper T cells?
To prevent undesirable immune responses.
What is the function of effector cytotoxic T cells?
To recognize and kill cells infected with intracellular pathogens through antigen presentation of pathogen-specific epitopes associated with MHC I.
What is the consequence of genetic rearrangement in the thymus?
It provides the genetic diversity required to produce millions of TCRs with unique epitope-specific variable regions.
What is the consequence of an unregulated and excessive T cell response triggered by superantigens?
It can be life-threatening.
What is the difference between humoral immunity and cellular immunity?
Humoral immunity fights pathogens in extracellular spaces while cellular immunity targets intracellular pathogens through T cells.
What is the primary difference between humoral immunity and cellular immunity?
Humoral immunity fights pathogens in extracellular spaces while cellular immunity targets intracellular pathogens.
What is the role of peripheral tolerance mechanisms?
To prevent self-reactive T cells from causing autoimmune disease.
What are the three categories of T cells?
Helper, regulatory, and cytotoxic T cells.
What is the difference in antigen presentation between helper/regulatory T cells and cytotoxic T cells?
Helper/regulatory T cells recognize antigens associated with MHC II, while cytotoxic T cells recognize antigens presented in association with MHC I.
What is the role of helper T cells in adaptive immunity?
They serve as the central orchestrators for both humoral and cellular immunity.
What is the role of regulatory T cells?
To prevent undesirable immune responses.
What is the role of cytotoxic T cells in cellular immunity?
To recognize and kill cells infected with intracellular pathogens.
What is the mechanism by which TCRs recognize specific foreign epitopes?
By recognizing the MHC II antigen-binding cleft during the activation process.
What is the source of genetic diversity required to produce millions of TCRs?
Genetic rearrangement in the thymus.
What are the different subtypes of activated helper T cells?
TH1 cells, TH2 cells, and memory helper T cells.
What is the consequence of superantigen binding to MHC II molecules and TCR β chains?
All of the above.
What is the primary consequence of superantigens?
They can lead to unregulated and excessive T cell response.
Which of the following is true about humoral immunity?
It fights pathogens in extracellular spaces
What is the role of peripheral tolerance mechanisms?
To prevent self-reactive T cells from causing autoimmune disease
Which class of T cells serves as the central orchestrators for both humoral and cellular immunity?
Helper T cells
What is the consequence of superantigen binding to MHC II molecules and TCR β chains?
Release of cytokines leading to excessive inflammatory response
What is the primary site of T cell maturation?
Thymus
What are the three critical steps involved in thymic selection?
Positive selection, negative selection, and peripheral tolerance
Which class of T cells prevents undesirable immune responses?
Regulatory T cells
What is the consequence of a cytokine storm caused by superantigens?
Release of cytokines leading to excessive inflammatory response
Which class of T cells recognizes antigens presented in association with MHC I?
Cytotoxic T cells
What is the consequence of T cell activation by superantigens?
Release of cytokines leading to excessive inflammatory response
What is the mechanism by which T-cell receptors (TCRs) recognize specific foreign epitopes during the activation process?
Genetic rearrangement
Which class of T cells is the primary effector cells for cellular immunity?
Cytotoxic T cells
Which type of immunity targets intracellular pathogens through T cells?
Cellular immunity
Where are T cells formed and matured?
In the thymus
What is the purpose of positive and negative selection steps in thymic selection?
Both of the above
What is the purpose of peripheral tolerance mechanisms?
To prevent autoimmune disease
How are helper and regulatory T cells activated?
By APCs presenting antigens associated with MHC II
What is the role of helper T cells in adaptive immunity?
Central orchestrators for both humoral and cellular immunity
What do T-cell receptors (TCRs) recognize during the activation process?
Specific foreign epitopes presented within the MHC II antigen-binding cleft
Where does genetic rearrangement occur to produce millions of TCRs with unique epitope-specific variable regions?
In the thymus
What are the subtypes that activated helper T cells differentiate into?
TH1 cells, TH2 cells, and memory helper T cells
What do cytotoxic T cells recognize and kill?
Cells infected with intracellular pathogens through antigen presentation of pathogen-specific epitopes associated with MHC I
What is the consequence of superantigen binding to MHC II molecules and TCR β chains?
Activation of T cells outside of the antigen-binding cleft of MHC II
What is the potential consequence of superantigen-induced cytokine storm?
Decrease in blood pressure
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