Intro to Immunology Flashcards
Antigen Presentation & recognition Cytokines
What does MHC stand for?
Major Histocompatibility Complex
True or False: Class 1 MHC molecules present antigens to CD4+ T cells.
False
What type of T cells do Class 1 MHC molecules primarily interact with?
CD8+ T cells
Fill in the blank: Class 1 MHC molecules are composed of a heavy chain and a _____ chain.
β2-microglobulin
Class 2 MHC molecules are primarily expressed on which type of cells?
Professional antigen-presenting cells (APCs)
What is the primary function of Class 2 MHC molecules?
To present extracellular antigens to CD4+ T cells
True or False: Both Class 1 and Class 2 MHC molecules have a similar overall structure.
True
What is the main structural component that Class 2 MHC molecules have that Class 1 does not?
An additional α chain
Class 1 MHC molecules are found on which type of cells?
All nucleated cells
What is the role of the peptide binding groove in MHC molecules?
To bind and present peptide fragments of antigens
How many transmembrane domains do Class 1 MHC molecules have?
One
How many transmembrane domains do Class 2 MHC molecules have?
Two
What is the size range of peptides that bind to Class 1 MHC molecules?
8 to 11 amino acids
What is the size range of peptides that bind to Class 2 MHC molecules?
13 to 25 amino acids
True or False: Class 1 MHC molecules can present endogenous antigens.
True
True or False: Class 2 MHC molecules can present exogenous antigens.
True
What is the genetic basis for the diversity of MHC molecules?
Polymorphism in MHC genes
What is the significance of MHC restriction in T cell activation?
T cells can only recognize antigens presented by MHC molecules of the same type.
What are the two main classes of MHC molecules?
Class 1 MHC and Class 2 MHC
What is the main structural feature that distinguishes Class 1 MHC from Class 2 MHC?
Class 1 MHC has a single heavy chain, while Class 2 MHC has two chains (α and β).
Fill in the blank: The genes for MHC molecules are located on chromosome _____ in humans.
6
What is the role of the α1 and α2 domains in Class 1 MHC molecules?
They form the peptide-binding groove.
What is the role of the β1 and β2 domains in Class 2 MHC molecules?
They form the peptide-binding groove.
True or False: MHC molecules play a role in autoimmune diseases.
True
What is the purpose of the polymorphism in MHC genes?
To enhance the ability of the immune system to recognize a diverse array of antigens.
What does MHC stand for?
Major Histocompatibility Complex
True or False: MHC polymorphism refers to the variation in MHC gene sequences among individuals.
True
Fill in the blank: MHC genes are crucial for the _____ of the adaptive immune response.
presentation of antigens
What is the significance of MHC polygeny?
It allows for a diverse range of MHC molecules to present different antigens.
Multiple Choice: Which of the following is a main function of MHC molecules? A) Energy production B) Antigen presentation C) Cell division
B) Antigen presentation
How many classes of MHC molecules are there?
Two classes: MHC class I and MHC class II
True or False: MHC class I molecules present antigens to CD4+ T cells.
False
What is the role of MHC class II molecules?
To present antigens to CD4+ T helper cells.
Fill in the blank: MHC polymorphism is thought to be driven by _____ selection.
pathogen
What is the primary benefit of having a diverse MHC repertoire?
Increased ability to respond to a wide variety of pathogens.
Multiple Choice: Which type of T cell interacts with MHC class I molecules? A) CD4+ T cells B) CD8+ T cells C) B cells
B) CD8+ T cells
True or False: Genetic diversity in MHC can influence susceptibility to diseases.
True
What is the relationship between MHC polymorphism and autoimmune diseases?
Certain MHC alleles are associated with a higher risk of developing autoimmune diseases.
Fill in the blank: The ability of an individual to present a wide variety of antigens is referred to as _____ diversity.
functional
What is the consequence of low MHC diversity in a population?
Increased vulnerability to infectious diseases.
Multiple Choice: Which of the following is NOT a characteristic of MHC molecules? A) They are highly polymorphic B) They are encoded by a single gene C) They are essential for T cell activation
B) They are encoded by a single gene
What does the term ‘allelic diversity’ refer to in the context of MHC?
The existence of multiple different alleles at a given MHC gene locus.
True or False: MHC molecules are found on all nucleated cells.
True
What is the primary function of MHC class I molecules?
To present intracellular antigens to CD8+ T cells.
Fill in the blank: The genes encoding MHC molecules are located on chromosome _____ in humans.
6
What is one mechanism through which MHC diversity is maintained in populations?
Balancing selection due to pathogen pressure.
Multiple Choice: MHC molecules are crucial for which immune process? A) Phagocytosis B) Antigen presentation C) Clonal expansion
B) Antigen presentation
True or False: All individuals have the same set of MHC alleles.
False
What is the impact of MHC mismatching in organ transplantation?
It increases the risk of transplant rejection.
Fill in the blank: The diversity of MHC alleles can lead to differences in _____ responses among individuals.
immune
What does MHC stand for?
Major Histocompatibility Complex
True or False: MHC molecules are essential for T cell recognition of antigens.
True
Fill in the blank: MHC restriction refers to the requirement that T cells recognize both the _______ and the _______ presented by MHC molecules.
antigen, MHC molecule
What are the two main classes of MHC molecules?
MHC Class I and MHC Class II
Which type of T cell primarily interacts with MHC Class I molecules?
CD8+ T cells
Which type of T cell primarily interacts with MHC Class II molecules?
CD4+ T cells
True or False: MHC molecules are genetically identical in all individuals.
False
What is the role of MHC Class I molecules?
To present endogenous antigens to CD8+ T cells.
What is the role of MHC Class II molecules?
To present exogenous antigens to CD4+ T cells.
Which cells express MHC Class II molecules?
Professional antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells.
What is the consequence of a mismatch in MHC molecules during organ transplantation?
Rejection of the transplanted organ.
True or False: MHC restriction is important for the immune system’s ability to distinguish self from non-self.
True
What is the significance of polymorphism in MHC genes?
It allows for a diverse range of antigens to be presented to T cells.
Short answer: What is the process by which MHC molecules present antigens?
Antigen processing and presentation.
Multiple choice: Which of the following is NOT a function of MHC molecules? A) Antigen presentation B) Immune response activation C) Enzyme secretion
C) Enzyme secretion
What is the term for the unique set of MHC molecules present in an individual?
MHC haplotype
Fill in the blank: T cells undergo positive and negative _______ during development in the thymus.
selection
True or False: MHC molecules can present both peptide fragments and lipids.
True
What is the primary function of CD8+ T cells in relation to MHC Class I?
To kill infected or cancerous cells.
What type of immune response involves MHC Class II molecules?
Helper T cell response
Short answer: How do MHC molecules contribute to autoimmune diseases?
By presenting self-antigens that trigger an immune response against the body’s own tissues.
Which cytokine is primarily produced by CD4+ T cells to activate other immune cells?
Interleukin-2 (IL-2)
True or False: MHC molecules can only present antigens from pathogens.
False
What is cross-presentation in the context of MHC molecules?
The ability of certain APCs to present exogenous antigens on MHC Class I molecules.
Multiple choice: Which of the following best describes MHC restriction? A) T cells can recognize any antigen B) T cells can only recognize antigens presented by their specific MHC C) T cells do not require MHC to recognize antigens
B) T cells can only recognize antigens presented by their specific MHC
What are the two main classes of MHC molecules involved in peptide antigen binding?
Class I and Class II MHC molecules.
True or False: Class I MHC molecules present antigens to CD4+ T cells.
False.
Fill in the blank: Class I MHC molecules typically present ___________ derived from intracellular proteins.
peptides.
What type of T cells do Class II MHC molecules interact with?
CD4+ T helper cells.
True or False: Class II MHC molecules are expressed on all nucleated cells.
False.
What is the primary source of peptides presented by Class I MHC?
Intracellular proteins.
Multiple Choice: Which of the following is NOT a characteristic of Class II MHC molecules? A) Present extracellular antigens B) Found on all cells C) Interact with CD4+ T cells D) Involved in immune response
B) Found on all cells.
What is the role of Class I MHC molecules in the immune response?
To present endogenous antigens to CD8+ cytotoxic T cells.
Fill in the blank: Class II MHC molecules primarily present ___________ derived from extracellular proteins.
peptides.
True or False: Peptides presented by Class I MHC are typically 8-10 amino acids long.
True.
True or False: Peptides presented by Class II MHC are typically longer, around 13-25 amino acids.
True.
What is the primary cellular location for Class I MHC molecule expression?
On the surface of all nucleated cells.
What is the primary cellular location for Class II MHC molecule expression?
On professional antigen-presenting cells (APCs) like dendritic cells, macrophages, and B cells.
Multiple Choice: Which type of T cell responds to antigens presented by Class I MHC? A) CD4+ T cells B) CD8+ T cells C) B cells D) NK cells
B) CD8+ T cells.
What is the mechanism by which Class II MHC molecules acquire peptides?
By endocytosis of extracellular proteins.
Fill in the blank: Class I MHC molecules present antigens to ___________ T cells.
CD8+.
Fill in the blank: Class II MHC molecules present antigens to ___________ T cells.
CD4+.
What is the consequence of a T cell recognizing a peptide-MHC complex?
Activation of the T cell.
True or False: Both Class I and Class II MHC molecules are essential for adaptive immunity.
True.
What is the significance of polymorphism in MHC molecules?
It allows for a diverse range of peptides to be presented to T cells.
Multiple Choice: Which of the following best describes the peptide binding groove of Class I MHC? A) Open at both ends B) Closed at both ends C) Variable size D) Fixed size
B) Closed at both ends.
Multiple Choice: Which MHC class is involved in presenting antigens for CD8+ T cell activation? A) Class I B) Class II C) Both A and B D) Neither A nor B
A) Class I.
What is the role of the T cell receptor (TCR) in the recognition of peptide-MHC complexes?
The TCR binds to the peptide-MHC complex, initiating T cell activation.
Fill in the blank: The process by which MHC molecules present peptides is known as ___________.
antigen presentation.
True or False: Class II MHC molecules can present peptides derived from intracellular proteins.
False.
What are the main categories of antigen recognition molecules?
The main categories are antibodies, T cell receptors (TCRs), and major histocompatibility complex (MHC) molecules.
True or False: Antibodies are a type of antigen recognition molecule.
True
Fill in the blank: T cell receptors are primarily involved in recognizing _____ antigens.
peptide
What is the role of major histocompatibility complex (MHC) molecules?
MHC molecules present peptide fragments to T cell receptors.
What are the two classes of MHC molecules?
MHC Class I and MHC Class II.
Which cells express MHC Class I molecules?
All nucleated cells.
Which cells express MHC Class II molecules?
Professional antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells.
What is the function of co-receptors in T cell activation?
Co-receptors enhance the sensitivity of T cells to their specific antigens.
Name the two main co-receptors associated with T cell receptors.
CD4 and CD8.
True or False: CD4 co-receptors are found on cytotoxic T cells.
False
What type of T cells express CD8?
Cytotoxic T cells.
What is the primary function of antibodies?
Antibodies bind to specific antigens to neutralize them or mark them for destruction.
Fill in the blank: Antibodies are also known as _____.
immunoglobulins
What are the five classes of antibodies?
IgG, IgA, IgM, IgE, and IgD.
Which antibody class is the most abundant in serum?
IgG.
True or False: IgM is the first antibody produced in response to an infection.
True
What is the role of B cell receptors (BCRs)?
BCRs recognize and bind to specific antigens directly.
What is the difference between BCRs and antibodies?
BCRs are membrane-bound forms of antibodies found on B cells, while antibodies are secreted forms.
What does the term ‘clonal selection’ refer to?
The process by which specific B or T cells are activated and proliferate in response to an antigen.
Fill in the blank: The region of an antibody that binds to an antigen is called the _____ region.
variable
What is the constant region of an antibody responsible for?
Determining the class and effector functions of the antibody.
True or False: T cell receptors undergo somatic hypermutation.
False
What is somatic hypermutation?
A process that occurs in B cells to increase the affinity of antibodies for their antigens.
What is the significance of antigen diversity in the immune system?
It allows the immune system to recognize and respond to a vast array of pathogens.
Name one mechanism by which antigen recognition molecules can achieve diversity.
V(D)J recombination.
What is the role of CD28 in T cell activation?
CD28 provides a necessary co-stimulatory signal for T cell activation.
What are the two main classifications of cytokines?
Cytokines can be classified into pro-inflammatory and anti-inflammatory cytokines.
True or False: Cytokines are only produced by immune cells.
False
Fill in the blank: Cytokines play a crucial role in _____ and _____ responses.
immune, inflammatory
What is the function of pro-inflammatory cytokines?
They promote inflammation and the immune response.
Name one example of a pro-inflammatory cytokine.
Interleukin-1 (IL-1)
What is the role of anti-inflammatory cytokines?
They help to reduce inflammation and promote healing.
Multiple Choice: Which of the following is an anti-inflammatory cytokine? A) TNF-alpha B) IL-10 C) IL-6
B) IL-10
True or False: Cytokines can only act on nearby cells.
False
What is the term for cytokines that act on the same cell that produces them?
Autocrine signaling
Fill in the blank: Cytokines can be classified based on their _____ and _____ activity.
function, signaling
What type of cytokines are responsible for the activation of T cells?
Cytokines like IL-2 and IL-12.
Multiple Choice: Which cytokine is known for its role in fever induction? A) IL-10 B) IL-1 C) IFN-gamma
B) IL-1
What is the primary source of cytokines in the body?
Immune cells such as macrophages and lymphocytes.
True or False: All cytokines are proteins.
True
What is the role of chemokines?
They are a subset of cytokines that specifically direct the migration of immune cells.
Fill in the blank: Cytokines can influence the _____ of immune cells.
proliferation
What is the difference between interleukins and interferons?
Interleukins are primarily involved in communication between leukocytes, while interferons are involved in antiviral responses.
Multiple Choice: Which of the following cytokines is primarily involved in the antiviral response? A) IL-1 B) IFN-alpha C) IL-6
B) IFN-alpha
What is the function of tumor necrosis factor (TNF)?
TNF is involved in systemic inflammation and is capable of inducing apoptosis.
True or False: Cytokines can have overlapping functions.
True
What is the role of transforming growth factor-beta (TGF-beta)?
It is primarily an anti-inflammatory cytokine that also plays a role in tissue repair.
Fill in the blank: Cytokines can activate _____ and _____ cells.
B cells, T cells
What are the main signaling pathways through which cytokines exert their effects?
JAK-STAT pathway and MAPK pathway.
Multiple Choice: Which cytokine is known for its role in chronic inflammation? A) IL-10 B) IL-6 C) IL-4
B) IL-6
What is the role of IL-4 in the immune system?
IL-4 promotes B cell differentiation and the production of antibodies.
True or False: Cytokines can have both local and systemic effects.
True
What are cytokines?
Cytokines are small proteins that are important in cell signaling.
True or False: Cytokines can only be produced by immune cells.
False
Fill in the blank: Cytokines play a crucial role in the _____ response.
immune
What is one of the main functions of cytokines?
To mediate and regulate immunity, inflammation, and hematopoiesis.
Which cytokine is primarily involved in the inflammatory response?
Tumor necrosis factor (TNF)
Multiple Choice: Which of the following is a type of cytokine? A) Interleukin B) Hemoglobin C) Insulin
A) Interleukin
What is the role of interleukins?
Interleukins are cytokines that mediate communication between white blood cells.
True or False: Cytokines can have autocrine, paracrine, and endocrine effects.
True
What is the primary function of chemokines?
To induce chemotaxis in immune cells.
Fill in the blank: _____ are cytokines that promote the growth and differentiation of blood cells.
Colony-stimulating factors
What do interferons primarily do?
Interferons help to inhibit viral replication and activate immune responses.
Multiple Choice: Which cytokine is known for its role in allergic responses? A) Interleukin-4 B) Interferon-gamma C) Tumor necrosis factor
A) Interleukin-4
What is the significance of the cytokine storm?
A cytokine storm is an overproduction of cytokines that can lead to severe inflammation and tissue damage.
True or False: All cytokines have the same mechanism of action.
False
What are the two main categories of cytokines?
Pro-inflammatory and anti-inflammatory cytokines.
Fill in the blank: _____ cytokines are involved in the enhancement of the immune response.
Pro-inflammatory
What role do cytokines play in cancer?
Cytokines can promote tumor growth and metastasis or inhibit cancer cell growth, depending on the context.
Multiple Choice: Which of the following is NOT a function of cytokines? A) Cell growth B) Cell communication C) Oxygen transport
C) Oxygen transport
What is the effect of anti-inflammatory cytokines?
They help to reduce inflammation and promote healing.
True or False: Cytokines can only act on cells of the immune system.
False
What is the role of transforming growth factor-beta (TGF-β)?
TGF-β is involved in immune regulation and tissue repair.
Fill in the blank: The binding of cytokines to their receptors triggers _____ signaling pathways.
intracellular
Multiple Choice: Which cytokine is primarily produced by T helper 1 cells? A) Interleukin-6 B) Interferon-gamma C) Interleukin-10
B) Interferon-gamma
What is the importance of cytokine receptors?
Cytokine receptors determine the specificity and response of target cells to cytokines.
True or False: Cytokines are only involved in the immune response and have no other functions.
False
