Immunology and Cancer Quiz

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Questions and Answers

Which of the following statements accurately describes a type of immunity?

Allergy immunity results in hypersensitivity towards non-infectious agents only.

Autoimmunity is a normal immune response that targets only pathogens.

Immunity against self is exclusively caused by genetic mutations.

Immunity against infectious agents involves responding to non-self antigens. (correct)

What is a significant factor that can contribute to tumor development?

Stable genetic mutations only.

Enhanced immune responses.

Exposure to chemical carcinogens. (correct)

Unrelated to environmental factors.

Which mechanism describes how tumors can avoid detection by the immune system?

There is a complete lack of immune cell infiltration in tumors.

Tumor cells can suppress immune responses. (correct)

Tumor derived factors can enhance T-cell activity.

Tumor cells always express PD-L1.

What role do immune checkpoint inhibitors play in cancer treatment?

They block PD-L1/PD-1 interactions to activate T-cells. Signup and view all the answers

What is the nature of autoimmunity in relation to the immune system?

It occurs when the immune system mistakenly targets body tissues. Signup and view all the answers

What role do cytokines play in direct target cell killing?

They can directly kill target cells. Signup and view all the answers

What is the main purpose of chemotaxis in the immune response?

To direct immune cells to the site of infection. Signup and view all the answers

Which of the following is a characteristic of chronic granulomatous disease (CGD)?

It results from a deficiency in NADPH oxidase. Signup and view all the answers

Which type of immunodeficiency is primarily genetic in nature?

Intrinsic immunodeficiency. Signup and view all the answers

What characterizes opportunistic infections?

They primarily affect individuals with compromised host defenses. Signup and view all the answers

Which of the following is associated with secondary immunodeficiency?

AIDS caused by HIV infecting Th cells. Signup and view all the answers

Which mediators are involved in the effector mechanisms for phagocyte-mediated killing?

Reactive oxygen intermediates and reactive nitrogen intermediates. Signup and view all the answers

Pyrogenic toxins are primarily associated with which symptoms?

Fever and rash. Signup and view all the answers

Which cells are primarily involved in innate immunity?

Macrophages Signup and view all the answers

What is the main characteristic of the adaptive immune response's memory?

It provides a quick response upon re-exposure to the same pathogen Signup and view all the answers

Which of the following statements accurately describes the secondary immune response?

It exhibits a shorter lag phase and a higher peak of antibody levels. Signup and view all the answers

What is the primary function of T-helper 1 cells (Th1)?

To secrete cytokines that activate macrophages Signup and view all the answers

Which type of immune response is primarily involved in targeting intracellular pathogens?

Cell-mediated response Signup and view all the answers

Which immunoglobulin is mainly involved in affinity maturation and antibody class switching?

IgG Signup and view all the answers

What role do cytokines play in immune responses?

They mediate interactions between inflammatory cells Signup and view all the answers

What characterizes the role of natural killer (NK) cells in the immune system?

They are involved in innate immunity and can target stressed cells. Signup and view all the answers

What is the function of T-dependent antibodies?

They require T cell help for activation and response. Signup and view all the answers

How does the production of high-affinity antibodies occur?

Through somatic hypermutation of Ig variable region genes Signup and view all the answers

Study Notes

Immune System in Health and Disease

Innate immunity is fast, but limited in strength
Involves macrophages and natural killer (NK) cells
Adaptive immunity is slower but highly effective
Involves B and T lymphocytes
Takes time to develop, but provides powerful specific responses
Has memory, so subsequent infections are faster. The response is much stronger
First infection results in pathogen proliferation, disease, and symptoms, while subsequent infections, because of memory, will be faster, causing little to no symptoms

Principle of Vaccination

Primary vaccination response is characterized by a short lag (1-4 days) and an early peak (3-5 days) of antibody production.
Subsequent vaccination leads to a stronger response (100-1000X) and a longer duration
Secondary response involves memory B cells and is highly similar to the response from the first infection

Somatic Hypermutation

V region activation by enzyme for affinity selection for high affinity
Antibodies produced have higher affinity

Isotype Switching

Change in recombination in immunoglobulin formation
Middle part is spliced to form the IgM molecule, then VDJ genes can join with gamma genes to form IgG
Occurs in B cells, and switching occurs between different antibody classes (isotypes) like from IgM to IgG.

Immune Response to Infections

Pathogens can be extracellular or intracellular
Extracellular pathogens include fungi, yeasts, molds, parasites, worms, protozoa
Intracellular pathogens include viruses (as viruses replicate inside living cells)

Humoral Responses

Non-specific responses include: complements, acute phase proteins, histamine.
Specific responses include: antibodies, B cell derived effector molecules, opsonization, and neutralization (of viruses, toxins)

Cell-Mediated Responses

T-dependent, non-specific responses include: phagocytes, macrophages, natural killer (NK) cells
CD16+ CD56dim/neg: cytotoxic NK cells (90%)
CD16-CD56 bright: regulatory or cytokine-secreting NK cells
Similar to cytotoxic T cells (CD8+) and helper T cells (CD4+)

Mechanisms of Target Cell Killing by T and LGL

T-dependent, specific cytotoxic T cells kill infected cells
Helper T cells help other cells

Cytokine-Mediated Direct Target Cell Killing

TNFα/β and IFNγ directly kill cells

Phagocytes

Non-specific, innate part
Neutrophils circulate in blood and move to infection sites.
Chemotaxis induces cell movement in a specific direction
Complement attracts phagocytes to approach bacteria
Reactive oxygen intermediates (ROIs)
Reactive nitrogen intermediates (RNIs)

Defects in Immune System

Defects in immunoglobulins, complements, phagocytosis
Infections, e.g. AIDS (HIV infects Th cells), drugs, radiation, malnutrition
Primary immunodeficiencies, most genetic, linked to T cells or B cells (e.g. SCID)
Traditional T and B cell deficiencies, or both (e.g. T and B cell deficiencies)
Defects in components necessary for phagocyte function like NCF1 and NCF2
X-linked deficiencies are the most severe (70% of the cases). These are defects in an enzyme NADPH oxidase which produces reactive oxygen intermediates

Immunity against Infectious Agents

Immunity against "non-self" and "self" (autoimmunity)
Genetic mutations, viral infections, chemical carcinogens, radiation, immunodeficiencies,
Vaccines against viruses prevent some cancers

Immune Escape Mechanisms of Tumors

Tumor-cell surveillance theory
Tumor cells use mechanisms to escape detection and destruction. These cells have molecular mechanisms to break from detection and destruction by immune cells, to aid in the proliferation of the tumor
Lack of important molecules for the immune system, tumor-derived factors that suppress immunity

Immune Checkpoint Inhibitors

PD-L1 binds to PD-1 and inhibits T-cell killing of tumor cells
Blocking PD-L1 or PD-1 allows T-cell killing of tumor cells
These are treatment approaches that aim to enhance the immune system by blocking these proteins as they interfere with the functioning of the immune cell

Immunopathologic Responses and Hypersensitivity

Systemic hypersensitivity reactions like anaphylaxis are often initiated by allergens
Allergens can bind to IgE and trigger strong reactions in some individuals (e.g. allergic reactions to bee venom)

Autoimmunity

Adaptive immune response directed against self antigens
"Self"/“non-self” concepts are crucial to understanding adaptive immunity.
Tolerance mechanisms regulate these responses to avoid the body attacking itself (autoimmunity)

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Description

Test your knowledge on the immune system's role in cancer, including mechanisms of tumor development and immune response. This quiz covers various topics, such as types of immunity, tumor evasion strategies, and the impact of immune checkpoint inhibitors. Enhance your understanding of how immunology intersects with cancer treatment.