Immunology- Pt 1A

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Questions and Answers

What is the role of the immune system in the body?

To generate antibodies against its own cells

To prevent the growth of hematopoietic cells

To induce inflammation in response to non-self elements

To mediate resistance to foreign elements (correct)

What is the result of the immune system failing to distinguish between foreign elements and components of its own organism?

Hematopoiesis

Immune response

Autoimmunity (correct)

Inflammation

What is the term for a part of an antigen that is responsible for inducing the immune response?

Epitope (correct)

Immune response

Antibody

Lymphocyte receptor

What is the term for the collection of cells, tissues, and molecules that mediate resistance to foreign elements?

Immune system Signup and view all the answers

What is the origin of all cells of the immune system?

Bone marrow Signup and view all the answers

What is the term for the coordinated reaction of immune cells and molecules to antigens?

Immune response Signup and view all the answers

What is the function of B lymphocytes in adaptive immunity?

To produce antibodies Signup and view all the answers

Which type of immunity is always active and has a fast response time?

Innate immunity Signup and view all the answers

What is the main mechanism of action of mast cells in response to a threat?

Release of lipid mediators and cytokines via degranulation Signup and view all the answers

What is the result of the absence of antigens in adaptive immunity?

No immune response Signup and view all the answers

What is the primary role of macrophages in the immune response?

Immune surveillance and phagocytosis Signup and view all the answers

What is the role of complement in the immune response?

To eliminate microbes Signup and view all the answers

What is the main function of dendritic cells in the immune response?

Antigen processing and presentation to T-cells Signup and view all the answers

Which cell type is primarily involved in innate immune response and can differentiate into dendritic cells?

Macrophages Signup and view all the answers

What is the origin of B cells and T cells in the immune system?

Common lymphoid progenitor Signup and view all the answers

What is the result of the release of vasoactive amines from mast cells?

Vasodilation and increased vascular permeability Signup and view all the answers

What is the primary mechanism of action of macrophages?

Phagocytosis of microbes Signup and view all the answers

Which cell type is primarily involved in the adaptive immune response and can activate T-cells?

Dendritic cells Signup and view all the answers

What is the primary function of mast cells in the immune response?

Immune surveillance and release of inflammatory mediators Signup and view all the answers

What is the primary function of neutrophils in the body?

Antimicrobial effector Signup and view all the answers

What is the mechanism by which neutrophils capture and kill microbes?

All of the above Signup and view all the answers

What is the characteristic of eosinophils that distinguishes them from neutrophils?

Visibly pink/orange granules Signup and view all the answers

What is the primary role of eosinophils in the body?

Antiparasitic effector Signup and view all the answers

What is the characteristic of eosinophils that is similar to neutrophils?

Segmented nucleus Signup and view all the answers

What is the main function of Chemokines in the immune system?

Chemotaxis Signup and view all the answers

What is the key characteristic that distinguishes Natural Killer cells from T-cells and B-cells?

Lack of antigen receptors Signup and view all the answers

What is the primary function of Interleukins in the immune system?

Communication between cells Signup and view all the answers

How do Natural Killer cells induce cell death in virally infected or abnormal host cells?

Through the targeted release of cytotoxic granules Signup and view all the answers

What is the purpose of cytokines in the immune system?

To facilitate cell growth and activation Signup and view all the answers

Which statement is incorrect in regards to basophils?

They have the same mediators as mest cells, but more effective Signup and view all the answers

Study Notes

Infectious Disease: General Info

Infectious disease requires a susceptible host and pathogen to be in the same environment at the same time.
The immune system prevents infection and consists of cells, tissues, and molecules that mediate resistance to foreign elements.
The immune response is a coordinated reaction of immune cells and molecules to antigens.
Immunology is the study of the immune system, including its responses to microbial pathogens and damaged tissues and its role in disease.
An antigen is a molecule that induces an immune response when introduced into the body, generating antibodies.
Epitopes (or antigenic determinants) are parts of an antigen responsible for inducing the immune response and binding to lymphocyte receptors and antibodies.

Immune System: General Info

The immune system must discriminate foreign elements from its own components to prevent autoimmunity.
Autoimmunity occurs when the immune system attacks its own cells, leading to autoimmune disorders/diseases.
Immune responses should only be generated when components of the immune system come into contact with non-self-elements, such as antigens or microbes.
Inflammation causes pain, swelling, and redness.

Cellular Origins

All cells of the immune system originate from hematopoietic cells, which come from bone marrow.
Hematopoietic cells differentiate into either common lymphoid progenitor or common myeloid progenitor.
Common lymphoid progenitor is the source of B-cells and T-cells, which are part of adaptive immunity, as well as NK cells and ICL.
Common myeloid progenitor is the source of mast cells, basophils, dendritic cells, monocytes (macrophages), eosinophils, and neutrophils.

Cells of the Immune System

Granulocytes: neutrophils, basophils, and eosinophils
Lymphocytes: NK cells (part of innate immunity), T-cells and B-cells (part of adaptive immunity)
Others: mast cells, monocytes/macrophages, and dendritic cells

Innate vs. Adaptive Immunity

Innate immunity involves a non-specific immune response, always active, with a fast response time and lacks memory.
Examples of innate immunity include inflammation, complement, and physical barriers (such as skin or stomach pH).
Adaptive immunity involves a specific immune response, only active when in contact with antigens, with a slow response time and has memory.
Examples of adaptive immunity include humoral immunity and cellular immunity.

Neutrophils

Neutrophils have a segmented nucleus and granules in their cytoplasm.
Roles: antimicrobial effectors, particularly in acute bacterial infections and inflammation.
Mechanisms: phagocytosis, degranulation, and neutrophil extracellular trap formation.

Eosinophils

Eosinophils have a segmented nucleus and granules in their cytoplasm, which are visibly pink/orange.
Roles: antiparasitic effector, some antiviral action, and an allergy role.
Mechanisms: degranulation and very limited phagocytosis.

Basophils

Basophils have a segmented nucleus and granules in their cytoplasm, which are visibly purple.
Roles: mediator of inflammation.
Mechanisms: degranulation.
Found in tissue, not typically in blood.

Mast Cells

Mast cells have a segmented nucleus and granules in their cytoplasm, which are visibly purple.
Roles: immune surveillance, mediator and amplifier of inflammation and allergy.
Mechanisms: detection of threats and release of inflammatory mediators via degranulation (vasoactive amines) or synthesis of lipid mediators and cytokines.
Found in tissue and connective tissue.

Macrophages

Macrophages are monocytes that have left the blood and gone to the tissue, primarily part of the innate immune response.
Roles: immune surveillance, moderate antimicrobial capacity, and limited antigen presentation.
Mechanisms: detection of threats and release of inflammatory mediators, and phagocytosis.
Can differentiate into dendritic cells.

Dendritic Cells

Roles: immune surveillance and antigen processing and presentation.
Mechanisms: endocytosis, phagocytosis, and detection of threats and release of inflammatory mediators.
Can sometimes be phagocytic, but primary role is antigen presenting.
Capture microbes, break them down, and present their antigens to T-cells, initiating the adaptive immune response.

NK (Natural Killer) Cells

NK cells are lymphocytes that lack antigen receptors.
Roles: destruction of virally infected or abnormal host cells (including tumor cells).
Mechanisms: recognition of virally infected or abnormal host cells and targeted release of cytotoxic granules.
Induce apoptosis.

Lymphocytes (T-cells and B-cells)

Roles: recognition of specific antigens/epitopes via TCR (T cell receptors) and BCR (B cell receptors) within adaptive immunity.
T cells produce cytokines.
B cells produce antibodies.
Mechanisms: activation and regulation of cell-mediated and antibody responses; memory cells.
Each T cell and B cell have multiple receptors on their surface, but each cell will only have specificity to 1 thing.

Immune System: Cell to Cell Communication

Receptors are expressed on the surface of a cell or in intracellular compartments.
Ligands are molecules that activate receptors, can be soluble or membrane-bound.
Ligands can be time-consuming to travel to receptors, so cytokines can be used instead for a faster response time.
Cytokines are proteins with functions of cell growth and activation.
Cytokines can differentiate into T-cells.
There are 2 types of cytokines: Interleukins (used for communication between cells) and Chemokines (used for chemotaxis).

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Description

Learn about the fundamental concepts of infectious disease, including the immune system, immune response, and immunology.