Immunology Review: Cytokines, Immunity Types, Antibody Functions, and Blood Cells

Practice flashcards covering cytokine functions, types of adaptive immunity, antibody effector mechanisms, systemic inflammatory cytokine effects, and blood cell characteristics.

What are the source cells and primary functions of Interleukin-1 ($IL-1$)?

Source: Macrophages, endothelial cells, and some epithelial cells. Function: Activates endothelium in inflammation, induces fever and acute-phase response, and stimulates neutrophil production.

What cells produce Interleukin-2 ($IL-2$), and what are its main functions?

Source: $CD4^+$ and $CD8^+$ T cells. Function: Growth factor for activated T cells, induces synthesis of other cytokines, and activates NK and $CD8^+$ cells.

What is the primary function of Interleukin-3 ($IL-3$)?

Source: $CD4^+$ T cells. Function: Acts as a growth factor for hematopoietic cells.

What are the sources and functions of Interleukin-4 ($IL-4$)?

Source: $CD4^+\text{TH2}$ cells and mast cells. Function: Promotes growth and survival of T, B, and mast cells, drives $\text{TH2}$ differentiation, and activates B lymphocytes and eosinophils.

Which cells produce Interleukin-5 ($IL-5$), and what is its main function?

Source: $CD4^+\text{TH2}$ cells. Function: Induces the growth and development of eosinophils.

What are the sources and functions of Interleukin-6 ($IL-6$)?

Source: Macrophages, endothelial cells, and T lymphocytes. Function: Stimulates the liver to produce acute-phase mediators and promotes proliferation of antibody-producing cells.

What is the origin and function of Interleukin-7 ($IL-7$)?

Source: Bone marrow stromal cells. Function: Stimulates the development and proliferation of pre-B cells and thymocytes.

What are the sources and functions of Interleukin-8 ($IL-8$)?

Source: Macrophages and endothelial cells. Function: Serves as a chemoattractant for neutrophils and T cells, regulates lymphocyte growth, and controls neutrophil infiltration.

What local inflammatory changes are induced by $IL-1$ and $TNF$ on endothelial cells and leukocytes?

On endothelial cells, they increase permeability and expression of adhesion molecules. On leukocytes, $TNF$ and $IL-1$ cause activation, leading to the secretion of $IL-1$, $IL-6$, and chemokines.

What are the protective systemic effects of $TNF$, $IL-1$, and $IL-6$ on the brain, liver, and bone marrow?

Brain (encephalon): Induces fever. Liver: Stimulates synthesis of acute-phase proteins. Bone marrow: Increases leukocyte production.

What pathological systemic effects does $TNF$ exert on the heart, endothelium, and muscle tissue?

Heart: Causes low cardiac output. Endothelium: Induces thrombus formation and increases permeability. Muscle: Causes insulin resistance.

How is Humoral Immunity defined by its target microbes, reactive lymphocytes, and primary function?

Target: Extracellular microbes. Reactive Lymphocyte: B Lymphocyte. Mediators: Plasma (secreted antibodies). Function: Blocks infections and eliminates extracellular microbes.

How does Cell-Mediated Immunity involving Helper T Lymphocytes eliminate phagocytosed microbes?

Helper T Lymphocytes ($CD4^+$) respond to phagocytosed microbes in macrophages by activating neutrophils and macrophages, which then kill the phagocytosed microbes.

What is the mechanism and function of Cytotoxic T Lymphocytes ($CD8^+$) in Cell-Mediated Immunity?

Cytotoxic T Lymphocytes recognize microbes with intracellular replication, killing infected cells to eliminate infection reservoirs.

How do antibodies mediate opsonization and phagocytosis of microbes?

Secreted antibodies coat microbes and bind to $Fc\gamma$ receptors on phagocytes, triggering opsonization and phagocytosis.

What role do NK lymphocytes play in antibody-mediated immunity?

NK lymphocytes recognize antibody-bound targets via $Fc$ interaction to execute antibody-dependent cellular cytotoxicity (ADCC).

What three pathways or outcomes are triggered by antibody-induced complement activation?

1. Phagocytosis of microbes opsonized via $C3b$ receptors. 2. Inflammation. 3. Direct lysis of microbes.

What are the morphological characteristics, tissue locations, and functions of Macrophages?

Location: All tissues. Morphology: Agranulocyte with irregular cytoplasmic membrane, vacuoles, and cytoplasmic vesicles. Function: Phagocyte, antigen-presenting cell, and T-cell activator.

What are the key morphological features, locations, and functions of Dendritic Cells?

Location: Epithelial and lymphatic tissue. Morphology: Agranulocyte with thin, star-shaped cytoplasmic projections. Function: Phagocyte, antigen-presenting cell, and T-cell activator.

What are the location, morphology, and functions of Eosinophils?

Location: Bloodstream, recruited to connective tissue of respiratory and digestive tracts. Morphology: Granulocyte with bilobed nucleus and large pink-stained granules. Function: Attacks extracellular parasites and involved in Type I hypersensitivity.

What are the location, morphology, and functions of Mast Cells?

Location: Most tissues adjacent to blood vessels. Morphology: Granulocyte with a small nucleus and large blue-stained granules. Function: Attacks extracellular parasites and involved in Type I hypersensitivity.

What are the location, morphology, and functions of Basophils?

Location: Low presence in bloodstream. Morphology: Granulocyte with bilobed nucleus and large blue-stained granules (which can obstruct the nucleus). Function: Attacks extracellular parasites and involved in Type I hypersensitivity.