Innate Immune Cells and Responses end of chapter3

Flashcards covering key immunology vocabulary from the lecture transcript, including macrophage states, dendritic cell subsets, neutrophil features, and natural killer cell biology.

M1 Macrophage Polarization

A pro-inflammatory polarized state that macrophages enter in response to pathogen-derived signals or infection (such as interferon gamma), shifting surface molecules and gene expression to better cooperate with NK cells and T cells.

M2 Macrophage Polarization

A wound-healing macrophage phenotype adopted in response to damage signals or sterile inflammation rather than invading pathogens.

Dendritic Cells

Myeloid innate immune cells that sample the environment for infections and serve as messengers between the innate and adaptive immune systems by traveling to lymph nodes to stimulate T and B lymphocytes.

Plasmacytoid Dendritic Cells

A specific subset of dendritic cells that produces significantly higher amounts of type 1 interferon than any other cell type.

Pyogenic Bacteria

Bacteria that are capable of producing pus during an infection.

Pus

A thick yellowish fluid found in infected wounds, composed of dead microorganisms, tissue debris, and dead or dying white blood cells (primarily neutrophils).

Polymorphonuclear Leukocytes (PMNs)

An alternative term for neutrophils, named for the irregular and multi-shaped structure of their nuclei.

Neptosis

A unique form of programmed neutrophil cell death where the nucleus swells and bursts, releasing nuclear chromatin and granule proteins to trap and kill extracellular microbes.

Neutrophil Extracellular Trap (NET)

A net-like structure composed of released chromatin (DNA and histone proteins) combined with granule proteins that physically traps and kills microbes.

Chronic Granulomatous Disease

A disease caused by defective subunits in NADPH oxidase that results in a failed respiratory burst, rendering individuals unable to efficiently clear infections and prone to chronic intracellular infections and granulomas.

Innate Lymphoid Cells (ILCs)

A family of innate lymphoid cells that helps regulate immune responses, including helper groups (ILC1, ILC2, ILC3), cytotoxic natural killer cells, and lymphoid tissue inducer cells.

CD3

A defining surface marker protein expressed specifically on T cells that is absent on natural killer cells.

CD56 Bright Natural Killer Cells

A subpopulation of natural killer cells expressing high surface levels of CD56 that are primarily dedicated to cytokine production and helper functions.

CD56 Dim Natural Killer Cells

A subpopulation of natural killer cells derived from CD56 bright cells that express lower surface levels of CD56 and possess higher cytotoxic killing capabilities.

Immunological Synapse

A specialized contact zone formed between a cytotoxic lymphocyte (such as an NK cell) and its target cell, regulated by activating and inhibitory receptors to direct granule release and prevent bystander cell death.