Lecture 5- Innate Immune Responses

Question-and-answer flashcards covering key concepts from the notes on innate immune responses, including serous/catarrhal/purulent/histiocytic/granulomatous inflammation, transudate/exudate, and key cell types (neutrophils, macrophages, NK cells, eosinophils, basophils, mast cells).

What term describes the innate nonspecific 'prepared' immune response that animals are born with and which proceeds in a similar way regardless of the encountered agent?

Innate immune response; nonspecific, born with; each response type is named by the cell product or responder observed in tissues.

Which innate response type is associated with watery fluid produced by membranes and is labeled 'serous'?

Serous response; watery fluid produced by serous membranes.

Which innate response type involves mucus production and is labeled 'catarrhal'?

Catarrhal response; increased mucus production by goblet cells on epithelial surfaces.

Which innate response type is primarily neutrophil-driven and can form purulent lesions or abscesses?

Suppurative/Purulent inflammation; neutrophils respond to bacteria, fungi, foreign matter and form pus.

Which innate response type features macrophages/histiocytes and granulomatous lesions?

Histiocytic/Granulomatous inflammation; monocytes become macrophages/histiocytes; phagocytic and form granulomas.

What is the difference between transudate and exudate?

Transudate is clear to watery fluid from fluid leakage; Exudate contains inflammatory cells, fibrin and fluid due to inflammation.

What conditions increase hydrostatic pressure leading to transudate formation?

Venous outflow obstruction (e.g., congestive heart failure).

What conditions decrease colloid osmotic pressure leading to exudate formation?

Decreased colloid osmotic pressure due to decreased protein synthesis (liver disease) or increased protein loss (kidney disease).

What is serous transudate and when does it occur?

Serous transudate occurs in early viral infection or in response to environmental irritants; caused by vascular leakage; can flush microorganisms; examples include runny eyes and nose.

What is the catarrhal response and what produces mucus?

Catarrhal response; mucus produced by goblet cells embedded in epithelial surfaces; coats surfaces; can be excessive.

In suppurative/purulent inflammation, which cells are the main players and how do they reach the site?

Neutrophils; attracted by chemical mediators, travel via blood, exit vessels by extravasation.

What is a key enzyme associated with neutrophil activity in tissues?

Myeloperoxidase.

How is pus formed and what is the colloquial name describing neutrophil action?

Pus is formed as neutrophils destroy bacteria and tissue; described as the 'suicide bomber' of the white blood cell family.

What can happen to pus over time and how does this affect removal?

Pus can inspissate (dry out) forming solid lesions; these can be difficult to remove and can protect agents from clearance.

What is an abscess?

Localized collection of pus; mass lesion of suppuration; center often contains etiologic agents.

What cell types comprise histiocytic/granulomatous inflammation and what is their role?

Monocytes in blood become macrophages/histiocytes; phagocytic and digest material.

What is granulomatous inflammation and what are its characteristic features?

Granulomatous inflammation is a mass lesion comprised of macrophages; may include giant cells and epithelioid cells; center may contain etiologic agents.

What is Multinucleated Giant Cell (MNGC) formation and when does it occur?

Fusion of multiple macrophages into a single giant cell; occurs in response to foreign bodies or chronic infection (e.g., TB).

Which cells are in the miscellaneous category of innate responses and what do they do?

Eosinophils, Basophils, and Mast Cells; respond to allergic and parasitic disease; release histamine and heparin causing tissue swelling; not typically named grossly; identified microscopically by granules.

What are Natural Killer (NK) cells and what is their function?

Specialized lymphocytes that kill virally infected and cancer cells by forming perforin pores in target cell membranes; not observed grossly.

What is Kurloff cell and which animals have it?

Kurloff cell is a natural killer cell unique to capybaras and guinea pigs.

What are examples of unintended consequences of innate responses mentioned in the notes?

Bystander effects and mass effects from abscess or granuloma; tissue damage beyond the primary target.

What are the key takeaways about innate immune responses from the summary slide?

Innate responses have a limited, set pattern of reactions; named for the cell product or responder; can have unintended consequences such as bystander or mass effects.

What is fibrinous inflammation and what does fibrin do?

Fibrinous inflammation involves leakage of clotting protein fibrin from vessels; fibrin coats tissue surfaces during inflammation.