Innate Immunity Overview

Question 1

Innate Immunity

Answer 1

An acient defense form that is found in all multicellular plants and aninmals

Question 2

What are the 2 major components of innate immunity?

Answer 2

Physical/chemical barriers and Cellular responses to infection

Question 3

What makes up the physical and chemical barriers against infection?

Answer 3

• epithilial layers of the skin
• mucosal and glandular tissue surfaces (mucoid barriers)
• cilia (mechanical removal of foreign material)
• commensal microbiota
• chemical barriers (low pH, degrative enzymes, and directed mucus flow)
• Antimicrobial peptides and proteins

Question 4

Chemical Barriers

Answer 4

Molecular factors that provide innate immune protection against infection

Question 5

Antimicrobial peptides and proteins

Answer 5

Molecules released by several cell types. Some are constitutively secreted, whereas others are induced upon activation of innate receptors. These can directly kill microbs

Question 6

peptides

Answer 6

<100 amino acids

Question 7

Proteins

Answer 7

> 100 amino acids

Question 8

What makes up the cellular responces to infection?

Answer 8

• triggered bt the cell surface or intracellular innate PRRs
• Phagocytosis
• production of antimicrobial substances as well as cytokines and chemokines to induce inflammation

Question 9

Phagocytosis

Answer 9

The cellular uptake of particulate materials by engulfment

Question 10

Inflammation

Answer 10

Tussue response to infection or damage that eliminates/ contains the insult. Classical signs include heat, pain, redness, swelling, and loss of function.

Question 11

Epithelial Cells

Answer 11

A specilized cell type that protects the body from external stimuli. Lines all body cavities continuous with the external surface

Question 12

Endothelial Cells

Answer 12

Specilized cells that line organs that are not continuous with the external surface such as the peritoneal cavity ans the inner syrfaces of blood vessels

Question 13

Mucus

Answer 13

An aqueous, viscous fluid secreted by goblet cells in the eithelial layer that protects it from dehydration and physical injury. Consists of highly glycosylated glycoproteins (mucins) as well as proteoglycans, lipids, DNA, and other proteins

Question 13

Goblet Cells

Answer 13

Mucous Producing cells

Question 14

Where is most of our mucus produced?

Answer 14

In the GI tract (protects stomach lining from the stomach acid and limits bacterial interactions withh intestinal epithelial cells)

There is less of a barrier in the small intestine compared to other areas of the GI tract to allow for absorbtion of nutrients during digestion

Question 15

Cilia

Answer 15

Hairlike projections onn cells that can propel mucus with trapped microbes out of the respiratory tract

Question 16

Decribe how cilia is a physical barrier against infection?

Answer 16

The synchronous movement of cilia propels mucus and particles upward from the lungs and downwards from the nose to be swallowed or expelled by coughing/ sneezing

Question 17

What fluids in our body conain antimicrobial substances?

Answer 17

Saliva, tears, urine, and breast milk

Question 18

Commensal Microbiota

Answer 18

The diverse community of microbes that coexist with our barrier tissues without causeing damage. They provide diverse benifits to barrieer tissues throughout the body. The species of bacteria are reigonally determined throughout the body.

These direcctly inhibit the growth of pathogens by controlling the local microenviroment (their metabolites can also enhance barrier strength). They ARE part of the innate immune system.

Question 19

What cells produce AMPs?

Answer 19

Neutrophils, monocytes, epithelial cells, and salivary mammalian gland cells

Question 20

WHat are the different ways the anti-microbial peptides/ proteins (AMPs) target microbes?

Answer 20

They can…
- Cleave essencial cellular components
- Hyrolyze membranes
- Disrupt essencial cellular structures/ processes
- Bind to the microbe
- Block the access of crucial metabolites/ components to the microbe
- Create channels in the membranes

Question 21

Describe the major properties of AMPs.

Answer 21

• peptides (10-50 aa); proteins (>100 aa)
• Cysteine rich (creating intramolecular disulfide bonds)
• Amphipathic (water and fat loving)
• They interact with acidic phospholipids in bacterial membranes
• They can disrupt membrane integrity (through hydrolysis, enzymatic cleavage or disruption)
• They can inhibit nucleic acid and protein synthesis

Question 22

How do local AMPs control the reigonal microbiota?

Answer 22

Different cells in different areas of the body contribute different barriers/ AMPs which target specific bacteria.

Example: on our fingers there are different AMPs produced that do not harm our commensal bacteria S, aureus but it will target foreign bacteria such as E. coli which is normally found in our GI tract

Question 23

Antigen presenting cells (APCs)

Answer 23

Cells that communicate the infection to the lymphoid cells, which the corrdinate the adptive response to the infection

Question 24

Primary Lymphoid Organs

Answer 24

Place where lymphoid precursors mature into antigenically commited, immunocompetent cells

These lymphoid organs are the bone marrow and thymus

Question 25

Secondary lymphoid organs

Answer 25

Organs and tissue which mature, immunocompetent lymphocytes encounter trapped antigens and are activated into effector cells

These lymphoid organs include lymph nodes, spleen, and specilized mucosal tissues in the gut