CH 16 Innate Immunity

What are the 2 kinds of Immunity?

Innate & Adaptive Immunity.

What is Innate Immunity.

• Defenses are present at birth

• Provides a rapid response

• No Memory Response.

How is Innate immunity activated?

It’s activated by protein receptors on defensive cells.

What are Toll-Like Receptors?

• Found on defensive cells

• Attaches to pathogen-associated molecular patterns on pathogens. (PAMPS)

What is a PAMP? Give an example!

PAMPS stand for pathogen associated molecular patterns.
It’s anything unique to a virus or a bacteria.

An example would be envelopes & spikes on viruses.

Teichoic Acids, Pili, Flagellin, Fimbriae for Bacteria.

When Toll-Like Receptors encounter PAMPS on microbes, what type of cells do they release?

They release cytokines.

What are cytokines?

They regulate intensity and duration of immune responses.

Recruits other immune responding cells to destroy microbes.

What is adaptive immunity?

• Has a specific response to a specific microbe.

• Slower to respond

• Has Memory Response

• Has Lymphocytes → Can activate B cells & T cells

What are the 2 lines of Innate Immunity?

First Line

• Skin

• Mucous Membranes

Second Line

• Phagocytes

• Inflammation

• Fever

• Antimicrobial Substances

What are the Physical Factors & Chemical Factors for First Line of Defense?

Physical Factors..

• Skin

• Mucous Membranes

• Lacrimal Apparatus

• Earwax *

• Saliva *

• Epiglottis

• Vaginal Secretions *

• Urine *

• Peristalsis, Defecation, Vomitting & Diarrhea

Chemical Factors..

• Sebaceous Glands

• Earwax *

• Saliva *

• Perspiration

• Gastric Juice

• Vaginal Secretions *

• Urine *

What does skin do?

• It is the first line of defense.

• Epidermis is in direct contact with environment

• It contains protein Keratin.

  • Periodic shedding removes microbes at the surfaces

  • Dryness inhibit microbial

What does Mucous Membranes do?

• They line the entire gastrointestinal, respiratory and genitourinary tracts

• Secretes mucus to trap microorganisms that enter these tracts.

• Pathogens can thrive in moist secretions and can penetrate the membrane.

What can mucous coated hairs in nasal membrane do?

• They filter inhaled air

• Traps microorganisms, dust & pollutants → propelled towards the throat

• Ciliary escalator keeps the mucous blanket moving towards the throat → cigarette smoke is toxic to cilia

What does the Lacrimal Apparatus do?

• Group of structures that manufactures and drains tears.

• It produces tears that are passed over the eyeball

• Continuous washing keeps microbes at bay

• If something irritating lands on eyes, heavy tear production occurs.

What is earwax? Physically and Chemically.

Physically → Helps prevent microbes from entering the ear

Chemically → Secretes are rich in fatty acids, low pH

What is saliva? Physically & Chemically?

Physically → Helps dilute m-o in the mouth and prevent them from colonizing.

What is an epiglottis?

It covers the larynx and prevents microorganisms from entering lower respiratory tract.

What is Peristalsis, Defecation, Vomitting and Diarrhea?

What is vaginal secretions? Physically and Chemically?

Physically → Moves m-o out the female body

Chemically → Cervical mucus has antimicrobial activity

What is urine? Physically and Chemically?

Physically → Prevents microbial colonization in the genitourinary tract

Chemically → ph 6 inhibits microbes.

What is sebaceous glands?

• Produces sebum to prevent hair from drying out and becoming brittle. 

What is perspiration?

• Helps maintain body temperature, eliminates waste, and flushes m-o from surface of the skin

• It has lysozyme which is an enzyme that breaks down gram-positive walls.

What is gastric juice?

Has a low pH that can destroy bacteria and their toxins.

What are the formed elements in blood?

Blood consists of plasma and formed elements..

• Erythrocytes

• Leukocytes

• Platelets

How does Hematopoiesis start?

It begins in the red bone marrow with pluripotent stem cell. 

What type of leukocytes are there?

Granulocytes → Neutrophils, Basophils, Eosinophils (They have granules)

Agranulocytes → Monocytes, Dendritic Cells, Lymphocytes (No granules)

What are NK? (Nature Killer Cells)

• Kills a wide variety of infected body cells and certain tumor cells.

• It attacks any cell displaying  abnormal proteins.

The binding of NK cells to a target cell release what?

Releases perforins & granzymes. 

What does perforins & granzymes do?

Perforins → they create perforations in the membrane

Granzymes → protein they digest enzymes

What are phagocytes?

They are cells that digest harmful particles. 

Whats the difference between a fixed vs free macrophage?

Fixed Macrophages reside in certain tissues and organs.

Free Macrophages roam tissues and they gather at sites of infection or inflammation.

What is inflammation?

• They destroy injurious agents, remove it and its by products from the body.

• Limits the effects on the body by confining off injurious agents and by-products

• They repair and replace damaged tissue

• It can be local or systemic.

Whats Acute Inflammation?

• Signs and Symptoms develop rapidly.

• Lasts for a few days or weeks.

• Usually mild and self-limiting

What is Chronic Inflammation?

• Signs and symptoms develop more slowly

• Lasts for several months or years.

• It can be severe and progressive.

study the phagocyte cycle and inflammation stages.

Refer to notes.

What is a fever? How does the body respond?

A fever is a systemic response to injury to the body. Our body responds by constricting blood vessels and shivering. 

• It continues to maintain temperature until cytokines are eliminated.

• As the infection dies down..the skin becomes warm and sweating begins.

• The crisis point of fever indicates temperature is decreasing.

What does the complement system consist of?

It has 30 proteins that circulate blood serum and tissue. The proteins here can do immune response.

What does the complement system do?

• It enhances cells of the immune system in destroying microbes

• It’s NOT adaptable.

• Complement proteins are inactive until it’s split into fragments

• It will become activated and will help with inflammation.

What are the 3 different pathways for the complement system?

1. Classical Pathway

2. Alternative Pathway

3. Lectin Pathway

C3 splits into 2 different groups. What does the 2 groups stand for and what do they do?

C3 is split into C3a and C3b.

C3a is responsible for inflammation

C3b is responsible for opsonization and cytolysis.

What is cytolysis ? C3a or C3b?

C3B

Cytolysis → membrane attack complex resulting in cytolysis.

C5b-C8 and C9 make lesions in cell membranes that lead to cell death.

Gram - m-o are susceptible to cytolysis because they have a thin peptidoglycan layer.

What is Opsonization ? C3a or C3b?

C3B

It promotes the attachment of a phagocyte to a microbe.

What is inflammation? C3a or C3b?

C3a 

• Mast cells will release histamine

• Increases blood vessels

• Attracts phagocytes to infection site.

Why are microbes not killed by phagocytes? What do these microbes have that make it difficult?

They either have capsules or leukocidins.

What are capsules in microbes?

• It makes it more challenging to be phagocytized 

What are leukocidins in microbes?

• It kills phagocytes by releasing phagocytes own lysosomal enzymes into its cytoplasm..