Chapter 9 Innate Immune System

immune system

defense system to work together to eliminate foreign pathogens

• innate (humoral)

• adaptive (chemical)

innate immunity

natural immunity

• first and second lines of defense

• immediate and always the same no matter the threat; non-specific

adaptive immunity

specific immunity that the responses are tailored and specific to the pathogens encountered

• Third and final defense

• Activated by vaccines; takes 14-15 days to fully activate

  • slower than innate

• specific

vaccines

introduce antigens to train the immune system against a specific pathogen

• builds antibodies

lines of defense

1.) skin, mucous membranes, anti-microbial substance

2.) inflammation, fever, phagocytes

3.) humoral and cellular immunity

plasma

the liquid portion of the blood containing antibodies making up most of the blood

• helps with Covid recovery

Red blood cells

• no nucleus

• replaceable

• filtered out by liver when dead

• females have less because of filtration by periods

  • based on age

white blood cells

Never Let Monkeys Eat Bananas

• neutrophiles

• lymphocytes

• monocytes

• eosinophils

• basophils

neutrophils

makes up majority of WBC

• a high number = bacterial infection

• pus = dead WBC fighting against infection

• FIRST to the sight of injury

monocytes

matures into macrophage

• agranulocytes

lymphocytes

T cells and B cells and NK

• agranulocytes

eosinophils

indicates foreign pathogens

• parasite infections

basophils

least abundant

• works with mast cells in allergic reactions

allergies

1.) foreign object enters cell and mast cells and basophils are triggered

2.) cells dump histamines triggering

• vasodilation

• drop in blood pressure (hypotension)

• vessels are more leaky allowing fluid to escape into surrounding tissues causing swelling and runny nose

• take anti-histamines to vasoconstrict and dry up

immunity

the ability to fight off disease

susceptibility

lack of resistance to a disease or pathogen

• due to lack of sleep, stress

spleen

filters blood

• asplenic people are susceptible to infection because they are not filtering blood the whole time

smooth; has receptors

the cell surface is not ____.

toll-like receptors

class of proteins found on the surface of certain cells.

• how viruses feel for receptors

• recognizes PAMPs on pathogens

• uses ATP (tollbooth)

• People with autoimmune diseases cannot recognize their own cells

pathogen-associated molecular patterns (PAMPs)

act as identification tags for our immune system

• unique to bacteria, viruses, and fungi

  • LPS, peptidoglycan

• pathogen specific

• absent in heart cells

cytokines

signaling proteins that send chemical messages and play a role in cell signaling and regulating immune responses and inflammation

• Blanket term (interferons)

skin

one of the most important physical barrier

• first line of defense

• gram +

• epidermis - sheds skin

  • hot water dries out skin and skin tries to overcompensate with more oil than needed

• dermis - contains hair follicles and sabum

• acidic pH 3-5

  • suppresses bacterial growth

sebum

fungistatic oil) reducing the rate of fungal infections

burn victims

_____ _____ are susceptible to infections because of their lack of barrier so burns must be covered as a priority.

• air is not even sterile

1st degree burn

only epidermis

• nerve endings

• red/no blisters

2nd degree burn

epidermis and upper dermis

• blisters

• nerve endings

3rd degree burn

all epidermis and dermis

• burns nerves

• no pain

4th degree burn

burns to the bone

Mucous membranes

Protects from getting sick all the time and traps microbes

• sinus, mouth, respiratory system, tears

  • tears have lysozyme that cuts beta 1,4-glycosidic bonds

Ciliary escalator

pushes foreign substances upward, feeds toward mouth away from the lungs

• Lines airway along with mucus

• Can be infected by cigarettes but can heal in sleep

earwax

protects the ear canal by trapping small foreign materials

• Contains lysozyme which inhibits bacterial growth

urine

flushes microbes out of the body

• UTI bacteria can either be gram - or + since its close to the “holes”

  • Could be either skin bacteria or e. coli; determined through EMB, MSA

vaginal secretions

acidic discharge

• UTI infections are usually gram +

Peristalsis, defection, vomiting, diarrhea

Tries to get pathogens and microbes out through waste to the large intestine

• Naturally or can induce with sodas

chemical factors

sebum, lysozyme, gastric juice, vaginal secretions

gastric juice

acidic enough to kill pathogens

lysozyme

breaks down bacterial cell walls

• In tears

• Breaks beta 1,4 glycosidic bonds

normal microbiota

microbes that live in our body and fight pathogens and tolerate non-pathogens, food, and tissues

• keeps us healthy

• commensalism

microbial antagonism

competitive exclusion from regular microbes that prevent new organisms or pathogens from living on the body and causing infection

• transient

probiotics

live beneficial bacteria that is ingested to fight off pathogens

• good bacteria in gut

• in fermented foods and yogurt

prebiotics

non-digestible fibers found in food that feeds the probiotics

• onion, garlic

hematopoiesis

The process of blood cell formation; WBC, plasma, and RBC are formed

• Continuous process

• when cells differentiate

T-cell

messenger to B cell or cytotoxic goes and fights

• matures in the thymus of the chest

• HIV target

• main reason for memory cells

stem cells

has the ability to regenerate to certain amount

holin

small membrane proteins produced by the bacteriophages that trigger and control the degradation of the host cell

• accumulate and form holes in the membrane leading to cell lysis

mast cells

granular cell that release histamines

• Dumps out histamines in an allergic reaction

• Mast cell stabilizer needed

• agranulocyte

B cell

produces the antibodies

• Attaches to pathogen or antigen

• Matures in lymph nodes and tissues

  • Antigens can bring out allergic reaction

• Can kill infected and damaged cells or they’re messengers

• Same as natural killer cell

antigen presenting cells

• engulfs antigen that it shows up on the surface to be taken away by T cell

• macrophage, dendrite

____ produces all cells that are highly regulated.

bone marrow

granulocytes

Consists of neutrophils, eosinophils, basophils

• Has “granules” under the microscope

agranulocytes

Consists of monocytes, dendritic cells, lymphocytes

Antimicrobial peptides

We produce peptides have a positive charge

• bacteria have negative charge

• disrupt bacterial membranes

• HOLIN

lymphatic system

No pump, no second heart 

• Lymph nodes

  • Swollen when fighting off pathogens

• Lymph moves by gravity and movement 

• One-way valve opening 

• lymphedema

lymphedema

• build up of lymph fluid caused by damage to the lymphatic system 

  • Primary (birth) and secondary (later in life)

  • No mechanism to fix the lymphatic system

candida aureus

• fungus

  • antibiotics are no help

  • very tiny

• fatality is 30-60%

• catheters and ports can be a gateway

lymphedema

• build up of lymph fluid caused by damage to the lymphatic system 

  • Primary (birth) and secondary (later in life) 

  • No mechanism to fix the lymphatic system 

phagocytes

cells that eat pathogens

• neutrophils

• second line of defense

• fixed and wandering macrophages

innate cells

baso, eosin, mast cell

innate and adaptive

neutrophil, mono, dendritic, NK

adaptive cells

plasma cell, B cell, T cell

chemotaxis

 chemical signals that allow for the phagocytes to attach to the pathogens to engulf it

opsonization

protein tags on pathogens for phagocytosis

• Coat pathogens making them stand out to the phagocytes

• Comes from the liver

• Like sprinkles aka complement proteins

phagolysosome

when lysosome and phagosome fuse to kill the pathogen

• Mixes with enzyme

intracellular killing

Phagocytes wrap around the pathogen to ingest it

• Only bacterial

complement proteins

helps send out waste

• Genetic; can have complement protein deficiency making them susceptible to bacterial infections

• Comes from liver

inhibit adherence

M protein, capsule

• streptococcus pyogenes, S. pneunoniae

kill phagocytes

leukocidins

• staphylococcus aureus

lyse phagocytes

produce pore forming toxin

• listeria monocytogenes

escape phagosome

induce proptosis (cell death)

• eats pathogen

• Shigella, Rickettsia

prevent phagosome

lysosome fusion

• HIV, mycobacterium tuberculosis

survive in phagolysosome

Coxiella burnetti

• dangerous bacteria in raw milk

pyroptosis

• Cell budges out and dies

• Refuses to merge with the virus

inflammation

An innate response that develops when tissues are damaged from physical factors or infectious agents 

• instant reaction

• helps limit spread of infectious agents to recruit the immune defenses to injured tissue

• vasodilation occurs

PRISH

pain, redness, inflammation, swelling, heat

acute-phase protein secretions

body releases certain proteins that help the body respond to injury infection by promoting inflammation and supporting tissue repair

kinins

pro-inflammatory

cytokines

chemical messages passed in between cells

process of inflammation/tissue repair

1. Histamine release; key trigger of inflammation

   • Cytokines are also release 

   • Walls get leaky from vasodilation 

2. Blood comes out and clot

3. Abscess starts to form (infection; doesn’t usually happen) 

4. Margination - phagocytes stick to the endothelium 

5. Diapedesis - phagocytes squeeze between cell walls to the sight of injury  

6. Phagocytosis of invading bacteria 

tissue repair

• Skin will not heal if a foreign substance is still in it 

• If not able to push out the substance it will wall it off 

• Must push all foreign objects out 

fever

• Abnormally high systemic body temperature as a response to an infection

  • 37 degrees and 40 degrees celsius is a big difference for pathogens 

  • Heat must be generated from muscles, shivering 

  • Thermogenesis is how temp goes up 

• meds can reduce thermostat artificially

• When body temp falls (fever breaks), vasodilation and sweating occurs and fever is gone 

hypothalamus

thermostat in our brain

complement system

involves complement proteins that fights off infections with a series of inflammation pathways 

• Assists the immune system working with both innate and adaptive

•  Helps antibodies recognize foreign pathogens by surrounding pathogens 

• Always in the background

• genetically set

• three pathways: opsonization, lysis, inflammation; help clean up some debris and memory

opsonization complement system

sprinkles of proteins around the pathogens

lysis complement system

small proteins that line up like flowers to poke holes in the pathogen; continuous

• membrane attack complex

inflammation complement system

cascade will cause body to recognize what is going on

interferon

cytokine that is specific to the viral infection

• Infect other cells 

• What happens when you feel like you’re sick but you’re not sick 

  • Virus is killed and resisted by neighboring cell 

siderophore

• pathogen produces, not us

  • Viruses want iron from our blood because we are a perfect target

  • Blanket term; each pathogen has siderophores 

transferrin and lactoferrin

are mechanisms that we use to hang onto the iron

ferritin

highest amount of iron-binding proteins

• everywhere in body

• from liver