immune system

innate immune system

fast non-specific first line of defense

phagocyte

white blood cell that destroys invading cells

(part of innate system)

adaptive immune system

specialized, highly specific system of defense

B lymphocyte

make specific proteins called antibodies

T lymphocytes

produced in bone marrow, mature in thymus

2 types (Helper T cells & Cytotoxic T cells)

Helper T cells

coordinate the defense by signaling other immune cells to fight (they don’t directly fight)

Cytotoxic T cells

find and kill cells in the body that are infected

antigen

bacteria, viruses, parasites, foreign tissues

antibody

Y-shaped molecule with 2 antigen binding sites

either blocks antigens or tags them to be destroyed

1st line of defense

skin and mucous layers (chemical - stomach acid, mechanical - coughing, sneezing)

fast response (<12 hours)

non specific

neutrophils

small, short lived cells produced in bone marrow

first responders - travel quickly and eat bacteria

uses phagocytosis

contributes to the formation of pus

monocytes & macrophages

large, long living

“big eaters” swallow germs, clean up dead cells

macrophages filter out neutrophil debris and kill large cells

eosinophil

involved in allergic and parasitic reactions

engulf some smaller cells

dendritic cells

messenger, but can engulf some particles

has projections that appear like dendrites

capture antigens and show them to T-cells

basophils

release active substances which play a role in allergic reactions

release chemicals to increase blood supply

mast cells

release histamine

participate in wound healing

release chemicals to increase blood supply

natural killer cells

are large lymphocytes

find and destroy body cells infected by viruses or cancer

non-antigen specific receptors

compliment system

>30 proteins

when activated the proteins interact to damage membranes of microbial cells, resulting in death

clotting system

block bacteria and viruses from moving deeper into body

release cytokines and chemokines

cytokines

small proteins that act as messengers

regulate immune cells, control inflammation, direct body’s response to infection

chemokines

small proteins acting as chemical guides

direct movement and positioning of immune cells

2nd line of defense

inflammatory response

vasodilation

increased blood volume, decreased blood speed

recruitment

more white blood cells in an area

movement

WBC stick to blood vessels and go through walls

fever

increases stress on pathogens

3rd line of defense

adaptive immunity

adaptive immunity

B and T cells

recognize threat, promote effective immune response, destroy invading pathogen, establish long term memory

1-3 days

phases of immune response

1. recognition phase

2. amplification phase

3. effector phase

4. termination phase

5. memory phase

recognition phase

innate immune receptors bind to pathogens or antibodies bound to invader

amplification phase

production of cytokines and recruitment of neutrophils

amplification of adaptive immunity

effector phase

removal of antigens

termination phase

dampens the immune system after the invader has been cleared

memory phase

generation of long live T and B lymphocytes

Active Natural Immunity

natural contact and infection with the antigen (environmental exposure)

Active Artificial Immunity

vaccines

Passive Natural Immunity

natural contact with antibody transplacentally (mother to fetus)

what can go wrong

1. immunodeficiency

2. hypersensitivity

3. auto immune

immunodeficiency

primary (genetic) - breaks in lymphocyte development

secondary (HIV, AIDS)

hypersensitivity

allergies

auto immune

lupus, fibromyalgia

HIV AIDS mechanism

HIV - RNA virus

genetic information is copied and virus is integrated into host’s DNA

HIV infects T4 (helper) lymphocytes

HIV AIDS transmission

1. contaminated blood

2. sexual activity

3. maternal to child

HIV AIDS diagnosis

nucleic acid test (*most effective short term)

antigen/antibody test (can take 6 months to show)

HIV disease progression

acute infection

-asymptomatic

-symptomatic

-AIDS

asymptomatic

CD4 levels above 500 cells/mm³

normal (500-1500)

medication can delay progression

symptomatic

CD4 levels between 200-500 cells/mm³

AIDS

CD4 levels below 200 cells/mm³

acute infection

1-6 weeks patient may experience flu like symptoms

symptomatic symptoms

-enlarged lymph nodes

-diarrhea, weight loss, fatigue, night sweats, fever

-neurological symptoms

-peripheral neuropathy (potential blindness)

-dermatologic conditions

-pain

auto immune disease

>56 autoimmune diseases

results from combination of factors

-genetic

-hormonal

-environmental influences

lupus

chronic inflammatory autoimmune disorder

most commonly women 20-40

cause is unknown

symptoms: arthralgias + arthritis (usually bilateral), skin rash, butterfly rash

fibromyalgia

chronic muscle pain syndrome

women > men

multifactorial, no obvious precipitating events

fibromyalgia diagnosis

no definitive test

WPI: self reported list of painful sites 0-19

SSS: symptom severity scale focuses on fatigue, cognitive dysfunction & sleep disturbance

positive fibromyalgia diagnosis

WPI equal or greater than 7 & SSS is equal or greater than 5

WPI is 4,5, or 6 & SSS is equal or greater than 9 horns

chronic fatigue syndrome

unexplained fatigue of greater than or equal to 6 months

ME (myalgic encephalomyelitis)

symptoms:

-severe exhaustion

-waking up tired after full night of sleep

-trouble with memory

-pain or dizziness

often cyclical

*unknown cause

CFS diagnosis and treatment

diagnosis - no physical signs or diagnostic lab tests

treatment - symptom relief and improved function

anti histamine

allergy meds (ends in -ine)

causes drowsiness and sedation

immunosuppressants

dampens or shuts down the chronic autoimmune inflammatory cascade

*severe susceptibility to infection

vaccine

stimulates the immune system to recognize and respond

injected pathogens