The Immune System.

What’s up with that.

What is it?

• The immune system is the network of specialized cells and organs that work together to defend the body against attacks by “foreign” invaders, a.k.a. antigens, such as bacteria or viruses

• An antigen is any substance that stimulates the immune system to make a specific immune response.

Self/Non-Self Recognition- THE MAIN, GENERALIZED FUNCTION OF IMMUNE CELLS

• Every cell in a human’s body displays a “marker” or “bar code” based on its major histocompatibility (MHC). These “codes” or “markers” let the body know that those cells are its own cells.

• Any other cells, that do not display the same MHC “marker”, are recognized by the immune system as “non-self” and are attacked.

So basically...

“If you’re not us, you’re dead.”

– The Immune System

What are the general cells

that are involved when an immune response is made?

•Macrophages•Helper T-cells• B-cells and Killer T cells

Macrophages*THE BIG EATERS*

Macrophages are found in all locations in the body, where

they await the entry of foreign material which they

then wrap themselves around and ingest. Macrophages are

the first immune cells to perform the “self/non-self

recognition” function. They identify antigens as “non-self”, and initiate the rest of

the immune response to attack it.

• 1) They *gobble up* the antigens

• 2) Break them up into little pieces

• 3) Display the pieces the helper T cells

Helper T Cellsthe heart of the immune system

• The little pieces of the antigen fit like keys into locks found on helper T cells, and thus "turn on" these cells. Once turned on, helper T cells then direct traffic in the immune system, using chemical messengers (called interleukins/lymphokines) to signal other immune cells to get involved in the battle.

The Helper T Cells “direct the traffic” of the immune cells.

If the antigen is recognized as

a germ or bacteria,

the B-cells will be

signaled

If the antigen is

recognized as

a cancer or virus-

infected cell,

the killer T cellswill be signaled.

Helper T Cell

B-cells• B cells, once given the proper information from

helper T cells, secrete proteins called antibodies.

Antibodies are “missiles” that move about our bodies

specifically targeting foreign material.

• The B-cells bind and neutralize the germ, and attract other immune system components which facilitate the destruction of the antibody-labeled target.

Killer T Cells• Once given the "go" signal from helper

T cells, these cells will “cozy up” beside cancer cells or virus-infected cells and then "stab" them so that the target cell ruptures and no longer serves as a reservoir for viral growth or as a cancer clone capable of generating more progeny.

SO, for example…

• Suppose this cell snuffs up a flu virus.

• We now have a virus-infected cell, which will need to be combated.

We have a “nose” (respiratory epithelial) cell

Step 1 =Macrophages

•The macrophage wraps itself around and ingests the infected cell (the nose cell + antigen).

•The macrophage breaks it up into little pieces, then displays it to the helper T cells.

Step 2

•The helper t cells recognize the infected “nose” cell as a virus-infected cell.

•Because it is a virus-infected cell, the helper t cells will signal the killer t cells to destroy the antigen.

Step 3

The killer T cells will move right up to the virus-infected cell and rupture it, so that the virus or cancer can no longer grow or multiply.

(If…)• If instead the antigen was a

bacteria and not a virus, the helper t cells would signal the b-cells to destroy the antigen.

Last but not least:

• Pieces of bacteria or virus from either scenario are mopped up by the macrophage scavengers.

We all have our flaws…

• Often the immune system has its flaws, and the body is unable to be 100% accurate in making its immune responses. This means that there may be a glitch in either the process of the macrophages, helper t-cells, b cells or killer T cells doing their jobs. The functioning of these processes together make up the generalized self/non-self recognition and attacking of foreign cells.

• So, if there is a problem with the immune system, it generally means that the body is unable to properly identify or fight off antigens.

• 2 examples of immune system response “problems” are asthma and allergies.• Asthma and Allergies deal with “triggers” – in relation to the antigens that “trigger” the

immune response.

Asthma

What is it?

• a.k.a. “chronic inflammatory disease of the airway”

• Cause unknown• Currently no cure• Symptoms: -shortness of breath -tightness in chest -coughing -wheezing

• Any age can develop it• Usually #1 chronic condition

found in young people; needs monitoring and to be controlled over a persons life time

• Episodes vary from one to the next

• Can break out time to time /wont appear for long period of time

A chronic respiratory disease, in which the airways unexpectedly and suddenly narrow, often in response to an allergen, cold air, exercise, or emotional stress

“Triggers”• Anything that will cause

inflammation in the airways

• 2 types: Inflammatory and symptom

Inflammatory (allergic): causes inflammation/tightness of the lungs airways muscles

Symptom (non-allergic): low chance at causing inflammation; can set off “twitchy” airways (especially if airways are already inflamed)

• Symptoms occur;

flow of airway is interrupted as it passes in/out of lungs

• More inflammation; more sensitive airways become-more symptoms occur (muscles circling airway; more sensitive)

• Leads to breathing problems

• Asthma patients-airways inflamed all the time (certain degree)

Controlling asthma- -avoid asthma

triggers -take medication -form health care

team -follow asthma

action plan

Treatments- (2 types)

-each medication serves diff. purpose

Controllers: reduces inflammation

Symptoms occur less & less

Relievers: lightens symptoms

right away

The 3 stages

1. Histamine release

2. Arachidonic acid cascade

3. Leukotrienes

Histamine Release• Important protein; entangled in many

allergic reactions• Histamine-known as vasoactive

amine• Release of histamine:-contributes to an inflammatory

response-constriction of smooth muscles occur

Allergies• Often treated by antihistaminesEffects of Antihistamines:-restrains histamines release of

inflammatory mediators by leukocytes-results in neutralization of histamine

(deters histamine from binding/activating immune related cells in the area)

Arachidonc Acid Cascade

• series of chemical reactions that make leukotrienes

• Response to many inflammatory stimuli (change in internal or external environment)

Leukotrienes

• Are naturally produced lipid mediators

Function:

-involved in asthmatic and allergic reactions

(leukotrienes act to maintain inflammatory response)

Leukotrienes in asthma• Assist in the study of the

biological and physical reveal of the disease (asthma)

causes these symptoms:

-air flow obstruction-increased secretion of

mucus -mucosal accumulation-Bronchoconstriction-infiltration of

inflammatory cells in airway walls

Role of Cysteinyl Leukotrienes

• During interaction process, receptors encourage pro-inflammatory activities

• Induces asthma and other inflammatory activities which therefore reduces the airflow to the alveoli

Allergies

Abnormal reactions to ordinarily harmless substances.

Description• Normally, the body learns to defend itself through experience through recognition.– Vaccinations help create immunity

• Allergic Reactions occur after the immune system mistakenly learns to recognize innocent foreign substances (allergens) as potentially harmful.– Allergens can be inhaled, swallowed, or come into contact with skin.

Popular Allergens• Pollen• Mold Spores• House dust mites• Animals• Foods• Insect bites• Latex rubber• Viruses• Bacteria• …. And much more!

Causes• Fundamental cause

unknown• Tendency to run in

families – genetic• Infants that are breast-

fed are less likely to develop allergies

• Expose to certain allergens

SymptomsMild Moderate Severe

Rash Itchy,

watery eyesCongestion

Mild reactions do not spread

to other parts of the

body

Itchiness Difficulty

breathingCan spread to other parts of

body

a.k.a. anaphylaxisSwellingHard

breathingAbdominal

painCrampsVomitingDiarrhea

Treatment

• Antihistamines– Triggers immune system to go to action.

“Mast cells” in immune system release histamine; causes blood vessels to enlarge redness, swelling and itching. Block histamine receptors and prevent those symptoms• Over counter: Benadryl, Claritin, Dimetane,

Zyrtec• Prescription: Clarinex, Allegram Astelin

(nasal spray)

…continues

• Decongestants– Relieve congestion– Allergic reaction cause tissue in nose to swell in

response with allergies. The swelling produces fluid and mucous. Blood vessels in eyes also swell which then cause redness. They shrink swollen nasal tissues and blood vessels to relieve the symptoms of nasal swelling, congestion, mucous, secretion and redness.

• Over counter: zyrtec-d, sudafed, Afrin (nasal spray)• Prescription: Allegra-D

Anaphylaxissevere, potentially life-threatening allergic

reaction. • Can occur within seconds or minutes of exposure

to allergen• The flood of chemicals released by your immune

system during anaphylaxis can cause you to go to shock; blood pressure drops and airways narrow- blocking normal

Causes

• Certain allergies make immune systems overreact and when this

happens the immune system goes on a chemical chain reaction=

ANAPHYLAXIS• Allergens: medication, foods

(peanuts, shellfish, etc), insect bites, etc

• Exercise

Symptoms:

• Skin reactions (pale, itching, hives, rash)

• Constriction of airways and swollen tongue/throat= breathing trouble

• Weak and rapid pulse• Nausea, dizziness• Vomiting, diaherra

Complications

Can be life-threatening when a severe anaphylactic attack occurs . It can stop

breathing and heartbeat.

Treatment• CPR- Cardiopulmonary Resuscitation• Epinephrine (adrenaline): reduce body’s

allergic response• Oxygen- compensate restricted breathing• IV antihistamines/cortisone: reduce

inflammation or airways• Steroid Medication: treat and prevent

prolonged symptoms

•Always be properly stocked with medicines

and avoid allergens