The Human Immune System

Immunology and Disease

Basic Definitions

Disease:– Types of diseases

Hereditary Materials in Environment Pathogen induced

Pathogens: Infectious Disease: Vector:

Examples of Vector-Bourne Diseases

A Case study

See Overhead Questions:

1. What is the cause of the disease?- Heredity, Chemicals, pathogen

2. What specific steps would you take to determine the exact cause of the disease?

Immunology History

For thousands of years people believed that diseases were caused by the devil and medicinal techniques would rely upon spiritual cures

– Examples:

1800’s – Germ Theory of Disease– Definition:– Who was responsible?

Question still existed:

How do you identify the specific pathogen?

Koch’s Postulates – The Guideline

Pathogen should only be found in a sick organism

Isolate the pathogen from the sick organism and grow it in a pure culture

Koch’s Postulates – Take 2

Place purified pathogen in new host and compare symptoms

Re-isolate the pathogen and make sure it is identical to the original

Miscellaneous Topics

Why is the human body so perfect for infection?– 3 Reasons

Normal Flora– Definition:– Example

The Immune System

The Immune System

2 types of responses to an invading pathogen– Non-specific Defenses:

– Specific Defenses:

Which type of response occurs first?

Progression of a pathogen in the body:Breach the outer surface

What makes the skin so difficult to breach?

Function: Mechanism: Specific or Non-specific defense?

What if the pathogen attacks thru the mouth, nose or throat?

Mucus and lysozymes

Progression of a pathogen in the body:The Inflammatory Response

Histamine

Histamine

Increase Blood Flow

Veins swell and release blood and WBC’s into infected area

White Blood cells attack pathogen

The Inflammatory Response

Responds to a local infection Damaged cells release histamine Blood flow near the wound increases Blood vessels swell and release phagocytes

into surrounding area Additional white blood cells are made and

drawn towards the wound

Progression of a pathogen in the body:The Inflammatory Response

Histamine

Histamine

Increase Blood Flow

Veins swell and release blood and WBC’s into infected area

White Blood cells attack pathogen

Progression of a pathogen in the bodyFEVER

Definition: Why would you raise your body temperature?

(3 Reasons) What is Interferon?

The Immune System: Progression of a pathogen in the body

What if fever does not work?– Specific Defenses

Background: Every pathogen has an antigen

The antigen triggers the immune response

Humoral Response

Definition: Key Players:

– B-Lymphocytes (B-cells)– T-Lymphocytes (T-cells)– Plasma cells– Antibodies– Phagocyte– The pathogen (Booo!)

Humoral Response

Antigen

THE PATHOGEN!!!

BOOOO!

HISS!!!

BOOO!

Blood vessel

Humoral Response

1000’s of B-Cells

YEAH!!!

WE’RE SAVED!!!

MY HERO!

Humoral Response

One Right B-Cell that recognizes the antigen

MACHO MACHO MAN

I GOT TO BE A MACHO MAN

Humoral Response

T-Cell Helps to activate the B-Cell

P

Plasma Cell

Humoral Response

B-cell makes specific antibody

S

Y

Humoral Response

Antibody grabs 2 pathogens

YHelp Me!

Humoral Response

Phagocyte engulfs and destroys both pathogens and the antibody

T

A review of Humoral Response

A B-cell recognizes the pathogen’s antigen The B-cell is activated by the T-cell and

becomes a plasma cell The plasma cell makes antibodies The antibodies capture the pathogen and

cluster together Phagocyte destroys the entire complex

(antibodies and pathogens)

Humoral Response

It’s better to be prepared– Memory:

Humoral Immunity Review Websitehttp://bcs.whfreeman.com/thelifewire/content/chp18/1802004.html

CELL MEDIATED RESPONSE

If the pathogen begins to infect cells Immune system must destroy the infected

cells or the entire organism will die Key Players

– Macrophage– T-cells (Killer T-cells)– Pathogen (Booo!)

CELL MEDIATED RESPONSE

THE PATHOGEN

Antigen

CELL MEDIATED RESPONSE

Macrophage

A Large WBC (Macrophage) Engulfs a Pathogen

CELL MEDIATED RESPONSE

Macrophage learns antigen of pathogen and displays it on its membrane

Learned Antigen

CELL MEDIATED RESPONSE

T-Cell Binds to macrophage and learns the antigen and in doing so BECOMES…

CELL MEDIATED RESPONSE

Well, actually only a killer t-cell

CELL MEDIATED RESPONSE

Infected Cell

Killer T-cell recognizes the infected cell, binds to the cell and destroys the cell!

CELL MEDIATED RESPONSE

YEAH, WE’RE SAVED

CELL MEDIATED RESPONSE

Macrophage engulfs the pathogen and displays the antigen for a T-cell

T-cell learns pathogen and hunts out infected cells

Once found, T-cells destroy infected cells (thru a process known as apoptosis)

Cell mediated response

Importance of T-cells in immune system?

Cell Mediated Response Review Websitehttp://bcs.whfreeman.com/thelifewire/content/chp18/1802003.html

Types of Immunity

Permanent Immunity

Number of pathogens

Duration of Sickness

Critical time when sickness becomes symptomatic

Types of Immunity

Active Immunity (Vaccination)– Definition– Who invented the 1st vaccine?

– Immunity is permanent to that specific type of pathogen

– Question: Why must we get multiple vaccines during our lives?

Types of Immunity

Passive Immunity– Definition:– Provides temporary immunity

WHY???

– Why would you get this type of immunity?