A CALL TO ARMS KOCH’S POSTULATES - PowerPoint Presentation

Slide1

A CALL TO ARMS

KOCH’S POSTULATES

In the 1880s German doctor, Robert Koch, developed a series of methods for identifying which organism was the cause of a particular disease. These postulates are still in use today.

This led the way for specific treatment for many disease- causing pathogens.

Response of Immune System to Disease-Causing Organisms

A

. RECOGNITION:

white blood cell surrounds pathogen and signals killer T cells (not shown)

;

more T cells

are produced; helper T cells signal B cells

B

. MOBILIZATION:

B cells produce antibodiesC. DISPOSAL: antibodies destroy pathogensD. IMMUNITY: some antibodies remain for future use (memory B cells)

Antigen-Antibody

C

omplex

Antibodies all have the same basic Y structure

Antibodies have different antigen binding sites designed to fit the shape

of specific antigens

Antibodies bind to antigens like a lock and key to form the Antigen-Antibody

C

omplex

INDIRECT ELISA (

e

nzyme –

l

inked

i

mmunoab

s

orbant

a

ssay)Used to detect infection by testing patients’ blood serum for the presence or absence of antibodies against a particular pathogen Presence of antibodies indicates the individual has been infected and that

their body has launched an immune response against the disease-causing agent

Test for: HIV, Avian Flu, West Nile, Lyme Disease, Smallpox, SARS, Syphilis,

Rocky Mountain Spotted Fever

H

uman

I

mmunodeficiency

V

irus

Virus responsible for causing

A

cquired

I

mmune Deficiency Syndrome orAIDS

Rates of Persons Aged 18–64 Years Living with a Diagnosis of HIV Infection, Year-End 2008—United States

Reported Cases

in the

United States, 2012

LYME DISEASE

Vector =

deer

tick

Avian Influenza (Bird Flu)

ELISA TEST RESULTS

ELISA

data from three patients. Numbers are expressed as optical density at 450 nm. The cutoff value indicating a positive result is 0.500. Optical densities of 0.300 to 0.499 are indeterminate and need to be retested. Values below 0.300 are considered to be negative. In most cases, a patient will be retested if the serum gives a positive result. If the ELISA retests are positive, the patient will then be retested by western blotting analysis.

Positive Control

Negative Control

Patient A

Patient B

Patient C

Assay Control

1.689

0.153

O.055

0.412

1.999

0.123

ELISA SIMULATION RESULTS

In this simulated ELISA, all reaction wells will turn light

green

when the chromogen

substrate is added. A change in color from light

green

to

purple

indicates a positive result.