Aim: How do vaccinations protect us against disease ?

Immunity is the ability of an organism to resist disease by identifying and destroying foreign

substances or organisms.

Active immunity

• Naturally acquired active immunity occurs when the person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response

• Artificially acquired active immunity can be induced by a vaccine, a substance that contains the antigen.

and cells…

Vaccination

• means of producing immunity against pathogens, such as viruses and bacteria, by the introduction of live, killed, or altered antigens that stimulate the body to produce antibodies against more dangerous forms.

Vaccine is made from

• an antigen isolated or produced from the disease-causing microorganism

• vaccine is injected into the blood stream. The B cells in the blood stream respond to the antigen by producing antibodies

• antibodies bind to the antigen to "neutralize"or inactivate it

• memory cells are produced and remain ready to mount a quick protective immune response against subsequent infection with the same disease causing agent.

Memory Cells and Immunity

Vaccine Mass Production

There is no vaccine for the HIV virus

Electron Micrographs and schematic of HIV

Yellow – lipid bilayer

Red, Black & green – different proteins

HIV attacks the CD4 immune cell

Macrophage

T Cell

Helper T Cell

Killer T Cell

Infected CellAntigens are displayed on surface of macrophage

T cell binds to activated macrophage

T cell, activated by macrophage, becomes a helper T cell

Helper T cell activates killer T cells and B cells

Killer T cells bind to infected cells, disrupting their cell membranes and destroying them

Section 40-2Normal function of a T Cell

Immune cells…

HIV affects T-cells

• A normal T cell count is usually over 1000, although it may dip occasionally to even 400 in response to other infections.

• In HIV we see a decrease in T cells (CD4 cells) over time which does not recover without adequate and long-term control of the HIV virus.

HIV doesn't kill anybody directly…

instead, it weakens the body's ability to fight disease.

Brainstorm

• What vaccinations have you received?

Recommended Vaccinations:

• Hepatitis B • Pneumococcal conjugate vaccine (PCV) • DTaP (diphtheria, tetanus, acellular pertussis) • Hib (meningitis) • IPV (polio) • Influenza WGBH American Experience - The Polio

Crusade• MMR (measles, mumps, rubella) • Varicella (chickenpox) • MCV4 (bacterial meningitis) • Hepatitis A

The Pros and Cons of Vaccinations

The practice of vaccinating ourselves, our children, and our animals to prevent disease is the subject of a great deal of debate. Heated discussions arise over what to vaccinate with, when to vaccinate, who to vaccinate, and even whether to vaccinate at all.