Immunity

Rikki, Trevor, Heather, and Clarease

The Importance of Cell Surfaces

Human immune system recognizes foreign surfaces Microorganisms

bacteria, yeast Non-living infectious agents:

viruses, tumor cells, transplanted cells

Virus structure

Pathogens

Bacteria-prokaryotes (no organelles) Antibiotic drugs used for

bacterial infections

Viruses-a single or double strand of RNA or DNA coated in protein Very few drugs can be

used for viral infections A Virus

How Viruses Reproduce

Viral DNA- implants into host cell’s DNA, replicates along with the host RNA, without causing harm

OR Takes over and kills host cell by

Replicating viral DNA Making viral proteins Cell then fills with viral DNA and proteins creating

new ones until the cell bursts which releases the new virus into the body

Genetic Control of Immunity

Proteins that directly attack foreign antigens Antibodies Cytokine

Antigen-a molecule that creates an immune response (usually being a protein or a carbohydrate)

Immunity is controlled by genes, mutations impair immune function and cause immune deficiencies, autoimmune disorders, allergies, and cancer

Autoimmune disorder-attacks own tissues

Blood Types Different blood types have unique self-antigen patterns on

red blood cells that make the blood type what it is

Transfusion

The Human Immune System

2 levels Macroscopic (large)

lymphatics transport a watery fluid called lymph to lymph nodes located throughout the body

Microscopic (small) white blood cells, lymphocytes and macrophages get rid of bacteria and viruses B & T cells are 2 main

types of lymphocytes

Human Immune Defense System 2 levels

Innate Immunity-fast and generalized

Adaptive Immunity-slow and specific B and T cells carry out Humoral immune response-

antibodies carried in fluids Cellular immune response- T

cells produce cytokines and activate other cells

These act once physical barriers have blocked pathogens Physical barriers- skin, mucous

membranes, earwax, and cilia

Abnormal Immunity

AIDS-(Acquired Immune Deficiency Syndrome) acquired by an infection with HIV, which degenerates immune system, killing helper T cells causing bacterial infections because B cells aren’t producing antibodies.

Autoimmunity-when the body produces antibodies that attack the body’s healthy tissues

Allergies-auto immune response to an allergen. An overly sensitive immune system causes allergies.

Allergies

Inherited susceptibility-higher “eosinophils” white blood cell count

Environmental factor-”hygiene hypothesis” underutilized immune

1. Allergen activates B cells

2. B cells divide, create antibody-secreting plasma cells

3. Antibodies attach to mast cells.

4. At next exposure, allergens combine with antibodies on mast cells

5. Mast cells burst, releasing chemicals that cause allergic reactions (lower right)

Vaccine-disables part or all of a pathogen, then sends them to create a primary immune response

Transplant types-Allograft, Isograft, Xenograft, and Autograft

Immunotherapy-uses the immune system to fight disease.

Altering Immune Function

A Genomic View of Immunity:The Pathogen’s Perspective

Genome sequences of pathogens provide clues to how they infect, which can suggest new treatments

Pathogen genome information also used to protect against infection-”reverse vaccinology” Identify antigens that provoke immune response Used to treat SARS

A Genomic View of Immunity:The Pathogen’s Perspective

Crowd Diseases-spread rapidly throughout a population that hasn’t had any prior exposure, vanish quickly because of vaccines or treatments.

Bioweapons-pathogens (bacteria and viruses) used to intentionally do harm to people.

Small Pox, historically an example of both

Bibliography

Lewis, R., 2007, Human Genetics: Concepts and Applications. McGraw-Hill, New York, pages 331-351.