Immune System & Disease A Brief Introduction

What Is Your Immune System? AAAACHHOOO!! Your friend has a terrible cold, and he sneezes right next to you without covering his mouth. Not only is this gross, it sprays millions of cold viruses into the air around you. Luckily, you don’t get sick. Why not?

Your Immune System Our bodies have an amazing internal defence mechanism called the immune system which protects you from bacteria and viruses that can lead to illness. A healthy immune system produces a variety of different cells to attack the invading bacteria and viruses

Your Immune System Your blood contains many different types of cells Red blood cells carry oxygen to all the parts of your body White blood cells, known as leukocytes (LUKE-oh-sites), make up the immune system portion of the blood.

Your Clever Immune System How does your immune system know which cells to attack and which cells are part of your own body? Your immune system can recognize cells based on the proteins present on the surface of cells. Viruses, bacteria, and other foreign cells are recognized as being different from your own cells and are attacked by your immune system.

However..... Sometimes, one of your own cells changes, or mutates, giving the cell the ability to multiply continuously. Such mutations often are the cause of cancer Your immune system has the ability to recognize mutated cells and attack them before they can grow into a tumor.

But It’s Not Foolproof.... Not only can certain viruses outwit your immune system's defences, but genetic malfunctions can result in an ineffective immune system. If enough cells are killed, the immune system no longer functions and the person becomes susceptible to many different diseases.

Disease Illness or sickness often characterized by typical patient problems (symptoms) and physical findings (signs). Diabetes, cancer, genetic diseases, immune system diseases, etc.

Antibiotics Antibiotics inhibit and prevent the growth of bacteria Antibiotics DO NOT affect viruses, fungi or other microbes

Antibiotics Antibiotics that destroy bacteria are termed bactericidal (“bacteria killing”) Antibiotics that prevent bacteria from multiplying are termed bacteriostatic (“bacterial inhibiting”) Type of infection dictates what type to use!

Bacteriostatic Antibiotics Prevent cell wall formation during cell division of gram positive bacteria Penicillin destroys the bacterial cell wall making the bacterium very susceptible to damage. Erythromycin and tetracycline disrupts bacterial protein synthesis by binding to their ribosomes and inhibiting translocation

Antibiotics Once, there were only natural products: a) Penicillin came from the fungus genus Penicillium b) Streptomycin came from the bacteria genus Streptomyces

Antibiotics Now, many can be chemically synthesized with all the advances in organic chemistry Example: sulfa drugs were the first synthetic drugs with widespread antibiotic activity to be put into clinical use in the 1930s

Antibiotics Oral antibiotics are ingested e.g.- For strep throat, urinary tract infection Intravenous antibiotics are used in more serious cases e.g.- For deep infections of body systems like infection after surgery, sepsis, flesh eating disease (necrotizing fasciitis)

Antibiotics Topical antibiotics are placed on the skin Eye drops for pink eye or ointment for a skin infection

Antibiotic Resistance Occurs when bacteria in your body change so that antibiotics don't work effectively to fight them anymore Can happen when bacteria are repeatedly exposed to the same antibiotics or when bacteria are left in your body after you have been taking an antibiotic (such as when someone does not take the full course of their antibiotic medicine) These bacteria can multiply and become strong enough to resist the antibiotic in the future.

Interesting to Know... Links have also been made between giving drugs to animals and the development of resistance in humans Drugs are often given to food-producing animals to treat and prevent infections in the agri-food industry and to promote growth In the U.S., 50% of antibiotic use is in farm animals in the absence of disease!! There are many organizations and 2 federal U.S. Bills which are trying to restrict antibiotic use in food animal production

Farm Animals & Antibiotic Resistance Products are also sprayed on fruit trees to prevent or control disease These can then be transferred to humans in meat, milk, fruit or drinking water, adding to the resistance problem An example of this is drug-resistant Salmonella, which can be transferred from animals to humans through the food chain

Antibiotic Resistance

The Result? Misuse and resistance causes low cost antibiotics to be useless - meaning we must use more expensive and newer compounds The fear is that eventually we will not be able to keep up with the race to create new antibiotics for bacterial infections Is research into bacteriophages for use as antibiotics; appear to be several types of bacteriophage that are specific for each bacterial taxonomic group species