How do the components of the immune system work together to keep us free from disease? SC.912.L.14.52 Explain the basic functions of the human immune system, including specific and nonspecific immune response, vaccines, and antibiotics.

Bellringer Scientists developed a vaccine to protect humans from the H1N1 virus, which caused 17,000 deaths in 2009. Which of the following persons would most likely contract the H1N1 virus? A. A person who did not receive the vaccine and has a weakened immune system due to other conditions. B. A person who received the vaccine and has a weakened immune system due to other conditions. C. A person who did not receive the vaccine but has a normal immune system. D. A person who received the vaccine and has a normal immune system. Students need to answer the 2 bellringer questions without being given the answer.

Bellringer The body uses nonspecific immune responses as the first line of defense when we are exposed to pathogenic or disease causing organisms. Which of the following factors is a nonspecific response? A. Antibodies are produced after an infection. B. Bacterial cell surface proteins start a response. C. Unbroken skin provides a physical barrier. D. Vaccine injections will imitate viral exposure.  

Pathogenic agents Infectious disease is caused by pathogens (examples) Bacteria (Lyme disease, anthrax, botulism) Viruses (Common cold, flu, warts, Ebola) Left – bacteria from a kitchen sponge; middle – deer tick carrier for Lyme disease; right - anthrax Additional facts if needed: Lyme disease – spiral bacteria carried by deer ticks cause arthritis-like symptoms; anthrax is caused by Bacillus anthracis (found naturally in soil) and can affect the skin, lungs and gastrointestinal tract; botulism causes dry mouth and muscle paralysis and can be found in improperly canned food. From WedMD: Although more than 200 viruses can cause the common cold, the perpetrator is usually the rhinovirus, which is to blame for causing 10% to 40% of colds. Also, the coronaviruses cause about 20% of colds and the respiratory syncytial virus (RSV) causes 10% of colds. Influenza, commonly known as the "flu," is an extremely contagious respiratory illness caused by influenza A or B viruses. Flu appears most frequently in winter and early spring. The flu virus attacks the body by spreading through the upper and/or lower respiratory tract. Ebola disease symptoms are like a bad case of the flu: high fever, muscle aches, headache, sore throat, and weakness. They are followed quickly by vomiting, diarrhea, and internal and external bleeding, which can spread the virus.

Pathogenic agents Infectious disease is caused by pathogens (examples) Protists (African sleeping sickness, malaria, ameobic dysentery) Fungi (Athlete’s foot, ringworm, nail infections) Worms (Trichinosis, pinworms, hookworms) Left – Trypansoma next to a red blood cell; center – Candida fungal nail infection; right– filaria, a tropical parasite that is normally not deadly. Additional facts if needed: African sleeping sickness - carried by the tsetse fly with symptoms of fever, headaches and swelling; malaria – thought to be the single most damaging infectious disease with flu-like symptoms and anemia; ameobic dysentery – extreme diarrhea; trichinosis – diarrhea and abdominal cramps after eating incompletely cooked pork (also found in bears, walruses and foxes) containing these roundworms.

Transmission (spread) of disease Physical contact with a sick person or animal; insect bites Indirect contact (sneezes, coughs, touching contaminated surfaces) Eating contaminated food or drinking water containing pathogens

Disease prevention and treatment Prevention of infection - Wash hands thoroughly before touching eyes, mouth, or nose Proper food storage and water treatment Antibiotics – kill bacteria without harm to cells (no effect on viruses) Drugs – treat disease symptoms; give body’s immune system time to work

Nonspecific Immune Responses Responses that do not discriminate and are the same for all pathogens Intact skin Mucous membranes in mouth and nose Lysozyme – enzyme that kills bacteria in tears and saliva Skin – 1st line of defense to keep pathogens out; phagocytosis – white blood cells engulf and destroy pathogens Picture of foreign material in cilia of the nose

Nonspecific Immune Responses Responses that do not discriminate and are the same for all pathogens Inflammation – entry of fluid (swelling) and white blood cell activity (phagocytosis) Fever – elevated temperature slows down pathogens Interferons – antiviral proteins released by virus-infected cells; help healthy cells fight the virus Skin – 1st line of defense to keep pathogens out; phagocytosis – white blood cells engulf and destroy pathogens Picture of inflammatory response

Specific Immune Responses Reaction to a specific pathogen that gets past nonspecific defenses – active immunity Production of specific antibodies by B cells (white blood cells) against antigens found on pathogen’s surface Antibodies (AKA immunoglobulins) help pathogen destruction prevent future disease by the same pathogen

Specific Immune Responses Phagocytosis – white blood cells attack and engulf pathogens keep antigens T cells (different white blood cells) create antigenic memory attack and kills infected body cells T cell (red) attaches to infected body cell

Vaccines Passive immunity – the body gets antibodies from an outside source transferred from fetus to mother or through breast milk Vaccines antigens from part of a disabled pathogen or its close relative stimulate an antibody response some preventative shots contain specific antibodies

D. A person who received the vaccine and has a normal immune system. Scientists developed a vaccine to protect humans from the H1N1 virus, which caused 17,000 deaths in 2009. Which of the following persons would most likely contract the H1N1 virus? A. A person who did not receive the vaccine and has a weakened immune system due to other conditions. B. A person who received the vaccine and has a weakened immune system due to other conditions. C. A person who did not receive the vaccine but has a normal immune system. D. A person who received the vaccine and has a normal immune system. With the bellringer questistions, correct any misconceptions from incorrect answers if students still do not understand the reason for the correct choice.

The body uses nonspecific immune responses as the first line of defense when we are exposed to pathogenic or disease causing organisms. Which of the following factors is a nonspecific response? A. Antibodies are produced after an infection. B. Bacterial cell surface proteins start a response. C. Unbroken skin provides a physical barrier. D. Vaccine injections will imitate viral exposure.   Recap nonspecific vs. specific immune responses.

Exit ticket question 1 Antibiotics such as penicillin and streptomycin have been used to treat diseases such as Lyme disease and tuberculosis. Which types of disease causing organisms can be killed or reduced in number by antibiotics? A. Both bacteria and viruses respond to antibiotic treatment. B. Only bacteria respond to antibiotics, and viruses are not affected. C. Only viruses respond to antibiotics, and bacteria are not affected. D. Neither bacteria nor viruses are affected by the use of antibiotics. This question and the ones on the next two slides are provided on a separate exit ticket. Answer: B

Exit ticket question 2 One student feels that a person who has just recovered from a cold cannot get the flu, while another student says that this statement is wrong. What facts about the immune system can be used to determine who is right? A. Antibodies made against the cold virus will help white blood cells prevent the flu virus. B. Nonspecific responses triggered by the cold such as inflammation will stop the flu virus. C. The cold virus antibodies are too specific and will have no effect on the flu virus. D. The cold will deplete defensive blood proteins and the flu virus will multiply faster. Answer: C

Exit ticket question 3 The immune system has both specific and nonspecific defenses against viral infections. Which statement describes a nonspecific response of the immune system in fighting viral infections? A. T cells are produced to search out and destroy the viruses. B. Memory B cells are activated to rapidly respond to the viral infection. C. Plasma cells quickly replicate and release antibodies that bind to the viruses. D. Virus-infected cells produce interferons that lead to the inhibition of viral replication Answer: D