More Immune System...

esophagus stomach Taking in food and oxygen exposes us to pathogens

Pathogen: a disease causing agent

Viruses only harm cells by invading them and using the cell to reproduce

basic viral reproductive cycle CB 19.4

The Lytic and Lysogenic Cycles CB 19.6 Lytic cycle Lysogenic cycle

the relationship between viruses and disease

Membrane protein Viruses enter cells via specific membrane proteins; thus viral infections are usually cell specific.

Spanish flu of

How many people die from the flu in a “normal” year in the U.S.? ~36,000 About 90% are over 65 years old

Spanish flu of Killed between million people worldwide; 675,000 in the U.S. (2.5%-5% of world population) Infected 1/5 to 1/4 of world population Was most lethal to people years old

Spanish flu of People on their way to work suddenly developing the flu and dying within hours (Henig). One physician writes that patients with seemingly ordinary influenza would rapidly "develop the most viscous type of pneumonia that has ever been seen" and later when cyanosis appeared in the patients, "it is simply a struggle for air until they suffocate," (Grist, 1979). Another physician recalls that the influenza patients "died struggling to clear their airways of a blood-tinged froth that sometimes gushed from their nose and mouth," (Starr, 1976).

The high fatality rate from the Spanish flu was probably due to an immune system over-reaction

HIV, a retrovirus, infects Helper T-cells CB 19.8

HIV reproduction CB 19.8 Reverse Transcriptase: RNA to DNA

HIV has both a lytic and lysogenic cycle CB 19.8

Where did HIV come from, and where is the next HIVesque virus?

The Immune System Non-specific: –barriers Specific : –B-cells -> antibodies –T-cells Fig 43.2

Marked for destruction by WBC B-cells make antibodies that bind to antigens marking them for destruction Fig 43.19

T-cells recognize and destroy abnormal cells Fig 43.18

CB 43.16

Fig It can take 7-14 days to produce sufficient antibodies to eliminate a pathogen

Memory B-cells make the response to a second exposure more rapid This is how vaccines work. Fig 43.14

Vaccines work via memory B-cells that make the response to a second exposure more rapid Fig 43.15

When politics and science collide...

Human Papilloma Virus

Human Papilloma Virus: the leading cause of Genital warts Cervical cancer

At least 50% of sexually active people will get HPV at some time in their lives. Every year in the United States, about 6.2 million people get HPV. HPV is most common in young women and men who are in their late teens and early 20s.

The American Cancer Society estimates that in 2006, over 9,700 women were diagnosed with cervical cancer and 3,700 women died from this cancer in the U.S.

The HPV vaccine developed by Merck, Gardasil, protects against four HPV types which account for 70% of cervical cancers and 90% of genital warts.

The HPV vaccine is made up of proteins from the outer coat of the virus. Human Papilloma Virus: the leading cause of Genital warts Cervical cancer

The Texas Department of Health has ruled that students must be current with immunizations in order to attend school unless an exemption has been filed with the school in accordance with Texas Education Code, Health and Safety, Chapter

Current (2011) mandated vaccines for attendance in Texas schools: 3 doses of DPT, DTaP, DT, Td 4 doses of Polio 1 dose of Measles on/after 1st birthday and 1 dose MMR on/after 1st birthday. 3 doses of Hepatitis B 1 dose of Varicella on/after 1st birthday (if the child has NOT had chickenpox) 1 dose of Meningococcal before entry to 7 th grade 2 doses of Hepatitis A

The HPV vaccine is recommended for year-old girls, and can be given to girls as young as 9.

The HPV vaccine is recommended for year-old girls, and can be given to girls as young as 9. For the vaccine to be effective, you must be vaccinated prior to exposure to HPV.

Controversy

Effectiveness of HPV vaccine against cervical cancer

Effectiveness of HPV vaccine against genital warts

The length of vaccine protection (immunity) is usually not known when a vaccine is first introduced. So far, studies have followed women for five years and found that women are still protected.

The length of vaccine protection (immunity) is usually not known when a vaccine is first introduced. So far, studies have followed women for five years and found that women are still protected. More research is being done to find out how long protection will last, and if a booster vaccine is needed years later.

The retail price of the vaccine is $120 per dose ($360 for full series). While some insurance companies may cover the vaccine, others may not.

The Specific Immune System: Self vs Non-self

CB Allergies are an immune response to a non- pathogen

/disorders.aspx Antibodies attached to Mast cells cause release of histamines... cause inflammation

Autoimmune diseases occur when the immune system recognizes self as “foreign”

Some forms of diabetes are caused by the immune system destroying the insulin producing cells in the pancreas

Autoimmune diseases (partial list): Crohns disease, diabetes (type 1), lupus, narcolepsy, pernicious anemia, psoriasis, rheumatoid arthritis, ulcerative colitis

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