Immune System
how is HIV spread? how can it be prevented?
1) by not using a condom when having sex w/ a person who has HIV (sexual fluids) 2) having multiple sex partners or presence of other sexually transmitted disease, unprotected oral sex 3) sharing needles, syringes, rinse water or other equipment used to prepare illicit drugs for injection 4) being born to an infected mother; can be passed from mother to child during pregnancy, birth, or breast-feeding 5)blood 1) try and abstain from sexual intercourse 2) be in a long-term, mutually monogamous relationship with an uninfected partner 3) abstain from sharing needles and or syringes for nonprescription drugs
describe the HIV life cycle.
1. infects helper T-cells (CD4) 2. uses its own RNA and host DNA to make more viruses 3. known for long incubation periods (clinical latency) not have symptoms for 10 years or more 4. causes sever damage to the immune system and ultimately destroys it 5. causes the signs and symptoms of AIDS
what is AIDS? what is its relationship to HIV?
AIDS is acquired immune deficiency syndrome and its relationship to HIV is that this disease develops from having the HIV virus. AIDS develops when HIV has caused serious damage to the immune system.
how did Salk and Sabin's vaccines for polio differ? which was successful?
Albert Sabin developed a live-virus vaccine. Like many researchers of the day, Sabin strongly disagreed with Salk's approach of using injected, "killed" virus. He believed that long-term immunity could only be achieved with a live, attenuated—or weakened—virus. Sabin's oral live vaccine largely replaced Salk's killed vaccine everywhere in the world. However, because the live virus in the vaccine occasionally became strong enough to cause actual disease, Salk killed-type vaccine has replaced the live type in the United States.
what is HIV? what part of the body does it infect? why is it so harmful?
HIV is the human immunodeficiency virus that can lead to acquired immune deficiency syndrome or AIDS HIV damages a persons immune system by destroying specific blood cells called CD4 T cells which are crucial to helping the body fight diseases.
how was the smallpox vaccine discovered?
On May 14, 1796, Edward Jenner took fluid from a cowpox blister and scratched it into the skin of James Phipps, an eight-year-old boy. A single blister rose up on the spot, but James soon recovered. On July 1, Jenner inoculated the boy again, this time with smallpox matter, and no disease developed. The vaccine was a success.
what are opportunistic infections? why are they associated with HIV? provide examples
Opportunistic infections are infections that occur more frequently and are more severe in individuals with weakened immune systems, including people with HIV. Typically people are at greater risk for opportunistic infections when there CD4 counts are below 200. However, many people with HIV still develop opportunistic infections because they did not know they had HIV for many years after they were infected and the virus is weakening their immune system examples: thrush, tuberculosis
what is the purpose of other vaccine additives? are there side effects?
Purposes of additives: 1. to prevent contamination during manufacturing 2. to maintain a vaccine's potency at less than optimal temps 3. to keep multi-dose vials of vaccine sterile after they are opened side effects: could lead to acidosis.... cant find others
how did HIV come about? is it a new disease?
Scientists identified a type of chimpanzee in West Africa as the source of HIV infection in humans. They believe that the chimpanzee version of the immunodeficiency virus most likely was transmitted to humans and mutated into HIV when humans hunted these chimpanzees for meat and came into contact with their infected blood. Over decades, the virus slowly spread across Africa and later into other parts of the world. This is not considered a new disease because it has been around for many years.
what are two types lymphocytes and their roles in the immune response?
T-cells ~killer T cells sense diseased cells that are harboring the microbe and latch onto them and release chemicals that destroy infected cells and microbes ~helper T cells defend the body by secreting chemical signals that direct the activity of other immune system cells. they also assist in activating killer T cells and work closely with B cells. B-cells ~B cells mature in the bone marrow and make and secrete extremely important molecular weapons called antibodies ~they each produce a unique antibody that it displays on the surface ~stimulated to divide into many larger cells called plasma cells which secrete mass quantities of antibodies to bind the microbe
what symptoms are associated with HIV and when? include the term 'latency period'
a person with HIV will not show symptoms for 10 years or more which is their latency period. after that, within 2 to 4 weeks after a person becomes infected with HIV, they may have flu-like symptoms, such as fever, chills, or rash. The symptoms may last for a few weeks after they become infected.
what are antibodies? where are they found? how do they work to rid the body of pathogens?
antibodies are any of numerous Y -shaped protein molecules produced by B cells, each molecule and its clones having a unique binding site that can combine with the complementary site of a foreign antigen, thereby disabling the antigen and signaling other immune defenses. they are found throughout the body they signal macrophages and defensive cells to eat microbe, they then bind with them and make the microbe unable to function, then the microbe is destroyed.
what is the cause of polio?
caused by a virus that lives in the throat and intestinal tract
compare flu to the common cold?
common cold ~symptoms develop gradually ~low-grade fever (if present) ~slight headache, stuffy or runny nose w/ sneezing ~feeling tired, sore throat, mild to moderate hacking cough ~near normal appetite flu ~symptoms develop abruptly ~sudden high fever and chills ~severe headache ~nausea and vomiting ~feeling exhausted ~all over muscular aches and pains ~dry cough; can become sever ~loss of appetite
what are the benefits of vaccines in terms of cost and the people around you?
cost- for every $1 spent, $5 is saved in direct costs and approximately $11 in additional costs to society people around you-it will protect not only individuals but entire communities, and there will be herd immunity which is when an entire group of people is vaccinated and then everyone is less likely to get sick. also spreading of the disease would stop
what are antigenic drift and shift? how does each one occur and how do they lead to seasonal and pandemic flu?
drift~ slow random mutations over time as the virus replicates ~it produces viruses that are pretty closely related and is contained within 1 species ~leads to seasonal flu because it is not as virulent of strain and the body has a better chance of fighting it off due to vaccines for it shift~ fast genetic changes to create a unique virus from another species that infects humans ~could possibly stem from multiple different species (ex- pigs->birds->humans= new strain) ~leads to pandemic flu because it is spreading at a very high rate and the creation of a vaccine is much more difficult (why more people die from it)
what are the four categories of influenza? how is influenza A named? what types of influenza are in the seasonal flu vaccine?
four categories: A, B, C, D influenza A is named based on the surface proteins hemagglutinin (H) and neuraminidase (N) H1N1, H3, and a type B virus
what are the two types of immune response and which lymphocyte is the prime worker?
humoral response: the immune response involving the transformation of B cells into plasma cells that produce and secrete antibodies to a specific antigen. cell-mediated: the immune response produced when sensitized T cells attack foreign antigens and secrete lymphokines that initiate the body's humoral immune response.
why did polio become bigger rather than a smaller problem after the adoption of modern sanitation systems?
it became a bigger problem because after the child no longer had the mother's immune system, they were left defenseless from various diseases. the modern sanitation system made it worse because children were not being exposed to microbes that they need to become immune to, so they got very sick with polio.
how is the flu spread?
it is spread by droplets made when people with the flu cough, sneeze, or talk and then the droplets are inhaled. also, a person can touch a surface w/ droplets on it and then touch their mouth or nose.
when are you immune to the flu after vaccination?
it takes about two weeks for your body to develop the necessary antibodies and provide protection against the virus
compare and contrast live/attenuated, inactive and subunit vaccines? provide examples for each.
live attenuated vaccine ~contains a version of the living microbe (the weakened version) ~it elicits strong cellular and antibody responses ~often confer lifelong immunity with only 1 or 2 doses ~the microbe could revert to a virulent form and causes disease ~not everyone can receive this vaccine ~easy to create for viruses, harder for bacteria ~example- this approach has been used to create a vaccine against the bacterium that causes cholera inactive vaccine ~they are produced by killing the disease ~can't mutate back to their disease causing state ~don't require refrigeration (accessible to people in developing countries) ~most stimulate a weaker immune system response than do live vaccines. So it would likely take several additional doses, or booster shots, to maintain a person's immunity. ~people who don't have access to health care like we do here could not get there booster shots on time ~example- hepatitis A vaccine subunit vaccine ~only includes antigens that best stimulate the immune system ~identifying these antigens is a tricky and time consuming process ~example- hepatitis B vaccine
what part of a microbe is recognized by the immune system?
marker molecules
what are memory cells? when and how are they made? what do the cells do if there is re-exposure to the same microbe in the future?
memory cells are any small, long-lived lymphocyte that has previously encountered a given antigen. they are created during the humoral response and are made when the helper T-cells activate the B-cells, the B-cells turn into B plasma cells, which then become memory B-cells to fight the virus in the future if there is re-exposure, the cells rapidly initiate the immune response (memory T cell) or produces large amounts of specific antibodies (memory B cell).
is there a cure or treatment for HIV?
no
polio is eradicated in the U.S., so do we not need to worry about it?
no, because some countries are still dealing with cases of polio. Even though it is eradicated in the U.S., it can still easily spread to those who are not vaccinated and come into contact with stool or oral secretions of infected individuals.
is smallpox a disease to be feared anymore? why?
no, it is eradicated. everyone has been vaccinated for it.
compare seasonal flu and pandemic flu in terms of symptoms, time of year, and antibodies.
seasonal flu ~dec-feb ~symptoms: already listed ~a person infected with a particular flu virus develops antibodies against that virus. The antibodies created against the older viruses no longer recognize the "newer" virus, and the person can get sick again. Genetic changes that result in a virus with different antigenic properties is the main reason why people can get the flu more than one time. This is also why the flu vaccine composition must be reviewed each year, and updated as needed to keep up with evolving viruses. pandemic flu ~rarely happens (a few times a century) ~symptoms: may be more severe and complications more frequent ~antibodies can't be properly created because of how many times it is mutating
what are the symptoms? death rate? side effects? treatment? (ex: iron lung) mode of infection?
symptoms: fever, sore throat, upset stomach, flulike symptoms. 1-2% develop aseptic meningitis or abnormal/increased sensation. less than 1% develop paralysis death rate: ? treatment: iron lung, vaccine side effects: soreness at vaccine site... mode of infection: person to person contact with stool, spread by nasal and oral secretions
what are the symptoms of smallpox? death rate? treatment? mode of infection?
symptoms: high fever, head and body aches, vomiting, a rash that turns into pus-filled blisters that scab and fall off after weeks to form a pitted scar. death rate: 30% of cases treatment: none, but cidofovir fights it mode of infection: face to face contact, contact w bodily fluids or contaminated objects, rarely spread by virus carried in the air
what are the benefits of immunity through vaccination as opposed to being infected with the microbe?
the benefits of artificial immunity: gain immunity without getting sick, not contagious, no risk of complications, easier, less risky, prevent a disease in the first place. if infected w/ a microbe, you are contagious, you have the symptoms of the disease, you risk complications
which immune response is stimulated by vaccines? why is this beneficial?
the humoral immune response is stimulated and this is beneficial because the B cells in humoral response work with other defensive molecules that circulate in the blood
what are the social and economic ramifications of pandemic flu? (why does it matter if it won't kill us?)
the social and economic ramifications of the pandemic flu include people turning on each other and the economy going way down because resources are harder to find and more people are stealing to get the necessary products they need to survive
what is the cause of smallpox?
the variola virus
why is there not a vaccine for HIV? could there be one in the future?
there is no vaccine because it is mutating at such a fast rate that it is hard to keep up with. The long-term goal is to develop a safe and effective vaccine that protects people worldwide from getting infected with HIV. A partially effective vaccine could decrease the number of people who get infected with HIV, and further reduce the number of people who can pass the virus on to others. By substantially reducing the number of new infections, we can stop the pandemic.
how do vaccines work to cause immunity?
they work to cause immunity by detecting marker molecules, they then detect the microbes that have different marker molecules and attack them, the macrophages digest the foreign microbes, the macrophage takes the antigens to the lymph nodes, and then regurgitates them and displays them so other cells can recognize them as foreign.
what is the purpose of an adjuvant? provide an example of an adjuvant. are there side effects?
to improve the immune response produced by the vaccines and help keep vaccine antigens at site of injection example: alum (which is composed of aluminum salts) side effects: there is the risk that an adjuvant may either act as the tigger or increase the likelihood of a vaccine causing an autoimmune disease
what individuals are at risk for flu-related complications? what are possible complications?
young children, pregnant women, people with asthma, diabetes or heart and lung disease, and people 65 years and older pneumonia, bronchitis, sinus and ear infections worsened chronic heart problems and congestive heart failure asthma attacks
how can you prevent getting the flu? how can you prevent the spread of the flu if you are infected?
~avoid close contact with sick people ~cover your mouth and nose with a tissue when you cough or sneeze ~wash hands w/ soap and water (if unavailable use an alcohol based hand rub) ~avoid touching your eyes nose and mouth ~if sick, limit contact with others and stay home for at least 24 hours after your fever is gone
what is a macrophage and its role in the immune response?
~known as "big eater," it is a kind of white blood cell that is the first cell at the scene of an infection and travel from your blood. ~It recognizes foreign (non-self) antigens of the virus and eats it up (phagocytosis) ~it brings the foreign antigens to the lymph nodes to find and activate the marching helper T-cell
what type of immunity is acquired by being infected by a microbe? by vaccines?
~natural immunity ~artificial immunity