Foundations of Misunderstanding: Bio 446, Sept 26, 2011 YOUR NAME_______________

What's wrong about each of these widely-believed myths? What further mistakes does each lead to?

#1) The function of histocompatibility antigens is to prevent tissue grafting?

#2) The immune system works by distinguishing between self and non-self molecules and cells?

#3) Antigens stimulate lymphocytes to rearrange V, D and J regions of DNA in whatever combination will code for an amino acid sequence that will fold into the shape that will fit the antigen's shape?

#4) Some mechanism prevents random VDJ recombination from producing binding sites that bind to molecules of your own body?

#5) Autoimmune diseases result from failure to prevent those anti-self recombinations?

#6) Normally, your immune system would never produce lymphocytes whose binding sites fit any normal molecule of the body? (By "binding sites" I include both T-cell receptors and antibodies.)

#7) Individual molecules of monoclonal antibodies bind more specifically, and therefore more tightly, than individual molecules of ordinary, "polyclonal" antibodies?

#8) Autoimmunity is caused by over-activity of the immune system, so that it produces antibody binding sites that have too many different shaped binding sites?

#9) B-lymphocytes do not produce any antibody molecules until they come in contact with antigen molecules?

#10) Antigens control the shape of the antibody binding sites produced by whatever B-lymphocyte that it comes into contact with.

#11) All the normal proteins and other molecules of your body are tagged with markers that identify them as being "self".

#12) Any of the following three possibilities might be the cause of autoimmune diseases:

    * Loss of these "self" tags from some of your cells?
    * Mutation of genes for the "self" tags?
    * Failure of lymphocytes to recognize the "self" tags?

#13) Each new kind of monoclonal antibody requires hundreds of thousands of person-hours of research, and millions of dollars worth of special equipment, to discover and manufacture?

#14) When cancer patients undergo testing of new, experimental anti-cancer drugs, they are paid money in return for the pain and the risk to their lives?

#15) People who are immune to poison ivy will not get a skin rash if they touch poison ivy?

#16) Immunity to particular diseases is evolved, like any other genetic variation, by different rates of survival and reproduction in our ancestors who were exposed to each particular disease? This is why the Aztecs were so susceptible to epidemics of smallpox, measles and other European diseases?

#17) If no human had ever been exposed to molecules of any particular synthetic chemical, then it would not be possible for humans to make antibodies that bind specifically to that chemical?

#18) Part of the function of the immune system is "immune surveillance" against cancer cells, attacking and killing many or most cells that mutate in such a way as to make them become cancerous?

#19) Cancer is caused by cells growing and dividing too fast?

#20) "Natural killer" T-lymphocytes serve the function of attacking cells that have foreign antigens?

Extra credit will be given for finding a web site that has accurate information about these points.


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