DEFENDING THE BODY FROM WITHIN
We are awash in a sea of microbes that invade our bodies routinely and in vast numbers. We withstand these constant intruders with immunological defenses that are highly evolved — incorporating complex cellular (cell-based) and humoral (fluid-based) systems that identify intruders — and aim to destroy them in a sequence of increasingly specific attacks. Cellular systems consist of specialized cells such as T cells and B cells while humoral systems include antibodies circulating in the bloodstream.
In recent decades, our knowledge of the mammalian immune system has expanded dramatically, revealing an exquisitely complex system. With sustained molecular and gene-based research, scientists are now beginning to understand the precise mechanisms by which our immune systems distinguish between invading microbes and cells of our own bodies. This research is beginning to lead to custom-designed drugs and therapies that mimic or modify the workings of our natural defenses.
The timing is fortunate, because new and threatening drug-resistant pathogens are emerging as a result of the overuse of drugs and for reasons having to do with microbes' own remarkable versatility.
Drugs, vaccines, and other interventions
Drugs, vaccines, and inoculations are now widely used to stimulate or
supplement the natural immune system. Some create immunity; others kill
off bacteria and other microbes; and still others diminish the effects
of pathogens.
A) Diphtheria antitoxin, 1925 - National Museum of American History, Smithsonian Institution
B) Tetanus and rabies antitoxins - National Museum of American History, Smithsonian Institution
C) Hepatitis A vaccine - Terry Sharrer
D) Vaccination card from the first patient to receive the polio vaccine - National Museum of American History, Smithsonian Institution
E) Typical daily dosage of medications currently prescribed for AIDS patient with drug-resistant HIV - National Cancer Institute
Because HIV mutates readily, medications are more likely to become ineffective when key proteins that are targeted change due to the mutations. As a result, drug-resistant strains emerge with high frequency. Some of the medications shown here act directly against HIV while others are designed to counteract drug interactions and other unwanted side effects.