Word: antigenic
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Dates: during 1980-1989
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...tremendous synergy" between alpha interferon and IL-2 in attacking cancer cells. While IL-2 works to make the killer cells more potent, he explains, they "have to recognize something unique on the surface of the cancer cell in order to kill it." That something is an antigen, and interferon seems to make it more "visible" to the killer cells...
...macrophage as friend, or self, and not attack it. After digesting the virus, the macrophage proudly displays strips of protein from the virus in the grooves of some of its MHC molecules. Once a bit of protein -- which is part of the virus's own identity molecule, or antigen -- is nestled in the groove of the macrophage's MHC molecule, it acts as a red flag for the immune system, warning it that a particular type of virus is loose in the body...
...safe from scavengers and antibodies, but the free lunch is over quickly. While the B cells are being activated, other helper T cells have been creating an army of killer T cells. These killers recognize the flu-ridden cells because, like macrophages, infected cells display a bit of viral antigen on their outer membranes. Says Coffman: "For many viral infections, the most important response is the killer T cell. Viruses live inside cells, so it's essential to kill not only the viruses themselves but those cells that are infected with the virus...
These days the explosive growth of both molecular biology and immunology has enabled vaccine makers to take a safer and more effective approach to their work. Instead of using dead or attenuated bacteria or viruses, they remove from the bug's surface the marker protein, or antigen, that provokes the immune response. Employing gene-splicing techniques, they mass-produce the antigen, or a portion of it, and use it as the prime ingredient of the vaccine...
Researchers are also creating vaccines that consist largely of antigens synthesized from chemicals on the laboratory shelf. When these vaccines prove ineffective, scientists can now usually determine why. Says M.I.T. Molecular Biologist Malcolm Gefter: "Today, when a vaccine doesn't elicit a protective response, it is possible to detect what is or is not working -- the B cells, the T cells, the lymphokines, whatever." Scientists can then "fix" the vaccine. For example, the 1985 vaccine against Hemophilus influenzae Type B, which causes bacterial meningitis, was only partially effective; although it protected older children, it did not work for babies under...