Ancient System Gets New Respect

INNATE IMMUNITYUnlike the so-called acquired immune system, with its disease-fighting cells and antibodies, innate immunity depends on peptides and small proteins to fight off dangerous microbes. As genomic information has flooded out of sequencing labs within the last few years, researchers have identified hundreds of these peptides from a broad range of species. They are also now working out exactly what trips these defenses and how they specialize to fight off the pathogens that attack each kind of organism--information that may make peptides a new source of antibiotics.