A new vaccine headed for market protects cattle against the pneumonia-causing bacterium Pasteurella haemolytica . At the heart of the new vaccine is the world's first genetically engineered strain of P. haemolytica , produced by ARS researchers. The new vaccine could be marketed next year. Laboratory tests show some cytokines inhibit development of coccidia parasites in the bird. They also turn precursor cytotoxic cells into active cytotoxic cells that hunt down and kill parasite-infected host cells.
Cytokines rally white blood cells called macrophages to devour and destroy the parasites.
Unfortunately, coccidia thwart pharmaceutical treatments by rapidly developing resistance to the drugs used against them. The protein was isolated and purified in studies in 1994-95 by scientists with ARS and the Institut National de la Recherches Agronomique, Nouzilly, France. When a cow's udder becomes infected, neutrophils rush to attack the invading bacteria. Until now, researchers had little information on what triggered the neutrophils' charge. The protein might someday be used in cows to protect against mastitis-causing bacteria.