Abstract: Described are vaccine compositions, methods of manufacture thereof, and methods of treating or preventing certain bacterial infections in humans and other mammals. For example, described are compositions comprising bacterial cell extracts that have undergone pretreatment such that lipid moieties have been cleaved from bacterial lipoproteins, thereby forming a vaccine composition that can stimulate a desired mammalian immune response while avoiding unwanted negative effects.

Abstract: The present invention relates to a live cytadherence-deficient M. gallisepticum strain that does not express at least two of three proteins, the Gap-A molecule, crnA protein, and the 45 kDa protein, expressed by wildtype M. gallisepticum Strain R and its use as a vaccine for preventing and protecting birds, especially chickens and turkeys against the respiratory diseases attendant with wildtype Mycoplasma gallispeticum infection. The invention also relates to the use of the vaccine as a vector for the delivery of genes encoding protective antigens from other bacterial and viral avian pathogens, such as avian influenza virus. There is also disclosed a method for identifying the attenuated cytadherence-deficient M. gallisepticum Rhigh or a strain thereof.