Immunization studies with attenuated strains of Bacillus anthracis.

Live, attenuated strains of Bacillus anthracis lacking either the capsule plasmid pXO2, the toxin plasmid pXO1, or both were tested for their efficacy as vaccines against intravenous challenge with anthrax toxin in Fischer 344 rats and against aerosol or intramuscular challenge with virulent anthrax spores in Hartley guinea pigs. Animals immunized with toxigenic, nonencapsulated (pXO1+, pXO2-) strains survived toxin and spore challenge and demonstrated postimmunization antibody titers to the three components of anthrax toxin (protective antigen, lethal factor, and edema factor). Immunization with two nontoxigenic, encapsulated (pXO1-, pXO2+), Pasteur vaccine strains neither provided protection nor elicited titers to any of the toxin components.

Respiratory tularemia: comparison of selected routes of vaccination in Fischer 344 rats.

Fischer 344 rats were given the attenuated live vaccine strain of Francisella tularensis by small-particle aerosol, intranasal instillation, or intraperitoneal, intramuscular, or subcutaneous injection. All of the vaccinated rats developed subclinical infection by 3 days after exposure, which cleared by day 28. Temporal patterns and concentrations of the live vaccine strain organism within the hosts were dependent on the route of vaccination.

Glucan-induced enhancement of host resistance to selected infectious diseases.

We conducted studies with mice, rats, and monkeys which demonstrated the ability of glucan to induce either nonspecific or specific enhancement of host resistance to infectious diseases. Intravenous pretreatment of mice with glucan significantly enhanced the survival of mice challenged with either Venezuelan equine encephalomyelitis (VEE) virus or Rift Valley fever virus. Pretreatment was beneficial when initiated 3 days before challenge with VEE virus and 7 days before challenge with Rift Valley fever virus.

Immunoprophylaxis of experimental Mycoplasma pneumoniae disease: effect of aerosol particle size and site of deposition of M. pneumoniae on the pattern of respiratory infection, disease, and immunity in hamsters.

The distribution of Mycoplasma pneumoniae infection in the respiratory tract and the extent of pulmonary pathology were determined by the site of deposition and the number of organisms administered to hamsters. Infection of the upper and lower areas of the respiratory tract occurred when organisms were introduced into both areas by small-particle aerosol (2.3 micrometer) or by intranasal (i.

Aerosol vaccination of mice with a live, temperature- sensitive recombinant influenza virus.

Mice were vaccinated intranasally (i.n.) or with small-particle aerosols (SPA; 2 mum) or large-particle aerosols (LPA; 8 mum) of an attenuated, temperature-sensitive, recombinant A influenza (H3N2) virus, ts-1 (E).

Effect of aerosol age on the infectivity of airborne Pasteurella tularensis for Macaca mulatta and man.

Sawyer, William D. (U.S.

Studies on the activation of serum protease by an antigen-antibody system.

The results obtained in this study indicate that serum protease is not activated by either a rabbit or guinea pig antiovalbumin-ovalbumin system, in vitro. A precipitin reaction occurring in the presence of a serum protease precursor of three species (human, rabbit, and guinea pig) failed to activate the protease precursor. Furthermore, particulate material as preformed precipitates could not be shown to activate the protease of either human or rabbit serum or their euglobulin fractions.