Immunization against anthrax with Bacillus anthracis protective antigen combined with adjuvants.

The protective efficacy of immunization against anthrax with Bacillus anthracis protective antigen (PA) combined with different adjuvants was tested in Hartley guinea pigs and CBA/J and A/J mice. Adjuvant components derived from microbial products that were tested included threonyl-muramyl dipeptide (threonyl-MDP); monophosphoryl lipid A (MPL); trehalose dimycolate (TDM); and the delipidated, deproteinized, cell wall skeleton (CWS) from either Mycobacterium phlei or the BCG strain of Mycobacterium bovis. Non-microbially derived adjuvants tested included aluminum hydroxide and the lipid amine CP-20,961. In guinea pigs, all adjuvants and adjuvant mixtures enhanced antibody titers to PA as well as survival after a parenteral challenge of virulent B. anthracis Ames spores. In contrast, PA alone or combined with either aluminum hydroxide or CP-20,961 failed to protect mice. Vaccines containing PA combined with threonyl-MDP or MPL-TDM-CWS protected a majority of female CBA/J mice. Statistical analysis of survival data in the guinea pigs indicated that PA-MPL-CWS and PA-MPL-TDM-CWS were more efficacious than the currently licensed human anthrax vaccine.

Cross-reactivity and neutralization by rabbit antisera raised against crotoxin, its subunits and two related toxins.

Antisera were raised against intact crotoxin (Crotalus durissus terrificus), Mojave toxin (Crotalus scutulatus scutulatus) and concolor toxin (Crotalus viridis concolor), as well as the subunits of crotoxin. Double immunodiffusion and enzyme-linked immunosorbent assays (ELISA) demonstrated antigenic similarity between these three purified toxins and their subunits. Additionally, when crotoxin antisera were pre-incubated with each of the three toxins before injection, the lethal activity of all were neutralized equally well. Antiserum was considerably more effective in neutralizing crotoxin in vivo when the toxin was injected i.m. than when injected i.v. Antisera against both intact crotoxin and its basic subunit were an order of magnitude more effective than crotoxin acidic subunit antiserum in crotoxin neutralization. Purified phospholipase A2 from Crotalus adamanteus and Crotalus atrox showed weak cross-reactivity with antisera raised against intact crotoxin and its subunits in the ELISA. Our results suggest that crotalid neurotoxins can be detected and neutralized by polyclonal antibodies raised against any intact toxin or basic subunit in this group of homologous toxins.

Immunochemical cross-reactions between type III group B Streptococcus and type 14 Streptococcus pneumoniae.

Serological cross-reactions between certain streptococci and some serotypes of Streptococcus pneumoniae have been reported. These studies detail the serological cross-reactivity observed between hot HCl-extracted group b streptococcus type III (GBS III) antigens and S. pneumoniae type 14 (Pn 14) polysaccharide. Similar electrophoretic migration patterns of GBS III and Pn 14 were observed when either type-specific BGS III antisera or pneumococcal omniserum was utilized to precipitate these antigens. Both the GBS III antigen and the Pn 14 polysaccharide migrated toward the cathode, whereas all other pneumococcal polysaccharides migrated toward the anode. No cross-reactions were observed between GBS III antisera and the 11 other types of pneumococcal polysaccharides. Lines of identity were observed between type-specific GBS III antisera and monospecific Pn 14 antiserum with either GBS III antigens or purified Pn 14 polysaccharide. The cross-reacting antigens of GBS III and Pn 14 appear to be identical by immunodiffusion and immunoelectrophoresis.

Immunoprecipitation and opsonic cross-reaction between type-14 pneumococcus and group-B streptococcus type III.

Antisera directed against type-14 pneumococcus was opsonic for several strains of type-III group-B streptococcus. Furthermore, the polysaccharide antigen in the polyvalent pneumococcal vaccine reacted to form precipitation lines with antisera directed against type-14 pneumococcus and group-B streptococcus type III Immunisation with currently available pneumococcal vaccine may provide opsonic antibody against group-B streptococci and provide a method of preventing neonatal group-B streptococcal infections.

Demonstration of opsonic activity and in vivo protection against group B streptococci type III by Streptococcus pneumoniae type 14 antisera.

The present studies demonstrate that antisera directed against Streptococcus pneumoniae type 14 is opsonic for group B streptococci type III in a neutrophile-mediated bactericidal assay. Specificity was demonstrated by the observations that group B streptococci type III and S. pneumoniae type 14 adsorbed the opsonic activity of anti-S. pneumoniae type 14 antisera. Group B streptococci strain 090R (devoid of type antigens) and S. pneumoniae type 3, did not remove the opsonic activity of anti-S. pneumoniae type 14 serum. In vivo studies using a suckling rat model of neonatal group B streptococcal type III sepsis demonstrated that antisera directed against S. pneumoniae type 14 was highly protective.

Evaluation of miconazole therapy in experimental disseminated candidiasis in laboratory rats.

Miconazole, a broad-spectrum antimycotic agent with some antibacterial activity, has recently become available for experimental parenteral use in the United States. Its efficacy as an anticandidal drug was tested in adult Wistar rats. A previously established infectious dose of 5 x 10(6)Candida albicans was intravenously injected into 250- to 300-g animals. This dose was fatal to 95% (20/21) of placebo-treated control animals within the 2-week postinfection observation period. Only 4% (2/53) of rats receiving intramuscular miconazole treatment died. Miconazole therapy in Candida-infected rats at a dosage of 50 mg/kg per day resulted in 85% survival, and, although 100 mg/kg per day was 100% efficacious, it was a relatively large volume to give intramuscularly to a rat. Therefore, 75 mg/kg per day was used as a therapeutic dose, and it gave favorable results in this study. Histological examination of all placebo-treated animals revealed C. albicans and a marked inflammatory response in the kidney, brain, and heart. C. albicans organisms were observed to be very prominent in these tissues by using the Gomori methenamine silver stain, and were cultured from these organs. Miconazole-treated rats that were killed after surviving the 2-week observation period had minimal histopathological changes, and the organisms present did not exhibit the same staining characteristics, nor were they isolated like those in the placebo-treated group. Miconazole appears to be an efficacious drug for parenteral therapy, as demonstrated in this reproducible model of disseminated candidiasis in laboratory rats, and more extensive experimental studies are indicated.

Immunopotentiation and antiviral chemotherapy in a suckling rat model of herpesvirus encephalitis.

Encephalitis was induced in 10-day-old Wistar rats by intraperitoneal injection of approximately 100 50% tissue culture infective doses of herpes simplex virus type 2. Treatment regimens included immunopotentiation with levamisole and combined therapy with levamisole and an antiviral agent, adenine arabinoside. Rats treated with levamisole alone had significantly higher rates of survival than placebo-treated controls 14 days after injection of virus. Combination therapy with levamisole and adenine arabinoside prolonged survival, but there was no significant difference between treated animals and controls given placebo. Because adenine arabinoside inhibits the beneficial effect of levamisole in this model, antiviral chemotherapy in conjunction with immunopotentiation should be used with caution in humans. Further studies will be necessary to determine the value of immunopotentiation therapy in the treatment of life-threatening viral infections.

Small-sample blood culture method for identification of bacteria in central arterial and peripheral blood.

A blood culture technique that utilized small arterial blood samples or peripheral capillary blood was tested in beagle dogs and pig-tailed macaque monkeys. A bolus of 2.0 x 10(7)Escherichia coli (ATCC 25922) was injected intravenously into five animals of each species. Blood samples were taken before injection of the organisms and 10, 15, 20, 30, 60, and 120 min after injection. Arterial blood samples (2.0 and 0.2 ml) and peripheral capillary samples (0.14 ml) were taken at each sampling time. Pour plates were prepared from arterial blood for colony counts. All three blood sampling methods were equally effective in detecting sepsis when 10 or more organisms per ml of blood were present. Below this level, the 2.0-ml sample was more effective. Contamination of the peripheral sample with air or skin contaminants was a problem.

Microtiter plate agglutination test for Brucella canis antibodies.

A micro-agglutination test for the antibodies to Brucella canis produced similar results to those obtained with the standard tube agglutination method in human and canine sera. The micromethod does provide an economical means of screening sera for the presence of antibodies.

Transmission of Salmonella montevideo in wheat by stored-product insects.

Sitophilus oryzae (L.), S. granarius (L.), Tribolium castaneum (Hbst.), Oryzaephilus surinamensis (L.), Rhyzopertha dominica (F.), Tenebroides mauritanicus (L.), and Cryptolestes pusillus (Schon.) transmitted Salmonella montevideo from wheat contaminated with 10(6) organisms/g to clean wheat. The insects were fed on the contaminated grain for 21 days and were then transferred to clean grain and allowed to feed for 21 days. They were subsequently transferred to two more samples of clean wheat. All species carried S. montevideo into the initial sample of clean wheat but not into a second or third sample. Progeny of the original insects that developed in the contaminated wheat exhibited less ability than the original adults to contaminate clean wheat. Data indicated that few S. montevideo could be carried by the stored-product insects in large masses of grain.