Author
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Pugh Jr, George |
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Tabatabai, Louisa |
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Submitted to: Infection and Immunity
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/3/1995 Publication Date: N/A Citation: N/A Interpretive Summary: Brucellosis is an important zoonotic we well as an important economic disease. Although large sums of money and many different approaches have been directed at prevention, control, and eradication of brucellosis, caused by Brucella abortus, in cattle, the disease still is a major problem for the livestock industry and US regulatory personnel. Presently, however, the most important need for eradication is a highly effective (>90 percent) vaccine that does not rely on a potentially infectious and dangerous live organism, such as Brucella abortus strain 19 and vectors such as Salmonella typhimurium, or on use of a killed whole bacteria cell such as Brucella abortus 45/20 which requires multiple vaccinal inoculations. We hypothesized that the periplasmic proteins of Brucella abortus contained specific highly immunogenic epitopes that could be used in vaccines alone or in conjunction with immune response modifiers. Results indicated that some of the subfractional proteins serve as virulence factors for Brucella abortus while others are protective in mice especially when used in conjunction with monophosphoryl lipid A, a proven immune response modulator. Our results used in conjunction with those of others could lead to the identification of specific immune epitopes which can be used to design highly effective specific vaccines for brucellosis and other diseases. Technical Abstract: The study compared the immune and protective responses induced in BALB/c mice vaccinated with 6 salt-extractable proteinaceous periplasmic fractions (BCPS) of Brucella abortus strain 19 and later challenge exposed with Brucella abortus 2308. BCSP 0-70 was precipitated by using ammonium sulfate at 70% saturation and BCSP 70- 100 was precipitated by ammonium sulfate at 100% saturation using supernatant fluid of BCSP that had been extracted with 70% ammonium sulfate. Four subfractions were separated from the BCSP 70-100 by anion exchange high performance liquid chromatography. Monophosphoryl lipid A (MPL) from Salmonella typhimurium Re mutant was used as a potential immune response modifier in some vaccines. Results indicated that vaccines prepared from BCSP 0-70 and BCSP 70- 100 were moderately protective and immunogenic. However, the subfractions designated BCSP 70-100-1 through -4 purified by anion exchange high performance liquid chromatography (HPLC ) were not protective. Two subfractions were associated with significant (P<0.05) increases in colony forming units (CFU) per spleen and splenomegaly when compared with nonvaccinated challenge-exposed mice. The MPL had no effect on CFU and splenomegaly when used in combination with subfractions. Serologic results using an enzyme- linked immunosorbent assay indicated that MPL modulated the IgG responses induced by BCSP 0-70, BCSP 70-100, and subfraction BCSP 70- 100-2 vaccines only. The overall results suggest that certain proteinaceous periplasmic fractions might serve as virulence factors |
