The P39 and the bacterioferrin (BFR) antigens of Brucella melitensis 16M were previously identified as T dominant antigens able to induce both delayed-type hypersensivity in sensitized guinea pigs and in vitro gamma interferon (IFN-␥) production by peripheral blood mononuclear cells from infected cattle. Here, we analyzed the potential for these antigens to function as a subunitary vaccine against Brucella abortus infection in BALB/c mice, and we characterized the humoral and cellular immune responses induced. Mice were injected with each of the recombinant proteins alone or adjuvanted with either CpG oligodeoxynucleotides (CpG ODN) or non-CpG ODN. Mice immunized with the recombinant antigens with CpG ODN were the only group demonstrating both significant IFN-␥ production and T-cell proliferation in response to either Brucella extract or to the respective antigen. The same conclusion holds true for the antibody response, which was only demonstrated in mice immunized with recombinant antigens mixed with CpG ODN. The antibody titers (both immunoglobulin G1 [IgG1] and IgG2a) induced by P39 immunization were higher than the titers induced by BFR (only IgG2a). Using a B. abortus 544 challenge, the level of protection was analyzed and compared to the protection conferred by one immunization with the vaccine strain B19. Immunization with P39 and CpG ODN gave a level of protection comparable to the one conferred by B19 at 4 weeks postchallenge, and the mice were still significantly protected at 8 weeks postchallenge, although to a lesser extent than the B19-vaccinated group. Intriguingly, no protection was detected after BFR vaccination. All other groups did not demonstrate any protection.Brucella species are facultative intracellular gram-negative bacterial pathogens that infect both phagocytic and nonphagocytic cells (42). Brucella abortus causes abortion and infertility in cattle and also various chronic zoonotic infections in humans (8,42). The intracellular localization of these bacteria implies that the immunity against Brucella requires a cell-mediated immune response, which makes the Th1 arm of the response very crucial for controlling the infection (44).Brucella abortus strain B19 is one of the most commonly used attenuated live vaccines against bovine brucellosis and induces high level of protection in cattle (15). The presence of smooth lipopolysaccharide in the vaccine strain B19 may interfere with the discrimination between infected and vaccinated individuals (32) and impair the test and slaughter strategy. Moreover, this strain can cause abortion when administered to pregnant cattle (9) and is still fully virulent for humans (42). In order to avoid these drawbacks, alternative vaccination approaches are needed. Among these, subcellular vaccines able to induce protective Th1 cell-mediated immune response are being developed. Recombinant antigens of Brucella spp. such as HtrA (40), GroEL (2, 30, 34), GroES (34), Cu,Zn superoxide dismutase (SOD) (47, 49), YajC (52), UvrA (34), and L7 and L12 (37) have been sh...

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In this study, we evaluated the ability of DNA vaccines encoding the bacterioferritin (BFR) or P39 proteins of Brucella spp. to induce cellular and humoral immune responses and to protect BALB/c mice against a challenge with B. abortus 544. We constructed eukaryotic expression vectors called pCIBFR and pCIP39, encoding BFR or P39 antigens, respectively, and we verified that these proteins were produced after transfection of COS-7 cells. PCIBFR or pCIP39 was injected intramuscularly three times, at 3-week intervals. pCIP39 induced higher antibody responses than did the DNA vector encoding BFR. Both vectors elicited a T-cellproliferative response and also induced a strong gamma interferon production upon restimulation with either the specific antigens or Brucella extract. In this report, we also demonstrat that animals immunized with these plasmids elicited a strong and long-lived memory immune response which persisted at least 3 months after the third vaccination. Furthermore, pCIBFR and pCIP39 induced a typical T-helper 1-dominated immune response in mice, as determined by cytokine or immunoglobulin G isotype analysis. The pCIP39 delivered by intramuscular injection (but not the pCIBFR or control vectors) induced a moderate protection in BALB/c mice challenged with B. abortus 544 compared to that observed in positive control mice vaccinated with S19.

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Summary The present work was conducted to investigate antibacterial activity of methanol and acetone in leaf (LE) and stem-bark (SBE) of Ficus sycomorus L. crude extracts against sensitive and resistant species of Staphylococcus aureus and Acinetobacter baumannii pathogens. Antimicrobial activity expressed by disc-diffusion method (zone of inhibitions - ZIs), minimum inhibitory concentrations (MICs) and minimum bactericidal concentration (MBC) were measured as reported for many investigations. Similar study with 6 commercial antibiotics as a reference drug was undertaken. Based upon the estimated ZIs, MIC and MBC values, acetone LE exhibited higher antimicrobial activity than that of methanol one. Otherwise, standard antibiotics have lower effectiveness (ZIs, MICs and MBC) on all tested bacteria as compared to the SBE and LE. The highest antibacterial activity was recorded in sensitive A. baumannii isolate with MICs 2.5, 4.9 mg/ml and MBC 3.8, 9.7 mg/ml for acetone LE and SBE, respectively. Our data indicated that the lowest antibiotics antibacterial activity was recorded for resistant A. baumannii pathogen. It was lower than those of the both plant fractions extracts.

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