Current vaccines used for the prevention of brucellosis are ineffective in inducing protective immunity in animals that are chronically infected with Brucella abortus, such as elk. Using a gene discovery approach, in vivo-induced antigen technology (IVIAT) on B. abortus, we previously identified ten loci that encode products up-regulated during infection in elk and consequently may play a role in virulence. In our present study, five of the loci (D15, 0187, VirJ, Mdh, AfuA) were selected for further characterization and compared with three additional antigens with virulence potential (Hia, PrpA, MltA). All eight genes were PCR-amplified from B. abortus and cloned into E. coli. The recombinant products were then expressed, purified, adjuvanted, and delivered subcutaneously to BALB/c mice. After primary immunization and two boosts, mice were challenged i.p. with 5×104 CFU of B. abortus strain 19. Spleens from challenged animals were harvested and bacterial loads determined by colony count at various time points. While vaccination with four of the eight individual proteins appeared to have some effect on clearance kinetics, mice vaccinated with recombinant Mdh displayed the most significant reduction in bacterial colonization. Furthermore, mice immunized with Mdh maintained higher levels of IFN-γ in spleens compared to other treatment groups. Collectively, our in vivo data gathered from the S19 murine colonization model suggest that vaccination with at least three of the IVIAT antigens conferred an enhanced ability of the host to respond to infection, reinforcing the utility of this methodology for the identification of potential vaccine candidates against brucellosis. Mechanisms for immunity to one protein, Mdh, require further in vitro exploration and evaluation against wild-type B. abortus challenge in mice, as well as other hosts. Additional studies are being undertaken to clarify the role of Mdh and other IVI antigens in B. abortus virulence and induction of protective immunity.

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ABSTRACT:Brucellosis, which results in fetal abortions in domestic and wildlife animal populations, is of major concern in the US and throughout much of the world. The disease, caused by Brucella abortus, poses an economic threat to agriculture-based communities. A moderately efficacious live attenuated vaccine (B. abortus strain RB51) exists. However, even with vaccine use, outbreaks occur. Evidence suggests that elk (Cervus canadensis), a wild host reservoir, are the source of recent outbreaks in domestic cattle herds in Wyoming, USA. Brucella abortus establishes a chronic, persistent infection in elk. The molecular mechanisms allowing the establishment of this persistent infective state are currently unknown. A potential mechanism could be that concurrent pathogen burdens contribute to persistence. In Wyoming, elk are chronically infected with Trypanosoma cervi, which may modulate host responses in a similar manner to that documented for other trypanosomes. To identify any synergistic relationship between the two pathogens, we simulated coinfection in the well-established murine brucellosis model using Trypanosoma musculi and B. abortus S19. Groups of C57BL/6 mice (Mus musculus) were infected with either B. abortus strain 19 (S19) or T. musculi or both. Sera were collected weekly; spleens from euthanized mice were tested to determine bacterial load near the end of normal brucellosis infection. Although changes in bacterial load were observed during the later stages of brucellosis in those mice coinfected with T. musculi, the most significant finding was the suppression of gamma interferon early during the infection along with an increase in interleukin-10 secretion compared with mice infected with either pathogen alone. These results suggest that immune modulatory events occur in the mouse during coinfection and that further experiments are warranted to determine if T. cervi impacts Brucella infection in elk.

Filoviruses (Family Filoviridae genera Ebolavirus and Marburgvirus) are negative-stranded RNA viruses that cause severe health effects in humans and non-human primates, including death. Except in outbreak settings, vaccines and other medical countermeasures against Ebola virus (EBOV) will require testing under the FDA Animal Rule. Multiple vaccine candidates have been evaluated using cynomolgus monkeys (CM) exposed to EBOV Kikwit strain. To the best of our knowledge, however, animal model development data supporting the use of CM in vaccine research have not been submitted to the FDA. This study describes a large CM database (122 CM, 62 female and 60 male, age 2 to 9 years) and demonstrates the consistency of the CM model through time to death models and descriptive statistics. CMs were exposed to EBOV doses of 0.1 to 100,000 PFU in 33 studies conducted at three Animal Biosafety Level 4 facilities, by three exposure routes. Time to death was modeled using Cox proportional hazards models with a frailty term that incorporated study-to-study variability. Despite significant differences attributed to exposure variables, all CMs exposed to the 100 to 1,000 pfu doses commonly used in vaccine studies died or met euthanasia criteria within 21 days of exposure, median 7 days, 93% between 5 and 12 days of exposure. Moderate clinical signs were observed 4 to 5 days after exposure and preceded death or euthanasia by approximately one day. Viremia was detected within a few days of infection. Hematology indices were indicative of viremia and the propensity for hemorrhage with progression of Ebola viremia. Changes associated with coagulation parameters and platelets were consistent with coagulation disruption. Changes in leukocyte profiles were indicative of an acute inflammatory response. Increased liver enzymes were observed shortly after exposure. Taken together, these factors suggest that the cynomolgus monkey is a reliable animal model for human disease.

BackgroundAlthough survival is historically low for patients presenting with N2 lung cancer, patients who respond to chemotherapy have up to a 30% chance for long term survival or cure. Selective pulmonary artery perfusion (SPAP) has been examined in several animal studies as a method for delivering chemotherapy in non-small cell lung cancer; however, there is a paucity of data regarding the effect of SPAP on regional lymph nodes.MethodsLeft SPAP was performed using gemcitabine on five swine and compared with standard central venous infusion in controls. Samples were taken from lung, kidney, liver, plasma, and lymph nodes. Tissue was measured for gemcitabine concentration using mass spectroscopy.ResultsLeft SPAP resulted in significantly higher gemcitabine concentration than standard infusion in hilar and mediastinal lymph nodes while plasma gemcitabine concentration was not significantly different.ConclusionSPAP is a viable technique for concentrating a chemotherapeutic agent in the mediastinal and hilar lymph nodes. This could potentially increase the response to chemotherapy and render more patients to be surgical candidates who present with N2 disease.