Protective Potential of Antioxidant Enzymes as Vaccines for Schistosomiasis in a Non-Human Primate Model

Schistosomiasis remains a major cause of morbidity in the world. The challenge today is not so much in the clinical management of individual patients, but rather in population-based control of transmission in endemic areas. Recent large-scale efforts aimed at limiting schistosomiasis have produced limited success. There is an urgent need for complementary approaches, such as vaccines. We demonstrated previously that anti-oxidant enzymes such as Cu-Zn superoxide dismutase (SOD) and glutathione S peroxidase (GPX), when administered as DNA-based vaccines induced significant levels of protection in inbred mice, greater than the target 40% reduction in worm burden compared to controls set as a minimum by the WHO. These results led us to investigate if immunization of non-human primates with antioxidants would stimulate an immune response that could confer protection, as a prelude for human trials. Issues of vaccine toxicity and safety that were difficult to address in mice were also investigated. All baboons in the study were examined clinically throughout the study and no adverse reactions occurred to the immunization. When our outbred baboons were vaccinated with two different formulations of SOD (SmCT-SOD and SmEC-SOD) or one of GPX (SmGPX), they showed a reduction in worm number to varying degrees, when compared with the control group. More pronounced, vaccinated animals showed decreased bloody diarrhea, days of diarrhea and egg excretion (transmission), as well as reduction of eggs in the liver tissue and in the large intestine (pathology) compared to controls. Specific IgG antibodies were present in sera after immunizations and 10 weeks after challenge infection compared to controls. PBMC, mesenteric and inguinal node cells from vaccinated animals proliferated and produced high levels of cytokines and chemokines in response to crude and recombinant antigens compared with controls. These data demonstrate the potential of antioxidants as vaccine candidates

A BALB/c murine lung alveolar carcinoma used to establish a surgical spontaneous metastasis model

Line-1, a weakly immunogenic lung tumor cell line derived from the BALB/c mouse, metastasizes spontaneously to the lungs of mice following subcutaneous administration. The parameters that influence metastasis as well as the progression of metastatic lung disease following surgical resection of primary subcutaneous tumors were characterized. Histological analysis of the lungs obtained from mice bearing different size subcutaneous tumors demonstrated that >90% of the mice developed micrometastatic disease in the lungs when the tumor exceeded 650 mm 3 in size. Surgical resection of subcutaneous tumors resulted in the cure of primary disease in 95% of the mice. Macroscopic tumor nodules were grossly visible in the lungs of 75% of the mice 5 weeks after surgery. Serum amyloid A level correlated with primary tumor burden and was diagnostic for the presence of metastatic disease. The efficiency of metastasis, post-surgical primary tumor recurrence and long-term survival were significantly different between BALB/c mice obtained from different suppliers. The Line-1-BALB/c surgical metastasis model provides a clinically relevant tool for the evaluation of anti-cancer therapies, especially those that are designed to target long-term suppression of minimal residual disease following surgical intervention.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42586/1/10585_2004_Article_DO00000954.pd

Temporospatial shifts within commercial laboratory mouse gut microbiota impact experimental reproducibility

Experimental reproducibility in mouse models is impacted by both genetics and environment. The generation of reproducible data is critical for the biomedical enterprise and has become a major concern for the scientific community and funding agencies alike. Among the factors that impact reproducibility in experimental mouse models is the variable composition of the microbiota in mice supplied by different commercial vendors. Less attention has been paid to how the microbiota of mice supplied by a particular vendor might change over time. Results In the course of conducting a series of experiments in a mouse model of malaria, we observed a profound and lasting change in the severity of malaria in mice infected with Plasmodium yoelii; while for several years mice obtained from a specific production suite of a specific commercial vendor were able to clear the parasites effectively in a relatively short time, mice subsequently shipped from the same unit suffered much more severe disease. Gut microbiota analysis of frozen cecal samples identified a distinct and lasting shift in bacteria populations that coincided with the altered response of the later shipments of mice to infection with malaria parasites. Germ-free mice colonized with cecal microbiota from mice within the same production suite before and after this change followed by Plasmodium infection provided a direct demonstration that the change in gut microbiota profoundly impacted the severity of malaria. Moreover, spatial changes in gut microbiota composition were also shown to alter the acute bacterial burden following Salmonella infection, and tumor burden in a lung tumorigenesis model. Conclusion These changes in gut bacteria may have impacted the experimental reproducibility of diverse research groups and highlight the need for both laboratory animal providers and researchers to collaborate in determining the methods and criteria needed to stabilize the gut microbiota of animal breeding colonies and research cohorts, and to develop a microbiota solution to increase experimental rigor and reproducibility

Intratumoral IL-12 and TNF-α–Loaded Microspheres Lead To Regression of Breast Cancer and Systemic Antitumor Immunity

Background: Local, sustained delivery of cytokines at a tumor can enhance induction of antitumor immunity and may be a feasible neoadjuvant immunotherapy for breast cancer. We evaluated the ability of intratumoral poly-lactic-acid-encapsulated microspheres (PLAM) containing interleukin 12 (IL-12), tumor necrosis factor α (TNF-α), and granulocyte-macrophage colony stimulating factor (GM-CSF) in a murine model of breast cancer to generate a specific antitumor response.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41401/1/10434_2004_Article_147.pd

CTLA-4 blockade augments human T lymphocyte-mediated suppression of lung tumor xenografts in SCID mice

Previous studies by others using transplantable murine tumor models have demonstrated that the administration of antibodies that block CTLA-4 interaction with B7 can provoke the elimination of established tumors, and that the tumor suppression is mediated by T-cells and/or cells expressing NK1.1. Studies from our lab have established in a human/severe combined immunodeficient (SCID) mouse chimeric model that autologous peripheral blood leukocytes (PBL) can suppress the growth of tumor xenografts in a PBL dose-dependent fashion, and that this suppression is dependent upon the patient’s T and NK cells. Using this human/mouse chimeric model, we sought to determine whether an antibody blockade of CTLA-4 would enhance the anti-tumor response of a patient’s PBL. It was first important to determine whether the tumor suppression observed in the SCID model was dependent upon CD28/B7 co-stimulation. Blockade of B7 with a human CTLA-4-Ig fusion protein completely abrogated the lymphocyte-mediated tumor suppression, confirming in this model that tumor suppression is dependent upon a CD28/B7 co-stimulation. Using two different CTLA-4 specific monoclonal antibodies, we observed that CTLA-4 blockade significantly enhanced the human lymphocyte-mediated tumor suppression in mice co-engrafted with PBL and tumor cells. This enhancement was observed in both an allogeneic setting (in which the PBL were allogeneic with respect to the tumor) and an autologous setting (in which the PBL and tumor were from the same patient). These results sustain the notion that human anti-tumor immune response can be augmented (in vivo) by blocking the interaction between CTLA-4 and B7.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46864/1/262_2005_Article_668.pd