Location: Infectious Bacterial Diseases Research
2022 Annual Report
Objectives
Objective 1: Develop vaccines that prevent disease or mitigate disease spread with an emphasis on platforms that allow for extended antigen release and remote delivery for livestock and wildlife species.
Subobjective 1.A: Assess the potential of a polyanhydride delivery platform to enhance BCG availability and immunogenicity in order to promote protective anti-mycobacterial responses.
Subobjective 1.B: Evaluate the immune response of WTD to encapsulated lyophilized BCG delivered in oral vaccine delivery units (VDUs).
Objective 2: Improve current diagnostic tests for bovine TB and develop novel, next generation diagnostics which are amenable to remote or continuous disease surveillance and can be incorporated into precision livestock management.
Sub-objective 2.A: Assess the sensitivity and specificity of a fluorescence polarization assay (FPA) to detect serum antibodies against synthetic M. bovis antigens.
Subobjective 2.B: Develop a battery-free, self-contained sensor for the detection of biological IFN-' in vivo that could be used as a diagnostic platform.
Objective 3: To enable the rational-design of intervention strategies, using transcriptomic approaches,define the immunopathogenesis of bovine tuberculosis at the tissue and cellular level by analyzing gene expression of peripheral immune responses and those responses involved in granuloma formation and maintenance.
Subobjective 3.A: Characterize the presence of key T cell subsets and transcription factors in granulomas from BCG-vaccinated vs. non-vaccinated animals following experimental infection with M. bovis.
Subobjective 3.B: Characterize the gene transcription profiles of Mycobacterium bovis-specific T cells in the periphery following M. bovis infection or vaccination.
Approach
Characterize and compare cytokine and biomarker expression (immune responses) at the cellular level in lungs and lymph nodes of Mycobacterium bovis-infected cattle. Comparing responses between tissues, as well as over time, will aid in understanding the host response to M. bovis within the environment where host and pathogen interact (granuloma). We aim to improve the specificity of diagnostic tests by developing diagnostic reagents from proteins found in M. bovis but not in non-tuberculous mycobacteria, thus avoiding cross-reactivity elicited by environmental mycobacteria that contributes to false positive results on cattle tuberculosis diagnostic tests. Similarly, we aim to identify proteins/genes expressed by M. bovis in vivo that may be considered as potential diagnostic test targets and to use genomics/transcriptomics to characterize genes/gene profiles of M. bovis-infected vs non-infected cattle. These data will aid diagnosis and provide insight into the immunopathogenesis of bovine tuberculosis. In terms of vaccine evaluation, we aim to examine duration of immunity to experimental infection provided by the vaccine M. bovis BCG in white-tailed deer and examine the effects of oral BCG vaccination on deer-to-deer transmission of virulent M. bovis. In cattle, we aim to determine the efficacy of simultaneous administration of parenteral M. bovis BCG and a mucosally delivered bacterial-vectored subunit vaccine against aerosol M. bovis infection in neonatal calves.
Progress Report
Over 100 years ago, in 1917, USDA initiated a bovine tuberculosis (bTB) eradication program that is still in place today. Although significant progress has been made, eradication has proved elusive. Obstacles to eradication include, 1) lack of rapid and accurate diagnostic tests to detect animals infected with Mycobacterium bovis (M. bovis; the cause of tuberculosis in animals), and 2) wildlife acting as a source of infection for cattle. Research activities within the ARS bTB project in Ames, Iowa, provide direct support for the USDA bTB eradication program, specifically, through development of more sensitive diagnostics, efficacious vaccines, and improved animal disease models to enhance the capability to detect, prevent and control bTB.
Under Objective 1 (Develop vaccines that prevent disease or mitigate disease spread with an emphasis on platforms that allow for extended antigen release and remote delivery for livestock and wildlife species), ARS scientists in Ames, Iowa, developed a lyophilized form of the human TB vaccine, BCG, which was then encapsulated and placed within a bait material developed by colleagues at the USDA Wildlife Research Center. Deer were trained to accept the vaccine baits and their immune responses to BCG valuated. Previous work by ARS scientists using liquid forms of BCG demonstrated immune responses suggestive of acceptable levels of protection to tuberculosis; however, administering lyophilized BCG orally within a vaccine bait did not induce immune responses suggestive of any level of protection. The project is moving to evaluate other platforms capable of delivery of BCG in liquid form. Under Objective 2 (Improve current diagnostic tests for bovine TB and develop novel, next generation diagnostics which are amenable to remote or continuous disease surveillance and can be incorporated into precision livestock management), colleagues at Iowa State University had previously developed and reported in the scientific literature their creation of a biosensor for the cytokine IFN-gamma. Initial testing in vitro is currently underway and suggests the biosensor can detect bovine IFN-gamma. Under Objective 3 (To enable the rational design of intervention strategies, using transcriptomic approaches, define the immunopathogenesis of bovine tuberculosis at the tissue and cellular level by analyzing gene expression of peripheral immune responses and those responses involved in granuloma formation and maintenance) granulomas from BCG vaccinated animals and non-vaccinated animals are being analyzed for expression of various cytokines.
Accomplishments
1. Evaluated susceptibility of livestock, deer and mink to the COVID-19 virus. The pandemic caused by COVID-19 virus is believed to have originated in bats and passed through another unknown animal host before being transmitted to humans. ARS scientists in Ames, Iowa, performed emergency response, high-priority research to determine the susceptibility of various animal species to infection with the COVID-19 virus. Data indicated that cattle and swine were not susceptible to the COVID-19 virus; however, white-tailed deer were highly susceptible. Infected deer did not demonstrate clinical signs after infection but shed large amounts of virus in the first 5-6 days after infection and readily transmitted the disease to other deer. Upon obtaining this data, APHIS Wildlife Services initiated surveys of COVID-19 in wild white-tailed deer that demonstrated widespread infection nationally and prompted concerns that deer might be a reservoir for human infection. We also examined the pathogenesis of COVID-19 virus in mink and demonstrated the susceptibility of this species to infection and viral shedding, and the lack of clinical signs. This data will be of interest to consumers, scientists, livestock producers, and regulatory officials that have interests or responsibilities related to public health.
2. Documented that oral lyophilized (freeze-dried) human TB vaccine (BCG) does not induce immune responses. Wildlife reservoirs of tuberculosis are a challenging obstacle to eradication from U.S. cattle populations of this disease that affects multiple species including humans. Tuberculosis prevalence in wild deer populations in Michigan has not changed for over a decade. One intervention strategy would be use of an efficacious vaccine in wild deer. Mycobacterium bovis strain Bacillus Calmette-Guerin (BCG) has shown efficacy as an oral, liquid vaccine in white-tailed deer, but liquid vaccines have limitations for field use. Increasing shelf-life and ease of handling of BCG by freeze-drying would improve vaccines intended for use under field conditions. ARS scientists in Ames, Iowa, demonstrated that oral delivery of freeze-dried BCG did not induce protective immune responses against tuberculosis in deer and cattle. This data will be of interest to scientists, livestock producers, and regulatory personnel with interest in tuberculosis in livestock and wildlife.
Review Publications
Martins, M., Boggiatto, P.M., Buckley, A., Cassmann, E.D., Falkenberg, S.M., Caserta, L.C., Fernandes, M.H., Kanipe, C.R., Lager, K.M., Palmer, M.V., Diel, D.G. 2022. From Deer-to-Deer: SARS-CoV-2 is efficiently transmitted and presents broad tissue tropism and replication sites in highly susceptible white-tailed deer. PLoS Pathogens. 18(3). Article e1010197. https://doi.org/10.1371/journal.ppat.1010197.
Palmer, M.V., Kanipe, C.R., Boggiatto, P.M. 2022. The bovine tuberculoid granuloma. Pathogens. 11(1). Article 61. https://doi.org/10.3390/pathogens11010061.
Lyashchenko, K.P., Sikar-Gang, A., Sridhara, A.A., Johnathan-Lee, A., Lambotte, P., Esfandiari, J., Ireton, G.C., Duthie, M., Reed, S.G., Jones, G., Vordermeier, M.H., Thacker, T.C., Palmer, M.V., Waters, W.R. 2021. Novel polyprotein antigens designed for improved serodiagnosis of bovine tuberculosis. Frontiers in Veterinary Science. 240. Article 110320. https://doi.org/10.1016/j.vetimm.2021.110320.
Lyaschcenko, K., Sikar-Gang, A., Sridhara, A., Johnathan-Lee, A., Elahi, R., Greenwald, R., Lambotte, P., Esfandiari, J., Roos, E., Kerry, T., Miller, M., Thacker, T.C., Palmer, M.V., Waters, W.R. 2021. Use of blood matrices and alternative biological fluids for antibody detection in animal tuberculosis. Veterinary Immunology and Immunopathology. 239. Article 110303. https://doi.org/10.1016/j.vetimm.2021.110303.
