Development of Burkholderia mallei and pseudomallei vaccines

Department of Microbiology, Immunology, and Pathology, Regional Center of Excellence in Emerging Diseases and Bioterrorism, Colorado State University Ft. Collins, CO, USA.
Frontiers in Cellular and Infection Microbiology (Impact Factor: 3.72). 03/2013; 3:10. DOI: 10.3389/fcimb.2013.00010
Source: PubMed


B. mallei and B. pseudomallei are Gram-negative bacteria that cause glanders and melioidosis, respectively. Inhalational infection with either organism can result in severe and rapidly fatal pneumonia. Inoculation by the oral and cutaneous routes can also produce infection. chronic infection develops after recovery from acute infection with both agents, and control of infection with antibiotics requires prolonged treatment. Symptoms for both meliodosis and glanders are non-specific, making diagnosis difficult. B. pseudomallei can be located in the environment, but in the host, B. mallei and B. psedomallei are intracellular organisms. Thefection results in similar immune responses to both agents. Effective early innate immune responses are critical to controlling the early phase of the infection. Innate immune signaling molecules such as TLR, NOD, MyD88 and pro-inflammatory cytokines such as IFN- and TNF-α play key roles in regulating control of infection. Neutrophils and monocytes are critical cells in the early infection for these microorganisms. Both monocytes and macrophages are necessary for limiting dissemination of B. pseudomallei. In contrast, the role of adaptive immune responses in controlling Burkholderia infection is less well understood. However, T cell responses are critical for vaccine protection from Burkholderia infection. At present, effective vaccines for prevention of glanders or meliodosis have not been developed, although recently progress of Burkholderia vaccines has received renewed attention. This review will summarize current and past approaches to develop Burkholderia mallei and pseudomalllei vaccines, with emphasis on immune mechanisms of protection and the challenges facing the field. At present, immunization with live attenuated bacteria provides the most effective and durable immunity, and it is important therefore to understand the immune correlates of protection induced by live attenuated vaccines.

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    • "Burkholderia pseudomallei, a Gram-negative saprophyte, is the causative agent for melioidosis and is endemic in Southeast Asia and Northern Australia (Cheng and Currie, 2005). It is highly resistant to harsh environmental pressures, and it is classified as a potential class B bioterrorism weapon due to its high infectivity when aerosolized (Silva and Dow, 2013). Several virulence factors have been identified, including multiple Type III and VI secretion systems, toxins, capsular polysaccharide, and lipopolysaccharide (LPS; Nandi and Tan, 2013). "
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    ABSTRACT: Vaccines developing immune responses toward surface carbohydrates conjugated to proteins are effective in preventing infection and death by bacterial pathogens. Traditional production of these vaccines utilizes complex synthetic chemistry to acquire and conjugate the glycan to a protein. However, glycoproteins produced by bacterial protein glycosylation systems are significantly easier to produce, and could possible be used as vaccine candidates. In this work, we functionally expressed the Burkholderia pseudomallei O polysaccharide (OPS II), the Campylobacter jejuni oligosaccharyltransferase (OTase), and a suitable glycoprotein (AcrA) in a designer E. coli strain with a higher efficiency for production of glycoconjugates. We were able to produce and purify the OPS II-AcrA glycoconjugate, and MS analysis confirmed correct glycan was produced and attached. We observed the attachment of the O-acetylated deoxyhexose directly to the acceptor protein, which expands the range of substrates utilized by the OTase PglB. Injection of the glycoprotein into mice generated an IgG immune response against B. pseudomallei, and this response was partially protective against an intranasal challenge. Our experiments show that bacterial engineered glycoconjugates can be utilized as vaccine candidates against B. pseudomallei. Additionally, our new E. coli strain SDB1 is more efficient in glycoprotein production, and could have additional applications in the future.
    Frontiers in Microbiology 07/2014; 5(381). DOI:10.3389/fmicb.2014.00381 · 3.99 Impact Factor
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    • "B. pseudomallei is highly refractory to antibiotic treatment [10], suggesting that vaccination might be the most effective way of controlling melioidosis [11]. Significant effort has been directed towards identifying and testing candidate vaccines, but thus far there are no candidates which are nearing licensure (reviewed by [12] [13] [14]). A range of surface polysaccharides have been identified in B. pseudomallei, and lipopolysaccharide (LPS) and capsular polysaccharide have been evaluated as vaccine candidates [15]. "
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    ABSTRACT: Melioidosis is a severe infectious disease caused by Burkholderia pseudomallei. It is refractory to antibiotic treatment and there is currently no licensed vaccine. In this report we detail the construction and protective efficacy of a polysaccharide-protein conjugate composed of B. pseudomallei lipopolysaccharide and the Hc fragment of tetanus toxin. Immunisation of mice with the lipopolysaccharide-conjugate led to significantly reduced bacterial burdens in the spleen 48 hours after challenge and afforded significant protection against a lethal challenge with B. pseudomallei. The conjugate generated significantly higher levels of antigen-specific IgG1 and IgG2a than in lipopolysaccharide-immunised mice. Immunisation with the conjugate also demonstrated a bias towards Th1 type responses, evidenced by high levels of IgG2a. In contrast, immunisation with unconjugated lipopolysaccharide evoked almost no IgG2a demonstrating a bias towards Th2 type responses. This study demonstrates the effectiveness of this approach in the development of an efficacious and protective vaccine against melioidosis.
    Research Journal of Immunology 05/2014; 2014:392170. DOI:10.1155/2014/392170
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    Human Vaccines & Immunotherapeutics 07/2013; 9(9). · 2.37 Impact Factor
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