Glycoengineering a bioconjugate vaccine against Klebsiella pneumoniae

PROJECT SUMMARY Klebsiella pneumoniae is an increasingly prevalent drug resistant nosocomial pathogenCommonlyKpneumoniae isolates are carbapenem resistantwhich are referred to as carbapenem resistant EnterobacteriaceaeCREand present significantly less therapeutic intervention optionsFurthermorecommunity acquired infections associated with hypervirulent isolates of Kpneumoniae have emerged that are capable of causing a disseminated disease in healthy individualsMolecular studies indicate that the main virulence factor of Kpneumoniae is a thick capsular polysaccharide that facilitates immune evasionAlthoughKlebsiella capsular polysaccharides have been identifiedstudies indicate that two serotypesthe Kand Kserotypesaccount for two thirds of all community acquired infectionsand also cause a significant portion of hospital acquired infectionsWe are running out of antibiotics to treat drug resistant Kpneumoniaeand thereforea prophylactic vaccine would be an alternative method to drastically reduce the burden of Kpneumonia infections globallyCurrently there is no licensed vaccine available for individuals at risk of Kpneumoniae infectionindeedKlebsiella vaccines are not even undergoing clinical trialsConjugate vaccinescomposed of polysaccharides linked to proteinsare ideal vaccines for Kpneumoniae as conjugate vaccines are highly protective and generate immunological memory in all age groupsHowevertheir synthesis is complexcostlyand not conducive for all polysaccharidesTo fill this voidVaxNewMo will generate the first conjugate vaccine against two of the most frequently encountered Kpneumoniae serotypesKand Kusing our propriety conjugating enzyme technologyWith our platformwe utilize a glycoengineering approach to generate conjugate vaccines in vivo using the lab safe Ecoli through a process termed bioconjugationThis glycoengineering strategy eliminates the need for harsh chemicals to covalently link a polysaccharide to a proteinFurthermoreour conjugating enzyme is the first and only enzyme able to transfer Kpneumoniae capsular polysaccharides to an acceptor proteina feat other conjugating enzymes are unable to performThe proposed research in this phase I application will focus onAimglycoengineering two strains of Ecoli for the heterologous expression of the Kpneumoniae Kand Kcapsular polysaccharidesWe will then pair these KKpolysaccharide producing Ecoli strains with our proprietary conjugating enzyme technology to develop the first bivalent bioconjugate vaccine against Kand Kserotypes of KpneumoniaeSubsequentlyAimwe will demonstrate the immunogenicity and efficacy of our bivalent Kpneumoniae KKspecific bioconjugate vaccine compared to polysaccharide alone as there currently is no vaccine to compare non inferiority againstOur next step for phase II funding will be to expand the serotype coverage in our bioconjugate vaccine to include the remaining six hypervirulent serotypes as well as demonstrate the safetyimmunogenicityand efficacy of the first bioconjugate vaccine against Kpneumoniae to streamline FDA regulatory approval PROJECT NARRATIVE Conjugate vaccineshighly effective prophylactics used to prevent certain bacterial infectionsare composed of a bacterial polysaccharide covalently attached to a protein carrierCurrentlythere is no vaccine against Klebsiella pneumoniaean important multidrug resistant pathogen capable of causing community acquired infectionsThis proposal focus onfor the first timegenerating a novel conjugate vaccine against two of the most common Kpneumoniae isolates using a glycoengineering approach in the lab safe bacterium Escherichia coli