Evolutionary Implication of Outer Genes ompL1, lipL32 and lipL41 Membrane Lipoprotein-Encoding of Pathogenic Leptospira Species

Leptospirosisisrecognizedasthemostwidespreadzoonosiswithaglobaldistribution.Inthisstudy,theantigenicvariationinLeptospirainterrogansandLeptospiraborgpeterseniiisolatedfromhumanurineandfieldratkidneywaspreliminarilyconfirmedbymicroscopicagglutinationtestusingmonoclonalantibodies,andwasfurthersubjectedtoamplificationandidentificationofoutermembranelipoproteinswithstructuralgenevariation.Sequencesimilarityanalysisrevealedthattheseproteinsequences,namelyOmpL1,LipL32andLipL41,showednomorehomologiestooutermembranelipoproteinsofnon-pathogenicLeptospiraandothercloselyrelatedSpirochetes,butshowedastrongidentitywithinL.interrogans,suggestingintra-specificphylogeneticlineagesthatmightbeoriginatedfromacommonpathogenicleptospiralorigin.Moreover,theompL1geneshowedmoreantigenicvariationthanlipL32andlipL41duetolessconservationinsecondarystructuralevolutionwithincloselyrelatedspecies.Phylogenetically,ompL1andlipL41ofthesestrainsgaveaconsiderableproximitytoL.weiliiandL.santarosai.TheompL1geneofL.interrogansclustereddistinctlyfromotherpathogenicandnon-pathogenicleptospiralspecies.ThediversityofompLgeneshasbeenanalyzedanditenvisagedthatsequence-specificvariationsatantigenicdeterminantsiteswouldresultinslowevolutionarychangesalongwithnewserovaroriginationwithincloselyrelatedspecies.Thus,acrucialworkoneffectiverecombinantvaccinedevelopmentandengineeredantibodieswillhopefullymeettosolvethetherapeuticchallenges.