OmpL1 DNA vaccine cross-protects against heterologous Leptospira spp. challenge.
Available leptospirosis vaccines made up of inactivated bacteria or their membrane components elicit immunity which is serovar specific and unsatisfactory immunological memory. A vaccine that protects across Leptospira serogroups/serovars, i.e. broad spectrum, and induces long-lasting memory is needed for both human and veterinary uses. In this study, a plasmid DNA vaccine was constructed from cloning gene encoding a transmembrane porin protein, OmpL1, of pathogenic Leptospira interrogans, serogroup Icterohaemorrhagiae, serovar Copenhageni into a mammalian expression vector pcDNA3.1(+). The protective efficacy of the ompL1-pcDNA3.1(+) plasmid DNA vaccine was studied by immunizing hamsters intramuscularly with three doses of the vaccine (100 microg per dose) at two week intervals. The empty pcDNA3.1(+) and PBS were used as mock as negative vaccine controls, respectively. All animals were challenged with the heterologous Leptospira interrogans, serogroup Pomona, serovar Pomona (10 LD50), at one week after the last vaccine booster. The ompL1-pcDNA3.1(+) plasmid DNA vaccine rescued some vaccinated animals from the lethal challenge and delayed death time, reduced morbidity, e.g. fever, and/or the numbers of Leptospira in the tissues of the vaccinated animals. While the results are encouraging, further studies are needed to optimize the immunization schedule, vaccine dosage and formulation in order to maximize the efficacy of the vaccine.
Maneewatch
Santi
S
Graduate Program of Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University Rangsit Center, Pathum-thani 12121, Thailand.
Tapchaisri
Pramuan
P
Sakolvaree
Yuwaporn
Y
Klaysing
Buppa
B
Tongtawe
Pongsri
P
Chaisri
Urai
U
Songserm
Thaweesak
T
Wongratanacheewin
Surasakdi
S
Srimanote
Potjanee
P
Chongsa-nguanz
Manas
M
Chaicumpa
Wanpen
W
D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D019556:COS Cells; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003429:Cross Reactions; D005260:Female; D041383:Leptospira interrogans serovar icterohaemorrhagiae / Q000145:classification / Q000276:immunology*; D007922:Leptospirosis / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D008647:Mesocricetus; D010957:Plasmids; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*
D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D019444:Vaccines, DNA; C081904:ompL1 protein, Leptospira