Subunit Recombinant Vaccine against Leptospirosis: Evaluation of the Immunogenic Potential of Lipoproteins
Leptospirosis is a global concern for human and veterinary health. It is a zoonosis caused by bacteria belonging to the Leptospira genus, prevalent worldwide. The development of a potent and effective vaccine against leptospirosis is justified, once conventional induce only short lived and serovar-specific immunity. The search for multivalent vaccine, through the identification of conserved, antigenic and cross-protective proteins, is the focus in leptospirosis research and, for this reason, lipoproteins of Leptospira are potential candidates. In the present study, in silico analysis was used as a strategy for identification of potentially protective lipoproteins of L. interrogans serovar Copenhageni, aiming at developing recombinant vaccines. Eight genes were selected (LIC11058, LIC10054, LIC20172, LIC13059, LIC11567, LIC10091, LIC10009 and LIC13305), which code for lipoproteins associated to the membrane of L. interrogans. These genes were cloned in expression vector in E. coli, pQE30, that allows the fusion of the recombinant proteins to a histidine tag. The proteins were purified for affinity cromathography, inoculated in mice and the humoral immune response evaluated by ELISA. Seven of lipoproteins evaluated were able to induce humoral immune response in mice, however, the levels of immune response varied among them. The purified proteins were also evaluated regarding their reactivity against human sera, positive for leptospirosis. Six of the proteins were recognized by human sera, confirming the presence of antibodies against these proteins. The lipoproteins LIC11058, LIC13059, LIC11567 and LIC10091 were highly immunogenic for mice and antigenic when reacted against human sera. These proteins are potential vaccine antigen candidates and they will be selected for immunoprotection studies.
Advisor:Odir Antônio Dellagostin; José Antonio Guimarães Aleixo
School:Universidade Federal de Pelotas
Source Type:Master's Thesis
Date of Publication:03/17/2006