title: Identification of seroreactive proteins of Leptospira interrogans serovar copenhageni using a high-density protein microarray approach.
abstract: BACKGROUND
  Leptospirosis is a widespread zoonotic disease worldwide. The lack of an adequate laboratory test is a major barrier for diagnosis, especially during the early stages of illness, when antibiotic therapy is most effective. Therefore, there is a critical need for an efficient diagnostic test for this life threatening disease.
  
  
  METHODS
  In order to identify new targets that could be used as diagnostic makers for leptopirosis, we constructed a protein microarray chip comprising 61% of Leptospira interrogans proteome and investigated the IgG response from 274 individuals, including 80 acute-phase, 80 convalescent-phase patients and 114 healthy control subjects from regions with endemic, high endemic, and no endemic transmission of leptospirosis. A nitrocellulose line blot assay was performed to validate the accuracy of the protein microarray results.
  
  
  RESULTS
  We found 16 antigens that can discriminate between acute cases and healthy individuals from a region with high endemic transmission of leptospirosis, and 18 antigens that distinguish convalescent cases. Some of the antigens identified in this study, such as LipL32, the non-identical domains of the Lig proteins, GroEL, and Loa22 are already known to be recognized by sera from human patients, thus serving as proof-of-concept for the serodiagnostic antigen discovery approach. Several novel antigens were identified, including the hypothetical protein LIC10215 which showed good sensitivity and specificity rates for both acute- and convalescent-phase patients.
  
  
  CONCLUSIONS
  Our study is the first large-scale evaluation of immunodominant antigens associated with naturally acquired leptospiral infection, and novel as well as known serodiagnostic leptospiral antigens that are recognized by antibodies in the sera of leptospirosis cases were identified. The novel antigens identified here may have potential use in both the development of new tests and the improvement of currently available assays for diagnosing this neglected tropical disease. Further research is needed to assess the utility of these antigens in more deployable diagnostic platforms.
authors.affiliation: Bio-Manguinhos, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Rio de Janeiro, Brazil ; Department of Medicine, Division of Infectious Disease, University of California Irvine, Irvine, California, United States of America.
authors.forename: Carolina
authors.initials: C
authors.lastname: Lessa-Aquino
authors.forename: Camila
authors.initials: C
authors.lastname: Borges Rodrigues
authors.forename: Jozelyn
authors.initials: J
authors.lastname: Pablo
authors.forename: Rie
authors.initials: R
authors.lastname: Sasaki
authors.forename: Algis
authors.initials: A
authors.lastname: Jasinskas
authors.forename: Li
authors.initials: L
authors.lastname: Liang
authors.forename: Elsio A
authors.initials: EA
authors.lastname: Wunder
authors.forename: Guilherme S
authors.initials: GS
authors.lastname: Ribeiro
authors.forename: Adam
authors.initials: A
authors.lastname: Vigil
authors.forename: Ricardo
authors.initials: R
authors.lastname: Galler
authors.forename: Douglas
authors.initials: D
authors.lastname: Molina
authors.forename: Xiaowu
authors.initials: X
authors.lastname: Liang
authors.forename: Mitermayer G
authors.initials: MG
authors.lastname: Reis
authors.forename: Albert I
authors.initials: AI
authors.lastname: Ko
authors.forename: Marco Alberto
authors.initials: MA
authors.lastname: Medeiros
authors.forename: Philip L
authors.initials: PL
authors.lastname: Felgner
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007921:Leptospira interrogans / Q000276:immunology*; D007922:Leptospirosis / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D046228:Microarray Analysis; D008875:Middle Aged; D040081:Protein Array Analysis; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007074:Immunoglobulin G