title: Intradermal Immunization of Leishmania donovani Centrin Knock-Out Parasites in Combination with Salivary Protein LJM19 from Sand Fly Vector Induces a Durable Protective Immune Response in Hamsters.
abstract: BACKGROUND
  Visceral leishmaniasis (VL) is a neglected tropical disease and is fatal if untreated. There is no vaccine available against leishmaniasis. The majority of patients with cutaneous leishmaniasis (CL) or VL develop a long-term protective immunity after cure from infection, which indicates that development of an effective vaccine against leishmaniasis is possible. Such protection may also be achieved by immunization with live attenuated parasites that do not cause disease. We have previously reported a protective response in mice, hamsters and dogs with Leishmania donovani centrin gene knock-out parasites (LdCen-/-), a live attenuated parasite with a cell division specific centrin1 gene deletion. In this study we have explored the effects of salivary protein LJM19 as an adjuvant and intradermal (ID) route of immunization on the efficacy of LdCen-/- parasites as a vaccine against virulent L. donovani.
  
  
  RESULTS
  To explore the potential of a combination of LdCen-/- parasites and salivary protein LJM19 as vaccine antigens, LdCen-/- ID immunization followed by ID challenge with virulent L. donovani were performed in hamsters in a 9-month follow up study. We determined parasite burden (serial dilution), antibody production (ELISA) and cytokine expression (qPCR) in these animals. Compared to controls, animals immunized with LdCen-/- + LJM19 induced a strong antibody response, a reduction in spleen and liver parasite burden and a higher expression of pro-inflammatory cytokines after immunization and one month post-challenge. Additionally, a low parasite load in lymph nodes, spleen and liver, and a non-inflamed spleen was observed in immunized animals 9 months after the challenge infection.
  
  
  CONCLUSIONS
  Our results demonstrate that an ID vaccination using LdCen-/-parasites in combination with sand fly salivary protein LJM19 has the capability to confer long lasting protection against visceral leishmaniasis that is comparable to intravenous or intracardial immunization.
authors.affiliation: Laboratory of Emerging Pathogens, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America.|Laboratório de Imunologia Celular e Molecular, Centro de Pesquisas René Rachou-Fiocruz Minas, Belo Horizonte, Minas Gerais, Brasil.
authors.forename: Jacqueline Araújo
authors.initials: JA
authors.lastname: Fiuza
authors.affiliation: Laboratory of Emerging Pathogens, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America.
authors.forename: Ranadhir
authors.initials: R
authors.lastname: Dey
authors.affiliation: Laboratory of Emerging Pathogens, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America.
authors.forename: Dwann
authors.initials: D
authors.lastname: Davenport
authors.affiliation: Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: Maha
authors.initials: M
authors.lastname: Abdeladhim
authors.affiliation: Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: Claudio
authors.initials: C
authors.lastname: Meneses
authors.affiliation: Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: Fabiano
authors.initials: F
authors.lastname: Oliveira
authors.affiliation: Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: Shaden
authors.initials: S
authors.lastname: Kamhawi
authors.affiliation: Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America.
authors.forename: Jesus G
authors.initials: JG
authors.lastname: Valenzuela
authors.affiliation: Laboratory of Emerging Pathogens, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America.
authors.forename: Sreenivas
authors.initials: S
authors.lastname: Gannavaram
authors.affiliation: Laboratory of Emerging Pathogens, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America.
authors.forename: Hira L
authors.initials: HL
authors.lastname: Nakhasi
mesh_terms: D000818:Animals; D006224:Cricetinae; D017353:Gene Deletion; D007271:Injections, Intradermal; D007893:Leishmania donovani / Q000235:genetics* / Q000276:immunology; D007898:Leishmaniasis, Visceral / Q000517:prevention & control*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D016052:Protozoan Vaccines / Q000276:immunology*; D011576:Psychodidae / Q000378:metabolism*; D012471:Salivary Proteins and Peptides / Q000276:immunology*
chemical_list: D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D012471:Salivary Proteins and Peptides