Immunity to a salivary protein of a sand fly vector protects against the fatal outcome of visceral leishmaniasis in a hamster model

Visceral leishmaniasis (VL) is the most severe clinical form of leishmaniasis, fatal if untreated. Vaccination is the most cost-effective approach to disease control; however, to date, no vaccines against human VL have been made available. This work examines the efficacy of a novel vaccine consisting of the Leishmania membrane protein KMP11, LEISH-F3+ (a recombinant fusion protein, composed of epitopes of the parasite proteins nucleoside hydrolase, sterol-24-c-methyltransferase, and cysteine protease B), and the sand fly salivary protein LJL143, in two dose ratios. The inclusion of the TLR4 agonist GLA-SE as an adjuvant, and the use of virosomes (VS) as a delivery system, are also examined. In a hamster model of VL, the vaccine elicited antigen-specific immune responses prior to infection with Leishmania infantum. Of note, the responses were greater when higher doses of KMP11 and LEISH-F3+ proteins were administered along with the GLA-SE adjuvant and/or when delivered within VS. Remarkably, hamsters immunized with the complete combination (i.e., all antigens in VS + GLA-SE) showed significantly lower parasite burdens in the spleen compared to those in control animals. This protection was underpinned by a more intense, specific humoral response against the KMP11, LEISH-F3+, and LJL143 antigens in vaccinated animals, but a significantly less intense antibody response to the pool of soluble Leishmania antigens (SLA). Overall, these results indicate that this innovative vaccine formulation confers protection against L. infantum infection, supporting the advancement of the vaccine formulation into process development and manufacturing and the conduction of toxicity studies towards future phase I human clinical trials.

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ANTIGENIC DIVERSITY IN MAXADILAN, A SALIVARY PROTEIN FROM THE SAND FLY VECTOR OF AMERICAN VISCERAL LEISHMANIASIS

American Journal of Tropical Medicine and Hygiene ◽

10.4269/ajtmh.2004.70.286 ◽

2004 ◽

Vol 70 (3) ◽

pp. 286-293 ◽

Cited By ~ 28

Author(s):

RANIA S. MILLERON ◽

HUAIZHI YIN ◽

ALBERTO MONTOYA ◽

LYNN SOONG ◽

GREGORY C. LANZARO ◽

...

Keyword(s):

Visceral Leishmaniasis ◽

Salivary Protein ◽

Sand Fly ◽

Antigenic Diversity

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DETECTION OF LEISHMANIA INFECTION IN STRAY DOGS IN HUMAN LEISHMANIASIS ENDEMIC AREA IN MYMENSINGH DISTRICT WITH ITS POSSIBLE PUBLIC HEALTH SIGNIFICANCE IN BANGLADESH

Journal of Veterinary Medical and One Health Research ◽

10.36111/jvmohr.2019.1(1).0009 ◽

2019 ◽

Vol 1 (1) ◽

Author(s):

M. A. Hossen

Keyword(s):

Visceral Leishmaniasis ◽

Asymptomatic Carrier ◽

Asymptomatic Infection ◽

Reservoir Host ◽

Sand Fly ◽

Leishmania Infection ◽

Endemic Region ◽

Stray Dogs ◽

Human Leishmaniasis ◽

Strip Test

Background: Leishmaniasis is primarily caused by two species of Leishmania (L. donovani and L. infantum) of which clinical infection with L. infantum has been recognized in both humans and dogs as zoonotic disease with dogs as the main reservoir hosts in the Mediterranean, the Middle East, Asia and South America. Although L. donovani has been associated with both clinical and asymptomatic infection in humans but it is still associated with asymptomatic infection in dogs in Indian sub-continent without any evidence of zoonotic infection. Objectives: The objective of this research was to investigate the potentiality of dog as reservoir host for visceral leishmaniasis in the human leishmaniasis endemic regions in Bangladesh. Materials and Methods: A total of 20 stray dogs in the human VL endemic areas of Mymensingh district were captured for the detection VL during the period of November 2010 to May 2011. The dipstick test rK39 (Bios International; n = 20), Giemsa’s stained impression smears of liver and spleen (n = 6) and PCR with the tissue of liver and spleen (n = 6) were tested as per manufacturer instructions and conventional standard methods. Results: Out of 20 stray dogs examined, 4 (20.0%) were positive for L. donovani infection with rK39 strip test. Of the six randomly selected dogs tested with Modified Giemsa’s stained of impression smears of spleen and liver showed 2 (33.33%) positive whereas PCR technique detected 5 (83.33%) positive for L. donovani. Results of PCR showed 145bp amplicon, specific for L. donovani infection in 83.33% stray dogs. Conclusions: This study reveals that a high percentage of L. donovani asymptomatic carrier infections occur in dogs and evidence indicates that dogs and humans may potentially serve as a source of infection to sand fly vectors and accordingly dogs can be recognized as a probable animal reservoir for the Leishmania infection in the endemic region in Bangladesh. However, further studies are required to determine the ability of dogs to transmit the L. donovani to the vector sand fly in nature and its evidence on ‘One Health’ perspectives. Keywords: Visceral leishmaniasis, Endemic region, Stray dogs, rK39 strip test, Giemsa’s stained liver and spleen impression smears, PCR, Reservoir host, Mymensingh

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Exploring sand fly salivary proteins to design multiepitope subunit vaccine to fight against visceral leishmaniasis

International Journal of Infectious Diseases ◽

10.1016/j.ijid.2020.09.1248 ◽

2020 ◽

Vol 101 ◽

pp. 477

Author(s):

R. Pandey ◽

V.K. Prajapati

Keyword(s):

Visceral Leishmaniasis ◽

Subunit Vaccine ◽

Sand Fly ◽

Salivary Proteins

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A sand fly salivary protein acts as a neutrophil chemoattractant

Nature Communications ◽

10.1038/s41467-021-23002-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Anderson B. Guimaraes-Costa ◽

John P. Shannon ◽

Ingrid Waclawiak ◽

Jullyanna Oliveira ◽

Claudio Meneses ◽

...

Keyword(s):

Inflammatory Responses ◽

Calcium Influx ◽

Parasite Burden ◽

Salivary Protein ◽

Sand Fly ◽

Human Neutrophils ◽

Chemotactic Protein ◽

The Impact

AbstractApart from bacterial formyl peptides or viral chemokine mimicry, a non-vertebrate or insect protein that directly attracts mammalian innate cells such as neutrophils has not been molecularly characterized. Here, we show that members of sand fly yellow salivary proteins induce in vitro chemotaxis of mouse, canine and human neutrophils in transwell migration or EZ-TAXIScan assays. We demonstrate murine neutrophil recruitment in vivo using flow cytometry and two-photon intravital microscopy in Lysozyme-M-eGFP transgenic mice. We establish that the structure of this ~ 45 kDa neutrophil chemotactic protein does not resemble that of known chemokines. This chemoattractant acts through a G-protein-coupled receptor and is dependent on calcium influx. Of significance, this chemoattractant protein enhances lesion pathology (P < 0.0001) and increases parasite burden (P < 0.001) in mice upon co-injection with Leishmania parasites, underlining the impact of the sand fly salivary yellow proteins on disease outcome. These findings show that some arthropod vector-derived factors, such as this chemotactic salivary protein, activate rather than inhibit the host innate immune response, and that pathogens take advantage of these inflammatory responses to establish in the host.

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Clinical and laboratory profiles of visceral leishmaniasis among adult patients admitted to Felege Hiwot Hospital, Bahir Dar, Ethiopia

SAGE Open Medicine ◽

10.1177/20503121211036787 ◽

2021 ◽

Vol 9 ◽

pp. 205031212110367

Author(s):

Berhanu Tarekegn ◽

Ayanaw Tamene

Keyword(s):

Visceral Leishmaniasis ◽

Leishmania Donovani ◽

Clinical Presentation ◽

Winter Season ◽

Adult Patients ◽

Sand Fly ◽

Timely Initiation ◽

Vector Borne Disease ◽

Vector Borne ◽

Endemic Areas

Background: Visceral leishmaniasis is a vector-borne disease caused by Leishmania donovani transmitted by sand fly species. It is the third most common vector-borne disease globally. Visceral leishmaniasis is endemic in Ethiopia with an estimated annual incidence ranging from 3700 to 7400 cases. This research aimed to assess the clinical presentations and laboratory profiles of visceral leishmaniasis for early diagnosis and timely initiation of management. Objective: To describe the clinical and laboratory manifestation and diagnostic modalities of visceral leishmaniasis among adult patients admitted to Felege Hiwot Hospital, from 1 September 2016 to 30 August 2019. Method: Institution-based retrospective cross-sectional study was conducted among 141 patients admitted to Felege Hiwot Hospital from 1 September 2016 to 30 August 2019. Descriptive statistics were used to describe the clinical presentation and laboratory profiles of patients with visceral leishmaniasis. Results: Among a total of 141 enrolled patients in the study, males were affected 13-fold. Most of them were travelers to endemic areas during the winter season for labor work. The mean duration of illness was 48 days. Common symptoms were fever (96.5%), weightless (82.5%), jaundice (18.4%), vomiting/diarrhea (13.5%), and bleeding episodes (11.3%). Splenomegaly was seen in 98.6%, ascites in 35.5%, and lymphadenopathy in 9.9%. Lymphadenopathy was seen significantly in HIV patients (40%). Anemia was seen in 95%, thrombocytopenia in 90.2%, leukopenia in 86.4%, and pancytopenia in 79.4%. Half of the patients had coinfection. Neutropenic sepsis was seen in 21.3%. The diagnosis was made by tissue aspiration in 65% of patients. Conclusion: The majority of patients who were diagnosed to have visceral leishmaniasis were young male adults who traveled to the endemic areas seasonally. Fever and splenomegaly were seen as the commonest clinical presentation. Lymphadenopathy occurred in high frequency among HIV co-infected patients. Anemia was the commonest hematologic finding.

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LJM19, a salivary protein from the sand fly vector that transmits leishmaniasis, is a novel inhibitor of the classical pathway of complement

Immunobiology ◽

10.1016/j.imbio.2012.08.153 ◽

2012 ◽

Vol 217 (11) ◽

pp. 1182

Author(s):

Viviana P. Ferreira ◽

Gurpanna Saggu ◽

Marcos H. Pereira ◽

Ricardo N. Araújo ◽

Vladimir F. Vale ◽

...

Keyword(s):

Salivary Protein ◽

Sand Fly ◽

Classical Pathway

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A sand fly salivary protein vaccine shows efficacy against vector-transmitted cutaneous leishmaniasis in nonhuman primates

Science Translational Medicine ◽

10.1126/scitranslmed.aaa3043 ◽

2015 ◽

Vol 7 (290) ◽

pp. 290ra90-290ra90 ◽

Cited By ~ 66

Author(s):

Fabiano Oliveira ◽

Edgar Rowton ◽

Hamide Aslan ◽

Regis Gomes ◽

Philip A. Castrovinci ◽

...

Keyword(s):

Cutaneous Leishmaniasis ◽

Nonhuman Primates ◽

Mononuclear Cells ◽

Rhesus Macaques ◽

Parasite Burden ◽

Salivary Protein ◽

Sand Fly ◽

Protein Vaccine ◽

Peripheral Blood Mononuclear ◽

Phlebotomus Duboscqi

Currently, there are no commercially available human vaccines against leishmaniasis. In rodents, cellular immunity to salivary proteins of sand fly vectors is associated to protection against leishmaniasis, making them worthy targets for further exploration as vaccines. We demonstrate that nonhuman primates (NHP) exposed to Phlebotomus duboscqi uninfected sand fly bites or immunized with salivary protein PdSP15 are protected against cutaneous leishmaniasis initiated by infected bites. Uninfected sand fly–exposed and 7 of 10 PdSP15-immunized rhesus macaques displayed a significant reduction in disease and parasite burden compared to controls. Protection correlated to the early appearance of Leishmania-specific CD4+IFN-γ+ lymphocytes, suggesting that immunity to saliva or PdSP15 augments the host immune response to the parasites while maintaining minimal pathology. Notably, the 30% unprotected PdSP15-immunized NHP developed neither immunity to PdSP15 nor an accelerated Leishmania-specific immunity. Sera and peripheral blood mononuclear cells from individuals naturally exposed to P. duboscqi bites recognized PdSP15, demonstrating its immunogenicity in humans. PdSP15 sequence and structure show no homology to mammalian proteins, further demonstrating its potential as a component of a vaccine for human leishmaniasis.

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Visceral leishmaniasis (Kala-azar) in Qom Province, Iran: Report of two cases

F1000Research ◽

10.12688/f1000research.15805.1 ◽

2018 ◽

Vol 7 ◽

pp. 1371

Author(s):

Leyli Zanjirani Farahani ◽

Abedin Saghafipour ◽

Mehdi Mohebali ◽

Behnaz Akhoundi ◽

Hedayatollah Raufi

Keyword(s):

Visceral Leishmaniasis ◽

Rural Areas ◽

Control Strategies ◽

Sand Fly ◽

Recurrent Fever ◽

Kala Azar ◽

Periodic Monitoring ◽

History Of ◽

The Common

Visceral leishmaniasis (VL) is a fatal parasitic zoonotic worldwide disease, which transmits to humans by the infected Phlebotomine sand fly bite. The common form of VL in Iran is the Mediterranean type with the causative agent of Leishmania infantum, whose main reservoirs are stray and domesticated dogs. The disease has several endemic foci in Iran, mostly seen among children under the age of 10, living in rural areas and nomadic tribes. The first cases of Kala-Azar in Qom province, central Iran, were reported in the year 2001, from the villages of Ghahan district. After conducting VL control strategies in the area, no new cases of the disease had been reported until recently. The cases described here are two 2-year-old girls, living in the urban parts of Qom province, one of whom did not have a history of traveling to known endemic areas of the disease. The patients were admitted to hospital in 2016-2017, complaining from recurrent fever with unrecognized reason, associated with decreased appetite and weight loss. Disease follow-up demonstrated anemia and splenomegaly, which led to diagnosis of VL, and both patients are now fully recovered. VL was presumed to be controlled in Qom province but the present cases indicate that possible VL existence remains in the region. Therefore, urgent studies and periodic monitoring are needed to identify potential reservoirs of VL in the area.

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