Discovery of markers of exposure specific to bites of Lutzomyia longipalpis, the vector of Leishmania infantum chagasi in Latin America.
BACKGROUND
Sand flies deliver Leishmania parasites to a host alongside salivary molecules that affect infection outcomes. Though some proteins are immunogenic and have potential as markers of vector exposure, their identity and vector specificity remain elusive.


RESULTS
We screened human, dog, and fox sera from endemic areas of visceral leishmaniasis to identify potential markers of specific exposure to saliva of Lutzomyia longipalpis. Human and dog sera were further tested against additional sand fly species. Recombinant proteins of nine transcripts encoding secreted salivary molecules of Lu. longipalpis were produced, purified, and tested for antigenicity and specificity. Use of recombinant proteins corresponding to immunogenic molecules in Lu. longipalpis saliva identified LJM17 and LJM11 as potential markers of exposure. LJM17 was recognized by human, dog, and fox sera; LJM11 by humans and dogs. Notably, LJM17 and LJM11 were specifically recognized by humans exposed to Lu. longipalpis but not by individuals exposed to Lu. intermedia.


CONCLUSIONS
Salivary recombinant proteins are of value as markers of vector exposure. In humans, LJM17 and LJM11 emerged as potential markers of specific exposure to Lu. longipalpis, the vector of Leishmania infantum chagasi in Latin America. In dogs, LJM17, LJM11, LJL13, LJL23, and LJL143 emerged as potential markers of sand fly exposure. Testing these recombinant proteins in large scale studies will validate their usefulness as specific markers of Lu. longipalpis exposure in humans and of sand fly exposure in dogs.
Teixeira
Clarissa
C
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.
Gomes
Regis
R
Collin
Nicolas
N
Reynoso
David
D
Jochim
Ryan
R
Oliveira
Fabiano
F
Seitz
Amy
A
Elnaiem
Dia-Eldin
DE
Caldas
Arlene
A
de Souza
Ana Paula
AP
Brodskyn
Cláudia I
CI
de Oliveira
Camila Indiani
CI
Mendonca
Ivete
I
Costa
Carlos H N
CH
Volf
Petr
P
Barral
Aldina
A
Kamhawi
Shaden
S
Valenzuela
Jesus G
JG
D000818:Animals; D000906:Antibodies / Q000097:blood; D004199:Disease Vectors; D004285:Dogs; D005589:Foxes; D006801:Humans; D007299:Insect Bites and Stings / Q000276:immunology*; D019476:Insect Proteins / Q000235:genetics / Q000276:immunology*; D007843:Latin America; D011576:Psychodidae / Q000276:immunology*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D012463:Saliva / Q000276:immunology*; D012680:Sensitivity and Specificity
D000906:Antibodies; D019476:Insect Proteins; D011994:Recombinant Proteins