Saliva of laboratory-reared Lutzomyia longipalpis exacerbates Leishmania (Leishmania) amazonensis infection more potently than saliva of wild-caught Lutzomyia longipalpis.
In order to compare the saliva effect from wild-caught and lab-reared L. longipalpis on the development of experimental cutaneous leishmaniasis, C57BL/6 mice were inoculated subcutaneously into the hind footpads with promastigotes of L. (L.) amazonensis plus salivary gland lysate from wild-caught (SGL-W) and lab-colonized (SGL-C) vectors. Lesion sizes were significantly larger in the mice infected with both saliva compared to mice infected with parasites alone; moreover, the lesions caused by parasite+SGL-C were significantly larger than the lesions caused by parasite+SGL-W. Histopathological morphometric studies regarding the acute phase of infections showed lower numbers of polymorphonuclear cells, greater numbers of mononuclear cells and parasites in SGL-C infected mice compared to SGL-W infected mice. In the chronic phase of infection, the number of mononuclear cells was lower and the number of parasites was greater in SGL-C infected mice than SGL-W infected mice. In vitro studies showed increased infection index of macrophages infected with parasites plus saliva compared to infection with parasites alone, with no difference between the saliva infection indices. SDS-PAGE gel for SGL-C and SGL-W showed differences in the composition and quantity of protein bands, determined by densitometry. These results call attention to the experimental saliva model, which shows exacerbation of infection caused by sandfly saliva.
Laurenti
Márcia Dalastra
MD
Laboratory of Pathology of Infectious Diseases (LIM-50), Department of Pathology, Medical School, University of São Paulo, Av. Dr. Arnaldo 455, CEP: 01246-903, São Paulo (SP), Brazil. mdlauren@usp.br
Silveira
Veruska Marques dos Santos
VM
Secundino
Nágila Francinete Costa
NF
Corbett
Carlos Eduardo Pereira
CE
Pimenta
Paulo Paulocci Filemon
PP
D000818:Animals; D000830:Animals, Laboratory; D000835:Animals, Wild; D005260:Female; D007303:Insect Vectors / Q000469:parasitology / Q000472:pathogenicity; D007891:Leishmania / Q000145:classification / Q000254:growth & development / Q000472:pathogenicity*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology / Q000469:parasitology / Q000473:pathology*; D008264:Macrophages / Q000276:immunology / Q000469:parasitology; D051379:Mice; D008810:Mice, Inbred C57BL; D011576:Psychodidae / Q000469:parasitology / Q000502:physiology*; D012463:Saliva / Q000276:immunology* / Q000469:parasitology; D012469:Salivary Glands / Q000276:immunology