[leish-l] Promising molecules in sand flies saliva

[Nelder de Figueiredo Gontijo]

         The studies concerning to the imune modulation caused by sand fly 
saliva would be very fruitful. The following abstract refers to our work 
presented recently in the ISOPS IV (Salvador - BA - Brazil). It is 
noteworthy that other haematophagous insects such as Triatomine bugs 
presented the same kind of activity.

Inhibitory activity against the complement system in the Lutzomyia 
longipalpis and Lutzomyia migonei saliva.
Cavalcante, RR;  Pereira, MH  and   Gontijo, NF.
Departamento de Parasitologia, ICB, Universidade Federal de Minas Gerais, 
Belo Horizonte , MG, Cx. Postal 486, CEP 31 210 901, 
Brazil.   nelder at icb.ufmg.br

The objective of this study was to investigate the  inhibition of the 
complement system by saliva of two phlebotomine species, Lutzomyia 
longipalpis and Lutzomyia migonei. The inhibition of the classical pathway 
was measured using sensitised sheep erytrocytes and the alternative pathway 
using non sensitised rabbit erytrocytes in an haemolytic assay. Saliva from 
Lutzomyia longipalpis was capable to inhibit both the classical and the 
alternative pathways, while that from Lutzomyia migonei acted only on the 
classical pathway. The activity of Lutzomyia longipalpis saliva against the 
classical pathway was partially characterised. The inhibitor is a protein 
of M.W. 10  30 KDa which is very resistant to denaturation by heat. The 
physiological role of the inhibitory protein is probably to protect the 
insect gut against lysis by the complement system. The anti-complement 
activity would be very effective in protecting Leishmania promastigotes 
just after their introduction into the skin of a vertebrate host via the 
bite of a sandfly. Use of the inhibitor molecule is thus a promising 
component of a vaccine to target salivary immunomodulators.
FAPEMIG and CNPq