In vitro interaction profiles and midgut glycoconjugates of Trichophoromyia spp./Leishmania (Viannia) lainsoni.

BACKGROUND

Knowledge of sand fly-Leishmania attachment determinants is pivotal for providing evidence on vector status. Considering the Amazonian transmission context of Trichophoromyia spp.-L. (Viannia) lainsoni, the present study aimed to assess in vitro interactions and detect gut glycoconjugates associated with this vector-parasite association.

METHODS

Field-caught Trichophoromyia brachipyga and Trichophoromyia ubiquitalis were tested. Lutzomyia longipalpis reared in the laboratory was used as a control. The intestines were obtained by dissection, and the species were confirmed by morphology. Interactions for each sand fly-Leishmania association were individually performed via an in vitro incubation system. N-acetyl-D-glucosamine (GlcNAc), galactose-(β 1,3)-GalNAc (Gal/GalNAc), and N-acetyl-D-galactosamine (GalNAc) glycoconjugates of Trichophoromyia spp. were analyzed by Western blotting using corresponding peroxidase-conjugated lectins.

RESULTS

No difference was found between Th. ubiquitalis and Lu. longipalpis attachment with L. (V.) lainsoni, and Lu. longipalpis with Leishmania (Leishmania) infantum (control). However, Th. brachipyga-L. (V.) lainsoni attachment was weaker than that of the control. Trichophoromyia spp. were negative for residues of GlcNAc terminally exposed. Trichophoromyia ubiquitalis was positive for GalNAc and Gal/GalNAc, whereas Th. brachipyga presented only residues of GalNac terminally exposed.

CONCLUSIONS

The present study suggests that Trichophoromyia spp. sand flies, particularly Th. brachipyga, are susceptible to L. (V.) lainsoni, based on the observed vector-parasite attachment profiles and detection of GalNAc in their midguts. This supports early field data suggesting the vector status of these sand fly species.