Imaging of Toxocara canis larvae labelled by CFSE in BALB/c mice

Abstract

Mice are used most often as a model for human toxocariasis caused by Toxocara canis larvae. Variety of symptoms developing during the infection reflects behaviour of the larvae, which are able to escape from the intestine and further invade and damage various host organs. In order to find an approach enabling observation on parasite behaviour in mouse in vivo, we used an epifluorescence method and a small animal imaging system (SAIS). Larvae of T. canis were labelled by carboxyfluorescein succinimidyl ester (CFSE) which incorporated on the parasite gastrointestinal tract. Following infection of BALB/c mice by CFSE-labelled larvae it has been observed that staining had no influence on viability and further migratory activity of the parasites through the host organs (the intestine, liver, lungs and brain) where they were detected by SAIS until day 17 p.i. In addition, the dye did not affect larval antigenic activity as well as the development of related immune response. Imaging of parasites labelled by CFSE, therefore, may represent a promising way to study behaviour of T. canis larvae in a paratenic host.

Toxocara canis larvae reinfecting BALB/c mice exhibit accelerated speed of migration to the host CNS

“…However, SAIS also revealed that CFSE is not optimal for labeling of each worm species. Whereas T. canis was relatively resistant to each concentration of CFSE (Kolbeková et al 2011), T. cati larvae were more sensitive and most of them did not survive short-term stying within 1 h even when lower concentrations of the vital dye than recommended by a manufacturer protocol were used. In addition, staining of the larval intestine (Kolbeková et al 2011) never reached the level observed in T. canis.…”

“…The cerebellum was separated from the rest of the brain and hemispheres separated into left and right parts. The intact cerebellum and the hemispheres were examined by SAIS according to Kolbeková et al (2011). Immediately after the examination the tissues were taken away from slides by washing with 1% pepsin and further observation was performed by DT.…”

“…The isolation, cultivation, and subsequent staining with CFSE of T. cati larvae were performed according to Kolbeková et al (2011). In order to reach optimal degree of staining, several concentrations (1, 5, 10, and 40 μM) of CFSE in PBS were evaluated at various time intervals-15, 30, and 60 min, 1, 2, and 3 days.…”

“…The isolation and subsequent staining of T. canis larvae with CFSE (Invitrogen) was performed according methods described in our previous work (Kolbeková et al 2011).…”

“…In our previous work (Kolbeková et al 2011), we demonstrated a method of imaging viable T. canis larvae in mouse organs. Our data obtained from mice with a primary infection showed that staining of larvae by carboxyfluorescein succinimidyl ester (CFSE), followed by an epifluorescence detection method in a small animal imaging system (SAIS), allowed observation of the parasites in the organs of BALB/c mice till day 17 p.i.…”