The dynamics of trickle infections with Heligmosomoides polygyrus in syngeneic strains of mice

Abstract

Abstraet--Bv.AtL.SVOaO T. J. and BEHNKE J. M. 1992. The dynamics of trickle infections with Heligmosomoides polygyrus in syngeneie strains of mice. hzternational Journal for Parasitology 22: 351-359. NIH, CBA, SWR and C57B1/10 mice w~re repeatedly infected with Heligmosomoidespolygyrus, using doses of 10-50 larvae at frequencies of 2-16 days. NIH and SWR mice regulated the worm burdens at a stable dosedependent level for a period of several weeks, following which expulsion occurred and immunity to subsequent re-infection was established. This regulation did not occur in CBA or C57B1/10 mice, and was inhibited by cortisone treatment. Evidence was found to suggest that regulation is the result of an immune response directed against the late larval stages of the parasite, shortly after their emergence into the lumen of the gut. The frequency of infection was an important factor in determining the course of infection. Frequently infected mice expelled the parasites more rapidly than mice infected with the same total number of larvae in fewer less frequent doses.

Immunity to the model intestinal helminth parasite Heligmosomoides polygyrus

“…Hence, some investigators have developed trickle infection regimes, for example, administering twice weekly low doses of infective larvae. Under these conditions, different mouse strains show a gradation of resistance patterns similar to those seen with single-bolus primary infection, in that NIH and SWR strains resolve infection (showing an initial increase in adult worm burden, a period of stability, and then finally expulsion) while CBA and C57BL/10 mice continue to accumulate increasing adult worm burdens over the course of repeated infections [22]. …”

The hygiene hypothesis and atopy: Bring back the parasites?

“…In a mouse model, frequently infected mice demonstrated greater protective immunity against Heligmosomoides polygyrus than mice infected with the same total number of larvae in fewer doses. 48 In sheep, immunity induced by trickle infection results in significant differences in adult female worm length and egg counts. 49 In a porcine model, strong resistance to reinfection was induced by trickle inoculations with Trichuris suis (250 infective eggs twice weekly for 4 weeks).…”

Chasing the genes that control resistance to gastrointestinal nematodes

“…It is therefore a convenient and relevant model of chronic GI nematode infections, such as those experienced by domestic ruminants grazing on pasture (Behnke, 1987;Behnke et al, 1992;Monroy & Enriquez, 1992). We also chose a trickle infection protocol to mimic the continuous acquisition of larvae that occurs as animals graze on pasture (Brailsford & Behnke, 1992). The selection of mouse strains to be used as founders of the resource population for mapping was also critical.…”