The therapeutic potential of the recombinant antigen from Dirofilaria immitis (rDiAg) for immune-mediated pregnancy loss.

The mammalian fetuses are semi-allograft for mothers. Therefore the failure of immunological tolerance often causes pregnancy loss. Recently, the effects of helminthes therapy for immune mediated diseases have been reported. In the present study we employed the murine model to examine the therapeutic potential of the recombinant antigen from a nematoda parasite, Dirofilaria immitis for immune mediated pregnancy loss. Recombinant D. immitis polyproteins (rDiAg) had been cloned and selected by us for the strongest immuno-regulatory activities in parasite antigens. Female CBA/J mice were injected with sterilized rDiAg or PBS solution using micro-osmotic pumps before mating. Pregnant CBA/J mice were sacrificed on day 13.5 for scoring the number of resorbed and viable fetuses for histological and immunological analysis. The serum cytokine concentrations were measured using suspension array system. The resorption rate of mock-treated mice was 42.9% (resorbed fetus 12/total fetus 28). The resorption rate was decreased to 11.1% (resorbed fetus 3/total fetus 27) with rDiAg treatments. The IL-4, IL-23 and TNF-α concentrations in serum were significantly lower in rDiAg-treated mice than mock-treated mice. The serum IL-17 level was also reduced in rDiAg-treated mice but the difference was not significant. The rDiAg treatment reduced the resorption rates of CBA/J×DBA/2J mouse model, which mimic human pregnancy failures with allo-immune backgrounds. Our observations suggest as the first time of therapeutic potentials of the rDiAg for pregnancy loss.