Objective To investigate whether infection with Toxocara canis in early pregnancy affect humoral immunity of offspring.

Methods Took several groups of three-day pregnant female mice infected with different doses of Toxocara canis eggs (normal saline, 1×10³ eggs, 3×10³ eggs). When the offsprings were 6-week-old, they were divided into six groups, and aggressively infected with Toxocara canis eggs (normal saline, 0.5×10³ eggs). Serum cytokines(IL-2, IL-4, IL-10, IFN-γ)were measured by ELISA.

Results Serum cytokines of offspring were significantly different in each of the groups(P < 0.05). The variations among different serum cytokines appeared various patterns. IL-2 cytokine was produced from Th1 cells, showed an ascending trend at the early period of aggressive infection and attended the peak on four weeks, then descended gradually. IFN-γ also showed the ascending trend at the early period, and attended the peak on two weeks, then descended gradually. IL-4 and IL-10 cytokines were produced from Th-2 cells, which presented a descending trend after an aggressive infection along with significantly descending trend at early period, and then slow down in the later period.

Conclusions The infection with Toxocara canis eggs during pregnancy period may affect offspring's immune regulation. When the offspring were infected once again, they would produce protective immune memory. The acquired immune serum was possibly produced from the dominant position of Th-2 cells on the early period of aggressive infection.