Kinetics of specific IgG in sera of mice infected experimentally with plerocercoid of Spirometra mansoni.

To observe the changes of serum IgG levels in mice experimentally infected with plerocercoid of Spirometra mansoni,40 male mice were randomly divided into 5 groups(8 mice per group) and each mouse inⅠtoⅤgroups was orally infected with 1,2,4,6 or 8 plerocercoids respectively after blood collection.Blood was collected weekly for 18 weeks post-infection(wpi) and the anti-plerocercoid antibodies IgG in serum were assayed by ELISA using excretory-secretory(ES) antigens of Spirometra mansoni plerocercoid.The serum antibodies positive rate of mice infected with 2 plerocercoids was 87.5%(7/8)at 2 wpi and increased to 100%(8/8) at 3 wpi.However,in other four groups of mice infected with 1,4,6 and 8 plerocercoids,the antibody positive rate was 100%(8/8) at 2 wpi.The serum anti-plerocercoid antibody levels in the 5 groups of infected mice increased rapidly at 2 to 4 wpi,and reached the peak during 5 to 7 wpi.Thereafter,the antibody level in the 5 groups decreased slightly,but the antibody positive rate was still 100% and lasted to 18 wpi as the experiment was finished.The difference of serum antibody levels during 1 to 18 wpi in the 5 groups was statistically significant(F=245.296,P0.05),and the serum antibody levels elevated along with the increase of infection dose.Results showed that serum anti-plerocercoid antibodies in mice infected with different doses of plerocercoid could be detected at 2 wpi,and ES antigens ELISA of Spirometra mansoni plerocercoid could be applied in the diagnosis of early sparganosis and light infection.