Level of IL-2 and the distribution of muscle larvae in mice infected with different geographical isolates of Trichinella

Objective To investigate the levels of IL-2 and the distribution of muscle larvae in mice infected with Henan,Yunnan,and Heilongjiang isolates of Trichinella.Methods One hundred and twenty Kunming male mice(weight: 18 to 22 g) were grouped randomly into a group infected with a Henan isolate,a group infected with a Yunnan isolate,and a group infected with a Heilongjiang isolate(each were infected with 200 T.spiralis larvae) and a control group,with 30 mice in each group.ELISA was used to measure the level of IL-2 in serum from the first week to the sixth week after the mice were infected with Trichinella.The mice were sacrificed in the sixth week and the distribution of encapsulated muscle larvae was observed in each group.The distribution of muscle larvae at the same site was compared among the groups.Results The levels of IL-2 increased after the mice were infected with the Henan,Yunnan,and Heilongjiang isolates of Trichinella,and then they gradually returned to normal in the fifth week and were lower than normal in the sixth week.Different isolates resulted in an increase in the distribution of muscle larvae,but the number of muscle larvae differed in mice infected with different isolates.The group infected with the Henan isolate had the severest infection among the three groups.Conclusion The levels of IL-2 were the same in the three groups infected with different isolates of Trichinella.During the same time period,the highest levels of IL-2 were found in mice infected with the Henan isolate,the lowest levels of IL-2 were found in mice infected with the Heilongjiang isolate,and medium levels of IL-2 were found in mice infected with the Yunnan isolate.The number of muscle larvae in the same muscle differed in mice infected with different isolates.The group infected with the Henan isolate had a severe infection while the group infected with the Heilongjiang isolate had a mild infection.