The study on polarization of Th1 and Th2 immune responses in BALB/c mice infected with toxoplasma gondii / 中国免疫学杂志

ABSTRACT

Objective:To explore the polarization of Th1 and Th2 immune response and the changes of transcription factor(T-bet and GATA-3) in BALB/c mice infected with toxoplasma gondii.Methods:Sixty BALB/c mice were infected with toxoplasma tachyzoite(1?104/m,0.5 ml) by intraperitoneal injection and thirty BALB/c mice only received an injection of same amount of normal saline as control.After injection,two mice of infection group and one mouse of control group were killed in odd number days.Then,the serum IFN-? and IL-4 were measured by ELISA,and the mRNA expression of T-bet and GATA-3 in mice spleens were detected by Real-Time RT-PCR.Results:In the infection group of mice,the IFN-? was remarkable increased at the fourth day and kept the peak from the 5th day to 7th day.Then,it decreased to normal level at 9th day postinjection;but IL-4 was remarkable increased at the 8th day and reached to the peak at 9th day.Then it decreased to normal level at 15th day postinjection.The mRNA of T-bet expression was increased at the third day and kept the peak from the 5th day to 7th day.Then,it decreased to normal level at 9th day postinjection.The mRNA of GATA-3 expression was increased at the 7th day and rised to the peak at 11th day.Then,it decreased to normal level at 13th day postinjection.There were not obvious changes of IFN-? and IL-4 or T-bet and GATA-3 in normal mice.Conclusion:The Th1 immune response is dominant in acute infection when mice are infected by toxoplasma.Then it biases toward Th2 response at 9th day to 13th day postinfection.The shift of Th1/Th2 polarization influences the finale of toxoplasma infection.