Elevation of serum lgE is the most characteristic immune response in helminthic infections. Recently, expression of CD23(FcεRII on B lymphocytes play a major role in lgE production in allergic diseases. However, the mechanisms causing increased lgE production during helminthic infections are poorly understood. In the present study, the expression of CD 23 on splenic B lymphocytes during the course of infection with Paragonimus westermani was examined.

Female, 4-6-week old BALB/c mice were inoculated orally with 20 metacercariae of P. westermani. For detection of CD23 positive B lymphocytes by flow cytometry, splenocytes from infected mice and non-infected age matched controls were stained with FITC-conjugatedrat anti-mouse DB23 and PE-conjugated rat anti-mouse CD45R/B220 mono-clonal antibody. And also, to observe the effect of metacercarial ESP on the expression of CD23 antigen, splenocytes from non-infected mice were incubated in the presence of ESP at 37℃ for 6 h and 24 h.

The frequency of CD23 positive B lymphocytes of infected mice was increased significantly(p<0.05) at two and three weeks after infection(43.4±7.52% and 44.4±2.99%, respectively) and persisted the higher levels at four and six weeks after infection. Expression of CD23 antigen of cultured splenocytes from non-infected mice in the presence of metacercarial ESP was increased significantly(p<0.05) at 24 h after incubation(60.1±7.54%).

These results suggest that the expression of CD23 antigen induced by metacercarial ESP might play a important role in serum lgE production in mice infected with P. westermani.