[Study on the effect of monoclonal antibodies on Giardia lamblia in vitro]

Monoclonal antibodies (McAbs) were generated by fusion of SP2/0 myeloma cells with spleen cells from BALB/c mice immunized with Giardia lamblia trophozoites. To define the effect of the McAb on Giardia lamblia, trophozoites were subcultured axenically after contact with McAb for 1 h at 37 degrees C. The McAbs 1G5 and 1E2 (both IgG1) were able to inhibit the growth of trophozoite at the rate of 63.4% and 35%, respectively. The inhibitory effect was decreased along with the decreasing quantity of McAb (from dilution 1:45 to 1:225) added to the TYI-S-33 medium. The actions of McAbs could be eliminated by absorption with trophozoites and not be influenced by complement in fresh guinea-pig serum, thus the actions of McAbs appeared to be specific and complement independent.