Chimeric genes composed of immunoglobulin (Ig)-derived variable (V) regions and T-cell receptor (TCR)-derived constant (C) regions were constructed. The VL and VH genes showing anti-phosphorylcholine (PC) activity were used in this study. Two pairs of chimeric genes, VL-C beta and VH-C alpha genes, and VL-C alpha and VH-C beta genes, were inserted into an expression vector containing both Ecogpt and neo genes, and transfected into EL4 cells. Cells which express both chimeric receptor molecules were established. The activity of the transformants to the antigen was examined by using stopped-flow fluorometry. An increase in the concentration of cytoplasmic calcium ion was observed after addition of Staphylococcus pneumoniae R36A bacteria grown in the choline-containing medium which express PC molecules, but not after the PC-negative bacteria grown in the ethanolamine-containing medium.