To make further investigation of the IgE antibody repertoire in Trichosanthin (TCS) allergic responses, a murine IgE phage surface display library was constructed (3.0 x 10(5) independent clones). We first constructed the V epsilon cDNA library (4.6 x 10(5) independent clones) and V kappa cDNA library (3.0 x 10(5) independent clones). Then, the V epsilon and V kappa gene segments were amplified from both libraries by PCR respectively, and assembled into Fab fragment by SOE PCR. The phage library containing Fabs was thus constructed. The diversity of V epsilon from this library was analyzed and proved. Fab clones with high specificity to TCS have been screened out.