Antibodies have been raised by immunization of animals including mouse, goat and rabbit. However, only human or humanized antibody can be used for the therapeutic purpose due to immunogenicity of animal antibodies, which can induce immune response in human body. Thus, in order to isolate useful human antibodies, deeply and fully understanding human immune systems is required and high quality-human antibody libraries and precise selection processes are also demanded.
  In our laboratory, to develop useful human antibodies, we generated yeast surface-displayed, combinatorial synthetic human Fab libraries, designed to have similar amino acid compositions at each of six CDRs to those in the human germline repertoires. We took advantage of yeast mating between two haploid cells containing HC and LC libraries and constructed yeast surface-displayed Fab libraries with a colony diversity size of more than 109 through one round of mating.
  We are exploiting the libraries as antibody sources to rapidly isolate human antibodies having high-affinity and specificity to given antigens.