Abstract: This invention provides novel methods of obtaining autologous monoclonal antibodies (AMABs) to self-antigens or homologs thereof. The method involves obtaining a genetically engineered host animal that does not biosynthesize at least one epitope of the antigen and utilizes the lack of self-tolerance of the host to the epitope to produce antibodies specific to the antigen. The invention also encompasses the AMABs produced by the methods. The invention further encompasses methods of isolating cells comprising the use of such AMABs that have specificity for a cell surface antigen.

Abstract: This invention provides novel methods of obtaining autologous monoclonal antibodies (AMABs) to self-antigens or homologs thereof. The method involves obtaining a genetically engineered host animal that does not biosynthesize at least one epitope of the antigen and utilizes the lack of self-tolerance of the host to the epitope to produce antibodies specific to the antigen. The invention also encompasses the AMABs produced by the methods. The invention further encompasses methods of isolating cells comprising the use of such AMABs that have specificity for a cell surface antigen.

Abstract: The invention relates to a DNA sequence, which codes for a mutant of the bacteriophage P1 recombinase, in which a particular cryptic splicing site is disabled by means of a base mutation which alters the Cre protein sequence. The invention further relates to a DNA sequence which codes for a fusion protein from the named Cre mutants and a ligand-binding domain of a receptor protein. The invention furthermore relates to vectors, micro-organisms and transgenic organisms, containing such a DNA sequence and Cre mutants or Cre fusion proteins which are coded by said DNA sequence.

Abstract: Transgenic mice that produce high levels of humanized antibodies are described. Targeted gene replacement exchanges constant regions of the mouse immunoglobulin heavy and light chain genes with human genes, either through conventional gene targeting, or by use of the bacteriophage-derived Cre-loxP recombination system. The transgenic animals undergo antibody affinity maturation, and a class switch from the native immunoglobulin to the humanized form.

Abstract: Transgenic mice that produce high levels of humanized antibodies are described. Targeted gene replacement exchanges constant regions of the mouse immunoglobulin heavy and light chain genes with human genes, either through conventional gene targeting, or by use of the bacteriophage-derived Cre-loxP recombination system. The transgenic animals undergo antibody affinity maturation, and a class switch from the native immunoglobulin to the humanized form.