abstract |
Genetically modified non-human animals and methods and compositions for making and using them are provided, wherein the genetic modification comprises deletion of the immunoglobulin constant region CH1 gene of IgG, IgA, IgD, and / or IgE, Deletion), and the mouse is capable of expressing functional IgM. A genetically modified mouse is described that includes a functional IgM gene and a non-IgM heavy chain constant domain, for example, a CH1 domain at the IgG heavy chain prune region and a modification to have deletion of the hinge region. A human variable / mouse constant chimeric heavy chain antibody (an antibody lacking a light chain), a whole mouse heavy chain antibody, or a genetically modified mouse that produces a fully human heavy chain antibody. |