Provided herein are transgenic non-human animals whose genomes comprise two or more human genes selected from CD33, Siglec-5, Siglec-7, Siglec-9, Siglec-11, Siglec-14, and Siglec-16, to methods of screening candidate agents that bind to and/or modulate the function and/or activity of at least one of the human genes in the transgenic non-human animals, and to methods of screening candidate agents to determine their effect on one or more activities and/or functions associated with expression of at least one of the human genes in the transgenic non-human animals. Further provided herein are methods of recapitulating a human Siglec immune system in a non-human animal, and methods of generating a non-human animal disease model comprising a human Siglec repertoire.