Two high-affinity human-derived anti-HTT antibodies (Ab-A and Ab-B) and a human isotype control antibody (Ab-Ctrl) were analyzed for their ability to immunoprecipitate mHTT aggregates under native conditions from crude brain extracts from 12-week-old R6/2 and 9-month-old zQ175 HD mice. Here, HTT is linked to Huntington disease.