IMMUNIZATION AGAINST THE AGENT OF HUMAN GRANULOCYTIC EHRLICHIOSIS IN A MURINE MODEL

The agent of human granulocytic ehrlichiosis (HGE) is a newly recogniz ed tick-borne pathogen that resides within polymorphonuclear leukocyte s. C3H/HeN mice can become infected with the agent of HGE (designated aoHGE) by syringe inoculation or tick-borne infection and develop tran sient neutropenia, They thereby partially mimic human disease and prov ide a model in which to study immunity to this microorganism. Mice vac cinated with lysates of purified aoHGE, or administered aoHGE antisera , were partially protected from both syringe-and tick-transmitted chal lenge with aoHGE. These data suggest that antibodies are sufficient to provide substantial, but not complete, immunity against aoHGE.