Isolation of Anaplasma phagocytophilum Strain Ap‐Variant 1 in a Tick‐Derived Cell Line

: Ten isolates of the Ap-Variant 1 strain of Anaplasma phagocytophilum were made in the Ixodes scapularis (I. scapularis)–derived cell line, ISE6. Two isolates were obtained from laboratory-infected goats and eight isolates were obtained from field-collected I. scapularis ticks. Each isolate showed 16S rRNA sequences identical to those as previously described for the Ap-Variant 1 strain. These are the first tissue culture isolates of the Ap-Variant 1 strain and will allow for further characterization of the biological and antigenic properties of this strain.