TABLE 1.
Antigen preparations used among the JHU, NYMC, and MN laboratories
| Antigen | Laboratory testing site | Origin of isolate | Passage history |
|---|---|---|---|
| E. equi MRK in horse neutrophils | JHU | Calif. | In vivo |
| E. equi MRK in HL60 cells | JHU | Calif. | 16 in vitro |
| HGE agent Webster strain | JHU | Wis. | 8 in vitro |
| HGE agent Spooner strain | JHU | Wis. | 7 in vitro |
| HGE agent NY-3 strain | NYMC | N.Y. | 1 in vitro |
| HGE agent NY-6 strain | NYMC | N.Y. | 1 in vitro |
| HGE agent NY-8 strain | JHU, NYMC | N.Y. | 2, 1 in vitro |
| HGE agent HGE-2 strain | MN | Minn. | <20 in vitro |