Long ago I put juvenile beagle monocytes into culture for use in propagating Ehrlichia canis, which had just been done by Ristic and Holland at U. of Illinois. I was using the host dog's serum at 1-5% and, after about a week, smaller spherical cells appeared and were actively dividing. I took some of these cells and added culture supernate from my E. canis culture and overnight these smaller spherical cells became infected. Unfortunately, my donor dog ("Erny") dug his way under my backyard fence and ran away and I was left with 1-2 mL serum for the culture. I used this at 0.5-1.0% in the medium, but adult dog serum did not work and I lost this dream culture. My question is : How do I recreate this magic monocyte phenotype?