A standardized gating technique for the generation of flow cytometry data for normal canine and normal feline blood lymphocytes

Flow cytometry is becoming a commonly used technique to characterize a vari ety of cells. It provides a powerful application to rapidly determine the r elative percentages of T-lymphocyte subsets and B-lymphocytes. The effectiv eness of its application, however, is dependent on standardization, especia lly in a clinical setting. Application of flow cytometry to veterinary diag nostics has been limited by the unavailability of reagents and by the unsta ndardized characterization of normal values using antibodies not commercial ly available, but typically provided through the generosity of other resear chers. This paper presents a standardized gating protocol, and average valu es and ranges observed for normal canine and feline blood lymphocytes using commercially available antibodies to cell surface markers for CD5, CD3, CD 4, CD8, MHC II, and B lymphocytes. The averages for these markers on gated lymphocytes were as follows: Canine CD5 83.3%, Canine CD4 35.0%, Canine CD8 28.8%, Canine MHC II 98.0%, Canine B Cell 12.9%, Canine CD4/CD8 ratio 1.87 , Feline T lymphocytes 77.3 %, Feline CD4 44.5%, Feline CD8 25.7%, Feline B Cell 24.1%, Feline CD4/CD8 Ratio 1.75. Normal values were also established for a mixed breed group of dogs, and old versus young dogs. This informati on will provide researchers and clinicians with a standardized protocol for gating, which establishes a basis for comparison between techniques, and a measure of phenotypic percentages for flow cytometry in normal dogs and ca ts based on this standardization and commercially available antibodies. (C) 2000 Elsevier Science B.V. All rights reserved.