Isolation of equine neutrophils and analysis of functional characteristics by chemiluminescence and bacterial assays.

Equine neutrophils (PMN) were isolated to greater than 99% purity by isopyknic sedimentation on coated colloidal silica particles. A cell recovery of 84.7 +/- 4.0%, with a viability of greater than 99%, was observed with this method. The isolated PMN were compared with mixed population of equine peripheral leukocytes with respect to functional integrity by chemiluminescence and bactericidal assays. There was no significant difference (P less than 0.01) observed in either assay between the isolated equine PMN and the mixed-cell populations. The methods used in both the isolation as well as the functional characterization of the equine PMN, were rapid and highly reproducible and should readily find use in clinical and research laboratories. It is now feasible to rapidly assess equine PMN integrity in those cases which warrant this type of study. This is the first direct comparison of the chemiluminescence assay with the microbicidal assay, using equine PMN.