USE OF A DISCONTINUOUS PERCOLL GRADIENT TECHNIQUE FOR THE SEPARATION OF CHANNEL CATFISH, ICTALURUS-PUNCTATUS (RAFINESQUE), PERIPHERAL-BLOOD LEUKOCYTES

The use of a discontinuous density Percoll gradient in the separation of channel catfish peripheral blood leucocytes is described. The procedure yielded fractions enriched in monocytes and lymphocytes at the 1.060-1.065 g/ml interface, lymphocytes at the 1.065-1.070 g/ml interface, and neutrophils at the 1.070-1.080 g/ml interface. Cell purites among the fraction ranged from 14.4-51.6% for monocytes, 61.4-72.8% for lymphocytes, an 60.4-79.2% for neutrophils. Factors influencing the outcome of the separation procedure include the use of pooled blood samples and calcium-magnesium-free salt solutions.