COMPARATIVE PHAGOCYTIC AND PINOCYTIC ACTIVITIES OF LEUKOCYTES FROM PERIPHERAL-BLOOD AND LYMPHOMYELOID TISSUES OF THE NURSE SHARK (GINGLYMOSTOMA-CIRRATUM BONATERRE) AND THE CLEARNOSE SKATE (RAJA-EGLANTERIA BOSC)

Cells isolated from lymphomyeloid tissues and peripheral blood from tw o species of elasmobranch, the nurse shark (Ginglymostoma cirratum Bon aterre) and the clearnose skate (Raja eglanteria Bose) were assayed fo r in vitro phagocytic and pinocytic activities at various times during 24 h in culture. The purpose of this research was to begin to charact erise functional activities of cells isolated from unique lymphomyeloi d tissues found in elasmobranchs. Phagocytosis was evaluated by assess ing relative abilities of immune cells to ingest Congo Red stained yea st, and included determination of percentage of active cells and numbe rs of yeast per cell. Pinocytosis was assayed by spectrophotometric me asurement of neutral red dye accumulation by immune cells. Phagocytic activity was greatest in cells isolated from shark epigonal and skate epigonal and Leydig organs, with over 60% of skate Leydig cells contai ning yeast after 24 h in culture. Phagocytic activity was 2.5-6 times lower in cells from peripheral circulation or spleen. Pinocytosis was 1.5-3-fold greater in cells isolated from Leydig and epigonal organs c ompared to peripheral blood leucocytes or splenocytes. Documentation o f phagocytic and pinocytic activities by cells isolated from epigonal and Leydig organs suggests significant immune functional roles for the se unique tissues in the elasmobranch immune system. (C) 1998 Academic Press Limited.