Studies on Lymphokine Activity in the Amphibian Rana Temporaria

Abstract

This thesis describes experiments which demonstrate that an anuran amphibian, Rana temporaria, is capable of elaborating a range of soluble mediators, analogous to mammalian lymphokines. In vitro stimulation of Rana temporaria leucocytes, with both antigens and mitogens, was employed. The supernatants from such stimulated cultures were applied to assay systems, in which their effects on other leucocytes could be determined. Depending on the circumstances and kinetics of their production, a variety of activities, ascribed in mammals to lymphokines could be demonstrated. These are listed below in terms of their effects on a particular population of cells, and are accompanied by the lymphokine, which is thought to accomplish an equivalent effect in mammals. 1. Activity decreasing random movement of peritoneal cells, Migration inhibition factor or MIF 2. Activity increasing random movement of peritoneal cells, Migration stimulatory factor or MStF 3. Activity increasing glucose uptake by peritoneal cells, Macrophage activating factor or MAF 4. Activity causing directional movement of peritoneal cells, chemotactic factor or CF 5. Activity increasing tritiated thymidine uptake by splenocytes, Mitogenic factor or MF 6. Activity decreasing tritiated thymidine uptake by splenocytes, Inhibitor of DNA synthesis or IDS This is the first survey of lymphokine production by an ectothermic vertebrate, and shows that the properties, kinetics and methods of induction of amphibian lymphokines are remarkably similar to their mammalian counterparts. Rana MIF was also effective in inhibiting the migration of rat peritoneal cells. This conservation of function suggests that lymphokine production is a fundamental property of vertebrate leucocytes, provides further support for their having a central role to play in in vivo immunity; and reveals that in phylogeny, they are present at the amphibian level of evolution.