Nephrolysins

NEPHROLYSINS, lysins of renal tissue, a specific type of cytolysins (see also Lysins). Just as bacteriolysins are formed in the body upon the introduction of bacteria, the introduction of cellular elements of certain tissues into an organism causes the formation of special immune bodies—cytolysins, which are substances that cause the dissolution of the introduced elements. Lindemann showed that the serum of guinea pigs injected with an emulsion of rabbit kidney substance had a nephrolytic effect on the kidneys of rabbits (heteronephrolysins). The serum of an animal injected with kidney substance of the same species causes severe changes in the kidneys of these animals (isonefrolysins). Similar changes are also achieved by introducing the serum of animals in which renal damage was artificially induced. Unilateral kidney damage (resulting from ligation of the ureter, ligation of blood vessels, or freezing of the kidney) causes degenerative changes in the healthy kidney—a circumstance of known significance in renal surgery. The degree of toxicity of the serum depends on the speed and amount of the resorbed renal tissue. Upon the introduction of an emulsion from the cortical substance, the serum of the immunized animal is more nephrolytic than upon the corresponding introduction of the renal medulla (Pearce). Nephrolysins act on renal tissue also in vitro (Herzen, Rathery). The formation of nephrolysins, like all lysins in general, can occur only in a living organism. Nephrolysin is therefore a substance of an immuno-biological nature, is found only in the serum of an immunized animal, and plays the role of an amboceptor. The cytolytic reaction occurs at a temperature close to 37°. Upon heating to 56°, the cytolytic properties of the immune serum are lost (the system is deprived of complement) and are restored again by the addition of normal serum. Nephrolysin possesses preferential (incomplete) specificity, causing parenchymal changes mainly in the kidneys and to a lesser extent in other organs. Some authors are inclined to identify nephrolysins with nephrotoxins. Herzen distinguishes between these two concepts, understanding nephrolysin as the immune body, in contrast to nephrotoxin, which represents a renal poison formed when renal cells die.