Supravital staining of leukocytes from ragweed-sensitive individuals

Abstract

HIS STUDY was undertaken to determine whether differences exist in the staining properties of leukocytes from ragweed-sensitive individuals when these leukocytes have been exposed in vitro to ragweed antigen when compared with the results obtained when the same cells have not been exposed to antigen. Many reports indicate that the white blood cells from sensitive individuals or sensitized animals behave differently in various respects when exposed to a specific antigen, when contrasted with behavior of cells from the same individual or animal not exposed to the antigen. It has been reported, fol example, that leukocytes from ragweed-sensitive individuals, when exposed to a final concentration of 1:lOOO ragweed extract, undergo a significant degree of lysis,l although in another study2 this could not be verified. A similar study, in which a much higher concentration of antigen was used,” reported a marked degree of immobilization and lysis of leukocytes, although in other observers’ hands4 the same technique did not produce significant results. There has been more agreement on results in bacterial sensitivity studies in which leukocyt,es from tuberculin-sensitive individuals were exposed to either PPD or to old tuberculin. A significant amount of cytolpsis occurs when such leukocytes are exposed to tuberculin.” Likewise, exposure to specific antigen of rabbit leukocytes from animals sensitized to ovalbumin or bovine gamma globulin has produced a significant degree of cell lysis when compared with cells processed similarly but not exposed to the antigen.” Since the nuclear staining of leukocytes by neutral red stain is said to occur in dying or dead cells,’ it, was t,hought that the uptake of neutral red by leukocytes from ragweed-sensitive individuals might serve as a precise indicator of the reaction of such cells to the presence of ragweed antigen. The same principle has been used to determine the death of cells in tissue culture.h Accordingly, the following studies were undertaken.