The Toxicity of Streptolysin O for Beating Mammalian Heart Cells in Tissue Culture

Abstract

Pulsating mammalian myocardial cells were found to be highly susceptible in tissue culture to rapid destruction by streptolysin O. Cessation of beating occurred almost immediately, followed within minutes by multiple cell membrane bleb formation. Parallel with these changes, the cytoplasm became intensely granular and the nuclear membrane apparently thickened when viewed by phase microscopy. At the ultrastructural level, the cell membrane blebs were found to contain relatively small numbers of granular fragments. The endoplasmic reticulum of damaged heart cells was quite swollen, and its contents were considerably condensed. The myofibers were not strikingly altered, but cytoplasmic and mitochondria vacuoles were rather abundant. Cardiac endothelial, kidney epithelial, and fibroblast cells were also susceptible to lysis by this toxin, but the reactions occurred more slowly or bleb formation was less evident. An antiserotonin drug known to be protective against streptolysin-O in vivo (UML-491), did not protect against killing of cardiac cells at the tissue culture level. Serotonin could not be detected in the culture fluid after lysis of cardiac cells by streptolysin O.

In Vitro Organization of Dissociated Rat Cardiac Cells Into Beating Three-Dimensional Structures

“…In previous studies from our laboratory, dissociated beating newborn rat heart cells were cultivated on glass surfaces for investigations of the toxicity of cardiac antibodies or of streptolysin O (18,19). Under the tissue culture conditions used, the characteristic growth of these cells as beating sheets confirmed the findings of previous investigators.…”

“…The inoculum was 0.2 ml of the final suspension of dissociated cells, which was added to about 1.5 ml of complete medium. In previous experiments with this system (18,19), the heart cells were grown on the glass surface. In the studies being reported here, the cultures were grown on the opposite polystyrene surface instead.…”

Loaded Language and Drug Use

“…Recent studies have demonstrated that streptolysin O has a direct toxic effect on the isolated pul¬ sating mammalian heart cell. 3 Cholesterol, known to in¬ hibit the toxic and hemolytic activity4 of this streptococ-cal product, has been also shown to inhibit its antigenicity,5 particularly when the site of antigenic stim¬ ulation is the skin.6 Perhaps, ventures Wannamaker, rheu¬ matic fever is a result of direct damage to the heart by streptolysin O rather than the consequence, as is generally held, of immune antigen-antibody complexes. And, even if the latter are implicated, may hot the initial cardiotoxic action of streptolysin O be an essential prerequisite to noxious immunologie effects ?…”

The Cardiac Auto-Immune System

“…Cells from the cardiac ventricles of 1-to 4-day-old neonatal SpragucDawlcy rats (Holzman) were grown in 'Rose' chambers by the method of M ark and Strasser [22], as described previously [21]. The average number of trypsin-dissociated cells inoculated per chamber was 3 x 1 O'.…”

“…19], it was considered of potential importance to examine the cytotoxic activities in tissue culture of the above cardiac auto-antibodies experimentally produced in rabbits. For this purpose, the isolated pulsating heart cell culture [20,21] was felt to be an excellent test system, since the cells would be fully functional, and antibody penetration should not constitute a significant factor. Heterologous antibodies to rat and rabbit heart were also studied for their cytotoxicity to isolated pulsat ing rat and rabbit heart cells for comparison with the rabbit heart auto-antibodies.…”