ABSTRACT
Although sphering almost always occurs at some time before a mammalian red cell haemolyses, the shape change has to be placed in a variable position on the time scale to which the progress of the lytic reaction is referred. In the case of some lysins, e.g. saponin, the shape change is a late event, while in the case of others, e.g. sodium tetradecyl sulphate, it is an early event on the same time scale.
In the case of four lysins (sodium taurocholate, sodium tetradecyl sulphate, saponin and digitonin) the amount of lysin required for complete haemolysis increases with increasing pH, but the amount required to produce sphering decreases with decreasing pH.
Serum albumin produces a reversal of the disk-sphere transformation brought about by distearyl lecithin, sodium taurocholate, sodium tetradecyl sulphate, saponin and digitonin. Benzene has a weak reversing effect when the spheres are formed as the result of the action of the first three substances mentioned, and cholesterol produces reversal of the shape change only when it is brought about by sodium tetradecyl sulphate. The simple explanation that the reversing agents act by reacting with the lysins and reducing their concentration is not tenable, and the effect of the reversing agents must be regarded as something distinct from their inhibitory effect on the lysin in the system.
Some of the substances used can produce the disk-sphere transformation and can even bring about lysis when they are present in such small amounts that they cannot cover the red cell surface. Either the effects produced by each molecule of sphering agent or lysin extend to neighbouring regions on the cell surface and perhaps also into the interior, or sphering and lysis occur as the result of changes at spots on the surface.
These results differ from those described by Teitel-Bemard (1932) because the systems and the conditions of observation are not the same as in his experiments. His systems contained plasma diluted about 1 in 40, which is sufficient to prevent sphering at pH 8·4. Further, the zone of crenation described between pH 7·0 and 6· 0, corresponding to the intracellular crystallization of haemoglobin with its accompanying birefringence, was the result of observations made after some hours and not, as in the case of the experiments described here, after 30 min, only.
