An Experimental Study of the Neisser-Wechsberg Phenomenon

Abstract

(1) The inhibiting phenomenon of Neisser and Wechsberg, as frequently observed with bacteriolytic sera, can also be shown to occur with haemolytic sera.(2) This phenomenon develops early during immunisation, when it is very marked; but as immunisation proceeds it tends to disappear.(3) In sera examined some time after their removal the inhibiting faculty is seen to disappear first, before any marked change is noticed in its bactericidal titre. This can be shown to occur in vivo also.(4) The inhibiting faculty is observed only with inactivated sera; fresh and active sera showing complete bactericidal activity at all times. The effects are not however due to complementoids produced by inactivation.(5) The phenomenon is not due to the action of any of the known anti bodies, or special “inhibiting antibodies”; but it is due probably to dis sociation of the antigen-amboceptor complex. Such dissociation only occurs when amboceptors are present in excess. This explains why inhibition occurs only with high doses of an immune serum.The serum to be used should be without an antiseptic. Commercially prepared antisera usually contain a small amount of it. It is shown that corpuscles sensitised in them undergo haemolysis without the addition of complement (see p. 427).(6) Since it is known that the union of antigen and amboceptor is not always a firm one, it is suggested that during early days of immunisation amboceptors of a weak combining affinity are produced. These are replaced later by those which are capable of a more permanent union with them (antigens).(7) The name “complement-blocking” is not an appropriate one, as com plement could be shown to exist free in the inhibiting fluids. It should rather be spoken of as an “amboceptor-dissociation” effect.(8) Inhibition is specific. An attempt was made to utilise this fact in differ entiation of strains of true cholera but it was found to have no definite diagnostic value.The writer wishes to express his indebtedness to Prof. Hewlett for sug gesting the problem to him and also for his kind guidance and encouragement during the course of the experiments. His thanks are also due to Dr Taylor for his valuable assistance.