Studies on the Mechanism of Hypersensitivity Phenomena

Abstract

Experiments are described indicating that the magnitude and sensitivity of the passive cutaneous anaphylaxis (PCA) response in normal rats to a given level of immune reagents, may be enhanced by the addition of hemolytically active sera. A similar enhancement in normal rats has been obtained with C' component reagents possessing properties associated with the third component of C'. Parallelisms between in vitro fixation of C' and PCA induction by antigen and antibody are shown. The horse anti-pneumococcus system has low C'-fixing potencies and is also less efficient than the rabbit polysaccharide system in the induction of PCA. Findings of a similar nature were observed in the reaction of rabbit anti-ribonuclease with ribonuclease, the acetylated and guanidinated derivatives of the enzyme. The injection of hemolytically active serum into C'-deficient rats was accompanied by a partial restoration of PCA. Restorative effects were also noted with heated and ammonia-treated serum. The return of hemolytic potency and responsiveness to PCA in C'-depleted rats, follow a similar time course. The data presented indicate that the PCA reaction can be studied as a function of at least three variables, antigen, antibody, and a serum constituent resembling C'.

Antibodies Involved in Antigen-Induced Release of Slow Reacting Substance of Anaphylaxis (Srs-A) in the Guinea Pig and Rat

“…Whether it represents a single phenomenon or several different ones is uncertain; at least three associated factors have now been recognized. First, the intensity of the lesion can be correlated to some extent with the level of serum complement activity (38). Second, the reaction can be suppressed by rendering rats leukopenic (39).…”

The Role of Complement in the Passive Cutaneous Reaction of Mice

“…Ribonuclease has been previously shown to be able to elicit PCA (9), and its choice in our experiments was motivated by the extensive information available in our laboratory on the interaction between ribonuclease and the corresponding antibody (33,34). to 20 normal adult rabbits, bled from the carotid artery.…”

“…So far, most attempts to elucidate this question were based on experiments with animals in which the circulating level of complement was reduced experimentally. Such reduction can be caused by systemic injection of antigen-antibody precipitates before the injection of the reactants, leading to PCA (8)(9)(10). Another approach has been based on chemical modifications of antigen which result in reduced complement fixation by the complex of antigen and antibody.…”

“…Another approach has been based on chemical modifications of antigen which result in reduced complement fixation by the complex of antigen and antibody. On the basis of such experiments it was concluded that complement is involved in PCA of the rat (8,9), but not of mice (11).…”

Role of the adrenal gland in the leucocytosis caused by bradykinin or cellulose sulphate in the rat

“…Recent results by Eisen & Loveday (1970), however, demonstrate anticomplementary activity of cellulose sul-phate in the rat. Since the complement system is a requisite for heterologous PCA in the rat (Osler, Hawrisiak, Ovary, Siqueira & Bier, 1957), it could well be an alternative site of the inhibitory action of cellulose sulphate in this form of anaphylaxis.…”