Effect of ACTH, cortisone, sphingomyelin, sphingosine and phenergan (antihistamine) in inhibiting the skin reaction in cattle sensitized toTrichomonas foetusantigen

Abstract

1. ACTH, cortisone, sphingomyelin and sphingosine produce a delayed in-hibition of the skin reaction in cattle sensitized toTrichomonas foetusantigen when they are injected intramuscularly. The inhibition is greatest 6–9 hr. after injection of the inhibitor, but may sometimes be further delayed. This reaction is associated with an absolute lymphopoenia of slightly variable duration.N-acetylsphingosine retains the desensitizing effect of crude sphingomyelin and is of much the same potency as cortisone acetate of Merck.2. The lymphopoenia associated with the injection of ACTH and cortisone occurs also with sphingosine, and these three substances are also alike in not producing the desensitizing effect until some hours after the injection.3. Phenergan, a synthetic anti-histamine, has a different action, and its desensitizing effect which appears to depend on a direct antagonizing of the oedema-provoking substance resulting from the junction of antibody and antigen (hapten) takes effect apparently as soon as the injected drug itself is present at the site of the injection of the specific testing fluid.4. Methods of testing the capacity of the hormones and drugs to prevent the skin reaction locally and to nullify the action of thein vitroantigen-antibody mixtures which can produce a reaction in normal animals are described.Phenergan alone of the substances dealt with has any power to act locally. Phenergan mixed with the antigen-antiserum complexin vitroprevents the formation of the characteristic swelling in a normal animal.Phenergan mixed with the specific testing fluid prevents the development of the skin reaction when the mixture is injected intradermally into a sensitive animal.Cortisone and sphingosine do not have this action.We are indebted to the Medical Research Council for supplies of ACTH and cortisone and to Sir Charles Harington for N-acetylsphingosine.The personal encouragement of Prof. H. G. Lamont and the support afforded by the Ministry of Agriculture, Northern Ireland, are gratefully acknowledged.