Phenomenon of Local Skin Reactivity to Serum Precipitates

Abstract

Phenomenon of local skin reactivity to serum precipitates is elicited as follows:

The abdominal skin of a rabbit is injected with 0.25 cc. of undiluted B. typhosus “agar washings” filtrate. 1 Twenty-four hours later the rabbit receives a single intravenous injection of a suspension of serum precipitate prepared in the manner about to be described. Four to 5 hours after the intravenous injection there appears at the prepared skin site a severe hemorrhagic and necrotic lesion characteristic of the phenomenon of local skin reactivity to bacterial filtrates. 2

The serum precipitates with which the phenomenon could be consistently reproduced were obtained from the following mixtures:

1. Normal horse serum with anti-horse rabbit serum.

2. Antimeningococcus horse serum with anti-horse rabbit serum.

3. Antimeningococcus horse serum with anti-horse goat serum.

4. Antimeningococcus anti-human horse serum with normal human serum.

The mixtures were made in proportions yielding maximum amount of precipitate, incubated in water bath at 37° for 2 hours, kept in the refrigerator over night and centrifuged at high speed. The supernatant fluid was removed and the sediment taken up in 0.85% NaCl solution in volume equal to 1/4 of the volume of horse serum used.

A dose of 1 cc. of the suspension per kilo of body weight injected intravenously elicited severe reactions in a high percentage of rabbits. The reacting potency could be easily titrated by testing various dilutions of a suspension. Each dilution was tested in a group of 3 rabbits. The titer usually varied between 1:5 and 1:50 dilutions. The toxicity of the serum precipitates was quite stable since almost identical results were obtained on retests after a lapse of several weeks and months.

There was no apparent relationship between the amount of precipitate obtained in various preparations and their reacting potency.