Abstract
In the last few years a number of workers in this country have reported favorably on the use of cholesterinized antigens for Wassermann reaction. According to some reports, these so-called reinforced antigens gave even more satisfactory results than the acetone-insoluble fraction of tissue lipoids advocated by Noguchi. 1 In studying the rôle of cholesterin in the preparation of antigen we came to the following conclusions:
The apparent superiority of reinforced antigens is not due to the heightened specificity of these antigens, but to a heightened anticomplementary power of the same.
In addition, cholesterol retards and, if used in sufficient connection, greatly protects the blood cells from the action of hemolytic agents, thus further increasing the tendency towards a higher percentage of positive reactions.
That this influence of cholesterol is not specific is evidenced by the fact that more recently differeht authors noted the occurrence of nonspecific fixations obtained with reinforced antigen in a high percentage of normal cases.
The erroneous procedure recommended by some of the recent texts of using 1/2 to 1/3 of anticomplementary dose of reinforced antigen in the test may increase the occurrence of nonspecific fixations up to 40 per cent. of normal cases, as reported by some of the investigators.
On the other hand we found that removing all the cholesterol from the tissue extracts actually improves them for the use in the complement fixation test.
By redissolving and reprecipitating the acetone insoluble fraction of tissue lipoids one does not diminish its antigenic value, while one very markedly decreases its anticomplementary power.
The antigen prepared in this way can be used in the amount 10 or even 20 times smaller than the dose fixing I H E unit 1 of complement, and yet even such minute amounts of antigen may contain considerably more than 10 antigenic units.
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