Approximative molecular weight of the active component in toxoplasmin

The approximative molecular weight of toxoplasmin -- a skin reactive extract from Toxoplasma gondii -- was estimated by ultrafiltration through different Amicon membranes. The activity of the filtered and unfiltered product was compared with the aid of intradermal test on humans. The results indicate that the molecular weight of an active component in toxoplasmin is in the range from 10 000 to 50 000.