Antigenic properties of purified fractions from Ascaris lumbricoides var. Suum on naturally sensitized guinea-pig.

Purified extract of Ascaris injected intravenously into guinea-pigs produced a reaction very similar to the anaphylactic reaction. As shown by the ratio of deaths to survivals the toxic fraction contained in Ascaris extract was purified 3 to 4 times. After intravenous injection animals presented both anaphylaxis-like shock and mast cell damage similar to that observed in anaphylaxis. Perfusion of the lungs with Ascaris fractions released histamine. Isolated guinea-pig ileum when in contact with Ascaris fractions showed a response followed by desensitization. Heating the ileum to 45 degrees C or previous desensitization to anaphylatoxin excluded the participation of the latter in this contraction. In vitro, sensitization from one guinea-pig could be transferred to another, using spleen extract or a 50% ammonium sulphate precipitate obtained from the spleen extract. On the basis of these results it is concluded that guinea-pigs are naturally sensitized to antigen or antigens present in Ascaris lumbricoides.