A number of properties of bovine conglutinin and rabbit immuno-conglutinin (I-K) have been compared. These are summarized in Table 1. [Table: see text]
Bovine conglutinin is seen to be an antigenically specific β1 globulin which reacts with the alexinated complex only in the presence of calcium. A reaction with zymosan and with agar also occurs which is dependent on calcium ions but not on the presence of complement. For this reason EDTA-containing buffers should be used in immuno-diffusion studies on conglutinin. From conglutinated zymosan substantially purified preparations of conglutinin have been obtained.
Rabbit immuno-conglutinin is seen to show the properties to be expected of an antibody to fixed complement.
A preliminary account is given of an immuno-histological technique employing conglutination which will detect bound complement of various species in tissues.
By EDTA elution of conglutinated γ-globulin aggregates alexinated with guinea-pig complement a preparation of C′1 has been obtained which had C′1 haemolytic activity and which gives a single line in the β1 region on immunoelectrophoresis with an anti-guinea-pig globulin serum.