Complement Fixation Tests in Poliomyelitis **

Infection with poliomyelitis virus gives rise to complement-fixing (C-F) antibodies which may be detected with antigens prepared either from the brains of infected mice or tissue culture fluids, as shown with Type II by Casals et al."' and with all three types by Svedmyr et al.' These workers used sufficient antigen in each test to obtain maximum sensitivity. With this antigen concentration the presence of antibody could generally be detected within the first week after onset of the disease, but the sera usually gave similar C-F titers against antigens of the three types of poliomyelitis virus regardless of the type involved in the infection. It has now been found possible to obtain a more specific reaction in patients with the disease by a method in which not more than one conventional unit of antigen is used per test. In order to detect fixation with this low level of antigen, dilutions of serum were titrated at several complement concentrations by the plate method of Fulton and Dumbell.'