FIG. 8.

Comparison of ELISA (A and B) to the CDC assay (C) using natural IgM antibodies. The ELISA results show absorbances obtained with antigen-sensitized wells (A) and differences from those obtained with nonsensitized wells (B). Natural antibodies were obtained in an ascites form from mice inoculated with hybridoma clones 1D12 (closed circles), 5A5 (open circles), and 6A11 (closed triangles), as well as with control P3U1 cells (open triangles). For comparison, the day-4 serum (closed squares) was used. Each datum represents an average obtained in two separate experiments (standard deviations are indicated by bars).