Fig 7. Effect of PLL on assay of antibodies to tetanus toxoid.

ELISA plate wells were pre-coated with 500 ng/ml PLL, and then used to capture tetanus toxoid at various concentrations from 25 pg/ml to 500 ng/ml, or buffer alone as control. The same concentrations of tetanus toxoid were coated onto plate wells without the PLL pre-coat. Binding by antibodies in three SLE plasmas was assayed in a standard ELISA assay. Squares show data for direct coat; circles show data for PLL pre-coated plate. All plasmas were tested at 1/800 dilution. (A) Binding by SLE plasma 1. (B) Binding by SLE plasma 2. (C) Binding by SLE plasma 3.