Improved Procedure for Screening Expression Libraries for Novel Autoantigens

The standard method for immunoscreening of a cDNA expression library is time-consuming becauseof the production of a large proportion of false positives during the first and second round of screening.This problem is more important when a sensitive chemiluminescence detection system is used. Due tothe high sensitivity of the detection system, there is a need to avoid false positives which occur when theantibody reacts non-specifically. False positives are generally eliminated through absorption of the antibodywith the host bacteria and by eliminating any clones, which react with antibodies present in normalsera. Here we present a method of obtaining almost identical bacteriophage plates by culturing phage inparallel, and show that this technique produces positive plaques in duplicate and eliminates false positives.Using this method, we successfully screened a human fetal spinal cord lambda gt11 cDNA libraryusing purified immunoglobulin G (IgG) from patients with multiple sclerosis (MS) and Guillain – Barre syndrome (GBS).