Experiments are under way to investigate the level of autoantibodies to lens crystallins in the sera of normal volunteers and of individuals with cataract. The specific autoantibodies will be determined and measured using chemiluminescent Western blots of two-dimensional gels of human lens proteins. Our results indicate that one protein spot is immunoreactive with all the sera tested. Using cell lines that express a single human crystallin, it has been determined that this protein is gammaC-crystallin. Work is progressing to ensure that the sequence of the immunoreactive protein is identical to human gammaC- crystallin.