Sensitivity evaluation of the direct gp70 CMIA. (A) Detection of XMRV gp70-specific antibodies in RIl-10, RYh-10 and RLq-10 by the direct gp70 CMIA. All samples were diluted to 1:10 with negative human plasma prior to the testing. (B) Linear regression of signals at 10, 1 and 0 ng/ml of anti-His monoclonal antibody. Detection limit was determined based on the linear fitting equation with a cutoff value of 1000 RLU.