Sensitivity of real time viral detection by an optical biosensor system using a crude home-made antiserum against measles virus as a ligand.

Virus identification in clinical materials during acute phase infections could give necessary information for the treatment of infections by human immunoglobulin (hIg) or interferon (IF). But because of a lack of information, most virus infections have not been treated. We have tried to develop a real time detection system for viruses in general using an optical biosensor and a model virus, Herpes simplex virus Type 1 (HSV-1), and have proved that the HSV-1 virus propagated in Vero cells and diluted in minimum essential medium (MEM) with 10% fetal bovine serum (FBS) could be detected in high sensitivity close to 10 infectious units (50% tissue culture infective dose [TCID50] units) using purified cellular receptor molecules as the ligand because the receptor could be the most specific ligand. However, because ligands available for this system to identify various viral infections in general are limited, we also tested this system using a purified polyclonal antibody which contained many other antigens as the ligand, and produced sensitivity comparable to that using the receptor as a ligand. In this paper, we tested the sensitivity by this system under the worst condition. That is, we used a crude home-made rabbit antiserum against measles virus with host cell debris as a ligand. It was found that less than 500 infectious (TCID50) units of virus were required for detection in a 100 microl solution, and that the efficacy of the commercially available hIg was also estimated by this system. This result suggested that this real time viral detection and titration system was applicable for the diagnosis of all viral infections even under difficult conditions without requiring any complex skills, with high enough sensitivity for clinical purposes. The efficacy of hIg preparations could also be evaluated by this system at the same time of the clinical material sampling.