Determining the Specific Activity of Anti-Rabies Sera and Immunoglobulinusing Atomic Force Microscopy of Cell Cultures

Background: mouse neutralization test is widely used to determine the level of antirabiesantibodies, but it is labor-intensive and time consuming. alternative methodsfor determining the neutralizing activity of anti-rabies sera and immunoglobulin incell cultures are also known. methods such as favn and rffit involve the use of fluorescentdiagnostics. determination of cytopathic effect (cpe) is often complicateddue to features of rabies virus replication in cells. atomic force microscopy (afm) isable to detect the interaction of the virus with the cell at an early stage. therefore, inthis study, a method has been developed for determining the specific activity of antirabiessera and immunoglobulin using afm of cell cultures.methods: the method is based on the preliminary interaction of rabies virus withsamples of rabies sera or immunoglobulin drug, adding the specified reaction mixtureto cell culture (vero or bhk-21), and then measuring the surface roughness of the cellsusing afm. afm was carried out in the intermittent contact mode by the mismatchmethod in the semi-contact mode. the results were compared with the values obtainedin the mouse neutralization test. the consistency of the results obtained byboth methods was evaluated by bland-altman method.results: the increment in the surface roughness of the cells is a consequence of thedamaging effect of the virus, which is weakened as a result of its neutralization byrabies antibodies. a dilution allowing 50% suppression of the increase in the surfaceroughness of cells was selected as the titer of rabies sera or immunoglobulin. in thiscase, the recommended range for determining the antibody titer is from 1:100 to1:3000.conclusion: for the first time, a new methodological approach in virology and pharmaceuticalresearch is presented in this study. the use of the proposed methodologicaltechnique will reduce the time from 21 to 2 days to obtain results in comparison withthe mouse neutralization test; also, fewer laboratory animals are required in this approachwhich is in agreement with 3 r principle.