OBJECTIVE: Stocks of RNA viruses often contain divergent mixtures of infectious and defective particles (DPs). Since the surface of both particles share the same immunoreactivity, differing ratios of these particles in stocks used for virus neutralization tests might alter the results. Here the impact of such off-target effects were measured. METHODS: To determine the relative content of DPs in 3 stocks with high, medium and low titers of infectious virions, the amounts of nucleocapsid protein and viral RNA were quantified by Western blot and quantitative RT-PCR. Thereafter, stocks with different amount of DPs were used to determine the titer of neutralizing antibodies in serum from a convalescent Puumala virus-infected patient by a focus reduction neutralization test. RESULTS: The relative amount of DPs was at least 5-fold higher in the stock with the lowest titer compared to the stock with the highest. Stocks with lower levels of DPs led to higher antibody titers compared to the analysis performed with stocks containing higher levels of DPs. CONCLUSION: These results imply that DPs in virus stocks should be considered when performing virus neutralization tests to quantify neutralizing antibodies. Copyright 2009 S. Karger AG, Basel.
OBJECTIVE:Stocks of RNA viruses often contain divergent mixtures of infectious and defective particles (DPs). Since the surface of both particles share the same immunoreactivity, differing ratios of these particles in stocks used for virus neutralization tests might alter the results. Here the impact of such off-target effects were measured. METHODS: To determine the relative content of DPs in 3 stocks with high, medium and low titers of infectious virions, the amounts of nucleocapsid protein and viral RNA were quantified by Western blot and quantitative RT-PCR. Thereafter, stocks with different amount of DPs were used to determine the titer of neutralizing antibodies in serum from a convalescent Puumala virus-infectedpatient by a focus reduction neutralization test. RESULTS: The relative amount of DPs was at least 5-fold higher in the stock with the lowest titer compared to the stock with the highest. Stocks with lower levels of DPs led to higher antibody titers compared to the analysis performed with stocks containing higher levels of DPs. CONCLUSION: These results imply that DPs in virus stocks should be considered when performing virus neutralization tests to quantify neutralizing antibodies. Copyright 2009 S. Karger AG, Basel.
Authors: Stefan Hägele; Christian Nusshag; Alexander Müller; Alexandra Baumann; Martin Zeier; Ellen Krautkrämer Journal: Virol J Date: 2021-08-17 Impact factor: 4.099