Virus Titer
Virus Titer - Related Videos
06:23
A Focus-Forming Assay for Quantifying Virus Titers in the Organs of an Infected Mouse
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2025
The video demonstrates a procedure for quantifying the Zika virus in multiple mouse organs via a focus-forming assay. The process involves infecting mammalian cell monolayers with virus-infected tissue homogenates, followed by the use of methyl cellulose to prevent viral spread. Subsequently, immunostaining is employed to enable precise quantification and measurement of organ-specific infectivity.
05:01
An Assay to Measure the Neutralizing Antibody Titer Specific for Respiratory Syncytial Virus
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2025
This video demonstrates an assay for measuring neutralizing antibodies against respiratory syncytial virus (RSV). Pre-incubation with serum containing RSV-neutralizing antibodies neutralizes the virus particles, reducing cellular infection and plaque formation. Virus-infected cells are then subjected to fixation, blocking, and fluorophore-conjugated antibody labeling for plaque visualization. This process enables the identification of the highest serum dilution that neutralizes fifty percent of...
05:51
A Streamlined and Standardized Procedure for Generating High-Titer, High-Quality Adeno-Associated Virus Vectors Utilizing a Cell Factory Platform
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Cited by 1 •
2024
As the field of gene therapy continues to evolve, there is a growing need for innovative methods that can address these challenges. Here, a unique method is presented, which streamlines the process of generating high-yield and high-purity AAV vectors using a cell factory platform, meeting the quality standards for in vivo studies.
07:24
Production of High-Titer Recombinant Newcastle Disease Virus from Allantoic Fluid
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Cited by 3 •
2022
Here we provide a detailed procedure for production, purification, and quantification of high-titer recombinant Newcastle disease virus. This protocol consistently yields > 6 × 109 plaque-forming units/mL, providing virus quantities appropriate for in vivo animal studies. Additional quality control assays to ensure safety in vivo are described.
03:19
An Assay to Measure Influenza Neuraminidase Inhibition Antibody Titers
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2025
This video demonstrates an assay measuring influenza neuraminidase (NA) inhibiting antibody titers in a serum sample. A serum sample containing antibodies against NA is added to a fetuin-coated microwell plate. Upon adding the virus, the antibodies prevent viral NA from cleaving fetuin and exposing its galactose moiety. A peroxidase-conjugated lectin is then added, which binds to the exposed galactose. The NA-inhibiting antibody titer is determined using a colorimetric test, where a peroxidase...
FAQs
Virus titer can report two related but different quantities: infectious units and total viral particles. Infectious-unit measurements reflect virus capable of producing infection in the selected assay system, whereas particle-based measurements include particles whether or not they establish infection. This distinction matters when comparing samples, because equal particle concentrations may not produce equal biological effects.
Plaque assays and TCID50 answer the same practical need through different readouts. Plaque formation provides a count of infection-associated zones in susceptible cell cultures, while TCID50 uses dilution patterns to estimate the endpoint infecting half of the cultures. The selected method affects how results are expressed and compared across experiments.
Serial dilution places the sample across a range in which infection can be measured reliably. Each dilution is tested in susceptible cells or another assay system, allowing the observed infection pattern to be linked back to the original sample concentration. Consistent dilution handling is essential for producing measurements that support meaningful comparisons between samples.
Accurate titration links an experimental dose to a measured amount of infectious virus rather than relying on an unstandardized sample volume. That relationship helps investigators reproduce biological effects, compare viral growth, and distinguish dose-related changes from variation in preparation. The resulting value provides a common basis for setting inocula across experiments.
A typical workflow prepares serial dilutions of the virus sample, exposes susceptible cells or another assay system to those dilutions, and records either plaque formation or infection across the dilution series. Researchers then use the observed pattern to quantify the original sample. The assay readout determines whether the result is reported through infectious units or an endpoint measure such as TCID50.
Titer measurements help researchers standardize the amount of virus introduced into an experiment, making treatment groups more comparable. In vaccine studies, they support evaluation of how viral growth or infection changes under the experimental conditions. For antiviral research, consistent infectious-virus doses help investigators compare biological effects across treatments rather than confounding results with unequal starting amounts.
In gene-delivery work, titration helps investigators set a defined amount of infectious virus when testing delivery conditions. During virus production, measurements support comparisons among preparations and help optimize protocols for obtaining the intended biological effect. Using infectious-virus values rather than sample volume alone improves control over the dose and strengthens interpretation of performance differences.