Tcid50 Assay
Tcid50 Assay - Related Videos
08:01
A Streamlined, Label-Free Real-Time 50% Tissue Culture Infectious Dose (TCID50) Assay using Impedance for Automated Viral Titer Quantification
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2026
The TCID50 assay reported here leverages label-free real-time impedance measurements and the system's Virology module to objectively monitor virus-induced cytopathic effects (CPE) in real time. This streamlined assay significantly reduces hands-on time while supporting high-throughput, quantitative kinetic CPE measurements and enabling automated, real-time TCID50 calculations.
04:06
Use of Crystal Violet to Improve Visual Cytopathic Effect-based Reading for Viral Titration using TCID50 Assays
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Cited by 9 •
2022
This protocol shows an accurate and objective approach to visualize viral titrations using crystal violet, by comparing it with optical microscopy and immunocytochemical staining.
05:33
A Microneutralization Assay to Measure Neutralizing Antibody Titers in Human Serum
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2025
This video demonstrates Microneutralization assays to measure neutralizing antibodies using Madin-Darby Canine Kidney cells overexpressing α2,6-linked sialic acid in human sera. This assay is often used for influenza human...
08:12
The TUNEL Assay
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2023
One of the hallmarks of apoptosis is the nuclear DNA fragmentation by nucleases. These enzymes are activated by caspases, the family of proteins that execute the cell death program. TUNEL assay is a method that takes advantage of this feature to detect apoptotic cells. In this assay, an enzyme called terminal deoxynucleotidyl transferase catalyzes the addition of dUTP nucleotides to the free 3’ ends of fragmented DNA. By using dUTPs that are labeled with chemical tags that can produce...
09:12
Aortic Ring Assay
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Cited by 42 •
2009
Angiogenesis, the sprouting of blood vessels from pre-existing vasculature, is associated with both natural and pathological processes. Here we demonstrate an aortic ring assay that allows angiogenic potentiators and inhibitors to be directly added to aortic rings in culture. Sprouting and neovessel outgrowth can be determined by inspecting the aortic rings over a period of 6-12 days.
FAQs
The 50% endpoint provides a consistent reference for comparing infectious virus samples. Rather than relying on complete infection of every culture, the assay identifies the dilution at which half of the inoculated cell cultures show infection. This probabilistic measurement supports quantitative estimation of infectious dose and allows biologically active virus preparations to be compared using a shared endpoint.
TCID50 results reflect whether virus can produce infection in susceptible cell cultures, not how many viral particles or other viral components are present. A sample may therefore contain material that is not biologically infectious without producing a proportional assay signal. This distinction makes the method useful when the research question concerns functional infectivity rather than total viral quantity.
Cytopathic effects provide an observable indication that infection has occurred in exposed cell cultures. The assay records infection across the dilution series using these effects or another validated endpoint, then uses the pattern to estimate the 50% infectious dose. Selecting an endpoint that reliably reflects infection is important because the calculated result depends on how positive cultures are identified.
Reed–Muench and Spearman–Kärber are statistical approaches for converting infection results from serial virus dilutions into a 50% infectious-dose estimate. They use the distribution of positive and negative cultures across the dilution series rather than a single observation. Applying one of these calculations turns scored culture outcomes into a quantitative measure suitable for comparing virus samples.
A typical workflow begins by preparing serial dilutions of the virus sample and exposing susceptible cell monolayers to each dilution. Researchers then score infection in the cultures through cytopathic effects or another validated endpoint. The resulting pattern of infected and noninfected cultures is analyzed statistically to estimate the dilution associated with infection in 50% of cultures.
Viral stock titration is a central application because the assay estimates the amount of infectious virus in a preparation. By measuring biological activity rather than total particles, it helps researchers compare stock samples according to their capacity to infect cells. This information can support experiments that require characterization of infectious virus before further biological testing.
In vaccine-related studies, infectious-dose measurements can help assess virus preparations or responses in experiments where biological infectivity matters. For antiviral evaluation, comparing infection outcomes across treated and untreated conditions can provide an infectivity-based readout. The assay therefore connects cell-culture infection patterns with questions about how interventions affect the amount of biologically active virus.
Neutralization studies can use the assay to examine whether a test condition changes the ability of virus to infect susceptible cell cultures. Researchers compare infection patterns across virus dilutions and conditions, then calculate the corresponding 50% infectious-dose estimates. Because the readout is based on infection, the method helps evaluate changes in functional viral activity rather than only changes in particle abundance.