Virology and Vaccine Studies

Measuring Viral Cytopathic Effects (CPE) in real time

Developing novel methods to screen antivirals is important for creating broad-spectrum anti-viral drugs and vaccines. The accurate measurement of viral activity plays an essential role for viral vaccine development and infectious disease studies. When infected with a virus, host cells often display changes that are collectively referred to as a cytopathic effect (CPE) which include cell shrinkage or enlargement, deterioration/lysis, cell fusion, and the formation of inclusion bodies. Not all viruses cause a CPE in their host cell, but if they do, it can be a useful tool for various research applications, including everything from virus titer determination to the detection and quantification of neutralizing antibodies.

Example data for key virology/vaccine applications:
Virus Titer DeterminationNeutralizing Antibody Detection & QuantificationAnti-viral Drug StudiesViral Fitness ComparisonsOncolytic VirusesVirucide Efficacy 


The rapid, sensitive, and high throughput xCELLigence Real-Time Cell Analysis Assay is ideal for infectious viral assays:

Types of infectious viral assays with xCELLigence RTCA

Get Automatic and Rapid Results
Monitor viral CPE without using agar, dye, fixative, or labels, over time scales ranging from minutes to days

Improve Lab Safety
Greatly reduce workload and manual handling of samples, minimizing risk of exposure to infectious material

Highly Sensitive
Obtain quantitative kinetics for the entire virus life cycle with exquisite sensitivity and reproducibility

Eliminate the subjectivity of data analysis due to visual interpretation

Scalable and Adaptable
Compatible with both 96 and 384 well formats as well as disease relevant and primary cells


Vaccine & Virology Handbook
Download the Vaccine & Virology Handbook to discover a more accurate method to characterize viral activity. Applications include viral titer determination, detection and quantification of neutralizing antibodies, studying anti-viral drugs, testing virucides, oncolytic viruses, and assessing virus quality or fitness.
Download handbook

Say “good-bye” to Endpoint Assays

Typical endpoint methods to measure viral infectivity include

  • Plaque assays
  • Plaque reduction neutralization tests (PRNT)
  • Immunofluorescence foci assays (IFA)
  • Endpoint dilution assays (TCID50)
  • Indirect measurement of host cell viability (Cellular ATP)

Conventional endpoint assays are labor intensive, time consuming, and difficult to reproduce, since different cell types and cell densities, as well as viral strains, serotypes, and mutations can cause plaque formation rates and sizes to vary dramatically.

Endpoint assays do not provide an assessment or quantification of the full virus life cycle.

Suboptimal selection of a single assay endpoint can result in inaccurate calculation of viral titer and lytic activity.

Measuring viral infectivity in real time with xCELLigence RTCA

[The xCELLigence assay can] provide additional data when compared to classical methods. The system allowed dense real-time data collection over several days, combined with low operative effort, and avoided the danger of potentially missing significant events as may happen in end-point assays.

In summary, the presented [xCELLigence-based] methods outmatch end-point assays by observing the cell population throughout the entire experiment while workload and time to result are reduced.

Witkowski et al. Biochem Biophys Res Commun. 2010 Oct 8;401(1):37-4


New Techniques in Viral CPE Assessment using Real Time Cell Analysis
Watch the webinar to learn how xCELLigence Real Time Cell Analysis technology can be used for vaccine development.
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High throughput and Simple Workflow


Virology workflow with xCELLigence

More Accurate and Reproducible Data

A New Way to Monitor Virus-Mediated Cytopathogenicity
The data below shows dynamic monitoring of Vero E6 cells during VSV infection. Download the application note to learn how the xCELLigence RTCA assay can rapidly evaluate viral cytopathic effects in real time.
Download Application Note


Dynamic monitoring of Vero E6 cells during VSV infection

(A) Normalized Cell Index values of growing cells, (B) Normalized Cell Index values of confluent cells. The virus-‑mediated effect on adhesion, spreading, and proliferation of the cells was monitored by measuring cell impedance every 15 minutes using the RTCA SP instrument. Time of addition of virus at 20.5 hours is indicated by the black vertical line. The time point when the CI value had decreased to 50% of the maximum (CI50) value is indicated by the dotted orange lines. Green curves: control (no viral infection); blue curves: 80,000 PFU VSV; red curves: 800,000 PFU VSV.


Additional Resources:



Virus Titer Determination 

Antiviral Drug Studies

Neutralizing Antibody Detection & Quantification

Oncolytic Viruses

Virus Fitness Comparisons


For Research Use Only. Not for use in diagnostic procedures.