Covid-19 assays and studies
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covid-19 ASSAYS and studies
IITRI offers multiple types of in vitro and in vivo studies for testing antivirals and vaccines against SARS-CoV-2 under BSL-3 containment. All relevant and emerging strains in the mouse and hamster models available (wildtype and variants).
Efficacy assay (Immunostain)
- Looks at 50% inhibitory concentration (IC50) of the drug or serum against SARS-CoV-2
- Briefly, cells are plated in a 96 well plate. Serial dilutions (i.e. 1:2, 1:3 or 1:10) of TA or sera are mixed with equal volumes of the virus at a low MOI (i.e. 0.005 TCID50/cell). The virus:TA or sera mixture is added to the cells. The cells are washed and overlaid with media with or without the test article.
- Other variations are possible to sponsor’s specific requests (TA addition prior to virus inoculation (pretreatment) or after virus inoculation (post treatment).
- This assay looks at the extent of viral replication measured and expressed as a percentage of virus controls (set to 100% virus replication) and cell controls (set to 0% or background). Virus Controls and Cell Controls are loaded in each plate.
- 48 hours after virus inoculation, cells are fixed and detected with coronavirus specific monoclonal antibody.
Neutralization assays (PRNT, ELISA)
PRNT
– Plaques are visualized and counted using an ELISPOT instrument
– Plaque counts are fitted to a dose-response curve and plaque reduction neutralization test titers (PRNT) expressed in terms of conventional 50% PRNT end-point titers.
ELISA
– For each well, the inhibition of virus by neutralizing antibodies is calculated as the percentage of reduction of the absorbance value in respect of the virus control
– The neutralizing antibody titer is defined as the reciprocal dilution that caused 50% reduction of the absorbance value of the virus control (50% A450 reduction)
In vivo studies
Syrian Hamster Model
– General clinical observations
– Body weight loss
– Viral load in nasal washes (TCID50 for live virus, SARS-CoV-2-specific RTqPCR)
– Tissue viral burden by TCID50 and/or RT-qPCR
– Histopathology of tissues, to be evaluated with standard H.E. staining
– Neutralizing antibody titer
– Cytokine expression by RT-qPCR
More about this model: IITRI COVID-19 hamster model
K18- hACE2 Transgenic Mouse Model
– General clinical observations
– Body weight loss, mortality
– Tissue viral burden by TCID50 and/or RT-qPCR neutralizing antibody titer
– Histopathology of tissues, to be evaluated with standard H.E. staining
– Cytokine expression by RT-qPCR and/or ELISA
Dose range-finding data for the humanized ACE2 – transgenic mouse model
More about this model: IITRI COVID-19 mouse model
Ferret Model
– Infection model only, no clinical signs
– Viral load and shedding in nasal washes
– Viral load in nasal washes (TCID50 for live virus, SARS-CoV-2-specific RTqPCR)
– Tissue viral burden by TCID50 and/or RT-qPCR
– Histopathology of tissues, to be evaluated with standard H.E. staining
– Neutralizing antibody titer
– Cytokine expression by RT-qPCR (ELISA reagents for ferrets are very limited)
Read more about our ferret models: IITRI influenza ferret model
Contact us for more detailed information, to discuss with a PhD study director or request a cost estimate.