Viroclinics-DDL COVID-19 Expertise Center

Accelerating COVID-19 research through state-of-the-art preclinical, clinical diagnostics and global supply chain services

Immunological Assays

ELISA (titer or Elisa Unit (EU)/mL) [under development]  
  • SARS-CoV-2 antigens to be determined based on clinical program
  • Detect and quantitate antigen-binding IgG and IgA (others can be developed)
  • Method principles based on other ELISAs currently implemented for various clinical programs

SARS-CoV-2 Neutralization Assay

  • Serum and monoclonal antibodies; eight – eleven 2-fold dilutions
  • Wild type SARS-CoV-2, Vero-E6 cells, 96-well plates, overnight, reduction of infectivity by ViroSpot immunostaining
  • Virus strain: BavPat1/2020, Ref-SKU: 026V-03883; Other virus isolates to follow soon
  • Cell line: Vero-E6
  • Validated range BavPat1/2020: 80% microneutralization titer (MNA80) 21 – 3,972
  • Trending of QC samples

Other reportable values:

  • Titer – reciprocal dilution showing 50%, 80% or 90% infection reduction
  • International Units: Available after completion of ongoing calibration of in-house reference standard against WHO International Standard (NIBSC code: 20/136).


[Pseudo Virus Neutralization Assay under development]

ELISPOT Assays [under development]

T cell ELISPOT kits (CTL Europe, GmbH):

  • Human IFNg single color enzyme
  • Human IFNg/GRZB double color enzyme
  • Human IFNg/TNFa/IL2 triple color fluorospot
  • Other cytokines: to be determined base on clinical program

B cell ELISPOT kits (CTL Europe, GmbH):

  • IgG/IgA double color enzyme


  • T cell assay: pools of overlapping peptides; standard panels (e.g. JPT) or custom pools
  • B cell assay: viral protein to be determined based on clinical program

Reporting values:

Spot forming cells (SFC) per million cells

If you require any additional information or if you would like to discuss specific queries regarding your upcoming project, please feel free to contact our dedicated team at: