Digital PCR to quantify ChAdOx1 nCoV-19 copies in blood and tissues

Anita Badbaran; Reiner K Mailer; Christine Dahlke; Jannis Woens; Anahita Fathi; Sibylle C Mellinghoff; Thomas Renné; Marylyn M Addo; Kristoffer Riecken; Boris Fehse

doi:10.1016/j.omtm.2021.10.002

Digital PCR to quantify ChAdOx1 nCoV-19 copies in blood and tissues

Mol Ther Methods Clin Dev. 2021 Oct 16:23:418-423. doi: 10.1016/j.omtm.2021.10.002. eCollection 2021 Dec 10.

Authors

Anita Badbaran¹, Reiner K Mailer², Christine Dahlke^{3

4

5}, Jannis Woens^{1

6}, Anahita Fathi^{3

4

5}, Sibylle C Mellinghoff^{3

4

5

7

8}, Thomas Renné², Marylyn M Addo^{3

4

5}, Kristoffer Riecken^{1

6}, Boris Fehse^{1

5

6}

Affiliations

¹ Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf (UKE), Martinistraße 52, 20246 Hamburg, Germany.
² Institute of Clinical Chemistry and Laboratory Medicine, UKE, 20246 Hamburg, Germany.
³ Division of Infectious Diseases, 1st Department of Medicine, UKE, 20246 Hamburg, Germany.
⁴ Department for Clinical Immunology of Infectious Diseases, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, 20359 Hamburg, Germany.
⁵ German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany.
⁶ Research Department Cell and Gene Therapy, UKE, 20246 Hamburg, Germany.
⁷ University of Cologne, Faculty of Medicine and University Hospital Cologne, Department I of Internal Medicine, Excellence Center for Medical Mycology (ECMM), 50931 Cologne, Germany.
⁸ DZIF, Partner Site Bonn-Cologne, Cologne, Germany.

Abstract

Vaccination with the adenoviral-vector-based AstraZeneca ChAdOx1 nCov-19 (Vaxzevria) vaccine is efficient and safe. However, in rare cases vaccinated individuals developed life-threatening thrombotic complications, including thrombosis in cerebral sinus and splanchnic veins. Monitoring of the applied vector in vivo represents an important precondition to study the molecular mechanisms underlying vaccine-driven adverse effects now referred to as vaccine-induced immune thrombotic thrombocytopenia (VITT). We previously have shown that digital PCR (dPCR) is an excellent tool to quantify transgene copies in vivo. Here, we present a highly sensitive dPCR for in situ quantification of ChAdOx1 nCoV-19 copies. Using this method, we quantified vector copies in human plasma 24, 72, and 168 h post vaccination and in a variety of murine tissues in an experimental vaccination model 30 min post injection. We describe a method for high-sensitivity quantitative detection of ChAdOx1 nCoV-19 with possible implications to elucidate the mechanisms of severe ChAdOx1 nCov-19 vaccine complications.

Keywords: AZD1222; ChAdOx1 nCoV-19; SARS-Cov2; Vaxzevria; adenoviral vector; digital PCR; vaccination; vaccine-induced immune thrombotic thrombocytopenia (VITT).