Abstract
Background: There are limited data on the neutralizing activity of convalescent plasma (CP) administered in randomized controlled trials (RCT) of COVID-19 infection.
Study design and methods: As part of an RCT, CP was collected per FDA guidelines from individuals recovered from COVID-19 infection. CP donors had to have ≥145 optical density (OD) units (ideal target ≥300) using a semiquantitative, immunochromatographic test for IgG antibody to the nucleocapsid protein (NP) of SARS-CoV-2 (typical range 0-500 OD units). A random subset of samples [14 control plasma, 12 CP “medium-anti-NP” (145-299 OD units), and 13 CP “high” anti-NP (≥300 OD units)] were tested for neutralizing antibodies using an established viral luciferase antibody inhibition assay to detect the infection of SARS-CoV-2 pseudovirus that encoded spike protein (SARS2-S trunc ) on a human immunodeficiency virus 1 vector (NL43dEnvNanoLuc), using ACE2-expressing 293 T cells. The titer needed to neutralize 50% of viral activity (NT50) was calculated.
Results: The uptake of SARS-CoV-2 pseudovirus by 293T ACE2 cells was inhibited by pretreatment with CP compared to control CP (p < .001) with control plasma having a median (IQR) 50% neutralization titer (NT50) of 1:28 (1:16,1:36) compared to 1:334 (1:130,1:1295) and 1:324 (1:244,1:578), for medium anti-NP and high anti-NP CP units, respectively. The neutralizing activity of CP met minimum FDA criteria with neutralizing antibody titers >1:80 in 100% of randomly selected samples, using a conservative approach that excluded non-specific binding.
Discussion: Plasma from donors screened using an immunochromatographic test for IgG antibody to SARS-CoV-2 NP exhibited neutralizing activity meeting FDA’s minimum standard in all randomly selected COVID-19 CP units.
Keywords: FFP transfusion; immunology (other than RBC serology).
【저자키워드】 FFP transfusion, immunology (other than RBC serology), 【초록키워드】 COVID-19, Randomized controlled trial, convalescent plasma, neutralizing antibody, immunology, SARS-CoV-2, ACE2, Randomized controlled trials, Neutralizing antibodies, serology, antibody, T cells, Infection, FDA, RCT, Spike protein, nucleocapsid protein, Neutralizing activity, IgG antibody, Viral, COVID-19 infection, pseudovirus, titer, plasma, optical, SARS-CoV-2 pseudovirus, SARS2, donors, Human immunodeficiency virus, non-specific, Antibody titers, Neutralizing antibody titer, Donor, binding, criteria, optical density, medium, neutralizing antibody titers, individual, 293T, random, neutralization titer, immunochromatographic test, Administered, approach, Cell, RBC, neutralize, Randomly, 293 T cells, randomly selected samples, selected, tested, detect, inhibited, was collected, screened, exhibited, median, calculated, excluded, subset, IQR, 【제목키워드】 Randomized controlled trial, SARS-CoV-2, convalescent,