tetano
Editor, Senior Moderator
Microbiol Spectr
. 2022 Sep 20;e0281122.
doi: 10.1128/spectrum.02811-22. Online ahead of print.
Utilization of the Abbott SARS-CoV-2 IgG II Quant Assay To Identify High-Titer Anti-SARS-CoV-2 Neutralizing Plasma against Wild-Type and Variant SARS-CoV-2 Viruses
Yi-Chan J Lin[SUP] 1 [/SUP], David H Evans[SUP] 1 [/SUP], Ninette F Robbins[SUP] 2 [/SUP], Guillermo Orjuela[SUP] 3 [/SUP], Queenie Hu[SUP] 4 [/SUP], Reuben Samson[SUP] 4 5 [/SUP], Kento T Abe[SUP] 4 5 [/SUP], Bhavisha Rathod[SUP] 4 [/SUP], Karen Colwill[SUP] 4 [/SUP], Anne-Claude Gingras[SUP] 4 5 [/SUP], Ashleigh Tuite[SUP] 6 [/SUP], Qi-Long Yi[SUP] 7 8 [/SUP], Sheila F O'Brien[SUP] 7 8 [/SUP], Steven J Drews[SUP] 9 10 [/SUP]
Affiliations
Abstract
There is evidence that COVID-19 convalescent plasma may improve outcomes of patients with impaired immune systems; however, more clinical trials are required. Although we have previously used a 50% plaque reduction/neutralization titer (PRNT[SUB]50[/SUB]) assay to qualify convalescent plasma for clinical trials and virus-like particle (VLP) assays to validate PRNT[SUB]50[/SUB] methodologies, these approaches are time-consuming and expensive. Here, we characterized the ability of the Abbott severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG II Quant assay to identify high- and low-titer plasma for wild-type and variant (Alpha, Beta, Gamma, and Delta) SARS-CoV-2 characterized by both VLP assays and PRNT[SUB]50[/SUB]. Plasma specimens previously tested in wild-type, Alpha, Beta, Gamma, and Delta VLP neutralization assays were selected based on availability. Selected specimens were evaluated by the Abbott SARS-CoV-2 IgG II Quant assay [Abbott anti-Spike (S); Abbott, Chicago, IL], and values in units per milliliter were converted to binding antibody units (BAU) per milliliter. Sixty-three specimens were available for analysis. Abbott SARS-CoV-2 IgG II Quant assay values in BAU per milliliter were significantly different between high- and low-titer specimens for wild-type (Mann-Whitney U = 42, P < 0.0001), Alpha (Mann-Whitney U = 38, P < 0.0001), Beta (Mann-Whitney U = 29, P < 0.0001), Gamma (Mann-Whitney U = 0, P < 0.0001), and Delta (Mann-Whitney U = 42, P < 0.0001). A conservative approach using the highest 95% confidence interval (CI) values from wild-type and variant of concern (VOC) SARS-CoV-2 experiments would identify a potential Abbott SARS-CoV-2 IgG II Quant assay cutoff of ≥7.1 × 10[SUP]3[/SUP] BAU/mL. IMPORTANCE The United States Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for the use of COVID-19 convalescent plasma (CCP) to treat hospitalized patients with COVID-19 in August 2020. However, by 4 February 2021, the FDA had revised the convalescent plasma EUA. This revision limited the authorization for high-titer COVID-19 convalescent plasma and restricted patient groups to hospitalized patients with COVID-19 early in their disease course or hospitalized patients with impaired humoral immunity. Traditionally our group utilized 50% plaque reduction/neutralization titer (PRNT[SUB]50[/SUB]) assays to qualify CCP in Canada. Since that time, the Abbott SARS-CoV-2 IgG II Quant assay (Abbott, Chicago IL) was developed for the qualitative and quantitative determination of IgG against the SARS-CoV-2. Here, we characterized the ability of the Abbott SARS-CoV-2 IgG II Quant assay to identify high- and low-titer plasma for wild-type and variant (Alpha, Beta, Gamma, and Delta) SARS-CoV-2.
Keywords: COVID-19 convalescent plasma; SARS-CoV-2 antibody; method comparisons; neutralizing antibody; plaque reduction neutralization.
. 2022 Sep 20;e0281122.
doi: 10.1128/spectrum.02811-22. Online ahead of print.
Utilization of the Abbott SARS-CoV-2 IgG II Quant Assay To Identify High-Titer Anti-SARS-CoV-2 Neutralizing Plasma against Wild-Type and Variant SARS-CoV-2 Viruses
Yi-Chan J Lin[SUP] 1 [/SUP], David H Evans[SUP] 1 [/SUP], Ninette F Robbins[SUP] 2 [/SUP], Guillermo Orjuela[SUP] 3 [/SUP], Queenie Hu[SUP] 4 [/SUP], Reuben Samson[SUP] 4 5 [/SUP], Kento T Abe[SUP] 4 5 [/SUP], Bhavisha Rathod[SUP] 4 [/SUP], Karen Colwill[SUP] 4 [/SUP], Anne-Claude Gingras[SUP] 4 5 [/SUP], Ashleigh Tuite[SUP] 6 [/SUP], Qi-Long Yi[SUP] 7 8 [/SUP], Sheila F O'Brien[SUP] 7 8 [/SUP], Steven J Drews[SUP] 9 10 [/SUP]
Affiliations
- PMID: 36125288
- DOI: 10.1128/spectrum.02811-22
Abstract
There is evidence that COVID-19 convalescent plasma may improve outcomes of patients with impaired immune systems; however, more clinical trials are required. Although we have previously used a 50% plaque reduction/neutralization titer (PRNT[SUB]50[/SUB]) assay to qualify convalescent plasma for clinical trials and virus-like particle (VLP) assays to validate PRNT[SUB]50[/SUB] methodologies, these approaches are time-consuming and expensive. Here, we characterized the ability of the Abbott severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG II Quant assay to identify high- and low-titer plasma for wild-type and variant (Alpha, Beta, Gamma, and Delta) SARS-CoV-2 characterized by both VLP assays and PRNT[SUB]50[/SUB]. Plasma specimens previously tested in wild-type, Alpha, Beta, Gamma, and Delta VLP neutralization assays were selected based on availability. Selected specimens were evaluated by the Abbott SARS-CoV-2 IgG II Quant assay [Abbott anti-Spike (S); Abbott, Chicago, IL], and values in units per milliliter were converted to binding antibody units (BAU) per milliliter. Sixty-three specimens were available for analysis. Abbott SARS-CoV-2 IgG II Quant assay values in BAU per milliliter were significantly different between high- and low-titer specimens for wild-type (Mann-Whitney U = 42, P < 0.0001), Alpha (Mann-Whitney U = 38, P < 0.0001), Beta (Mann-Whitney U = 29, P < 0.0001), Gamma (Mann-Whitney U = 0, P < 0.0001), and Delta (Mann-Whitney U = 42, P < 0.0001). A conservative approach using the highest 95% confidence interval (CI) values from wild-type and variant of concern (VOC) SARS-CoV-2 experiments would identify a potential Abbott SARS-CoV-2 IgG II Quant assay cutoff of ≥7.1 × 10[SUP]3[/SUP] BAU/mL. IMPORTANCE The United States Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for the use of COVID-19 convalescent plasma (CCP) to treat hospitalized patients with COVID-19 in August 2020. However, by 4 February 2021, the FDA had revised the convalescent plasma EUA. This revision limited the authorization for high-titer COVID-19 convalescent plasma and restricted patient groups to hospitalized patients with COVID-19 early in their disease course or hospitalized patients with impaired humoral immunity. Traditionally our group utilized 50% plaque reduction/neutralization titer (PRNT[SUB]50[/SUB]) assays to qualify CCP in Canada. Since that time, the Abbott SARS-CoV-2 IgG II Quant assay (Abbott, Chicago IL) was developed for the qualitative and quantitative determination of IgG against the SARS-CoV-2. Here, we characterized the ability of the Abbott SARS-CoV-2 IgG II Quant assay to identify high- and low-titer plasma for wild-type and variant (Alpha, Beta, Gamma, and Delta) SARS-CoV-2.
Keywords: COVID-19 convalescent plasma; SARS-CoV-2 antibody; method comparisons; neutralizing antibody; plaque reduction neutralization.