The authors regret that the MPL/QS21 adjuvant mixture used in their study was mistakenly referred to as AS01. The MPL/QS21 adjuvant mixture differs from AS01 as it does not contain liposomes.
The corrected sections, Table and Figures of the manuscript appear below.
-
-Highlights:
-
oThe adjuvants effect of MPL/QS21 in COVID-19 recombinant protein vaccination was evaluated in mice model.
- oMPL/QS21 adjuvanted vaccine induced robust IgG binding antibody and virus-neutralizing antibody responses.
- oTwo doses may be enough for a clinical strategy design when using MPL/QS21 adjuvanted recombinant protein vaccination, especially in consideration of the limited production capacity of COVID-19 vaccine in a public health emergency.
-
o
-
-
Abstract Methods: “In this study, we utilized a mixture of MPL/QS21 as the adjuvant for an S1 protein-based COVID-19 vaccine.”
-
-
Main text results (paragraph 1): “To optimize a short-duration protocol of immunization for the recombinant S1 protein vaccine delivered with adjuvant MPL/QS21, BALB/c mice were vaccinated with single, double or triple doses of recombinant S1 protein with adjuvant.”
-
-
Main text results (paragraph 3): “To compare the adjuvants effect between MPL/QS21 and alum, a separate experiment was conducted using a lower concentration of antigen (1 μg/dose) adjuvanted with either MPL/QS21 or alum, and using adjuvant alone as control. As expected, the adjuvants alone showed negligible effects (data not shown). Importantly, the MPL/QS21 adjuvant induced slightly lower levels of IgG antibody responses at 2, 4, 6, 8, and 10 weeks after the final immunization (Table 1), supporting the conclusion that AS01 adjuvant could be used as an alternative adjuvant in the SARS-CoV-2 protein vaccine.”
Fig. 1.
The optimization of dosage schedule. (A) The vaccination schedule. BALB/c mice were vaccinated intramuscularly with vaccines in groups of six as indicated, then the mice were sacrificed at 2 weeks after the final vaccination for assays of IgG binding antibody and neutralizing antibody responses. (B) The S1-specific antibody responses. (C) The neutralizing antibody titer. Data are shown as mean values (mean ± SD) for each group of six mice.
Fig. 2.
Duration of responses after two-dose vaccination. (A) The vaccination schedule. BALB/c mice were vaccinated intramuscularly with vaccines as indicated, then the mice were sacrificed at 2 weeks, 4 weeks, and 6 weeks after the final vaccination for assays of IgG binding antibody and neutralizing antibody responses. (B) S1-specific antibody responses. (C) The virus-neutralizing antibody titer. Data are shown as mean values (mean ± SD) for each group of six mice.
Table 1.
The comparison of antibody responses with different adjuvanted S1 vaccination.
| Serum IgG binding endpoint titers |
|||||
|---|---|---|---|---|---|
| Week 4 | Week 6 | Week 8 | Week 10 | Week 12 | |
| S1/MPL/QS21 | 1:210 | 1:213 | 1:213 | 1:213 | 1:213 |
| S1/Alum | 1:210 | 1:214 | 1:214 | 1:214 | 1:214 |
BALB/c mice were immunized with 1 μg recombinant protein mixed with adjuvant with two doses two weeks apart. The adjuvants without antigen were used as controls. The plasma was collected at weeks 4, 6, 8, 10, and 12. The serum IgG binding endpoint titers are shown as mean values (mean ± SD) for each group of six mice.
The authors would like to apologise for any inconvenience caused.