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A truncated receptor-binding domain of MERS-CoV spike protein potently inhibits MERS-CoV infection and induces strong neutralizing antibody responses: implication for developing therapeutics and vaccines.

Du L, Kou Z, Ma C, Tao X, Wang L, Zhao G, Chen Y, Yu F, Tseng CT, Zhou Y, Jiang S - PLoS ONE (2013)

Bottom Line: Development of effective therapeutics and vaccines is crucial to save lives and halt the spread of MERS-CoV.The recombinant S377-588-Fc is able to induce in the vaccinated mice strong MERS-CoV S-specific antibodies, which blocks the binding of RBD to DPP4 receptor and effectively neutralizes MERS-CoV infection.These findings indicate that this truncated RBD protein shows promise for further development as an effective and safe vaccine for the prevention of MERS-CoV infection.

View Article: PubMed Central - PubMed

Affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America.

ABSTRACT
An emerging respiratory infectious disease with high mortality, Middle East respiratory syndrome (MERS), is caused by a novel coronavirus (MERS-CoV). It was first reported in 2012 in Saudi Arabia and has now spread to eight countries. Development of effective therapeutics and vaccines is crucial to save lives and halt the spread of MERS-CoV. Here, we show that a recombinant protein containing a 212-amino acid fragment (residues 377-588) in the truncated receptor-binding domain (RBD: residues 367-606) of MERS-CoV spike (S) protein fused with human IgG Fc fragment (S377-588-Fc) is highly expressed in the culture supernatant of transfected 293T cells. The purified S377-588-Fc protein efficiently binds to dipeptidyl peptidase 4 (DPP4), the receptor of MERS-CoV, and potently inhibited MERS-CoV infection, suggesting its potential to be further developed as a therapeutic modality for treating MERS-CoV infection and saving the patients' lives. The recombinant S377-588-Fc is able to induce in the vaccinated mice strong MERS-CoV S-specific antibodies, which blocks the binding of RBD to DPP4 receptor and effectively neutralizes MERS-CoV infection. These findings indicate that this truncated RBD protein shows promise for further development as an effective and safe vaccine for the prevention of MERS-CoV infection.

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Detection of S-RBD- and S1-specific IgG level in sera of mice immunized with S377-588-Fc protein.PBS was used as the control. (A) The titers of IgG specific to MERS-CoV S377-588-Fc (S-RBD) in sera (1:3,200 dilution) of mice at pre-immunization (pre-immune) and 10 days post-each vaccination. (B) Endpoint IgG titers in mouse sera from 10 days post-last vaccination. The data are presented as mean A450 ± standard deviation (SD) of five mice per group. Ability of IgG binding to MERS-CoV S-RBD (C) and S1 protein (D) was detected using mouse sera from 10 days post-last vaccination. Ability of IgG1 (E) and IgG2a (F) antibodies binding to MERS-CoV S-RBD was detected using sera from 10 days post-last vaccination. The data are presented as mean A450 ± SD of five mice per group at various dilution points.
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pone-0081587-g004: Detection of S-RBD- and S1-specific IgG level in sera of mice immunized with S377-588-Fc protein.PBS was used as the control. (A) The titers of IgG specific to MERS-CoV S377-588-Fc (S-RBD) in sera (1:3,200 dilution) of mice at pre-immunization (pre-immune) and 10 days post-each vaccination. (B) Endpoint IgG titers in mouse sera from 10 days post-last vaccination. The data are presented as mean A450 ± standard deviation (SD) of five mice per group. Ability of IgG binding to MERS-CoV S-RBD (C) and S1 protein (D) was detected using mouse sera from 10 days post-last vaccination. Ability of IgG1 (E) and IgG2a (F) antibodies binding to MERS-CoV S-RBD was detected using sera from 10 days post-last vaccination. The data are presented as mean A450 ± SD of five mice per group at various dilution points.

Mentions: To evaluate the ability of S377-588-Fc protein to elicit MERS-CoV S-specific antibody responses, we immunized mice subcutaneously (s.c.) using the purified protein in the presence of Montanide ISA 51 adjuvant and detected IgG antibody response, subtypes and neutralizing antibodies in the mouse sera collected at different time points after immunization. The results demonstrated that S377-588-Fc induced increasing IgG antibody responses after each boost, reaching the highest level at day 10 post-3rd vaccination, with the endpoint titer of IgG approaching 1:1.7×105±7.7×104 (Fig. 4A-B). The antibodies in the mouse sera could bind efficiently to both S-RBD fusion protein S377-588-Fc (Fig. 4C) and MERS-CoV S1 protein without Fc (Fig. 4D), suggesting that the antibodies are specific for the RBD in the S1 subunit of MERS-CoV S protein. Detection of IgG subtype antibody responses revealed that S377-588-Fc was able to induce both IgG1 (Th2) and IgG2a (Th1) antibody responses in the vaccinated mice (Fig. 4E-F). However, the PBS control group could not induce significant antibody responses against MERS-CoV S-RBD and S1 proteins (Fig. 4).


A truncated receptor-binding domain of MERS-CoV spike protein potently inhibits MERS-CoV infection and induces strong neutralizing antibody responses: implication for developing therapeutics and vaccines.

Du L, Kou Z, Ma C, Tao X, Wang L, Zhao G, Chen Y, Yu F, Tseng CT, Zhou Y, Jiang S - PLoS ONE (2013)

Detection of S-RBD- and S1-specific IgG level in sera of mice immunized with S377-588-Fc protein.PBS was used as the control. (A) The titers of IgG specific to MERS-CoV S377-588-Fc (S-RBD) in sera (1:3,200 dilution) of mice at pre-immunization (pre-immune) and 10 days post-each vaccination. (B) Endpoint IgG titers in mouse sera from 10 days post-last vaccination. The data are presented as mean A450 ± standard deviation (SD) of five mice per group. Ability of IgG binding to MERS-CoV S-RBD (C) and S1 protein (D) was detected using mouse sera from 10 days post-last vaccination. Ability of IgG1 (E) and IgG2a (F) antibodies binding to MERS-CoV S-RBD was detected using sera from 10 days post-last vaccination. The data are presented as mean A450 ± SD of five mice per group at various dilution points.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3852489&req=5

pone-0081587-g004: Detection of S-RBD- and S1-specific IgG level in sera of mice immunized with S377-588-Fc protein.PBS was used as the control. (A) The titers of IgG specific to MERS-CoV S377-588-Fc (S-RBD) in sera (1:3,200 dilution) of mice at pre-immunization (pre-immune) and 10 days post-each vaccination. (B) Endpoint IgG titers in mouse sera from 10 days post-last vaccination. The data are presented as mean A450 ± standard deviation (SD) of five mice per group. Ability of IgG binding to MERS-CoV S-RBD (C) and S1 protein (D) was detected using mouse sera from 10 days post-last vaccination. Ability of IgG1 (E) and IgG2a (F) antibodies binding to MERS-CoV S-RBD was detected using sera from 10 days post-last vaccination. The data are presented as mean A450 ± SD of five mice per group at various dilution points.
Mentions: To evaluate the ability of S377-588-Fc protein to elicit MERS-CoV S-specific antibody responses, we immunized mice subcutaneously (s.c.) using the purified protein in the presence of Montanide ISA 51 adjuvant and detected IgG antibody response, subtypes and neutralizing antibodies in the mouse sera collected at different time points after immunization. The results demonstrated that S377-588-Fc induced increasing IgG antibody responses after each boost, reaching the highest level at day 10 post-3rd vaccination, with the endpoint titer of IgG approaching 1:1.7×105±7.7×104 (Fig. 4A-B). The antibodies in the mouse sera could bind efficiently to both S-RBD fusion protein S377-588-Fc (Fig. 4C) and MERS-CoV S1 protein without Fc (Fig. 4D), suggesting that the antibodies are specific for the RBD in the S1 subunit of MERS-CoV S protein. Detection of IgG subtype antibody responses revealed that S377-588-Fc was able to induce both IgG1 (Th2) and IgG2a (Th1) antibody responses in the vaccinated mice (Fig. 4E-F). However, the PBS control group could not induce significant antibody responses against MERS-CoV S-RBD and S1 proteins (Fig. 4).

Bottom Line: Development of effective therapeutics and vaccines is crucial to save lives and halt the spread of MERS-CoV.The recombinant S377-588-Fc is able to induce in the vaccinated mice strong MERS-CoV S-specific antibodies, which blocks the binding of RBD to DPP4 receptor and effectively neutralizes MERS-CoV infection.These findings indicate that this truncated RBD protein shows promise for further development as an effective and safe vaccine for the prevention of MERS-CoV infection.

View Article: PubMed Central - PubMed

Affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America.

ABSTRACT
An emerging respiratory infectious disease with high mortality, Middle East respiratory syndrome (MERS), is caused by a novel coronavirus (MERS-CoV). It was first reported in 2012 in Saudi Arabia and has now spread to eight countries. Development of effective therapeutics and vaccines is crucial to save lives and halt the spread of MERS-CoV. Here, we show that a recombinant protein containing a 212-amino acid fragment (residues 377-588) in the truncated receptor-binding domain (RBD: residues 367-606) of MERS-CoV spike (S) protein fused with human IgG Fc fragment (S377-588-Fc) is highly expressed in the culture supernatant of transfected 293T cells. The purified S377-588-Fc protein efficiently binds to dipeptidyl peptidase 4 (DPP4), the receptor of MERS-CoV, and potently inhibited MERS-CoV infection, suggesting its potential to be further developed as a therapeutic modality for treating MERS-CoV infection and saving the patients' lives. The recombinant S377-588-Fc is able to induce in the vaccinated mice strong MERS-CoV S-specific antibodies, which blocks the binding of RBD to DPP4 receptor and effectively neutralizes MERS-CoV infection. These findings indicate that this truncated RBD protein shows promise for further development as an effective and safe vaccine for the prevention of MERS-CoV infection.

Show MeSH
Related in: MedlinePlus