A bacterium-like particle vaccine displaying Zika virus prM-E induces systemic immune responses in mice

The emergence of Zika virus (ZIKV) infection, which is unexpectedly associated with congenital defects, has prompted the development of safe and effective vaccines. The gram-positive enhancer matrix-protein anchor (GEM-PA) display system has emerged as a versatile and highly effective platform for delivering target proteins for vaccines. In this article, we developed a bacterium-like particle vaccine ZI-△-PA-GEM based on the GEM-PA system. The fusion protein ZI-△-PA, which contains the prM-E-△ protein of ZIKV (with a stem-transmembrane region deletion) and the protein anchor PA3, was expressed. The fusion protein was successfully displayed on the GEM surface, forming ZI-△-PA-GEM. Moreover, when BALB/c mice were immunized intramuscularly with ZI-△-PA-GEM combined with 201 VG and poly(I:C) adjuvants, durable ZIKV-specific IgG and protective neutralizing antibody responses were induced. Potent B cell/DC activation was also be stimulated early after immunization. Remarkably, splenocyte proliferation, the secretion of multiple cytokines, T/B cell activation and central memory T cell responses were elicited. These data indicate that ZI-△-PA-GEM is a promising bacterium-like particle vaccine candidate for ZIKV.

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A bacterium-like particle vaccine displaying Zika virus prM-E induces systemic immune responses in mice

10.1101/2021.08.13.456215 ◽

2021 ◽

Author(s):

Hongli Jin ◽

Yujie Bai ◽

Jianzhong Wang ◽

Cuicui Jiao ◽

Di Liu ◽

...

Keyword(s):

Fusion Protein ◽

B Cell ◽

Zika Virus ◽

Cell Activation ◽

Matrix Protein ◽

Neutralizing Antibody ◽

Poly I:C ◽

Congenital Defects ◽

B Cell Activation ◽

Specific Igg

The emergence of Zika virus (ZIKV) infection, which is an unexpectedly associated with congenital defects, has prompted the development of safe and effective vaccines. The gram-positive enhancer matrix-protein anchor (GEM-PA) display system has emerged as a versatile and highly effective platform for delivering target proteins for vaccines. In this article, we developed a bacterium-like particle vaccine ZI-△-PA-GEM based on the GEM-PA system. The fusion protein ZI-△-PA, which contains the prM-E-△ protein of ZIKV (with a stem-transmembrane region deletion) and the protein anchor PA3, was expressed. The fusion protein was successfully displayed on the GEM surface, forming ZI-△-PA-GEM. Moreover, when BALB/c mice were immunized intramuscularly with ZI-△-PA-GEM combined with 201 VG and poly(I:C) adjuvants, durable ZIKV-specific IgG and protective neutralizing antibody responses were induced. Potent B cell/DC activation was also be stimulated early after immunization. Remarkably, splenocyte proliferation, the secretion of multiple cytokines, T/B cell activation and central memory T cell responses were elicited. These data indicate that ZI-△-PA-GEM is a promising bacterium-like particle vaccine candidate for ZIKV.

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Expansion of SARS-CoV-2-specific Antibody-secreting Cells and Generation of Neutralizing Antibodies in Hospitalized COVID-19 Patients

10.1101/2020.05.28.118729 ◽

2020 ◽

Cited By ~ 1

Author(s):

Renata Varnaitė ◽

Marina García ◽

Hedvig Glans ◽

Kimia T. Maleki ◽

John Tyler Sandberg ◽

...

Keyword(s):

B Cell ◽

Specific Antibody ◽

Neutralizing Antibodies ◽

Cell Activation ◽

Neutralizing Antibody ◽

Antibody Responses ◽

B Cell Activation ◽

Immunological Parameters ◽

Antibody Secreting Cell ◽

Antibody Levels

AbstractCoronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in late 2019 and has since become a global pandemic. Pathogen-specific antibodies are typically a major predictor of protective immunity, yet B cell and antibody responses during COVID-19 are not fully understood. Here, we analyzed antibody-secreting cell (ASC) and antibody responses in twenty hospitalized COVID-19 patients. The patients exhibited typical symptoms of COVID-19, and presented with reduced lymphocyte numbers and increased T cell and B cell activation. Importantly, we detected an expansion of SARS-CoV-2 nucleocapsid protein-specific ASCs in all twenty COVID-19 patients using a multicolor FluoroSpot assay. Out of the 20 patients, 16 had developed SARS-CoV-2-neutralizing antibodies by the time of inclusion in the study. SARS-CoV-2-specific IgA, IgG and IgM antibody levels positively correlated with SARS-CoV-2-neutralizing antibody titers, suggesting that SARS-CoV-2-specific antibody levels may reflect the titers of neutralizing antibodies in COVID-19 patients during the acute phase of infection. Lastly, we showed that interleukin 6 (IL-6) and C-reactive protein (CRP) concentrations were higher in serum of patients who were hospitalized for longer, supporting the recent observations that IL-6 and CRP could be used to predict COVID-19 severity. Altogether, this study constitutes a detailed description of clinical and immunological parameters in twenty COVID-19 patients, with a focus on B cell and antibody responses, and provides tools to study immune responses to SARS-CoV-2 infection and vaccination.

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B cells discriminate HIV-1 Envelope protein affinities by sensing antigen binding association rates

10.1101/2022.01.14.476215 ◽

2022 ◽

Author(s):

Md. Alamgir Hossain ◽

Kara Anasti ◽

Brian Watts ◽

Kenneth Cronin ◽

Advaiti Pai Kane ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Cell Activation ◽

Neutralizing Antibody ◽

Antigen Binding ◽

B Cell Activation ◽

Kinetic Rates ◽

Env Protein ◽

Hiv 1

HIV-1 Envelope (Env) proteins designed to induce neutralizing antibody responses allow study of the role of affinities (equilibrium dissociation constant, KD) and kinetic rates (association/dissociation rates) on B cell antigen recognition. It is unclear whether affinity discrimination during B cell activation is based solely on Env protein binding KD, and whether B cells discriminate between proteins of similar affinities but that bind with different kinetic rates. Here we used a panel of Env proteins and Ramos B cell lines expressing IgM BCRs with specificity for CD4 binding-site broadly neutralizing (bnAb) or a precursor antibody to study the role of antigen binding kinetic rates on both early (proximal/distal signaling) and late events (BCR/antigen internalization) in B cell activation. Our results support a kinetic model for B cell activation in which Env protein affinity discrimination is based not on overall KD, but on sensing of association rate and a threshold antigen-BCR half-life.

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Genetic Immunization Converts the Trypanosoma cruzi B-Cell Mitogen Proline Racemase to an Effective Immunogen

Infection and Immunity ◽

10.1128/iai.00926-09 ◽

2009 ◽

Vol 78 (2) ◽

pp. 810-822 ◽

Cited By ~ 16

Author(s):

Marianne A. Bryan ◽

Karen A. Norris

Keyword(s):

B Cells ◽

Trypanosoma Cruzi ◽

B Cell ◽

Cell Activation ◽

B Cell Activation ◽

Genetic Immunization ◽

Murine Splenocytes ◽

Specific Igg ◽

Cell Mitogen ◽

Antibody Secretion

ABSTRACT Trypanosoma cruzi is the etiologic agent of Chagas' disease. Acute T. cruzi infection results in polyclonal B-cell activation and delayed specific humoral immunity. T. cruzi proline racemase (TcPRAC), a T. cruzi B-cell mitogen, may contribute to this dysfunctional humoral response. Stimulation of murine splenocytes with recombinant protein (rTcPRAC) induced B-cell proliferation, antibody secretion, interleukin-10 (IL-10) production, and upregulation of CD69 and CD86 on B cells. Marginal zone (MZ) B cells are more responsive to T-cell-independent (TI) rTcPRAC stimulation than are follicular mature (FM) B cells in terms of proliferation, antibody secretion, and IL-10 production. During experimental T. cruzi infection, TcPRAC-specific IgG remained undetectable when responses to other T. cruzi antigens developed. Conversely, intradermal genetic immunization via gene gun (GG) delivered TcPRAC as an immunogen, generating high-titer TcPRAC-specific IgG without B-cell dysfunction. TcPRAC GG immunization led to antigen-specific splenic memory B-cell and bone marrow plasma cell formation. TcPRAC-specific IgG bound mitogenic rTcPRAC, decreasing subsequent B-cell activation. GG immunization with rTcPRAC DNA was nonmitogenic and did not affect the generation of specific IgG to another T. cruzi antigen, complement regulatory protein (CRP). These data demonstrate the utility of genetic immunization for the conversion of a protein mitogen to an effective antigen. Furthermore, coimmunization of TcPRAC with another T. cruzi antigen indicates the usefulness of this approach for multivalent vaccine development.

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