A novel C3d-containing oligomeric vaccine provides insight into the viability of testing human C3d-based vaccines in mice

He, YG; Pappworth, IY; Rossbach, Andreas; Paulin, Joshua; Mavimba, T; Hayes, Christine; Kulik, Liudmila; Holers, V. Michael; Knight, AM; Marchbank, Kevin J.

doi:10.1016/j.imbio.2017.10.002

Cited by 10 publications

(9 citation statements)

References 50 publications

(70 reference statements)

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“…Enzyme Linked Immuno-Sorbent Assay 29 (ELISA) using native TTCF coated plates were employed to analyse the resultant immune response. As expected from previous studies 30 , we observed an early stage immune response in the mice injected with native TTCF. This immune response was matched when the mice were injected with TTCF which had been stored as ensilicated powder and released prior to immunisation (Fig.…”

Section: Resultssupporting

confidence: 91%

Ensilicated tetanus antigen retains immunogenicity: in vivo study and time-resolved SAXS characterization

Doekhie

Dattani

Chen

et al. 2020

Sci Rep

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our recently developed ensilication approach can physically stabilize proteins in silica without use of a pre-formed particle matrix. Stabilisation is done by tailor fitting individual proteins with a silica coat using a modified sol-gel process. Biopharmaceuticals, e.g. liquid-formulated vaccines with adjuvants, frequently have poor thermal stability; heating and/or freezing impairs their potency. As a result, there is an increase in the prevalence of vaccine-preventable diseases in low-income countries even when there are means to combat them. one of the root causes lies in the problematic vaccine 'cold chain' distribution. We believe that ensilication can improve vaccine availability by enabling transportation without refrigeration. Here, we show that ensilication stabilizes tetanus toxin c fragment (ttcf), a component of the tetanus toxoid present in the diphtheria, tetanus and pertussis (Dtp) vaccine. experimental in vivo immunization data show that the ensilicated material can be stored, transported at ambient temperatures, and even heat-treated without compromising the immunogenic properties of TTCF. To further our understanding of the ensilication process and its protective effect on proteins, we have also studied the formation of ttcf-silica nanoparticles via time-resolved Small Angle X-ray Scattering (SAXS). Our results reveal ensilication to be a staged diffusion-limited cluster aggregation (DLcA) type reaction. An early stage (tens of seconds) in which individual proteins are coated with silica is followed by a subsequent stage (several minutes) in which the protein-containing silica nanoparticles aggregate into larger clusters. our results suggest that we could utilize this technology for vaccines, therapeutics or other biopharmaceuticals that are not compatible with lyophilization. Biopharmaceuticals are biologically derived active compounds intended for therapeutic or diagnostic usage. Examples include monoclonal antibodies, vaccines, cells and blood components. Many of these are proteins and not stable ex vivo. They must be stabilised to increase their shelf-life. The main approach in stabilisation of biopharmaceuticals is regulating temperature. Maintaining low (2-8 °C) temperatures retains native states of these compounds. Many protein-based biopharmaceuticals are vulnerable not only to heating but also to freezing 1-3 , which can disrupt protein structure and lead to denaturation on thawing. Within cold chain transportation 1,2,4-7 , from manufacturing to endpoint destination, temperature control has proven challenging. Fluctuations in temperature, heating/freezing 1 , can affect biopharmaceuticals resulting in aggregation and protein unfolding, leading to loss of potency. This is a serious issue in global public health 8-10

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Section: Resultssupporting

confidence: 91%

Ensilicated tetanus antigen retains immunogenicity: in vivo study and time-resolved SAXS characterization

Doekhie

Dattani

Chen

et al. 2020

Sci Rep

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“…One possible approach to overcome this is attaching more C3d to test antigens, but that approach is also limited (42). In the light of these and other findings (11, 13, 43), we considered that with understanding of the mode of action of Sbi-III-IV we might be able to develop a new complement activation based immune adjuvant.…”

Section: Discussionmentioning

confidence: 90%

“…Indeed, these linear arrays of C3d multimers (3-mer to 20-mer) when fused directly to an antigen can act as potent activators of human B-cells. However, they do not mimic the natural opsonisation of antigens by C3d at a molecular level and do not always enhance immune responses (13). After activation of C3, C3b attaches directly to the antigen surface via the reactive thioester on the convex face of the protein's thioester domain (TED).…”

Section: Introductionmentioning

confidence: 99%

Utilization of Staphylococcal Immune Evasion Protein Sbi as a Novel Vaccine Adjuvant

et al. 2019

Self Cite

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Co-ligation of the B cell antigen receptor with complement receptor 2 on B-cells via a C3d-opsonised antigen complex significantly lowers the threshold required for B cell activation. Consequently, fusions of antigens with C3d polymers have shown great potential in vaccine design. However, these linear arrays of C3d multimers do not mimic the natural opsonisation of antigens with C3d. Here we investigate the potential of using the unique complement activating characteristics of Staphylococcal immune-evasion protein Sbi to develop a pro-vaccine approach that spontaneously coats antigens with C3 degradation products in a natural way. We show that Sbi rapidly triggers the alternative complement pathway through recruitment of complement regulators, forming tripartite complexes that act as competitive antagonists of factor H, resulting in enhanced complement consumption. These functional results are corroborated by the structure of the complement activating Sbi-III-IV:C3d:FHR-1 complex. Finally, we demonstrate that Sbi, fused with Mycobacterium tuberculosis antigen Ag85b, causes efficient opsonisation with C3 fragments, thereby enhancing the immune response significantly beyond that of Ag85b alone, providing proof of concept for our pro-vaccine approach.

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“…Our data herein firstly indicates that Sbi-III-IV can activate mouse complement in an analogous manner to that of the human complement system. This obviously allows direct analysis of these pro-vaccine compounds in both mouse and human model systems (a huge advantage to previous C3d based adjuvants) [13], indeed Sbi-III-IV has acted as a C3 activator in all species tested thus far (data not shown). As predicted from the in vitro work, the opsonisation of fusion proteins or co-immunised antigen by mouse complement breakdown fragments results in a significant increase in the immunogenicity of Ag85b, with increased IgG titres noted in the presence of fused or co-immunised Ag85b (Figure 6).…”

Section: Discussionmentioning

confidence: 99%

Utilisation of staphylococcal immune evasion protein Sbi as a novel vaccine adjuvant

Yang

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Graewert³

et al. 2018

Preprint

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42Co--ligation of the B cell antigen receptor with complement receptor 2 on B--cells 43 via a C3d--opsonised antigen complex significantly lowers the threshold required 44 for B cell activation. Consequently, fusions of antigens with C3d polymers have 45 shown great potential in vaccine design. However, these linear arrays of C3d 46 multimers do not mimic the natural opsonisation of antigens with C3d. Here we 47 investigate the potential of using the unique complement activating 48 characteristics of Staphylococcal immune--evasion protein Sbi to develop a 49 pro--vaccine approach that spontaneously coats antigens with C3 degradation 50 products in a natural way. We show that Sbi rapidly triggers the alternative 51 complement pathway through recruitment of complement regulators, forming a 52 tripartite complex that acts as a competitive antagonist of factor H, resulting in 53 enhanced complement consumption. These functional results are corroborated 54 by the structure of this complement activating Sbi--III--IV:C3d:FHR--1 complex. 55Finally, we demonstrate that Sbi, fused with Mycobacterium tuberculosis antigen 56 Ag85b, causes efficient opsonisation with C3 fragments, thereby enhancing the 57 immune response significantly beyond that of Ag85b alone, providing proof of 58 concept for our pro--vaccine approach. 59 antigens by C3d at a molecular level and do not always enhance immune 82 responses [13]. After activation of C3, C3b attaches directly to the antigen 83 surface via the reactive thioester on the convex face of the protein's thioester 84 domain (TED). In the presence of complement regulators (factor I (FI) and its 85 co--factors, such as factor H (FH) and CR1) this is rapidly converted to iC3b and 86 then to C3d, exposing the concave CR2 binding site of the TED fragment away 87 from the antigen surface [14]. It is likely that multiple iC3b/C3d molecules attach 88 to complex antigens/pathogen surfaces during the initial activation phases of 89 complement, creating high--avidity binding site for complement fragment 90 receptors. 91In the last two decades, structural biology has helped to unveil many of the 92 molecular aspects that are crucial for the activation and regulation of the 93 complement system. Most notable are the crystal structures of the central 94 complement component activation states, native C3 [15], activated C3b and 95 inactive C3c [16]. The structure of C3b in complex with factors B and D [17] 96 subsequently revealed a detailed view of the alternative pathway C3 convertase 97 assembly and its activation, leading to the amplified cleavage of C3 molecules 98 that result in opsonisation and clearance of microbial pathogens and host debris. 99 The covalent attachment of C3b to surfaces does not discriminate between self 100 or non--self surfaces and requires tight regulation to protect host surfaces. 101 Structures of C3b in complex with FH domains 1--4 [18] and domains 19--20 [19, 102 20] provided insights into protection of host cells [21] and demonstrated how 103 5 factor H--related prote...

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A novel C3d-containing oligomeric vaccine provides insight into the viability of testing human C3d-based vaccines in mice

Cited by 10 publications

References 50 publications

Ensilicated tetanus antigen retains immunogenicity: in vivo study and time-resolved SAXS characterization

Ensilicated tetanus antigen retains immunogenicity: in vivo study and time-resolved SAXS characterization

Utilization of Staphylococcal Immune Evasion Protein Sbi as a Novel Vaccine Adjuvant

Utilisation of staphylococcal immune evasion protein Sbi as a novel vaccine adjuvant

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