Research ArticleBIOMATERIALS

In situ pneumococcal vaccine production and delivery through a hybrid biological-biomaterial vector

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Science Advances  01 Jul 2016:
Vol. 2, no. 7, e1600264
DOI: 10.1126/sciadv.1600264
  • Fig. 1 The hybrid biological-biomaterial vector.

    (A) Electrostatic interactions between a positively charged PBAE (D4A4-Man, in this case) and negatively charged E. coli bacteria result in the hybrid vector composed of both components contributing to the delivery of antigenic cargo within the E. coli core of vehicle. (B) Scanning electron microscopy image of the final vector.

  • Fig. 2 Comparative assessment of vaccine outcomes for the hybrid vector across different formulations and administration routes.

    (A to C) The PspA protein antigen at two dose levels (5 and 15 μg) was formulated with either alum or CFA and compared to the hybrid vector housing PspA (via expression plasmid) at two dose levels (105 and 107) across intraperitoneal (IP), subcutaneous (SQ), and intranasal (IN) administration routes using sepsis (A) or pneumonia (B) mouse vaccination models that were challenged with S. pneumoniae strain D39. (C) Similarly, anti-PspA antibody titers are compared. ***P < 0.001, relative to controls on associated days. (D) Antibody distributions upon vaccination with the hybrid vector containing PspA are provided at days 14 and 28 across administration routes. The x axes for all plots represent PspA antigen delivered as either protein or within the hybrid vector; 105 and 107 hybrid vectors equate to ~0.007 and 0.7 μg of PspA, respectively. AbT, antibody titer.

  • Fig. 3 Directed pneumococcal disease antigen assessment via the hybrid vector.

    (A) Asymptomatic S. pneumoniae biofilm carriage is established in the nasopharynx and can be triggered (via signals such as viral infection) for virulent cellular release and dissemination characterized by extended tissue burden and disease. The antigens delivered with the hybrid vector were chosen to elicit a directed immune response to only the virulent subpopulation of S. pneumoniae. (B to D) Vaccine screening of individual virulent-specific antigens (x axis) (B) before consolidating the antigens to plasmids within the hybrid vector tested within sepsis (C) and pneumonia (D) disease challenge protection mouse model assays against the virulent S. pneumoniae strain D39. (E and F) Vaccination was extended to test other clinically relevant S. pneumoniae strains within sepsis (E) and pneumonia (F) challenge protection mouse models.

  • Fig. 4 Directed and extended protection using the hybrid vector.

    (A) Assessment of bacterial burden was conducted across anatomical sites for unimmunized (filled circles) and immunized (using the consolidated antigens; open circles) mice challenged with avirulent (planktonic; red) or virulent (biofilm-released; blue) S. pneumoniae strain EF3030. (B to D) Site-specific bacterial burden and protection were also tested over time for mice colonized with the S. pneumoniae strain EF3030 and triggered for virulence progression using influenza A virus (IAV) inoculation. Dotted lines represent limit of detection for bacterial counts. ***P < 0.001. (E) Protection assessment (using a mouse sepsis challenge model) was then extended to 10 additional clinically relevant S. pneumoniae strains.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/7/e1600264/DC1

    fig. S1. Dosing and toxicity assessment of hybrid and bacterial vectors.

    fig. S2. Histological intranasal toxicity evaluation of hybrid devices.

    fig. S3. The pLF consolidation design and organization.

    fig. S4. Challenge levels of D39.

    fig. S5. Bacterial burden assessed for hybrid vector vaccination with the consolidated antigens against pneumococcal challenge strains that included D39, A66.1, WU2, and TIGR4 in either a sepsis or pneumonia model.

    fig. S6. Probability of mutations occurring in S. pneumoniae genes (glpO, pncO, dexB, and stkP) through cellular division.

    fig. S7. Synthetic scheme for PBAE D4A4-Man.

    table S1. DexB, GlpO, StkP, and PncO antigen description and analysis.

    table S2. Antigen cloning summary.

    table S3. Consolidated plasmid (pLF) cloning summary.

    table S4. S. pneumoniae strains used in the current study.

    Reference (23)

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Dosing and toxicity assessment of hybrid and bacterial vectors.
    • fig. S2. Histological intranasal toxicity evaluation of hybrid devices.
    • fig. S3. The pLF consolidation design and organization.
    • ig. S4. Challenge levels of D39.
    • fig. S5. Bacterial burden assessed for hybrid vector vaccination with the consolidated antigens against pneumococcal challenge strains that included D39, A66.1, WU2, and TIGR4 in either a sepsis or pneumonia model.
    • fig. S6. Probability of mutations occurring in S. pneumoniae genes (glpO, pncO, dexB, and stkP) through cellular division.
    • fig. S7. Synthetic scheme for PBAE D4A4-Man.
    • table S1. DexB, GlpO, StkP, and PncO antigen description and analysis.
    • table S2. Antigen cloning summary.
    • table S3. Consolidated plasmid (pLF) cloning summary.
    • table S4. S. pneumoniae strains used in the current study.
    • Reference (23)

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