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Research Paper

Associated virus-bacterial vaccine based on seasonal LAIV and S. pneumoniae chimeric peptide provide protection against post-influenza pneumococcal infection in mouse model

ORCID Icon, , , , , & show all
Pages 558-568 | Received 10 Nov 2021, Accepted 01 Mar 2022, Published online: 10 Mar 2022

Figures & data

Table 1. Composition of trivalent LAIV 2017–2018

Figure 1. The scheme of experimental setup for mouse study.

Figure 1. The scheme of experimental setup for mouse study.

Figure 2. Viral load in the lungs on day 3 after immunization estimated in ELISA test (n = 5). * - P < .05. A. Viral titers were determined using quantitative rRT-PCR. Standard curves were built for each vaccine virus based on viral RNA isolated from allantois virus-containing fluid with virus titers of 7 log10 EID50/ml. B. the results of lung homogenates titration in CE starting from a dilution of 1:10. А value of 1.5 indicates the sensitivity threshold of the method.

Figure 2. Viral load in the lungs on day 3 after immunization estimated in ELISA test (n = 5). * - P < .05. A. Viral titers were determined using quantitative rRT-PCR. Standard curves were built for each vaccine virus based on viral RNA isolated from allantois virus-containing fluid with virus titers of 7 log10 EID50/ml. B. the results of lung homogenates titration in CE starting from a dilution of 1:10. А value of 1.5 indicates the sensitivity threshold of the method.

Figure 3. Early cytokine production in the lung homogenates estimated in ELISA (n = 5). * - P < .05, ** - P < .01. CBA mice were intranasally inoculated using trivalent seasonal LAIV and S. pneumoniae recombinant peptide PSPF. the lungs were collected on day 3 after immunization.

Figure 3. Early cytokine production in the lung homogenates estimated in ELISA (n = 5). * - P < .05, ** - P < .01. CBA mice were intranasally inoculated using trivalent seasonal LAIV and S. pneumoniae recombinant peptide PSPF. the lungs were collected on day 3 after immunization.

Figure 4. Early cytokine production in THP-1 cell culture, ELISA. * - P < .05, ** - P < .01. Cells were inoculated with 106 EID50/ml of A/17/New York (H1n1)pdm09 LAIV virus, the PSPF polypeptide (20 µg per ml) or the mixed LAIV+PSPF. Data from three independent experiments made in duplicates are presented.

Figure 4. Early cytokine production in THP-1 cell culture, ELISA. * - P < .05, ** - P < .01. Cells were inoculated with 106 EID50/ml of A/17/New York (H1n1)pdm09 LAIV virus, the PSPF polypeptide (20 µg per ml) or the mixed LAIV+PSPF. Data from three independent experiments made in duplicates are presented.

Figure 5. Immune response to A/H1N1, A/H3N2 and B/Victoria influenza viruses estimated using ELISA assay three weeks after 1st vaccination and revaccination (n = 6). A, B, C – serum IgG. D, E, F – local IgA. * - P < .05, ** - P < .01.

Figure 5. Immune response to A/H1N1, A/H3N2 and B/Victoria influenza viruses estimated using ELISA assay three weeks after 1st vaccination and revaccination (n = 6). A, B, C – serum IgG. D, E, F – local IgA. * - P < .05, ** - P < .01.

Figure 6. ELISA antibodies to PSPF three weeks after 1st vaccination and revaccination (n = 6).* - P < .05, ** - P < .01. A. Serum IgG. B. Local IgA. * - P < .05, ** - P < .01.

Figure 6. ELISA antibodies to PSPF three weeks after 1st vaccination and revaccination (n = 6).* - P < .05, ** - P < .01. A. Serum IgG. B. Local IgA. * - P < .05, ** - P < .01.

Figure 7. Post-Influenza pneumococcal infection of the non-immunized mice. A. Survival proportions (n = 10 per group). to infect mice, we used: 1) pandemic strain A/South Africa/3626/2013 (H1N1) pdm09 at 1 LD50 (blue line); 2) 5 × 104 CFU of S. pneumoniae (red line); 3) H1N1 influenza virus followed by S. pneumoniae infection 24 hours apart (green line). * - P < .05 compared to bacterial post-influenza infection. B. S. pneumonia content in the lungs 5 and 24 hours after bacterial infection performed without influenza infection (blue dots) and against the background of influenza infection (red dots) (n = 5). * - p < .05.

Figure 7. Post-Influenza pneumococcal infection of the non-immunized mice. A. Survival proportions (n = 10 per group). to infect mice, we used: 1) pandemic strain A/South Africa/3626/2013 (H1N1) pdm09 at 1 LD50 (blue line); 2) 5 × 104 CFU of S. pneumoniae (red line); 3) H1N1 influenza virus followed by S. pneumoniae infection 24 hours apart (green line). * - P < .05 compared to bacterial post-influenza infection. B. S. pneumonia content in the lungs 5 and 24 hours after bacterial infection performed without influenza infection (blue dots) and against the background of influenza infection (red dots) (n = 5). * - p < .05.

Figure 8. Protection against A/South Africa/3626/2013(H1N1) pdm09 influenza challenge followed by S. pneumoniae infection 24 hours apart. A, B. Data from one of two independent experiments are provided. the survival rate and weight loss (n = 10 in group). C. Infectious virus isolation from the lungs 48 hours after primary virus challenge (n = 5). D. S. Pneumoniae load in the lungs on 24 hours after bacterial superinfection; titers of 102 present method sensitivity threshold (n = 5).* - p < .05.

Figure 8. Protection against A/South Africa/3626/2013(H1N1) pdm09 influenza challenge followed by S. pneumoniae infection 24 hours apart. A, B. Data from one of two independent experiments are provided. the survival rate and weight loss (n = 10 in group). C. Infectious virus isolation from the lungs 48 hours after primary virus challenge (n = 5). D. S. Pneumoniae load in the lungs on 24 hours after bacterial superinfection; titers of 102 present method sensitivity threshold (n = 5).* - p < .05.

Data availability statement

The data supporting the findings obtained in this study are available in “Figshare” at http://doi.org/[10.6084/m9.figshare.16974706].