9 research outputs found

    DataSheet_1_Preclinical evaluation of safety and immunogenicity of a primary series intranasal COVID-19 vaccine candidate (BBV154) and humoral immunogenicity evaluation of a heterologous prime-boost strategy with COVAXIN (BBV152).docx

    No full text
    Most if not all vaccine candidates developed to combat COVID-19 due to SARS-CoV-2 infection are administered parenterally. As SARS-CoV-2 is transmitted through infectious respiratory fluids, vaccine-induced mucosal immunity could provide an important contribution to control this pandemic. ChAd-SARS-CoV-2-S (BBV154), a replication-defective chimpanzee adenovirus (ChAd)-vectored intranasal (IN) COVID-19 vaccine candidate, encodes a prefusion-stabilized version of the SARS-CoV-2 spike protein containing two proline substitutions in the S2 subunit. We performed preclinical evaluations of BBV154 in mice, rats, hamsters and rabbits. Repeated dose toxicity studies presented excellent safety profiles in terms of pathology and biochemical analysis. IN administration of BBV154 elicited robust mucosal and systemic humoral immune responses coupled with Th1 cell-mediated immune responses. BBV154 IN vaccination also elicited potent variant (omicron) cross neutralization antibodies. Assessment of anti-vector (ChAd36) neutralizing antibodies following repeated doses of BBV154 IN administration showed insignificant titers of ChAd36 neutralizing antibodies. However, the immune sera derived from the same animals displayed significantly higher levels of SARS-CoV-2 virus neutralization (p<0.003). We also evaluated the safety and immunogenicity of heterologous prime-boost vaccination with intramuscular (IM) COVAXIN-prime followed by BBV154 IN administration. COVAXIN priming followed by BBV154 IN-booster showed an acceptable reactogenicity profile comparable to the homologous COVAXIN/COVAXIN or BBV154/BBV154 vaccination model. Heterologous vaccination of COVAXIN-prime and BBV154 booster also elicited superior (p<0.005) and cross variant (omicron) protective immune responses (p<0.013) compared with the homologous COVAXIN/COVAXIN schedule. BBV154 has successfully completed both homologous and heterologous combination schedules of human phase 3 clinical trials and received the restricted emergency use approval (in those aged above 18 years) from the Drugs Controller General of India (DCGI).</p

    Immunization with the <i>emrA1</i> mutant results in minimal weight loss, rapid bacterial clearance, and histopathological lesions in lung, liver and spleen.

    No full text
    <p>C57BL/6 mice were immunized i.n. with 1×10<sup>6</sup> CFU of the <i>emrA1</i> mutant. Mice infected with equal numbers of wild type <i>Ft</i> LVS were used as controls. <b>(A)</b> The immunized mice were weighed at the indicated times post-immunization to track the progress of infection. <b>(B)</b> On days 1, 5, 7, 14 and 21 post-immunization, mice (n = 4 per group/time point) were euthanized and bacterial burdens were quantified in their lung, liver and spleen. Bacterial counts in organs are expressed as Log<sub>10</sub>CFU/mL. The <i>P</i> values were determined using one way ANOVA. *<i>P<0</i>.<i>05; **P<0</i>.<i>01; ***P<0</i>.<i>001</i>. <b>(C)</b> Excised lungs, livers and spleens were preserved in 10% formalin, paraffin embedded, sliced into 5 μM thin sections and stained with Hematoxylene & Eosin. Stained sections were observed for histopathological lesions under a light microscope (Magnification 100×). # = <i>Ft</i> LVS infected mice succumbed to infection.</p

    The <i>emrA1</i> mutant vaccinated mice induce sustained production of pro-inflammatory cytokines and a potent antibody response following lethal <i>Ft</i> LVS challenge.

    No full text
    <p>C57BL/6 mice immunized i.n. with 1×10<sup>6</sup> CFU of the <i>emrA1</i> mutant were challenged i.n. with 1×10<sup>7</sup> CFU of wild type <i>Ft</i> LVS 42 days post-immunization. <b>(A-D)</b> On days 5, 7 and 14 post-challenge, mice (n = 3 per group/time point) were euthanized and their excised lungs were homogenized. Clear lung homogenates were used for quantification of indicated pro-inflammatory cytokines using flow cytometric analysis. The data are represented as Mean ± S.D. <b>(E)</b> On day 21 post-challenge, mice (n = 3 per group) were anesthetized and bled retroorbitally to obtain serum. <i>Ft</i> specific total IgG, IgG2a, IgG2b, IgG1 and IgA levels in serum samples were determined by ELISA. The data are represented as Mean ± S.D. of absorbance values measured at 450 nm. Red arrows indicate antibody titers. ND = Not detected.</p

    Immunization with <i>emrA1</i> mutant using a prime-boost vaccination regimen improves the extent of protection against <i>Ft</i> SchuS4 challenge.

    No full text
    <p><b>(A)</b> C57BL/6 mice (n = 10 per group) were immunized i.n. with 1×10<sup>6</sup> CFU of the <i>emrA1</i> mutant and boosted i.d. on day 21 with a similar dose. On day 42 of the primary immunization mice were challenged i.n. with 17 CFU of <i>Ft</i> SchuS4. Age matched unvaccinated mice challenged with a similar dose of <i>Ft</i> SchuS4 served as controls. <b>(B)</b> C57BL/6 mice (n = 10 per group) were immunized i.d. with 1×10<sup>6</sup> CFU of the <i>emrA1</i> mutant and boosted i.n. on day 21 with a similar dose. On day 42 of the primary immunization mice were challenged i.n. with 17 CFU of <i>Ft</i> SchuS4. Age matched unvaccinated mice challenged with a similar dose of <i>Ft</i> SchuS4 served as controls. The survival results are expressed as Kaplan-Meier survival curves and P values were determined by Log-rank test.</p

    Mice immunized with the <i>emrA1</i> mutant induce regulated production of pro-inflammatory cytokines and a potent antibody response.

    No full text
    <p>C57BL/6 mice were immunized i.n. with <i>1</i>×10<sup>6</sup> CFU of the <i>emrA1</i> mutant or <i>Ft</i> LVS. On days 1, 5, 7 and 14 post-immunization, mice (n = 4 per group/time point) were euthanized and their excised lungs and spleens were homogenized. Clear lung <b>(A-D)</b> and spleen <b>(E-H)</b> homogenates were used for quantification of indicated pro-inflammatory cytokines using flow cytometric analysis. The data are represented as Mean ± S.D. The <i>P</i> values were determined using one way ANOVA. *<i>P<0</i>.<i>05; **P<0</i>.<i>01</i>. <b>(I)</b> On day 42 post-immunization, mice (n = 3 per group/ time point) were anesthetized and bled retroorbitally to obtain serum. <i>Ft</i> specific total IgG, IgG2a, IgG2b, IgG1 and IgA levels in serum samples were determined by ELISA. The data are represented as Mean ± S.D. of absorbance values measured at 450 nm. Red arrows indicate antibody titers. # = <i>Ft</i> LVS immunized mice succumbed to infection; ND = Not detected.</p

    Mice immunized with the <i>emrA1</i> mutant are protected against 1000LD100–10,000LD100 challenge dose of <i>Ft</i> LVS.

    No full text
    <p>C57BL/6 mice (n = 5–10 per group) were immunized i.n. with 1×10<sup>6</sup> CFU of the <i>emrA1</i> mutant. <b>(A, B)</b> On day 42 of the primary immunization mice were challenged i.n. with 1×10<sup>7</sup> CFU of wild type <i>Ft</i> LVS. Age matched unvaccinated mice challenged with a similar dose of <i>Ft</i> LVS were kept as controls. (<b>C, D)</b> On day 42 of the primary immunization mice were challenged i.n. with 1×10<sup>8</sup> CFU of wild type <i>Ft</i> LVS. Age matched unvaccinated mice challenged with a similar dose of <i>Ft</i> LVS were kept as controls. (<b>E, F)</b> On day 75 of the primary immunization mice were challenged i.n. with 1×10<sup>7</sup> CFU of wild type <i>Ft</i> LVS. Age matched unvaccinated mice challenged with a similar dose of <i>Ft</i> LVS were kept as controls. The Challenged mice were observed for morbidity and mortality for a period of 21 days post-challenge (<b>A, C, E</b>). The mice were weighed at the indicated times post-challenge to monitor the progression of infection (<b>B, D, F</b>). The survival results are expressed as Kaplan-Meier survival curves and P values were determined by Log-rank test. Body weights of mice are expressed percent body weights.</p

    Immunization with <i>emrA1</i>-mAb complexes improves the extent of protection against <i>Ft</i> SchuS4 challenge.

    No full text
    <p><b>(A)</b> C57BL/6 mice (n = 10 per group) immunized i.n. with 1×10<sup>6</sup> CFU of the <i>emrA1</i> mutant-mAb immune complexes. On day 42 of the primary immunization mice were challenged i.n. with 32 CFU of <i>Ft</i> SchuS4. Age matched unvaccinated mice challenged with a similar dose of <i>Ft</i> SchuS4 served as controls. The survival results are expressed as Kaplan-Meier survival curves and P values were determined by Log-rank test. <b>(B)</b> The mice were weighed at the indicated times post-challenge to monitor the progression of infection. <b>(C)</b> The indicated <i>Ft</i> specific antibodies were determined in serum from immunized mice on day 14 post-immunization. The results are expressed as antibody titers.</p

    The <i>emrA1</i> mutant vaccinated mice clear bacteria rapidly and exhibit minimal histopathological lesions in lung, liver and spleen following lethal <i>Ft</i> LVS challenge.

    No full text
    <p>C57BL/6 mice immunized i.n. with 1×10<sup>6</sup> CFU of the <i>emrA1</i> mutant or the unvaccinated control mice were challenged i.n. with 1×10<sup>7</sup> CFU of <i>Ft</i> LVS 42 days post-immunization. <b>(A)</b> On days 5, 7, and 14 post-challenge, mice (n = 3 per group/time point) were euthanized and bacterial burdens were quantified in their lung, liver and spleen. Bacterial counts in organs are expressed as Log<sub>10</sub> CFU/mL. The <i>P</i> values were determined using one way ANOVA. **<i>P<0</i>.<i>01;</i> ***<i>P<0</i>.<i>001</i>. <b>(B)</b> Lungs, livers and spleens collected at the indicated times post-challenge were preserved in 10% formalin, embedded in paraffin blocks, sliced into 5 μM thin sections and stained with Hematoxylene & Eosin. Stained sections were observed for histopathological lesions under a light microscope (Magnification 100×). # = Unvaccinated mice succumbed to infection.</p

    Immunization with <i>emrA1</i>-mAb complexes using a prime-boost vaccination regimen or a low dose immunization improves the extent of protection against <i>Ft</i> SchuS4 challenge.

    No full text
    <p><b>(A)</b> C57BL/6 mice (n = 10 per group) were immunized i.d. with 1×10<sup>6</sup> CFU of the <i>emrA1</i> mutant-mAb immune complex and boosted i.n. on day 21 with a similar dose. On day 42 of the primary immunization mice were challenged i.n. with 17 CFU of <i>Ft</i> SchuS4. Age matched unvaccinated mice challenged with a similar dose of <i>Ft</i> SchuS4 served as controls. <b>(B)</b> C57BL/6 mice (n = 10 per group) immunized i.n. with 1×10<sup>6</sup> CFU of the <i>emrA1</i>mutant-mAb immune complex and boosted i.d. on day 21 with a similar dose. On day 42 of the primary immunization mice were challenged i.n. with 17 CFU of <i>Ft</i> SchuS4. Age matched unvaccinated mice challenged with a similar dose of <i>Ft</i> SchuS4 served as controls. <b>(C)</b> C57BL/6 mice (n = 10 per group) immunized i.n. with 1×10<sup>3</sup> CFU of the <i>emrA1</i> mutant and boosted i.d. on day 21 with a similar dose. On day 42 of the primary immunization mice were challenged i.n. with 17 CFU of <i>Ft</i> SchuS4. Age matched unvaccinated mice challenged with a similar dose of <i>Ft</i> SchuS4 served as controls. <b>(D)</b> C57BL/6 mice (n = 10 per group) immunized i.d. with 1×10<sup>3</sup> CFU of the <i>emrA1</i> mutant and boosted i.n. on day 21 with a similar dose. On day 42 of the primary immunization mice were challenged i.n. with 17 CFU of <i>Ft</i> SchuS4. Age matched unvaccinated mice challenged with a similar dose of <i>Ft</i> SchuS4 served as controls. The survival results are expressed as Kaplan-Meier survival curves and P values were determined by Log-rank test.</p
    corecore