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Preclinical in vitro and in vivo profile of a highly-attenuated, broadly efficacious pneumolysin genetic toxoid.

ABSTRACT: Pneumolysin is a highly conserved, cholesterol-dependent cytolysin that is an important Streptococcus pneumoniae virulence factor and an attractive target for vaccine development. To attenuate pneumolysin toxicity, a genetic toxoid was constructed with two amino acid changes, G293S and L460D, termed PLY-D, that reduced cytolytic activity > 125,000-fold. In mice, PLY-D elicited high anti-PLY IgG antibody titers that neutralized the cytolytic activity of the wild-type toxin in vitro. To evaluate the protective efficacy of PLY-D, mice were immunized intramuscularly and then challenged intranasally with a lethal dose of 28 clinical isolates of S. pneumoniae originating from different geographical locations, disease states (i.e. bacteremia, pneumonia), or body sites (i.e. sputum, blood). PLY-D immunization conferred significant protection from challenge with 17 of 20 serotypes (85%) and 22 of 28 strains (79%). Further, we demonstrated that immunization with PLY-D provided statistically significant improvement in survival against challenge with serotype 4 and 18C strains compared to mice immunized with a pneumococcal conjugate vaccine Prevnar 13® (PCV13). Co-administration of PLY-D and PCV13 conferred greater protection against challenge with a serotype 6B strain than immunization with either vaccine alone. These data indicate that PLY-D is a broadly protective antigen with the potential to serve as a serotype-independent vaccine against invasive pneumococcal disease either alone or in combination with PCVs.

SUBMITTER: Thanawastien A

PROVIDER: S-EPMC8237519 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Purpose: Authentic preclinical models of renal cell carcinoma (RCC) are lacking. We aimed to establish and characterize primary RCC cultures and demonstrate the feasibility of evaluating drug responses in vitro and in vivo. Materials and Methods: Previously published methodology, with minor modifications, was used to establish, cryopreserve, and serially passage RCC cells from nephrectomy and tumorgraft specimens. Cells were characterized for immuno- and molecular phenotype by immunochemistry, DNA sequencing and gene expression profiling. Tumorigenic potential was evaluated by implanting cells under the renal capsule of immunocompromised mice. The ability to monitor xenograft growth by magnetic resonance imaging (MRI) was investigated. Responses to a tyrosine kinase inhibitor (TKI) and an mTOR inhibitor were measured. Results: Primary cultures were successfully established from 11 clear cell and 1 chromophobe RCC, cryopreserved and serially passaged. Retention of immuno- and molecular phenotypes was demonstrated. Cultured cells formed xenografts in mice that could be measured by MRI. Patient-specific responses to drugs were observed in vitro and response to an TKI was confirmed in vivo. Conclusions: Our study is the first to show the derivation of primary cultures from RCC tumorgrafts, and to demonstrate the ability of primary RCC cultures to generate xenografts in mice. Our results suggest the feasibility of establishing large, well-annotated banks of RCC primary cultures for high-throughput drug screening in vitro and validation in vivo, providing a versatile platform together with xenografts and patient-derived precision-cut tissue slice tumorgrafts we developed previously for precilinical studies of RCC. Microarray analyses were performed to compare the gene expression profile of one of the primary cultures (case 7) to its parental tumor and tissue slice tumorgrafts in the study. Tissue slice grafts and parent tumors were preserved in Allprotect tissue reagent (Qiagen, Valencia, CA) at -20Â°C prior to RNA extraction using an AllPrep DNA/RNA/Protein Mini Kit (Qiagen, Valencia, CA). The quality of RNA was determined using an Agilent 2100 Bioanalyzer (Agilent Biotechnologies, Santa Clara, CA). Microarray hybridization was performed using Illumina Human HT-12 v4 Beadchips (Illumina Inc., San Diego, CA) according to the manufacturerâ??s directions. Expression data was rank invariant normalized using BeadStudio software (Illumina Inc.).

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Preclinical in vitro and in vivo profile of a highly-attenuated, broadly efficacious pneumolysin genetic toxoid.

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