Structure-based programming of lymph-node targeting in molecular vaccines

In cancer patients, visual identification of sentinel lymph nodes (LNs) is achieved by the injection of dyes that bind avidly to endogenous albumin, targeting these compounds to LNs, where they are efficiently filtered by resident phagocytes1, 2. Here we translate this ‘albumin hitchhiking’ approach to molecular vaccines, through the synthesis of amphiphiles (amph-vaccines) comprising an antigen or adjuvant cargo linked to a lipophilic albumin-binding tail by a solubility-promoting polar polymer chain. Administration of structurally optimized CpG-DNA/peptide amph-vaccines in mice resulted in marked increases in LN accumulation and decreased systemic dissemination relative to their parent compounds, leading to 30-fold increases in T-cell priming and enhanced anti-tumour efficacy while greatly reducing systemic toxicity. Amph-vaccines provide a simple, broadly applicable strategy to simultaneously increase the potency and safety of subunit vaccines.David H. Koch Institute for Integrative Cancer Research at MIT (Koch Institute Support (core) Grant P30-CA14051)National Cancer Institute (U.S.)National Institutes of Health (U.S.) (grant AI091693)National Institutes of Health (U.S.) (grant AI104715)National Institutes of Health (U.S.) (AI095109)United States. Dept. of Defense (contract W911NF-13-D-0001)United States. Dept. of Defense (contract W911NF-07-D-0004)Ragon Institute of MGH, MIT, and Harvar

Genetic Evidence for Single-Strand Lesions Initiating Nbs1-Dependent Homologous Recombination in Diversification of Ig V in Chicken B Lymphocytes

Homologous recombination (HR) is initiated by DNA double-strand breaks (DSB). However, it remains unclear whether single-strand lesions also initiate HR in genomic DNA. Chicken B lymphocytes diversify their Immunoglobulin (Ig) V genes through HR (Ig gene conversion) and non-templated hypermutation. Both types of Ig V diversification are initiated by AID-dependent abasic-site formation. Abasic sites stall replication, resulting in the formation of single-stranded gaps. These gaps can be filled by error-prone DNA polymerases, resulting in hypermutation. However, it is unclear whether these single-strand gaps can also initiate Ig gene conversion without being first converted to DSBs. The Mre11-Rad50-Nbs1 (MRN) complex, which produces 3′ single-strand overhangs, promotes the initiation of DSB-induced HR in yeast. We show that a DT40 line expressing only a truncated form of Nbs1 (Nbs1p70) exhibits defective HR-dependent DSB repair, and a significant reduction in the rate—though not the fidelity—of Ig gene conversion. Interestingly, this defective gene conversion was restored to wild type levels by overproduction of Escherichia coli SbcB, a 3′ to 5′ single-strand–specific exonuclease, without affecting DSB repair. Conversely, overexpression of chicken Exo1 increased the efficiency of DSB-induced gene-targeting more than 10-fold, with no effect on Ig gene conversion. These results suggest that Ig gene conversion may be initiated by single-strand gaps rather than by DSBs, and, like SbcB, the MRN complex in DT40 may convert AID-induced lesions into single-strand gaps suitable for triggering HR. In summary, Ig gene conversion and hypermutation may share a common substrate—single-stranded gaps. Genetic analysis of the two types of Ig V diversification in DT40 provides a unique opportunity to gain insight into the molecular mechanisms underlying the filling of gaps that arise as a consequence of replication blocks at abasic sites, by HR and error-prone polymerases

Neoadjuvant chemotherapy or primary surgery in stage IIIC or IV ovarian cancer.

Contains fulltext : 89523.pdf (publisher's version ) (Open Access)BACKGROUND: Primary debulking surgery before initiation of chemotherapy has been the standard of care for patients with advanced ovarian cancer. METHODS: We randomly assigned patients with stage IIIC or IV epithelial ovarian carcinoma, fallopian-tube carcinoma, or primary peritoneal carcinoma to primary debulking surgery followed by platinum-based chemotherapy or to neoadjuvant platinum-based chemotherapy followed by debulking surgery (so-called interval debulking surgery). RESULTS: Of the 670 patients randomly assigned to a study treatment, 632 (94.3%) were eligible and started the treatment. The majority of these patients had extensive stage IIIC or IV disease at primary debulking surgery (metastatic lesions that were larger than 5 cm in diameter in 74.5% of patients and larger than 10 cm in 61.6%). The largest residual tumor was 1 cm or less in diameter in 41.6% of patients after primary debulking and in 80.6% of patients after interval debulking. Postoperative rates of adverse effects and mortality tended to be higher after primary debulking than after interval debulking. The hazard ratio for death (intention-to-treat analysis) in the group assigned to neoadjuvant chemotherapy followed by interval debulking, as compared with the group assigned to primary debulking surgery followed by chemotherapy, was 0.98 (90% confidence interval [CI], 0.84 to 1.13; P=0.01 for noninferiority), and the hazard ratio for progressive disease was 1.01 (90% CI, 0.89 to 1.15). Complete resection of all macroscopic disease (at primary or interval surgery) was the strongest independent variable in predicting overall survival. CONCLUSIONS: Neoadjuvant chemotherapy followed by interval debulking surgery was not inferior to primary debulking surgery followed by chemotherapy as a treatment option for patients with bulky stage IIIC or IV ovarian carcinoma in this study. Complete resection of all macroscopic disease, whether performed as primary treatment or after neoadjuvant chemotherapy, remains the objective whenever cytoreductive surgery is performed. (Funded by the National Cancer Institute; ClinicalTrials.gov number, NCT00003636.

Cost-effectiveness of laparoscopy as diagnostic tool before primary cytoreductive surgery in ovarian cancer

Objective: To evaluate the cost-effectiveness of a diagnostic laparoscopy prior to primary cytoreductive surgery to prevent futile primary cytoreductive surgery (i.e. leaving >1cm residual disease) in patients suspected of advanced stage ovarian cancer. Methods: An economic analysis was conducted alongside a randomized controlled trial in which patients suspected of advanced stage ovarian cancer who qualified for primary cytoreductive surgery were randomized to either laparoscopy or primary cytoreductive surgery. Direct medical costs from a health care perspective over a 6-month time horizon were analyzed. Health outcomes were expressed in quality-adjusted life-years (QALYs) and utility was based on patient's response to the EQ-5D questionnaires. We primarily focused on direct medical costs based on Dutch standard prices. Results: We studied 201 patients, of whom 102 were randomized to laparoscopy and 99 to primary cytoreductive surgery. No significant difference in QALYs (utility=0.01; 95% CI 0.006 to 0.02) was observed. Laparoscopy reduced the number of futile laparotomies from 39% to 10%, while its costs were € 1400 per intervention, making the overall costs of both strategies comparable (difference € -80 per patient (95% CI -470 to 300)). Findings were consistent across various sensitivity analyses. Conclusion: In patients with suspected advanced stage ovarian cancer, a diagnostic laparoscopy reduced the number of futile laparotomies, without increasing total direct medical health care costs, or adversely affecting complications or quality of life.Roelien van de Vrie, Hannah S. van Meurs, Marianne J. Rutten, Christiana A. Naaktgeboren, Brent C. Opmeer, Katja N. Gaarenstroom, Toon van Gorp, Henk G. Ter Brugge, Ward Hofhuis, Henk W.R. Schreuder, Henriette J.G. Arts, Petra L.M. Zusterzeel, Johanna M.A. Pijnenborg, Maarten van Haaften , Mirjam J.A. Engelen, Erik A. Boss, M. Caroline Vos, Kees G. Gerestein, Eltjo M.J. Schutter, Gemma G. Kenter, Patrick M.M. Bossuyt, Ben Willem Mol, Marrije R. Buis

Molecular study of Mhc-DRB in wild chacma baboons reveals high variability and evidence for trans-species inheritance

International audienceThe MHC class II genes of many primate species were investigated extensively in recent years. However, while Mhc-DRB genes were studied in Old World monkeys such as rhesus macaques, the Mhc-DRB of baboons was only studied in a limited way. Because of their close anatomical and physiological relationship to humans, baboons are often used as models for reproduction and transplantation research. Baboons are also studied as a model species in behavioural ecology. Thus, identification of MHC genes would provide a foundation for studies of Mhc, biology and behaviour. Here, we describe the use of PCR, cloning, denaturing gradient gel electrophoresis (DGGE) and sequencing to identify Mhc-DRB sequences in wild chacma baboons (Papio ursinus). We amplified the highly variable second exon of baboon Mhc-DRB sequences using generic DRB primers. To validate and optimize the DGGE protocol, four DNA samples were initially studied using cloning and sequencing. Clones were screened using a novel RFLP approach to increase the number of clones identified for each individual. Results from cloning and sequencing were used to optimise DGGE conditions for Mhc-DRB genotyping of the remaining study subjects. Using these techniques, we identified 16 Paur-DRB sequences from 30 chacma baboons. On the basis of phylogenetic tree analyses, representatives of the Mhc-DRB1 and Mhc-DRB5 loci, and 13 different DRB lineages were identified. Evidence for trans-species inheritance of some Mhc-DRB sequences comes from high identity between the new Paur-DRB sequences and sequences from Papio cynocephalus, Macaca mulatta and possibly Galago moholi