Photochemical inactivation as an alternative method to produce a whole-cell vaccine for uropathogenic Escherichia coli (UPEC)

Uropathogenic Escherichia coli (UPEC) is the primary causative agent of lower urinary tract infection (UTI). UTI presents a serious health risk and has considerable secondary implications including economic burden, recurring episodes, and overuse of antibiotics. A safe and effective vaccine would address this widespread health problem and emerging antibiotic resistance. Killed, whole-cell vaccines have shown limited efficacy to prevent recurrent UTI in human trials. We explored photochemical inactivation with psoralen drugs and UVA light (PUVA), which crosslinks nucleic acid, as an alternative to protein-damaging methods of inactivation to improve whole-cell UTI vaccines. Exposure of UPEC to the psoralen drug AMT and UVA light resulted in a killed but metabolically active (KBMA) state, as reported previously for other PUVA-inactivated bacteria. The immunogenicity of PUVA-UPEC as compared to formalin-inactivated UPEC was compared in mice. Both generated high UPEC-specific serum IgG titers after intramuscular delivery. However, using functional adherence as a measure of surface protein integrity, we found differences in the properties of PUVA- and formalin-inactivated UPEC. Adhesion mediated by Type-1 and P-fimbriae was severely compromised by formalin but was unaffected by PUVA, indicating that PUVA preserved the functional conformation of fimbrial proteins, which are targets of protective immune responses. In vitro assays indicated that although they retained metabolic activity, PUVA-UPEC lost virulence properties that could negatively impact vaccine safety. Our results imply the potential for PUVA to improve killed, whole-cell UTI vaccines by generating bacteria that more closely resemble their live, infectious counterparts relative to vaccines generated with protein-damaging methods.

IMPORTANCE

Lower urinary tract infection (UTI), caused primarily by uropathogenic Escherichia coli, represents a significant health burden, accounting for 7 million primary care and 1 million emergency room visits annually in the United States. Women and the elderly are especially susceptible and recurrent infection (rUTI) is common in those populations. Lower UTI can lead to life-threatening systemic infection. UTI burden is manifested by healthcare dollars spent (1.5 billion annually), quality of life impact, and resistant strains emerging from antibiotic overuse. A safe and effective vaccine to prevent rUTI would address a substantial healthcare issue. Vaccines comprised of inactivated uropathogenic bacteria have yielded encouraging results in clinical trials but improvements that enhance vaccine performance are needed. To that end, we focused on inactivation methodology and provided data to support photochemical inactivation, which targets nucleic acid, as a promising alternative to conventional protein-damaging inactivation methods to improve whole-cell UTI vaccines.

The Immunogenicity and Properties of a Whole-Cell ETEC Vaccine Inactivated with Psoralen and UVA Light in Comparison to Formalin

Inactivated whole-cell vaccines present a full repertoire of antigens to the immune system. Formalin treatment, a standard method for microbial inactivation, can modify or destroy protein antigenic epitopes. We tested the hypothesis that photochemical inactivation with psoralen and UVA light (PUVA), which targets nucleic acid, would improve the immunogenicity of an Enterotoxigenic E. coli (ETEC) vaccine relative to a formalin-inactivated counterpart. Exposure of ETEC H10407 to PUVA using the psoralen drug 4'-Aminomethyltrioxsalen hydrochloride (AMT) yielded replication-incompetent bacteria that retained their metabolic activity. CFA/I-mediated mannose-resistant hemagglutination (MRHA) was equivalent for PUVA-inactivated and live ETEC, but was severely reduced for formalin-ETEC, indicating that PUVA preserved fimbrial protein functional integrity. The immunogenicity of PUVA-ETEC and formalin-ETEC was compared in mice ± double mutant heat-labile enterotoxin (dmLT) adjuvant. Two weeks after an intramuscular prime/boost, serum anti-ETEC IgG titers were similar for the two vaccines and were increased by dmLT. However, the IgG responses raised against several conserved ETEC proteins were greater after vaccination with PUVA-ETEC. In addition, PUVA-ETEC generated IgG specific for heat-labile toxin (LT) in the absence of dmLT, which was not a property of formalin-ETEC. These data are consistent with PUVA preserving ETEC protein antigens in their native-like form and justify the further testing of PUVA as a vaccine platform for ETEC using murine challenge models.

Retrograde Parotid Gland Infusion through Stensen's Duct in a Non-Human Primate for Vectored Gene Delivery

Salivary glands are an attractive tissue target for gene therapy with promising results already leading to human trials. They are inherently capable of secreting proteins into the bloodstream and are easily accessible, making them potentially superior tissue sites for replacement hormone production or vaccination by gene transfer. Suggested methods for gene delivery include transcutaneous injection and retrograde infusion through salivary ducts. We demonstrate how to perform Retrograde Salivary Gland Infusion (RSGI) in non-human primates. We describe the important anatomic landmarks including identification of the parotid papilla, an atraumatic method of cannulating and sealing Stensen's Duct utilizing basic dental tools, polyethylene tubing, and cyanoacrylate, and the appropriate rate of infusion. While this is the least traumatic method of delivery, the method is still limited by the volume able to be delivered (<0.5 mL) and the potential for trauma to the duct and gland. We demonstrate using fluoroscopy that an infusate can be fully delivered into the gland, and further demonstrate by immunohistochemistry the transduction of a typical vector and expression of the delivered gene.

Tetravalent dengue DNA vaccine is not immunogenic when delivered by retrograde infusion into salivary glands

Introduction and background

A tetravalent DNA vaccine for Dengue virus is under development but has not yet achieved optimal immunogenicity. Salivary glands vaccination has been reported efficacious in rodents and dogs. We report on a pilot study testing the salivary gland as a platform for a Dengue DNA vaccine in a non-human primate model.

Materials and methods

Four cynomolgus macaques were used in this study. Each macaque was pre-medicated with atropine and sedated with ketamine. Stensen’s duct papilla was cannulated with a P10 polyethylene tube, linked to a 500ul syringe. On the first two infusions, all macaques were infused with 300ul of TVDV mixed with 2 mg of zinc. For the 3rd infusion, to increase transfection into salivary tissue, two animals received 100uL TVDV mixed with 400uL polyethylenimine 1μg/ml (PEI) and the other two animals received 500uL TVDV with zinc. Antibody titers were assessed 4 weeks following the second and third infusion.

Results and conclusions

SGRI through Stensen’s duct is a well-tolerated, simple and easy to reproduce procedure. TVDV infused into macaques salivary glands elicited a significantly weaker antibody response than with different delivery methods.

Comparison of purified psoralen-inactivated and formalin-inactivated dengue vaccines in mice and nonhuman primates

Dengue fever, caused by dengue viruses (DENV 1-4) is a leading cause of illness and death in the tropics and subtropics. Therefore, an effective vaccine is urgently needed. Currently, the only available licensed dengue vaccine is a chimeric live attenuated vaccine that shows varying efficacy depending on serotype, age and baseline DENV serostatus. Accordingly, a dengue vaccine that is effective in seronegative adults, children of all ages and in immunocompromised individuals is still needed. We are currently researching the use of psoralen to develop an inactivated tetravalent dengue vaccine. Unlike traditional formalin inactivation, psoralen inactivates pathogens at the nucleic acid level, potentially preserving envelope protein epitopes important for protective anti-dengue immune responses. We prepared highly purified monovalent vaccine lots of formalin- and psoralen-inactivated DENV 1-4, using Capto DeVirS and Capto Core 700 resin based column chromatography. Tetravalent psoralen-inactivated vaccines (PsIV) and formalin-inactivated vaccines (FIV) were prepared by combining the four monovalent vaccines. Mice were immunized with either a low or high dose of PsIV or FIV to evaluate the immunogenicity of monovalent as well as tetravalent formulations of each inactivation method. In general, the monovalent and tetravalent PsIVs elicited equivalent or higher titers of neutralizing antibodies to DENV than the FIV dengue vaccines and this response was dose dependent. The immunogenicity of tetravalent dengue PsIVs and FIVs were also evaluated in nonhuman primates (NHPs). Consistent with what was observed in mice, significantly higher neutralizing antibody titers for each dengue serotype were observed in the NHPs vaccinated with the tetravalent dengue PsIV compared to those vaccinated with the tetravalent dengue FIV, indicative of the importance of envelope protein epitope preservation during psoralen inactivation of DENV.

Influenza vaccine immunogenicity in patients with primary central nervous system malignancy

BACKGROUND

Patients with central nervous system (CNS) malignancies represent an "at-risk" population for contracting influenza, particularly if they are receiving ongoing chemotherapy, radiation, and/or glucocorticoid treatment. The Centers for Disease Control endorses vaccination for these patients, although data are not available to indicate whether they mount an immunologic response adequate to achieve clinical protection.

METHODS

A pilot prospective cohort study was designed to evaluate the immunogenicity of the standard-dose trivalent inactivated influenza vaccine in patients with malignant CNS tumors. Baseline data collection included diagnosis, chemotherapy, timing of chemotherapy or radiation relative to vaccination, and glucocorticoid dose. Serum samples were collected at baseline, day 14, day 28, and month 3 following vaccination. Samples were tested using hemagglutinin inhibition to determine seroconversion (4-fold rise in titer) and seroprotection (titer >1:40).

RESULTS

A total of 38 patients were enrolled (mean age, 54 years ±13.5 years, 60.5% male, 94.7% Caucasian, and 5.3% African American). CNS tumor diagnoses included glioblastoma multiforme (55.2%), other high-grade glioma (13.2%), low-grade glioma (15.8%), and primary CNS lymphoma (15.8%). At enrollment, 20 patients (52.6%) were taking glucocorticoids, 25 (65.8%) were on active chemotherapy, and 3 (7.9%) were undergoing radiation. Seroconversion rates at day 28 for the A/H1N1, A/H3N2, and B strains were 37%, 23% and 23%, respectively. Seroprotection was 80%, 69%, and 74%, respectively. All rates were significantly lower than published rates in healthy adults (P < .001).

CONCLUSION

Influenza vaccine immunogenicity is significantly reduced in patients with CNS malignancies. Future studies are needed to determine the causative etiologies and appropriate vaccination strategies.

Overcoming the perceived barriers to health care access among single mothers in coastal Kenya

OBJECTIVES

This study assesses the effects of a comprehensive empowerment intervention on barriers to health care access for single mothers in coastal Kenya.

METHODS

We surveyed 41 single mothers who completed a pilot empowerment program and 60 single mothers who had not yet initiated the program. Comparisons were made using bivariate tests of association and logistic regression.

RESULTS

Women in the pilot program were less likely to report transportation costs (OR = 0.26; 95 % CI [0.11-0.59], p = 0.001) and hospital fees (OR = 0.22 [0.10-0.49], p < 0.001) as barriers. Pilot program mothers were more likely to visit a public hospital for their children (OR = 4.38; [1.58-12.1], p = 0.004) and self (OR = 4.70; [1.54-14.4], p = 0.007) when ill.

CONCLUSIONS

Empowerment programs can alleviate perceived barriers to health care among vulnerable populations.

Enrolment and programmatic trends and predictors of antiretroviral therapy initiation from president's emergency plan for AIDS Relief (PEPFAR)-supported public HIV care and treatment sites in rural Mozambique

Many countries in sub-Saharan Africa have made antiretroviral therapy (ART) available in urban settings, but the progress of treatment expansion into rural Africa has been slower. We analysed routine data for patients enrolled in a rural HIV treatment programme in Zambézia Province, Mozambique (1 June 2006 through 30 March 2009). There were 12,218 patients who were ≥15 years old enrolled (69% women). Median age was 25 years for women and 31 years for men. Older age and higher level of education were strongly predictive of ART initiation (P < 0.001). Patients with a CD4+ count of 350 cells/μL versus 50 cells/μL were less likely to begin ART (odds ratio [OR]: 0.19, 95% confidence interval [CI]: 0.16-0.23). In rural sub-Saharan Africa, HIV testing, linkage to care, logistics for ART initiation and fears among some patients to take ART require specialized planning to maximize successes. Sustainability will require improved health manpower, infrastructure, stable funding, continuous drug supplies, patient record systems and, most importantly, community engagement.

Effects of aging on vaccine efficacy in nonhuman primate models (104.1)

Vaccines are frequently less efficacious in the elderly and correlates of protection in older adults often differ from those seen in younger individuals. However, clinical testing of new vaccine formulations is typically limited and does not include elderly subjects. In order to identify a nonhuman primate (NHP) model that would recapitulate the effects of immunosenescence in humans, we assessed immune responses in three different NHPs: baboons (Papio), rhesus macaques (Macaca), and African green monkeys (Chlorocebus). The F1-antigen, a capsular protein encoded on the plague bacterium Y. pestis pFra plasmid, was chosen because it should elicit naive responses in all subjects. The animals were bled following primary and booster immunizations; B cell (antibody titer) and T cell parameters were assessed. As in humans, significant heterogeneity between individuals was seen. In rhesus and vervets, T cell responses to F1 were generally lower with increasing age. However, less of an age effect was observed in the baboons; this is consistent with the finding that antibody titers to F1 were not significantly diminished in older baboons and with our previous work showing immunization of old baboons with Y. pestis LcrV elicited high titer protective antibodies [JI 181:109]. Flow cytometric analyses of the T cell populations in old and young NHPs reveal differences across the species and provide additional insight into the immune parameters that correlate with healthy aging.

Challenges to bonnet monkey (Macaca radiata) social groups: Mother-infant dyad and infant social interactions

The mother-infant dyad is crucial to early development in a variety of species. The complexity of social groupings in nonhuman primates makes this relationship resilient as well as susceptible to early challenges associated with environmental chaos. Quantitative behavior observations of bonnet monkey mother-infant interactions were collected from 28 mother-infant dyads between one and twelve months of age. Social groups were subjected to several prenatal and/or postnatal housing relocations within a single year resulting in two study groups. One group experienced relocations (ATYPICAL, n = 14) and the second group (TYPICAL, n = 14) was conceived and reared in the same location. Behaviors in the ethogram included mother-infant interactions and infant social interactions with other members of the group. Observations between ages of two to four months were analyzed by a mixed model analysis of variance including fixed effects of per and postnatal history (TYPICAL, ATYPICAL), age, and history by age interaction and random effects of mother and infant nested within mother. A significant effect of relocation history was noted on a number of infant behaviors. ATYPICAL infants were out of direct contact with their mother at an earlier age but remained in her proximity. Control of proximity shifted to offsrping in the ATYPICAL group compared to the TYPICAL group. Furthermore, greater social interactions between two and four months of age with other members of the social group as well as the ir mother were observed in the ATYPICAL group. It is suggested that continuous challenge associated with relocation may affect the infant at later developmental ages due to these early differences in ways that are yet unclear.

ACRIN 6665/RTOG 0132 phase II trial of neoadjuvant imatinib mesylate (IM) for primary and recurrent operable malignant GIST: Imaging findings and correlation with genotype and GLUT4 expression

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Background: IM has improved the treatment of GIST patients (pts), but few achieve objective response despite significant clinical benefit. Imaging of tumor metabolism may provide earlier assessment of therapeutic response. In this study, FDG-PET metabolic response (MR) was compared with RECIST, GLUT4 expression, and KIT/PDGFRA mutation status. Methods: FDG-PET was done at baseline, 1–7 days, and 4 or 8 weeks (wk) after IM initiation. Best objective response was defined by RECIST. Immunohistochemical (IHC) tumor GLUT4 expression and mutation analyses were done at baseline and/or surgery. Background-subtracted SUVmax was measured in all lesions and summed; MR based on EORTC criteria was compared to RECIST, GLUT4 expression, and KIT/PDGFRA mutation status. Results: FDG-PET showed high tumor glycolytic activity at baseline (mean SUVmax = 14.2, range: 1.3–53.2), decreasing after 1 wk of IM (5.5, range: 0.5–47.7, p < 0.001, n = 44), and again prior to surgery (3.0, range: 0.5–36.1, p < 0.001, n = 40). FDG-PET response at wk 1 was 3 complete MR (CMR), 33 partial MR (PMR), 6 stable metabolic disease (SMD), and 2 progressive metabolic disease (PMD). Prior to surgery, FDG-PET response was 3 CMR, 33 PMR, 4 SMD, and no PMD. For 39 pts, RECIST best response was 2 PR, 36 SD, and 1 PD. GLUT4 expression decreased in 19 pts with PMR, and 3 with SMD. Among 12 pts with exon 11 mutation, 11 had PMR, 1 SMD; among 5 pts with wild-type genotype, 4 had PMR, and 1 SMD. Conclusions: After IM initiation, MR by FDG-PET was documented earlier (1–7 days), and was of much greater magnitude (36/40) than that documented by RECIST (2/39). IHC data suggest that: (1) GLUT4 plays a role in FDG uptake in GIST; (2) GLUT4 decreases in most pts with PMR; and, (3) the biologic action of IM interacts with glycolysis and GLUT4 expression. No difference in PMR was seen in pts with exon 11 vs. wild type mutations.

[Table: see text]