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Nicola Thomas

Publications and source records attributed to Nicola Thomas.

4 recordsLinked to original sources
PubMed2006

Construction and phase I clinical evaluation of the safety and immunogenicity of a candidate enterotoxigenic Escherichia coli vaccine strain expressing colonization factor antigen CFA/I.

Oral delivery of toxin-negative derivatives of enterotoxigenic Escherichia coli (ETEC) that express colonization factor antigens (CFA) with deletions of the aroC, ompC, ompF, and toxin genes may be an effective approach to vaccination against ETEC-associated diarrhea. We describe the creation and characterization of an attenuated CFA/I-expressing ETEC vaccine candidate, ACAM2010, from a virulent isolate in which the heat-stable enterotoxin (ST) and CFA/I genes were closely linked and on the same virulence plasmid as the enteroaggregative E. coli heat-stable toxin (EAST1) gene. A new suicide vector (pJCB12) was constructed and used to delete the ST and EAST1 genes and to introduce defined deletion mutations into the aroC, ompC, and ompF chromosomal genes. A phase I trial, consisting of an open-label dose escalation phase in 18 adult outpatient volunteers followed by a placebo-controlled double-blind phase in an additional 31 volunteers, was conducted. The vaccine was administered in two formulations, fresh culture and frozen suspension. These were both well tolerated, with no evidence of significant adverse events related to vaccination. Immunoglobulin A (IgA) and IgG antibody-secreting cells specific for CFA/I were assayed by ELISPOT. Positive responses (greater than twofold increase) were seen in 27 of 37 (73%) subjects who received the highest dose level of vaccine (nominally 5 x 10(9) CFU). Twenty-nine of these volunteers were secreting culturable vaccine organisms at day 3 following vaccination; five were still positive on day 7, with a single isolation on day 13. This live attenuated bacterial vaccine is safe and immunogenic in healthy adult volunteers.

Adolescent↗
PubMed2004

Immunomodulation induced by tucaresol in HIV infection: results of a 16 week pilot Phase I/II trial.

OBJECTIVE: Immune reconstitution in highly active antiretroviral therapy (HAART)-treated individuals is incomplete and immunomodulatory compounds are needed to improve the outcome of HIV therapy. In a Phase I/II clinical trial performed on HIV-positive patients we analysed the safety and immunomodulating effects of tucaresol, a novel compound that has previously been described tn enhance cell-mediated immune responses. PATIENTS AND METHODS: Sixteen weeks pulse dose escalation protocol. Four groups of HIV-positive patients were enrolled: group A (n=6): HAART, CD4+ 300-500 cells/microl, HIV RNA <80 copies/ml; group B (n=6): HAART-naive, CD4+ <500 cells/microl, HIV RNA >10 000 copies/ml; group C (n=3): HAART-naive, CD4+ >500 cells/microl, HIV RNA <10000 copies/ml; and group D (n=6): HAART, CD4+ <200cells/microl, HIV RNA <80 copies/ml. Tucaresol was added to HAART in group A and D patients; group B patients started tucaresol with HAART, group C patients received tucaresol alone. Clinical and immunological analyses were performed at different time points. RESULTS: Tucaresol-related serious adverse events were observed in the first week of therapy in 2/21 patients who were viraemic when commencing treatment, but did not occur in patients on stable HAART. Tucaresol did not affect HIV viraemia whereas increases in CD4+ percentages, mainly supported by naive CD4+ cells, were observed. CD8+/28-/45RA+ cells and HIV-specific CD8+ IFNgamma- and perforin-producing cells improved whereas IL-10 mRNA diminished in tucaresol-treated patients. The effects were greater with 25 mg given every other day for 1 week. CONCLUSION: In HAART-receiving patients with proper virus suppression, tucaresol was not associated with serious adverse events and resulted in qualitative and quantitative stimulation of HIV-specific cytotoxic T lymphocyte activity and generation of naive T cells. These data may support further exploration of tucaresol use in reconstitution of immune system parameters in HIV patients with proper virus suppression while on HAART.

Adult↗
PubMed2002

Comparative safety and immunogenicity of two yellow fever 17D vaccines (ARILVAX and YF-VAX) in a phase III multicenter, double-blind clinical trial.

Yellow fever (YF) is a significant health problem in South America and Africa. Travelers to these areas require immunization. The United States, infested with Aedes aegypti mosquitoes, is at risk of introduction of this disease. There is only a single U.S. manufacturer of YF 17D vaccine, and supplies may be insufficient in an emergency. A randomized, double-blind outpatient study was conducted in 1,440 healthy individuals, half of whom received the U.S. vaccine (YF-VAX) and half the vaccine manufactured in the United Kingdom (ARILVAX). A randomly selected subset of approximately 310 individuals in each treatment group was tested for YF neutralizing antibodies 30 days after vaccination. The primary efficacy endpoint was the proportion of individuals who developed a log neutralization index (LNI) of 0.7 or higher. Seroconversion occurred in 98.6% of individuals in the ARILVAX group and 99.3% of those in the YF-VAX group. Statistically, ARILVAX was equivalent to YF-VAX (P = .001). Both vaccines elicited mean antibody responses well above the minimal level (LNI 0.7) protective against wild-type YF virus. The mean LNI in the YF-VAX group was higher (2.21) than in the ARILVAX group (2.06; P = .010) possibly because of the higher dose contained in YF-VAX. Male gender, Caucasian race, and smoking were associated with higher antibody responses. Both vaccines were well tolerated. Overall, the treatment groups were comparable with respect to safety except that individuals in the ARILVAX group experienced significantly less edema, inflammation, and pain at the injection site than those in the YF-VAX group. No serious adverse events were attributable to either vaccine. YF-VAX participants (71.9%) experienced one or more nonserious adverse events than ARILVAX individuals (65.3%; P = .008). The difference was due to a higher rate of injection site reactions in the YF-VAX group. Mild systemic reactions (headache, myalgia, malaise, asthenia) occurred in roughly 10% to 30% of participants during the first few days after vaccination, with no significant difference across treatment groups. Adverse events were less frequent in individuals with preexisting immunity to YF, indicating a relationship to virus replication.

Alanine Transaminase↗