Low dose E. coli enterotoxin for urease-based oral immunization against H. pylori in healthy volunteers: Can it be safe and effective

Banerjee, Subhas; Medina-Fatimi, Anila; Nichols, Richard A.; Tendler, David A.; Michetti, Murielle; Mach, Marion; Šimon, Jan; Kelly, Ciarán P.; Monath, Thomas P.; Michetti, Pierre

doi:10.1016/s0016-5085(00)82765-1

Cited by 1 publication

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“…The first of the three studies with recombinant urease was a safety study with urease alone [15] while the other two trials were undertaken to explore the feasibility of native LT as an oral adjuvant for urease [16–17].…”

Section: Studies In Humansmentioning

confidence: 99%

“…A third trial testing the urease vaccine was conducted in healthy volunteers without H. pylori infection [16]. A dose of 60 mg of urease was delivered orally either in liquid form or in an enteric coated capsule with liquid native LT at varying dose levels (2.5, 0.5, and 0.1 μg).…”

Section: Studies In Humansmentioning

confidence: 99%

“…The relevance of these responses is currently uncertain because immunological surrogate markers for protection have not been defined in humans and gastric T‐cell responses are difficult to measure. The finding that activated T cells with mucosal homing receptors were stimulated by immunization [16] suggests that it should be possible to stimulate relevant immunity against H. pylori with the appropriate vaccine formulation.…”

Section: Future Endeavoursmentioning

confidence: 99%

“…The potential of parenteral immunization alone requires testing in humans. Studies in mice suggest that the correct combination of parenteral adjuvant and vaccination regimen may induce levels of protection equivalent to those achieved via mucosal immunization [2–25].…”

Section: Future Endeavoursmentioning

confidence: 99%

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Vaccination Against Helicobacter pylori in Non‐Human Primate Models and Humans

Lee

2001

Scand J Immunol

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Several vaccination studies have been performed in monkeys and humans testing the feasibility of prophylactic and therapeutic immunizations against Helicobacter pylori. The monkey studies showed that immune responses were induced by oral vaccination with the mucosal adjuvant LT (Escherichia coli heatlabile enterotoxin), parenteral administration with a cationic lipid adjuvant, and by mucosal priming followed by parenteral boosts. Both prophylactic and therapeutic activities were demonstrated in monkeys, providing a strong impetus for human vaccine trials. Preliminary studies in humans were undertaken in order to identify a tolerable dose of LT adjuvant or to test the effectiveness of mutant atoxic LT adjuvants. The results from these preliminary studies suggest that native LT causes diarrhoea at doses required for adjuvanticity while a mutant LT does not. In one study in which infected human subjects were vaccinated with orally administered urease antigen with native LT, there was a modest reduction in the level of H. pylori gastric colonization. A second clinical study employing H. pylori whole cell antigen and a mutant LT in infected subjects showed immune responses and although the subjects remained infected, the study was not designed to measure reduction in H. pylori colonization. Recombinant Salmonella expressing urease and other H. pylori antigens have been effective in mice (see accompanying Frontlines Topic Review by John O. Nedrud [1]), but monkey studies are not possible because of host range restriction. Human trials of parenteral immunization, mucosal immunization with mutant LT and live Salmonella vectors are needed to fully assess the ability of vaccines to prevent or treat H. pylori infections.

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Section: Studies In Humansmentioning

confidence: 99%

Section: Studies In Humansmentioning

confidence: 99%

Section: Future Endeavoursmentioning

confidence: 99%

Section: Future Endeavoursmentioning

confidence: 99%

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