[Show abstract][Hide abstract] ABSTRACT: According to the WHO, more than 1 billion people worldwide are overweight and at risk of developing chronic illnesses, including cardiovascular disease, type 2 diabetes, hypertension and stroke. Current therapies show limited efficacy and are often associated with unpleasant side-effect profiles, hence there is a medical need for new therapeutic interventions in the field of obesity. Gastric inhibitory peptide (GIP, also known as glucose-dependent insulinotropic polypeptide) has recently been postulated to link over-nutrition with obesity. In fact GIP receptor-deficient mice (GIPR(-/-)) were shown to be completely protected from diet-induced obesity. Thus, disrupting GIP signaling represents a promising novel therapeutic strategy for the treatment of obesity.
In order to block GIP signaling we chose an active vaccination approach using GIP peptides covalently attached to virus-like particles (VLP-GIP). Vaccination of mice with VLP-GIP induced high titers of specific antibodies and efficiently reduced body weight gain in animals fed a high fat diet. The reduction in body weight gain could be attributed to reduced accumulation of fat. Moreover, increased weight loss was observed in obese mice vaccinated with VLP-GIP. Importantly, despite the incretin action of GIP, VLP-GIP-treated mice did not show signs of glucose intolerance.
This study shows that vaccination against GIP was safe and effective. Thus active vaccination may represent a novel, long-lasting treatment for obesity. However further preclinical safety/toxicology studies will be required before the therapeutic concept can be addressed in humans.
PLoS ONE 02/2008; 3(9):e3163. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Despite the availability of efficacious drugs, the success of treating hypertension is limited by patients' inconsistent drug intake. Immunization against angiotensin II may offer a valuable alternative to conventional drugs for the treatment of hypertension, because vaccines induce relatively long-lasting effects and do not require daily dosing. Here we describe the preclinical development and the phase I clinical trial testing of a virus-like particle (VLP)-based antihypertensive vaccine.
An angiotensin II-derived peptide was conjugated to the VLP Qbeta (AngQb). AngQb was highly immunogenic in mice and rats. To test for efficacy, spontaneously hypertensive rats (SHR) were immunized with 400 microg AngQb or VLP alone. Group mean systolic blood pressure (SBP) was reduced by up to 21 mmHg (159 +/- 2 versus 180 +/- 5 mmHg, P < 0.001), and total angiotensin II levels (antibody-bound and free) were increased ninefold (85 +/- 20 versus 9 +/- 1 pmol/l, P = 0.002) compared with VLP controls. SHR treated with the angiotensin-converting enzyme (ACE) inhibitor ramipril (1 mg/kg per day by mouth) reached an SBP of 155 +/- 2 mmHg. Twelve healthy volunteers of a placebo-controlled randomized phase I trial were injected once with 100 microg AngQb. Angiotensin II-specific antibodies were raised in all subjects (100% responder rate) and AngQb was well tolerated.
AngQb reduces blood pressure in SHR to levels obtained with an ACE inhibitor, and is immunogenic and well tolerated in humans. Therefore, vaccination against angiotensin II has the potential to become a useful antihypertensive treatment providing long-lasting effects and improving patient compliance.
Journal of Hypertension 02/2007; 25(1):63-72. · 4.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In mice, highly repetitive antigens, such as those present on bacterial or viral surfaces, efficiently cross-link B-cell receptors and therefore induce strong IgG responses. In this study we covalently coupled a synthetic 16-amino-acid sequence of the allergen Der p 1 to a virus-like particle derived from the bacteriophage Qbeta (Qbeta-Der p 1).
We evaluated the safety and immunogenicity of Qbeta-Der p 1 in human subjects and compared different doses and routes of immunization.
In a phase I trial 24 healthy volunteers were randomly assigned to one of 4 treatment groups. Group 1 received 50 microg of Qbeta-Der p 1 intramuscularly, group 2 received 50 microg of Qbeta-Der p 1 subcutaneously, group 3 received 10 microg of Qbeta-Der p 1 intramuscularly, and group 4 received 10 microg of Qbeta-Der p 1 subcutaneously. Boosting immunizations with 10 microg were given after 1 and 3 months. Antibody titers were measured after 1, 3, 4, 6, 12, and 18 months.
The vaccine Qbeta-Der p 1 was well tolerated. Significant IgG responses were observed 4 weeks after a single injection. Individuals receiving 50 microg of the vaccine had significantly higher IgG titers than those vaccinated with 10 microg. However, the route of immunization (subcutaneous vs intramuscular) had no effect. In the 50-microg dose group, strong antibody responses against Der p 1 with average titers of 1:2000 were obtained.
Vaccination with a peptide antigen covalently coupled to highly repetitive virus-like particles represents an adjuvant-free means of rapidly inducing high antibody titers in human subjects.
Allergens coupled to virus-like particles can be used to enhance the efficiency of allergen-specific immunotherapy.
Journal of Allergy and Clinical Immunology 07/2006; 117(6):1470-6. · 12.05 Impact Factor