A virus-like particle-based anti-nerve growth factor vaccine reduces inflammatory hyperalgesia: potential long-term therapy for chronic pain.

Chronic pain resulting from inflammatory and neuropathic disorders causes considerable economic and social burden. For a substantial proportion of patients, conventional drug treatments do not provide adequate pain relief. Consequently, novel approaches to pain management, involving alternative targets and new therapeutic modalities compatible with chronic use, are being sought. Nerve growth factor (NGF) is a major mediator of chronic pain. Clinical testing of NGF antagonists is ongoing, and clinical proof of concept has been established with a neutralizing mAb. Active immunization, with the goal of inducing therapeutically effective neutralizing autoreactive Abs, is recognized as a potential treatment option for chronic diseases. We have sought to determine if such a strategy could be applied to chronic pain by targeting NGF with a virus-like particle (VLP)-based vaccine. A vaccine comprising recombinant murine NGF conjugated to VLPs from the bacteriophage Qß (NGFQß) was produced. Immunization of mice with NGFQß induced anti-NGF-specific IgG Abs capable of neutralizing NGF. Titers could be sustained over 1 y by periodic immunization but declined in the absence of boosting. Vaccination with NGFQß substantially reduced hyperalgesia in collagen-induced arthritis or postinjection of zymosan A, two models of inflammatory pain. Long-term NGFQß immunization did not change sensory or sympathetic innervation patterns or induce cholinergic deficits in the forebrain, nor did it interfere with blood-brain barrier integrity. Thus, autovaccination targeting NGF using a VLP-based approach may represent a novel modality for the treatment of chronic pain.

Transcutaneous immunization with inactivated influenza virus induces protective immune responses.

The recent outbreaks of highly pathogenic avian influenza in Asia and spread of the disease worldwide highlight the need to redefine conventional immunization approaches and establish effective mass vaccination strategies to face global pandemics. Transcutaneous immunization (TCI) is a novel route for vaccination, which uses the topical application of vaccine antigens on the skin. In this study, we investigated the potential of TCI using inactivated whole influenza virus. We found that TCI with whole inactivated influenza virus induced influenza virus-specific antibodies with hemagglutination inhibition and neutralizing activities as well as cellular immune responses, even without an adjuvant, and conferred protective immunity to virus challenge. Co-administration with cholera toxin (CT), a potent adjuvant for TCI, significantly enhanced immune responses against the influenza virus antigen. To enhance penetration of the skin barrier to the particulate influenza viral antigens, we tested the effects of the potential penetration enhancers/immunomodulators oleic acid (OA) and retinoic acid (RA). Pretreatment of mouse skin with OA elicited increased levels of influenza virus-specific binding and neutralizing antibodies to levels equivalent to those induced by intranasal immunization with inactivated influenza virus. OA and RA treatments differentially affected the pattern of cytokine production upon stimulation with influenza viral antigen and provided enhanced protection. These results reveal a promising perspective for the application of transcutaneous immunization to prevent influenza epidemics as well as a range of other infectious diseases.

Dengue vaccines: preparing to roll back dengue.

Dengue is an emerging viral pathogen of growing global importance, infecting up to 100 million people annually. Although there have been many efforts over the last six decades to produce a vaccine to combat this infection, few have been able to meet the challenges posed by the unusual interplay between this virus and its human host. However, recent progress in molecular-based vaccine strategies, as well as a renewed commitment by the World Health Organisation to co-ordinate global efforts on vaccine development, finally provides hope that control of this serious disease may be at hand.

The use of ELISA for detection of the antibody-induced conformational change in a viral protein and its intermolecular spread.

Antibody-induced conformational changes of proteins have been recently frequently suggested to explain a variety of observations. In spite of the fundamental importance of this phenomenon for both in vivo and in vitro antigen-antibody interactions, it is not generally accepted because of the lack of conclusive evidence. This report utilizes a novel approach to the study of antibody-induced antigenic conformational changes. Pairs of monoclonal antibodies (mAb) were used to induce and to assess conformational changes in potato virus X (PVX) protein. Blocking ELISA with native and glutaraldehyde treated virus was used to detect conformational changes. Double antibody sandwich (DAS) ELISA was designed to investigate possible inter-molecular spread of conformational changes. Detection of one way blocking in a blocking ELISA, with a pair of mAbs reacting to non-overlapping epitopes, suggested conformational change as the mechanism of blocking. The putative conformational change was confirmed when the one way blocking was prevented using conformationally restrained virus. Inter-molecular spread of the conformational change among the molecules of PVX protein was demonstrated in DAS-ELISA, when capture mAb inhibited binding of detecting mAb in the absence of steric hindrance. Unlike X-ray crystallography, the methodology utilized in this study indicates directly the significance of a changed conformation to antibody binding.