The immunological effects of intradermal particle-based vaccine delivery using a novel microinjection needle studied in a human skin explant model

For intradermal (ID) immunisation, novel needle-based delivery systems have been proposed as a better alternative to the Mantoux method. However, the penetration depth of needles in the human skin and its effect on immune cells residing in the different layers of the skin has not been analyzed. A novel and user-friendly silicon microinjection needle (Bella-mu^TM) has been developed, which allows for a perpendicular injection due to its short needle length (1.4-1.8 mm) and ultrashort bevel. We aimed to characterize the performance of this microinjection needle in the context of the delivery of a particle-based outer membrane vesicle (OMV) vaccine using an ex vivo human skin explant model. We compared the needles of 1.4 and 1.8 mm with the conventional Mantoux method to investigate the depth of vaccine injection and the capacity of the skin antigen-presenting cell (APC) to phagocytose the OMVs. The 1.4 mm needle deposited the antigen closer to the epidermis than the 1.8 mm needle or the Mantoux method. Consequently, activation of epidermal Langerhans cells was significantly higher as determined by dendrite shortening. We found that five different subsets of dermal APCs are able to phagocytose the OMV vaccine, irrespective of the device or injection method. ID delivery using the 1.4 mm needle of a OMV-based vaccine allowed epidermal and dermal APC targeting, with superior activation of Langerhans cells. This study indicates that the use of a microinjection needle improves the delivery of vaccines in the human skin.

Peptide-Based Vaccination for Antibody Responses Against HIV

HIV-1 is responsible for a global pandemic of 35 million people and continues to spread at a rate of >2 million new infections/year. It is widely acknowledged that a protective vaccine would be the most effective means to reduce HIV-1 spread and ultimately eliminate the pandemic, whereas a therapeutic vaccine might help to mitigate the clinical course of the disease and to contribute to virus eradication strategies. However, despite more than 30 years of research, we do not have a vaccine capable of protecting against HIV-1 infection or impacting on disease progression. This, in part, denotes the challenge of identifying immunogens and vaccine modalities with a reduced risk of failure in late stage development. However, progress has been made in epitope identification for the induction of broadly neutralizing antibodies. Thus, peptide-based vaccination has become one of the challenges of this decade. While some researchers reconstitute envelope protein conformation and stabilization to conserve the epitope targeted by neutralizing antibodies, others have developed strategies based on peptide-carrier vaccines with a similar goal. Here, we will review the major peptide-carrier based approaches in the vaccine field and their application and recent development in the HIV-1 field.

Kainyl-bovine serum albumin: a novel ligand of the kainate sub-type of glutamate receptor with a very high binding affinity

Bovine serum albumin has been conjugated with kainylaminooxyacetylglycine to afford a multivalent kainylated protein called kainyl-bovine serum albumin (KA-BSA). This derivative, radiolabelled with 125I to more than 5000 Ci/mmol, was found to interact in the chick, goldfish and rat brain to specific membranous sites displaying the pharmacological properties attributed to the kainate sub-type of glutamate receptor. Measurements of the kinetics of association and dissociation of KA-BSA showed a quasi-irreversible binding with dissociation constants in the subpicomolar and nanomolar range. The chemical properties and the binding characteristics of KA-BSA suggest that it interacts mainly with kainate binding sites present in clusters in the membrane. Localization of the KA-BSA binding sites, by autoradiography in the chick cerebellum and by immunoperoxidase staining in the goldfish cerebellum, revealed an exclusive association with the molecular layer.

[Progressive multifocal leukoencephalopathy after renal transplantation. Report of two cases]

Progressive multifocal leukoencephalopathy (PML) occurred in two patients after kidney transplantation. Two years after such a transplantation associated with immunosuppressive chemotherapy, a 54-year-old male developed polyneuropathy, diffuse alterations of the central nervous system and he died with the suspicion of hypertensive encephalopathy due to progressive renal failure. A 45-year-old female had kidney transplantation first complicated by Listeria monocytogenes meningoencephalitis. She was cured from this disease and had a satisfactory social rehabilitation for two years. Afterwards, she suffered from various neurological ailments, including epilepsy, that were attributed to combined renal failure and developing hydrocephalus. One year after the onset of these neurological symptoms, the grafted kidney was removed and chemotherapy was discontinued but she died a few weeks later. Both patients had typical PML. By electron microscopy, performed on formalin fixed brain tissue, intranuclear round particles (40-50 nm) could be recognized in the first case only. These two cases are confronted with the six published observations of PML following organ transplantation. The frequency of PML has been estimated at 1 for 5000 kidney transplantation, 1 for 2000 chronic lymphoid leukemia and 1 for 10,000 Hodgkin's disease.

Two cases of progressive multifocal leukoencephalopathy after renal transplantation

Progressive multifocal leukoencephalopathy (PML) occurred in two patients after kidney transplantation. Less than 2 years after such a transplantation associated with immunosuppressive chemotherapy a 54-year-old male developed polyneuropathy then clinical diffuse alteration of the central nervous system. He died three months later with the suspicion of hypertensive encephalopathy due to progressive renal failure. A 45-year-old female had a kidney transplantation first rapidly complicated by Listeria monocytogenes meningoencephalitis. She was cured from this disease and had a satisfactory social rehabilitation during two years. Afterwards, she suffered various neurological troubles, including epilepsy, that were attributed to combined renal failure and developing hydrocephalus. One year after the onset of these neurological symptoms, the grafted kidney was removed and chemotherapy was discontinued. She died three months later. Both patients had typical PML with eosinophilic intranuclear inclusions in presumptive oligodendroglial cells. By electron microscopy, performed on formalin fixed brain tissue, round particles (40-50 nm) could be recognized in some glial cell nuclei. These two cases are confronted with the four published observations of PML following organ transplantation.

Paradoxical embolism

Paradoxical embolization of venous thrombus into the abdominal aortic bifurcation has been diagnosed by means of aortography. Lower limb phlebothrombosis accounting for the embolus formation has been demonstrated by phlebography. Arterial embolectomy and venous thrombectomy were successfully performed. Recovery was complete without sequelae.