Concise synthesis of a heptasaccharide antigen found in the cell-wall lipopolysaccharide of Mycobacterium gordonae strain 990

A straight forward synthesis of a heptasaccharide part of the cell-wall lipopolysaccharide of Mycobacterium gordonae strain 990, known to have antigenicity, has been achieved in excellent yield. Judicious choice of protecting groups in the intermediates played a significant role throughout the synthesis. Most of the intermediate steps furnished satisfactory yield. Figure A concise synthesis of an antigenic heptasaccharide motif of the cell-wall glycolipid of Mycobacterium gordonae strain 990 in its preserved natural structure is presented using a general glycosylation condition and judicious protecting group manipulation C.D.R.I. communication number 7377.     

WHO Study Group on cell substrates for production of biologicals, Geneva, Switzerland, 11–12 June 2007

For many years, the World Health Organization (WHO) has provided global leadership in defining technical specifications for quality assurance and safety of biological medicines produced in cell substrates. Current WHO requirements for the use of animal cells as substrates for production of vaccines and other biologicals were adopted by the WHO Expert Committee on Biological Standardization in 1996 (WHO TRS 878). Since then, significant progress especially in the development of vaccines in novel continuous cell lines of mammalian origin as well as in insect cells has been made and consequently there is an increasing need for the re-evaluation of existing criteria for the acceptability of such cell lines. In addition there is also a need to consider new issues in cell substrate safety arising from these new cell types and developments in technology and scientific knowledge. In response to these demands, the WHO Study Group on Cell Substrates was formed in 2006 to initiate revision of WHO requirements and to address the need for further research in this area. At its second meeting on 11-12 June 2007, the Study Group reviewed scientific data that would form the basis for new recommendations and made a number of proposals for further investigations. The Study Group is working on the preparation of a revised WHO document, and a broad consultation with regulators, manufacturers, and other relevant parties is planned for 2008.     

Acute exposure and chronic retention of aluminum in three vaccine schedules and effects of genetic and environmental variation

Like the mechanisms of action as adjuvants, the pharmacodynamics of injected forms of aluminum commonly used in vaccines are not well-characterized, particularly with respect to how differences in schedules impact accumulation and how factors such as genetics and environmental influences on detoxification influence clearance. Previous modeling efforts are based on very little empirical data, with the model by Priest based on whole-body clearance rates estimated from a study involving a single human subject. In this analysis, we explore the expected acute exposures and longer-term whole-body accumulation/clearance across three vaccination schedules: the current US Centers for Disease Control and Prevention (CDC) schedule, the current CDC schedule using low aluminum or no aluminum vaccines, and Dr. Paul Thomas’ “Vaccine Friendly Plan” schedule. We then study the effects of an implicit assumption of the Priest model on whether clearance dynamics from successive doses are influenced by the current level of aluminum or modeled by the assumption that a new dose has its own whole-body dynamics “reset” on the day of injection. We model two additional factors: variation (deficiency) in aluminum detoxification, and a factor added to the Priest equation to model the potential impact of aluminum itself on cellular and whole-body detoxification. These explorations are compared to a previously estimated pediatric dose limit (PDL) of whole-body aluminum exposure and provide a new statistic: %alumTox, the (expected) percentage of days (or weeks) an infant is in aluminum toxicity, reflecting chronic toxicity. We show that among three schedules, the CDC schedule results in the highest %alumTox regardless of model assumptions, and the Vaccine Friendly Plan schedule, which avoids >1 ACV per office visit results in the lowest (expected) %alumTox. These results are conservative, as the MSL is derived from data used by FDA to estimate safety of aluminum in adult humans. These results demonstrate high potential utility of modeling variation in patient responses to aluminum. More empirical data from individuals who are suspected of being intolerant of aluminum from vaccines, evidenced by high aluminum retention, neurodevelopmental disorders and/or a myriad of chronic illnesses would help answer questions on whether the model predictions can be used to estimate parameter values tied to genetic factors including genomic sequence variation and family history of chronic illnesses tied to aluminum exposure.     

Trichinella spiralis: intranasal immunization with attenuated Salmonella enterica carrying a gp43 antigen-derived 30mer epitope elicits protection in BALB/c mice

Trichinellosis is a public health problem and is considered an emergent/re-emergent disease in various countries. The etiological agent of trichinellosis is the nematode Trichinella, which infects domestic animals such as pigs and horses, as well as wild animals and humans. A veterinary vaccine could be an option to control the disease in domestic animals. Although several vaccine candidates have shown promising results, a vaccine against trichinellosis remains unavailable to date. Attenuated Salmonella strains are especially attractive live vectors because they elicit mucosal immunity, which is known to be important for the control of Trichinella spiralis infection at the intestinal level and can be administered by oral or intranasal routes. In this study, the autotransporter ShdA was used to display, on the surface of the Salmonella enterica serovar Typhimurium SL3261, the 210–239 amino acid epitope, (designated as Ag30) derived from the 43 kDa glycoprotein of T. spiralis muscle larvae. The fusion protein elicited antibodies in BALB/c mice that were able to recognize the native epitope on the surface of T. spiralis muscle larvae. Mice immunized by intranasal route with the recombinant Salmonella induced a protective immune response against the T. spiralis challenge, reducing by 61.83% the adult burden at day eight postinfection. This immune response was characterized by the induction of antigen-specific IgG1 and of IL-5 production. This study demonstrates the usefulness of Salmonella as a carrier of nematode epitopes providing a surface display system for intestinal parasite vaccine applications.     

Intracellular sensing of viral DNA by the innate immune system

Recent years have seen a great advance in knowledge of how a host senses infection. Nucleic acids, as a common denominator to all pathogens, are at the centre of several of the sensing pathways, especially those involved with the recognition of viruses. In this review we discuss the current knowledge on how intracellular DNA is sensed by the mammalian host.     

Human papillomavirus genotype distribution in invasive cervical cancer in Bosnia and Herzegovina

PurposeCountries of the former Yugoslavia bear some of the highest cervical cancer burden in Europe. In Bosnia and Herzegovina (B&H), data on human papillomavirus (HPV) genotype distribution among cervical cancer cases is scarce. This baseline information is critical in order to evaluate the impact of prophylactic HPV vaccines. This study aims to provide specific information for B&H.MethodsThe final analysis comprised 283 cases of invasive cervical cancer identified at the Polyclinic for Laboratory Diagnostic, University Clinical Center Tuzla in B&H between 1984 and 2004. HPV was detected through amplification of HPV DNA using SPF-10 broad spectrum primers followed by deoxyribonucleic acid enzyme inmunoassay and genotyping by reverse line probe assay (LiPA₂₅, version 1).ResultsMost cases (92.2%) were histologically classified as squamous cell carcinoma (SCC). A total of 268 cases (94.7%) were positive for HPV. Infections were mainly present as single (95.5%) and HPV16 and 18 accounted for 77.8% of the positive cases. The next most common HPV types were HPV45 (4.4%), HPV33 (3.1%), HPV51 (2.3%) and HPV31 (2.2%). The mean age of cases infected with the seven most common types worldwide (HPV16/18/45/31/33/52/58) was 51.1 (SD = 11.6), six years younger than the one for cases infected with other types (56.3, SD = 12.9).ConclusionsAvailable HPV vaccines could potentially prevent 77.8% of Bosnian cervical cancer cases (i.e. those associated with HPV16/18). If the reported magnitude of the cross-protection of licensed vaccines for non-vaccine HPV types is long lasting, an additional 6 to 10% of cases could be prevented.     

Standardization and validation of a new atomic absorption spectroscopy technique for determination and quantitation of Aluminium adjuvant in immunobiologicals

In the present study, Aluminium quantification in immunobiologicals has been described using atomic absorption spectroscopy (AAS) technique. The assay was found to be linear in 25-125 microg/ml Aluminium range. The procedure was found to be accurate for different vaccines with recoveries of external additions ranging between 93.26 and 103.41%. The mean Limit of Variation (L.V.) for both intra- and inter-assay precision was calculated to be 1.62 and 2.22%, respectively. Further the procedure was found to be robust in relation to digestion temperature, alteration in acid (HNO(3) and H(2)SO(4)) ratio used for sample digestion and storage of digested vaccine samples up to a period of 15 days. After validation, AAS method was compared for its equivalency with routinely used complexometric titration method. On simultaneously applying on seven different groups of both bacterial and viral vaccines, viz., DPT, DT, TT, Hepatitis-A and B, Antirabies vaccine (cell culture) and tetravalent DPT-Hib, a high degree of positive correlation (+0.85-0.998) among AAS and titration methods was observed. Further AAS method was found to have an edge over complexometric titration method that a group of vaccines, viz., ARV (cell culture, adsorbed) and Hepatitis-A, in which Aluminium estimation is not feasible by pharmacopoeial approved complexometric titration method (possibly due to some interference in the sample matrix), this newly described and validated AAS assay procedure delivered accurate and reproducible results.     

A case for whole-parasite malaria vaccines

Malaria causes morbidity in 300-500 million people each year and claims 2-3 millions lives annually, mostly children in sub-Saharan Africa. In 1983, the cloning of malaria antigens offered great promise for developing a viable subunit vaccine. However, an efficacious human vaccine is still not available. Immunological studies on how the host's immune system interacts with the parasite and studies on the pathogenic aspect of Plasmodium have found that several factors can impede protection by current vaccines. These findings suggest a novel approach needs to be considered.     

Do aluminum vaccine adjuvants contribute to the rising prevalence of autism?

Autism spectrum disorders (ASD) are serious multisystem developmental disorders and an urgent global public health concern. Dysfunctional immunity and impaired brain function are core deficits in ASD. Aluminum (Al), the most commonly used vaccine adjuvant, is a demonstrated neurotoxin and a strong immune stimulator. Hence, adjuvant Al has the potential to induce neuroimmune disorders. When assessing adjuvant toxicity in children, two key points ought to be considered: (i) children should not be viewed as “small adults” as their unique physiology makes them much more vulnerable to toxic insults; and (ii) if exposure to Al from only few vaccines can lead to cognitive impairment and autoimmunity in adults, is it unreasonable to question whether the current pediatric schedules, often containing 18 Al adjuvanted vaccines, are safe for children? By applying Hill's criteria for establishing causality between exposure and outcome we investigated whether exposure to Al from vaccines could be contributing to the rise in ASD prevalence in the Western world. Our results show that: (i) children from countries with the highest ASD prevalence appear to have the highest exposure to Al from vaccines; (ii) the increase in exposure to Al adjuvants significantly correlates with the increase in ASD prevalence in the United States observed over the last two decades (Pearson r = 0.92, p < 0.0001); and (iii) a significant correlation exists between the amounts of Al administered to preschool children and the current prevalence of ASD in seven Western countries, particularly at 3-4 months of age (Pearson r = 0.89-0.94, p = 0.0018-0.0248). The application of the Hill's criteria to these data indicates that the correlation between Al in vaccines and ASD may be causal. Because children represent a fraction of the population most at risk for complications following exposure to Al, a more rigorous evaluation of Al adjuvant safety seems warranted.