First Detection of Swedish' Variant (nvCT) in a Russian Couple with Infertility.

Background: Chronic asymptomatic chlamydial genital infection caused by the wild-type of (wtCT) is the most common bacterial infection causing human infertility. The novel 'Swedish' variant of (nvCT) which contains a 377 bp deletion in a region that is specifically targeted in some nucleic acid amplification tests may impede diagnosis.

Objective: The study aimed to investigate whether nvCT may be a possible cause of infertility in a couple undergoing fertilization (IVF).

Quality, immunogenicity and stability of meningococcal serogroup ACWY-CRM, DT and TT glycoconjugate vaccines.

A physicochemical and immunological study of the stability of three different meningococcal (Men) ACWY conjugate vaccines was performed to evaluate any patterns of serogroup oligo- or polysaccharide-specific or carrier protein-specific stability that would affect immunogenicity. Critical quality and stability-indicating characteristics were measured, with the study supporting the suitability of both HPLC-SEC and HPAEC-PAD methods to detect changes following inappropriate vaccine storage. All three final products, ACWY-CRM, -DT and -TT conjugate vaccines had expected quality indicator values and similar immunogenicity in a mouse model (anti-PS IgG and rSBA) when stored at +2-8°C.

Russian vaccines against especially dangerous bacterial pathogens.

In response to the epidemiological situation, live attenuated or killed vaccines against anthrax, brucellosis, cholera, glanders, plague and tularemia were developed and used for immunization of at-risk populations in the Former Soviet Union. Certain of these vaccines have been updated and currently they are used on a selective basis, mainly for high risk occupations, in the Russian Federation. Except for anthrax and cholera these vaccines currently are the only licensed products available for protection against the most dangerous bacterial pathogens.

Investigation in a murine model of possible mechanisms of enhanced local reactions to post-primary diphtheria-tetanus toxoid boosters in recipients of acellular pertussis-diphtheria-tetanus vaccine.

In recipients primed with acellular pertussis diphtheria-tetanus combined vaccine (DTaP) an increased incidence of severe local reactions with extensive redness/swelling has been reported for each subsequent dose of diphtheria-tetanus based combination vaccine given as a booster. This has been attributed to residual active pertussis toxin (PT) in the primary vaccine. In this study, we investigated the possible contribution of the A-subunit enzymatic activity and the B-oligomer carbohydrate binding activity of residual PT in DTaP to local reactions in a murine model using Japanese DTaP batches produced before and after the introduction of a test for reversion of pertussis toxoid to toxin.

Relationship of immunogenicity to protective potency in acellular pertussis vaccines.

Comparison of the immunogenicity response and resistance to challenge in the modified intracerebral challenge assay induced by various acellular pertussis vaccines showed that these were not closely linked. The immunogenicity assay was effective for confirming the presence of specific antigenic components and was invaluable for detecting minor components present in co-purified vaccines. However, the magnitude of antibody responses was not consistently related to antigen concentration nor did it correlate with protection in the modified intracerebral challenge assay.

An international collaborative study of the effect of active pertussis toxin on the modified Kendrick test for acellular pertussis vaccines.

Speculation that the Japanese modified intra-cerebral challenge assay, which is used in several countries for control of acellular pertussis vaccines, depends on the presence of small amounts of active pertussis toxin led to an assumption that it may not be appropriate for highly toxoided or genetically detoxified vaccines. Consequently, at the recommendation of a World Health Organisation AD Hoc Working Group on mouse protection models for testing and control of acellular pertussis vaccine, the effect of pertussis toxin on the modified intra-cerebral challenge assay (modified Kendrick, MICA) was evaluated in an international collaborative study. Results of this study showed that for genetically detoxified vaccines both with and without active pertussis toxin the MICA clearly distinguished mice vaccinated with acellular vaccines from unvaccinated mice and gave a significant dose-response relationship.

A CpG-containing oligodeoxynucleotide adjuvant for acellular pertussis vaccine improves the protective response against Bordetella pertussis.

We investigated the adjuvant effect of CpG ODN alone or in combination with aluminum hydroxide on the immune response to the three main antigens presented in current acellular pertussis vaccines: pertussis toxoid, filamentous haemagglutinin and pertactin. The development of protection in mice was investigated for the intra-peritoneal and intra-nasal immunisation routes. The results showed that CpG ODN alone, or in combination with aluminum hydroxide, gave enhancement in anti-pertussis toxin, anti- filamentous haemagglutinin and especially anti-pertactin titers after mucosal immunisation.

Report of an International collaborative study to establish the first WHO reference reagents for BCG vaccines of three different sub-strains.

The WHO First International Reference Preparation for BCG vaccine is over forty years old and is no longer available for distribution due to stock depletion and its significant loss of viability. International consultations identified a demand for replacement with sub-strain specific BCG preparations. An International collaborative study was carried out to evaluate three candidates for WHO Reference Reagent for BCG vaccine of Danish 1331, Russian BCG-I and Tokyo 172-1 sub-strains.

Report of an international collaborative study to evaluate the suitability of multiplex PCR as an identity assay for different sub-strains of BCG vaccine.

Current methods for the identification of BCG vaccine in quality control settings involve acid-fast staining with microscopic examination. However, this method is unable to distinguish the many different sub-strains of BCG, or to differentiate BCG strains from virulent members of the Mycobacterium tuberculosis complex. A multiplex PCR (mPCR) which uses six target regions in mycobacteria has been developed to identify specific sub-strains of BCG.

An in vitro assay system as a potential replacement for the histamine sensitisation test for acellular pertussis based combination vaccines.

The histamine sensitisation test (HIST) for pertussis toxin is currently an official batch release test for acellular pertussis containing combination vaccines in Europe and North America. However, HIST, being a lethal endpoint assay, often leads to repeated tests due to large variations in test performance. Although a more precise HIST test based on measurement of temperature reduction after the histamine challenge is used in Asian countries, this test still uses animals.

Prospects for new plague vaccines.

The potential application of Yersinia pestis for bioterrorism emphasizes the urgent need to develop more effective vaccines against airborne infection. The current status of plague vaccines has been reviewed. The present emphasis is on subunit vaccines based on the F1 and LcrV antigens.

Vaccines and biosimilarity: a solution or a problem?

Biosimilarity is a significant issue for vaccines and a reasonable approach to this could facilitate licensing of follow-on products of similar design. However, the definitions and guideline criteria developed for similar versions of biotherapeutics may be too restrictive for vaccines, as the molecular composition of their active substances can rarely be defined precisely, and immunogenicity is an essential rather than an undesirable characteristic. Similarity in antigenic composition may be more relevant.

Characterization of reference materials for human antiserum to pertussis antigens by an international collaborative study.

Enzyme-linked immunosorbent assay (ELISA) has been widely used to evaluate antibody responses to pertussis vaccination and infection. A common reference serum is essential for the standardization of these assays. However, no internationally recognized reference serum is available.

Current progress with Moraxella catarrhalis antigens as vaccine candidates.

The success of the immunization programs against Haemophilus influenzae type b and, more recently, Streptococcus pneumoniae in developed and some developing countries has demonstrated that invasive disease caused by these bacteria can be very effectively controlled by vaccination. There is also evidence that pneumococcal vaccines can reduce the incidence of acute otitis media in children. More complete control of this disease would be achieved if infections caused by Moraxella catarrhalis and nontypeable H.

Transferability of dermal temperature histamine sensitization test for estimation of pertussis toxin activity in vaccines.

All current acellular pertussis vaccines (ACVs) contain detoxified pertussis toxin (PT) as a major component. An essential part of the safety evaluation of these vaccines, required by regulatory authorities, is to monitor their active PT content and to check for reversion to toxicity of the detoxified PT. Although various in vitro tests are under investigation, the only practicable means for detecting active PT at present is the histamine sensitization test.

Report of an international collaborative study to establish the suitability of using modified ATP assay for viable count of BCG vaccine.

As part of the World Health Organisation (WHO) initiative to update the current requirements for BCG vaccine a collaborative study was carried out to establish the robustness, reproducibility and the suitability of the modified ATP assay. This assay was developed by Statens Serum Institut, Denmark, as a potential replacement of the method for detection of viable counts of BCG vaccine which is routinely used as a quality control test for lot release. Two BCG preparations, of same strain but different production methods, were tested.

WHO Working Group on revision of the Manual of Laboratory Methods for Testing DTP Vaccines-Report of two meetings held on 20-21 July 2006 and 28-30 March 2007, Geneva, Switzerland.

This report reflects the discussion and conclusions of a WHO group of experts from National Regulatory Authorities (NRAs), National Control Laboratories (NCLs), vaccine industries and other relevant institutions involved in standardization and control of diphtheria, tetanus and pertussis vaccines (DTP), held on 20-21 July 2006 and 28-30 March 2007, in Geneva Switzerland for the revision of WHO Manual for quality control of DTP vaccines. Taking into account recent developments and standardization in quality control methods and the revision of WHO recommendations for D, T, P vaccines, and a need for updating the manual has been recognized. In these two meetings the current situation of quality control methods in terms of potency, safety and identity tests for DTP vaccines and statistical analysis of data were reviewed.

Perspectives for the treatment of brucellosis in the 21st century: the Ioannina recommendations.

The authors provide evidence-based guidance on treating human brucellosis, and discuss the future clinical trials that would help address the controversies surrounding treatment.

A retrospective study on the quality of Haemophilus influenzae type b vaccines used in the UK between 1996 and 2004.

Following the reduction in efficacy of Hib-TT vaccines in the primary immunization schedule observed in the UK between 1999 and 2003, batches of vaccine manufactured by two different companies were retrospectively examined by the National Institute for Biological Standards and Control. The study evaluated 41 batches of the Hib-TT vaccines manufactured between 1994 and 2003, assaying potency (total PRP saccharide content), integrity (% free saccharide), consistency (molecular sizing), and immunogenicity, as well as reviewing data previously obtained at the time of release. The study indicated the stability of the lyophilized final fill vaccines to extend well past their assigned shelf-lives, and found no trends in the endotoxin content, total saccharide or % free saccharide content.

Physico-chemical characterisation and immunogenicity of a multi-valent candidate vaccine against non-typeable Haemophilus influenzae and Moraxella catarrhalis.

The physico-chemical characteristics and immunogenicity of a candidate vaccine against otitis media, prepared from recombinant lipidated outer membrane proteins (rLP4 and rLP6) from non-typeable Haemophilus influenzae (NTHi) and of the ubiquitous cell surface protein UspA2 from Moraxella catarrhalis, were evaluated. Optical spectroscopy, size exclusion chromatography and gel electrophoresis were used to characterise the purified protein components and assess their purity and molecular sizes. The results showed that the three proteins were highly purified.

Evaluation of the saccharide content and stability of the first WHO International Standard for Haemophilus influenzae b capsular polysaccharide.

Haemophilus influenzae b conjugate vaccines (Hib) are almost entirely evaluated by physico-chemical methods to ensure the consistency of manufacture of batches. As different assays are employed for the quantification of Hib capsular polysaccharide PRP (polyribosyl ribitol phosphate; 5-D-ribitol-(1-->1)-beta-D-ribose-3-phosphate) in final formulations and bulk components, there was deemed a need for an International Standard of Hib PRP polysaccharide to be made available. Ten laboratories from 8 different countries participated in a collaborative study to determine the PRP content and assess the suitability of a candidate International Standard PRP preparation (02/208).

Preclinical laboratory evaluation of a bivalent Staphylococcus aureus saccharide-exotoxin A protein conjugate vaccine.

A bivalent, unadjuvanted conjugate vaccine composed of Staphylococcus aureus capsular polysaccharides type 5 and 8 (T5 and T8 PS) conjugated to a novel carrier protein, the mutant nontoxic recombinant Pseudomonas aeruginosa exotoxin A (rEPA), has been the subject of recent clinical trials. A program of preclinical laboratory evaluation was carried out in support of the clinical trials conducted by the National Vaccine Evaluation Consortium. This involved physical chemical characterization and limited assessment of toxicity and immunogenicity.

Tuberculin purified protein derivative (PPD) immunoassay as an in vitro alternative assay for identity and confirmation of potency.

Tuberculin purified protein derivative (PPD) currently can only be standardised by delayed hypersensitivity skin reactions in sensitised guinea pigs. An in vitro dot blot immunoassay was developed for both identity and confirmation of potency estimation of PPD. Polyclonal antibodies (mainly IgG) were generated and immunoreacted with human, bovine and, to lesser extent, avian PPD preparations.

Investigation in a model system of the effects of combinations of anthrax and pertussis vaccines administered to service personnel in the 1991 Gulf War.

The toxicity and immunogenicity of the anthrax and pertussis vaccine combinations used in the 1991 Gulf War was assessed in NIH, A/J and Balb/c mice. Inoculation of pertussis vaccines, vaccine combinations, or aluminium salt caused illness, splenomegaly and significant weight loss. Although some animals recovered eventually, a lethal form of ascites developed in some NIH mice and body weights of A/J and Balb/c mice remained below normal levels.

Development of an approach for the laboratory toxicological evaluation of Bordetella pertussis adenylate cyclase genetic toxoid constructs as multipurpose vaccines.

Detoxified recombinant CyaA constructs have been developed as potential viral and tumoral epitope carriers for immunoprophylactic and therapeutic vaccination and as antigen candidates for inclusion in acellular pertussis vaccines. In this work, we attempt to explore a test system for the laboratory safety evaluation of CyaA preparations. Endotoxin was determined in vitro by the Limulus amoebocyte lysate assay.