Streamlining Peptide Mapping LC-MS Approach for Studying Fusion Peptide-Conjugated Vaccine Immunogens.

A newly introduced HIV-1 vaccination utilizes a fusion peptide (FP)-based immunogen-carrier conjugate system, where the FP is coupled to a protein carrier via a bifunctional linker. Such heterogeneous materials present a challenge for the routine product quality assessment. Peptide mapping LC-MS analysis has become an indispensable tool for assessing the site-specific conjugation ratio, estimating site occupancy, monitoring conjugation profiles, and analyzing post-translational modifications (PTMs) and disulfide bonds as well as high-order protein structures. To streamline the peptide mapping approach to match the needs of a fast-paced conjugate vaccine product characterization, a selection of signature fragment ions generated by MSE fragmentation was successfully applied to assess the product quality at the different stages of a conjugates' manufacturing process with an emphasis on monitoring the amount of a reactive linker. This technique was employed in different conjugation studies of the protein carriers, linkers, and FP compositions as well as the cross-linked species formed during stress-degradation studies. Multiple derivatives of the intermediate and final conjugated products formed during a multistaged synthesis were monitored by means of the sensitive extracted-ion chromatogram (XIC) profiling and were included in the estimation of the site-specific conjugation loads. Differentiation of the conjugates with various FP compositions was demonstrated. The conjugation site occupancy was evaluated with respect to the solvent exposure of Lys residues. The findings of these LC-MS studies greatly aided in choosing the best conjugation strategy to ensure that the final recombinant tetanus toxoid heavy chain (rTTHc) product is chemically inert and represents a safe vaccine candidate for clinical evaluation.

Prefiltration enhances performance of sterile filtration for glycoconjugate vaccines.

Recent studies have reported very low capacity during sterile filtration of glycoconjugate vaccines due to rapid fouling of the sterile filter. The objective of this study was to explore the potential for significantly increasing the capacity of the sterile filter through the use of an appropriate prefilter. Data were obtained using prefilters with different pore size and chemistry, with the sterile filtration performed at constant filtrate flux using 0.22 µm nominal pore size Durapore® polyvinylidene difluoride membranes. Prefiltration through 5 µm pore size Durapore® or Nylon prefilters nearly eliminated the fouling of the sterile filter, leading to more than a 100-fold reduction in the rate of pressure increase for the sterile filter. This dramatic improvement in sterile filter performance was due to the removal of large components (greater than 1 µm in size) as confirmed by dynamic light scattering. These results demonstrate the potential of using large pore size prefilters to significantly enhance the performance of the sterile filtration process for the production of important glycoconjugate vaccines.

Use of NMR as an analytical tool in the process development of conjugate vaccines against Haemophilus influenzae type b (Hib) and meningococcal serogroup A (MenA).

The native structure of the bacterial polysaccharide is the key immunogenic component of conjugate vaccines and antibodies raised against the polysaccharide structure are responsible for providing protection against the corresponding pathogen. The manufacturing process of conjugate vaccines is very complex and has various biological and chemical steps. It is important to monitor the process to ensure that the structural identity of the polysaccharide is maintained throughout the process. NMR spectroscopy can be used as a versatile analytical tool to monitor the structural integrity of the polysaccharide component from isolated polysaccharide to conjugate vaccine and for identifying different impurities generated during the process.

Improving Analytical Characterization of Glycoconjugate Vaccines through Combined High-Resolution MS and NMR: Application to Neisseria meningitidis Serogroup B Oligosaccharide-Peptide Glycoconjugates.

Conjugate vaccines are highly heterogeneous in terms of glycosylation sites and linked oligosaccharide length. Therefore, the characterization of conjugate vaccines' glycosylation state is challenging. However, improved product characterization can lead to enhancements in product control and product quality. Here, we present a synergistic combination of high-resolution mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR) for the analysis of glycoconjugates. We use the power of this strategy to characterize model polysaccharide conjugates and to demonstrate a detailed level of glycoproteomic analysis. These are first steps on model compounds that will help untangle the details of complex product characterization in conjugate vaccines. Ultimately, this strategy can be applied to enhance the characterization of polysaccharide conjugate vaccines. In this study, we lay the groundwork for the analysis of conjugate vaccines. To begin this effort, oligosaccharide-peptide conjugates were synthesized by periodate oxidation of an oligosaccharide of a defined length, α,2-8 sialic acid trimer, followed by a reductive amination, and linking the trimer to an immunogenic peptide from tetanus toxoid. Combined mass spectrometry and nuclear magnetic resonance were used to monitor each reaction and conjugation products. Complete NMR peak assignment and detailed MS information on oxidized oligosialic acid and conjugates are reported. These studies provide a deeper understanding of the conjugation chemistry process and products, which can lead to a better controlled production process.

An ELISA method to estimate the mono ADP-ribosyltransferase activities: e.g in pertussis toxin and vaccines.

ADP-ribosyltransferase activities have been observed in many prokaryotic and eukaryotic species and viruses and are involved in many cellular processes, including cell signalling, DNA repair, gene regulation and apoptosis. In a number of bacterial toxins, mono ADP-ribosyltransferase is the main cause of host cell cytotoxicity. Several approaches have been used to analyse this biological system from measuring its enzyme products to its functions. By using a mono ADP-ribose binding protein we have now developed an ELISA method to estimate native pertussis toxin mono ADP-ribosyltransferase activity and its residual activities in pertussis vaccines as an example. This new approach is easy to perform and adaptable in most laboratories. In theory, this assay system is also very versatile and could measure the enzyme activity in other bacteria such as Cholera, Clostridium, E. coli, Diphtheria, Pertussis, Pseudomonas, Salmonella and Staphylococcus by just switching to their respective peptide substrates. Furthermore, this mono ADP-ribose binding protein could also be used for staining mono ADP-ribosyl products resolved on gels or membranes.

Determination of free polysaccharide in Vi glycoconjugate vaccine against typhoid fever.

Glycoconjugate vaccines based on the Vi capsular polysaccharide directed against Salmonella enterica serovar Typhi are licensed or in development against typhoid fever, an important cause of morbidity and mortality in developing countries. Quantification of free polysaccharide in conjugate vaccines is an important quality control for release, to monitor vaccine stability and to ensure appropriate immune response. However, we found that existing separation methods based on size are not appropriate as free Vi non-specifically binds to unconjugated and conjugated protein. We developed a method based on free Vi separation by Capto Adhere resin and quantification by HPAEC-PAD. The method has been tested for conjugates of Vi derived from Citrobacter freundii with different carrier proteins such as CRM197, Tetanus Toxoid and Diphtheria Toxoid.

Vacunas antineumocócicas. Nuevas vacunas conjugadas para el adulto / Pneumococcal vaccines. New conjugate vaccines for adults

Las infecciones neumocócicas son una importante causa de morbimortalidad y constituyen una de las 10 principales causas de muerte en el mundo. Los niños menores de 2 años son los que tienen una tasa de incidencia más elevada, seguidos de los adultos mayores de 64 años. El principal grupo de riesgo son los individuos con inmunodeficiencias de cualquier tipo y aquellos con asplenia anatómica o funcional, aunque también afecta a personas inmunocompetentes con ciertas enfermedades crónicas. En la última década se ha realizado un importante progreso en la prevención de estas infecciones. Hasta hace pocos años solo se disponía de la vacuna antineumocócica no conjugada 23-valente, con resultados controvertidos en cuanto a su eficacia y efectividad, y con limitaciones importantes por el tipo de respuesta inmune inducida. La posibilidad actual de utilizar la vacuna conjugada 13-valente en el adulto abre expectativas importantes en la mejora de la prevención de la enfermedad neumocócica en estos grupos de edad

Pneumococcal infections are a significant cause of morbidity and mortality, and are one of the 10 leading causes of death worldwide. Children under 2 years have a higher incidence rate, followed by adults over 64 years. The main risk group are individuals with immunodeficiency, and those with anatomical or functional asplenia, but can also affect immunocompetent persons with certain chronic diseases. Significant progress has been made in the last 10 years in the prevention of these infections. Until a few years ago, only the 23-valent non-conjugate pneumococcal vaccine was available. Its results were controversial in terms of efficacy and effectiveness, and with serious limitations on the type of immune response induced. The current possibility of using the 13-valent conjugate vaccine in adults has led to greater expectations in improving the prevention of pneumococcal disease in these age group

Pharmacokinetic correlates of the effects of a heroin vaccine on heroin self-administration in rats.

The purpose of this study was to evaluate the effects of a morphine-conjugate vaccine (M-KLH) on the acquisition, maintenance, and reinstatement of heroin self-administration (HSA) in rats, and on heroin and metabolite distribution during heroin administration that approximated the self-administered dosing rate. Vaccination with M-KLH blocked heroin-primed reinstatement of heroin responding. Vaccination also decreased HSA at low heroin unit doses but produced a compensatory increase in heroin self-administration at high unit doses. Vaccination shifted the heroin dose-response curve to the right, indicating reduced heroin potency, and behavioral economic demand curve analysis further confirmed this effect. In a separate experiment heroin was administered at rates simulating heroin exposure during HSA. Heroin and its active metabolites, 6-acetylmorphine (6-AM) and morphine, were retained in plasma and metabolite concentrations were reduced in brain in vaccinated rats compared to controls. Reductions in 6-AM concentrations in brain after vaccination were consistent with the changes in HSA rates accompanying vaccination. These data provide evidence that 6-AM is the principal mediator of heroin reinforcement, and the principal target of the M-KLH vaccine, in this model. While heroin vaccines may have potential as therapies for heroin addiction, high antibody to drug ratios appear to be important for obtaining maximal efficacy.

Quantification of each serogroup polysaccharide of Neisseria meningitidis in A/C/Y/W-135-DT conjugate vaccine by high-performance anion-exchange chromatography-pulsed amperometric detection analysis.

Invasive bacterial meningitis caused by Neisseria meningitidis can be prevented by active immunization with meningococcal polysaccharide or polysaccharide-protein conjugate vaccines. In a tetravalent A/C/Y/W-135-DT meningococcal conjugate vaccine vial, or in a final formulated bulk, accurate identification and quantification of each polysaccharide are critical in product release. Determination of sialic acid serogroups (C, W-135, and Y) unambiguously is complex since all these serogroups contribute to the sialic acid monosaccharide peaks that overlap in the high-performance anion-exchange chromatography-pulsed amperometric detection (HPAEC-PAD). We report a quantification method that involves generation of monosaccharide standard plots for respective sugars mannosamine-6-phosphate, sialic acid, galactose- and glucose-derived from hydrolysis of mixtures of the four serogroups A, C, W, and Y reference polysaccharides. These plots were then used to obtain the unknown polysaccharide concentrations of A/C/Y/W-135 in vialed vaccine or from formulated final bulks. We also present our results of the HPAEC-PAD profiles on groups C, W-135, and Y polysaccharides when hydrolyzed individually and/or in mixtures to discuss the individual sialic acid peak contributions.

Serotipos de neumococo en nasofaringe de niños preescolares sanos tras la vacunación antineumocócica conjugada heptavalente / Nasopharyngeal carriage of pneumococcal serotypes in healthy pre-school aged children after 7-valent pneumococcal vaccine

Fundamento y objetivo: Tras la introducción de la vacuna neumocócica conjugada heptavalente (VNC-7v) se plantea investigar en nuestro medio las características que influyen en la colonización por serotipos de neumococo en niños preescolares sanos, la distribución de serotipos y su sensibilidad a antimicrobianos.Sujetos y método: Entre febrero de 2008 y enero de 2009 se recogieron muestras nasofaríngeas a niños de entre 2 meses y 5 años de edad que acudían a revisiones del niño sano en 4 centros de atención primaria de la provincia de Zaragoza (España) para cultivo y serotipado. Mediante regresión logística se estudiaron diferentes variables relacionadas con el estado de portador y las resistencias.Resultados: De los 371 niños estudiados, un 30,7% portaban neumococo en la nasofaringe. Con una cobertura de VNC-7v del 66%, factores relacionados con el hecho de ser portador fueron el número de hermanos (odds ratio [OR] 1,44; intervalo de confianza del 95% [IC 95%] 1,05 a 1,97 por cada hermano), estar escolarizado o asistir a guardería (OR 3,99; IC 95% 2,00 a 7,96), y padecer afección leve de vías respiratorias altas en el momento de la toma (OR 1,72; IC 95% 1,02 a 2,90). Solamente correspondían a serotipos incluidos en la vacuna (STV) un 8,7%. Los serotipos no vacunales más frecuentemente aislados fueron 19A, 6A, 15B, 11 y 15A. Se detectaron significativamente más resistencias a antibióticos entre los STV. Conclusiones: Los niños menores de 6 años de nuestro medio portan neumococos más frecuentemente cuando tienen hermanos, están escolarizados o padecen afecciones leves de vías respiratorias altas. Tras la introducción de la vacuna VNC-7v, los STV son casi anecdóticos (8,7%) y los serotipos emergentes presentan mejor sensibilidad a antibióticos (AU)

Background and objective: To determine the characteristics influencing pneumococcal serotype colonization in healthy pre-school aged children, the distribution of serotypes and their antimicrobial susceptibility, after the introduction of pneumococcal 7-valent conjugate vaccine (VNC-7v). Sujetos and methods: Nasopharyngeal samples were collected from children under 6years of age attending well-child examinations in the province of Zaragoza (Spain). Logistic regression was used to study different variables related to the status of the carriers. Results:Of the 371 children studied 30.7% were found to be carriers. With a vaccine coverage rate of 66%, factors related with presence of pneumococcal carriage were found to be the number of siblings (OR 1.44; CI 95% 1.05-1.97 for each sibling), attending a school or child day care centre (OR 3.99; CI 95% 2.00-7.96) and suffering from a minor upper respiratory tract infection (URTI) (OR 1.72; CI 95% 1.02-2.90). Only 8.7% corresponded to VNC-7v serotypes. The most common non VNC-7v serotypes isolated were 19A, 6A, 15B, 11, and 15A. Significantly greater resistance was detected among VNC-7v serotypes. Conclusion: Children in the setting of this study carried pneumococci more commonly when they have siblings, attend school or day care, or suffer from minor URTI. In the VNC-7v vaccine era, VNC-7v serotypes have become rare occurrences (8.7%) and emerging serotypes present better susceptibility to antibiotics (AU)

Vacunación antineumocócica. Más allá de la infancia / Pneumococcal vaccination. Beyond childhood

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Neumonía neumocócica en la era de la vacuna conjugada heptavalente / Pneumococcal pneumonia in the era of heptavalent pneumococcal conjugate

Introducción: Describir las características clínicas, las complicaciones, los serotipos y las resistencias antibióticas en la neumonía neumocócica en nuestro medio tras la generalización de la vacuna conjugada heptavalente (VNC-7) en pediatría. Material y métodos: Estudio prospectivo de los episodios de neumonía neumocócica, con cultivos positivos, en pacientes atendidos en urgencias desde enero de 2006 hasta febrero de 2010.Resultados: Se estudiaron 346 episodios en 320 pacientes; 335 correspondían a 309 pacientes adultos,221 (71,5%) varones, mediana de edad 68 años (rango: 16-94) y 11 episodios a pacientes < 15 años. Fueron de adquisición comunitaria 237 episodios (68,5%). Presentaron bacteriemia 130 (37,6%) casos, evidenciando una tendencia al aumento de riesgo en los pacientes < 65 años (OR = 1,56; IC del 95%, 0,96-2,56;p = 0,07). Desarrollaron empiema 13 (3,8%) y shock séptico 33 (9,5%). La media de edad de los pacientes con empiema fue menor (p = 0,03). En el análisis multivariante se relacionaron con la presencia de bacteriemia: antecedente de patología respiratoria = (..) (AU)

Introduction: To describe clinical features, complications, serotypes and antibiotic resistance in pneumococcal pneumonia in our environment after the generalization of the heptavalent conjugate vaccine(PCV-7) in paediatrics. Material and methods: Prospective study of episodes of pneumococcal pneumonia, with positive cultures in patients treated in the emergency department from January 2006 to February 2010.Results: We studied 346 episodes in 320 patients, 335 belonged to 309 adult patients, 221 (71.5%) males, median age 68 years (range 16-94), and 11 episodes to patients < 15 years. Two-hundred and thirty-seven (68.5%) episodes were community acquired. Bacteraemia was present in 130 (37.6%) cases, with a tendency towards an increased risk in patients < 65 years (OR = 1.56, 95% CI 0.96- 2.56, P = .07). Thirteen (3.8%) patients developed empyema and 33 (9.5%) septic shock. The mean age of patients with empyema was lower (P = .03). In the multivariate analysis were related to the presence of bacteraemia: a history of chronic respiratory disease (OR = 0.45, 95% CI 0.25-0.81, P = .008), positive urinary antigen (OR 2.02,95% CI 1 13-3.62, P = .01) and pleural effusion (OR = 3.86, 95% CI 1.79-8.35, P = .001). Shock was associated with Fine IV-V stage (OR = 23.6, 95% CI 4.96-112.82, P < .001), age < 65 years (OR = 4.47, 95% CI 1.75-11.39,P = .002) and pleural effusion (OR = 4.15, 95% CI 1.65 to 10.41, P = .002).Increased mortality risk was associated with presence of any complication (OR = 6.6, 95% CI 1.5-27.2,P = .009) and specifically septic shock (OR = 3.3, 95% CI 1.06-10.3, P = .04). Most serotypes obtained were not included in the VNC-7.Conclusions: Pneumococcal pneumonia after generalisation of PCV-7 is mainly related to non-vaccine serotypes. Younger patients without respiratory disease are at increased risk of bacteraemia, empyema, and septic shock, the latter being associated with a higher mortality (AU)

Bioanalysis of meningococcal vaccines.

Meningococcal meningitis is feared because of the rapid onset of severe disease from mild symptoms and, therefore, is an important target for vaccine research. Five serogroups, defined by the structures of their capsular polysaccharides, are responsible for the vast majority of disease. Protection against four of these five serogroups can be obtained with polysaccharide or glycoconjugate vaccines, in which fragments of the capsular polysaccharides attached to a carrier protein generate anticarbohydrate immune responses, whilst protection against group B disease requires protein immunogens, often presented in vesicles containing outer membrane proteins. Glycoconjugate vaccines are now an established technology, but outer-membrane protein vaccines are still under development and present significant challenges. This review discusses physicochemical approaches to the characterization and quality control of these vaccines, as well as highlighting the problems and differences in vaccine design required for protection against different serogroups of the same species of pathogen.

Advantages of a synthetic peptide immunogen over a protein immunogen in the development of an anti-pilus vaccine for Pseudomonas aeruginosa.

The type IV pilus is an important adhesin in the establishment of infection by Pseudomonas aeruginosa. We have previously reported on a synthetic peptide vaccine targeting the receptor-binding domain of the main structural subunit of the pilus, PilA. The receptor-binding domain is a 14-residue disulfide loop at the C-terminal end of the pilin protein. The objective of this study was to compare the immunogenicity of a peptide-conjugate to a protein subunit immunogen to determine which was superior for use in an anti-pilus vaccine. BALB/c mice were immunized with the native PAK strain pilin protein and a synthetic peptide of the receptor-binding domain conjugated to keyhole limpet haemocyanin. A novel pilin protein with a scrambled receptor-binding domain was used to characterize receptor-binding domain-specific antibodies. The titres against the native pilin of the animals immunized with the synthetic peptide-conjugate were higher than the titres of animals immunized with the pilin protein. In addition, the affinities of anti-peptide sera for the intact pilin receptor-binding domain were significantly higher than affinities of anti-pilin protein sera. These results have significant implications for vaccine design and show that there are significant advantages in using a synthetic peptide-conjugate over a subunit pilin protein for an anti-pilus vaccine.

Vacunas antimeningocócicas / Vaccines against Neisseria meningitidisg

Se revisa la situación actual de las vacunasantimeningocócicas. Por una parte, las vacunaspolisacáridas simples frente a los serogrupos A, C, Y y W-135 y, por otra, las polisacáridas conjugadas a distintos transportadores proteicos, monovalentes o multivalentes.Respecto a las vacunas frente a Neisseria meningitidisserogrupo B, se analizan las experiencias basadas en lasproteínas de membrana externa y su uso en el control debrotes epidémicos, y las expectativas de una vacunauniversal que se podrían alcanzar con las técnicas devacunología inversa

The present article reviews the state of the art on vaccines against Neisseria meningitidis, from plain polysaccharide to mono- and multivalent protein-polysaccharide conjugate vaccines targeting A, C, Y and W-135 serogroups. We also review immunization againstserogroup B Neisseria meningitidis using protein-basedvaccines composed of outer membrane vesicles and theiruse in the control of epidemic outbreaks, as well asexpectations of a universal vaccine, which could beachieved with reverse vaccinology techniques (AU)

Vacunas neumocócicas conjugadas: presente y futuro / Conjugate pneumococcal vaccines: present and future

La introducción de la vacuna neumocócica conjugadaheptavalente en algunos países ha dado lugar a cambiossubstanciales en la epidemiología de las infeccionesproducidas por esta bacteria. La mayor repercusión ha sido una disminución global de la enfermedad invasora, sobre todo por un descenso de las infecciones producidas por los serotipos vacunales. La vacuna ha generado una inmunidad de grupo muy efectiva, extendiendo su efecto protector a las personas no vacunadas de todas las edades, entre ellas los mayores de 65 años, una población en la que la infección conlleva una morbimortalidad elevada.La inmunidad de grupo se debe, en parte, a la inducción de respuestas inmunitarias en las mucosas respiratorias. El resultado es una disminución de la colonizaciónnasofaríngea por los serotipos vacunales, que, sin embargo, son reemplazados por otros serotipos no contenidos en la vacuna. Como quiera que la colonización nasofaríngea es un hecho crucial en la epidemiología de las infecciones neumocócicas, no es de extrañar que los cambios en la misma den lugar a algunas consecuencias conocidas y otras que se empiezan a conocer. Más del 80% de las resistencias de neumococo van ligadas a 5 de los serotipos vacunales, cuya desaparición de la nasofaringe se ha acompañado de una disminución marcada de infecciones causadas por cepas resistentes. Un hecho preocupante ha sido la emergencia de serotipos no contenidos en la vacuna, como 19A, 3, 15, 33 y 6A, que podría, en un futuro, dar lugar a una disminución de la efectividad de la vacuna o a cambios en la epidemiología de la enfermedad

The introduction of the heptavalent pneumococcalconjugate vaccine in some countries has substantiallychanged the epidemiology of pneumococcal infections.The greatest effect has been an overall reduction ofinvasive disease, especially due to a decrease in infectionsproduced by vaccine serotypes. This vaccine has generatedhighly effective group immunity, extending its protectiveeffect to non-vaccinated individuals of all ages, includingthose older than 65 years, a population in which infection carries high morbidity and mortality. Group immunity is partly due to induction of immune responses in the respiratory mucosa. The result is a decrease innasopharyngeal colonization by vaccine serotypes which,however, can be replaced by other serotypes notcontained in the vaccine. Since nasopharyngealcolonization is a crucial factor in the epidemiology ofpneumococcal infections, changes in colonization lead tosome known consequences and others that are beginningto be known. More than 80% of pneumococcal-resistantstrains are linked to five vaccine serotypes; thedisappearance of these vaccine serotypes from thenasopharynx has been accompanied by a marked decreasein infections caused by resistant strains. A worrying recent finding has been the emergence of serotypes notcontained in the vaccine such as 19A, 3, 15, 33 and 6A,which could in future decrease the effectiveness of thevaccine or lead to changes in the epidemiology of pneumococcal disease (AU)

Vacuna de polisacárido meningocócico del grupo C conjugada con toxoide tetánico. Un meta-análisis de la inmunogenicidad, seguridad y posología / Group C Meningococcal Polysaccharide-Tetanus Toxoid Conjugate Vaccine. A Meta-Analysis of Immunogenicity, Safety and Posology

La vacuna que contiene polisacárido de meningococodel grupo C de-O-acetilado, conjugada con toxoidetetánico (GCMP-TT), se ha autorizado en 32países y se ha incorporado en un programa de vacunaciónrutinaria en el Reino Unido. Rápidamentese ha acumulado una gran experiencia, que es elobjeto de este meta-análisis, sobre la inmunogenicidad,seguridad y posología de GCMP-TT, así comosobre su impacto epidemiológico. GCMP-TT ha demostradoser efectiva tras una dosis única en individuosmayores de 12 meses de edad y su posologíainicial especificaba tres dosis en lactantes. Sin embargo,según un ensayo clínico reciente, la posologíase redujo a dos dosis en lactantes. La tasa deprotección recogida, definida como la proporción deindividuos con títulos de anticuerpos bactericidas ensuero (SBA) ≥1:8, fue del 99,4% (CI, 98.2-99.9%) ensiete estudios clínicos que abarcan todos los gruposde edad. Se han demostrado respuestas fuertes aGCMP-TT con respecto a SBA, niveles de IgG y deavidez a los anticuerpos. En la farmacovigilanciadespués de la comercialización, que abarca >12 x106 GCMP-TT dosis distribuidas por todo el mundo,la vacuna ha sido bien tolerada con una tasa de incidenciade 0,01% para todos los tipos de efectos adversosmás comúnmente encontrados. Después deuna campaña de vacunación general en el ReinoUnido, en la que a los niños de 5-8 años se les dioprimeramente GCMP-TT, se observó una disminucióndel 93% en la incidencia de enfermedad meningocócica.A la vista de esta inmunogenicidad, seguridady adaptación potencial al uso en lactantes enprogramas de posología reducida, la vacuna GCMPTTmarca un mayor avance sobre las vacunas depolisacárido predecesoras en la prevención de enfermedadmeningocócica C

A conjugate vaccine comprised of de-O-acetylatedgroup C meningococcal polysaccharide coupledto tetanus toxoid (GCMP-TT) has been licensed in32 countries and incorporated in a comprehensiveUK vaccination program. Extensive evidence, formingthe subject of this meta-analysis, has rapidlyaccumulated on the immunogenicity, safety and posologyof GCMP-TT as well as its epidemiologicalimpact. GCMP-TT has been shown effective after asingle dose in individuals > 12 months of age, andinitial posology specified three doses in infants. However,based on a recent clinical trial, posology wasreduced to two doses in infants. Pooled protectionrate, defined as proportion of subjects with serumbactericidal antibody (SBA) levels 1:8, was 99.4%(CI, 98.2-99.9%) in 7 clinical trials covering all agegroups. Robust responses to GCMP-TT have been demonstrated with respect to SBA, IgG levels andantibody avidity. In post-marketing pharmacosurveillanceencompassing > 12*106 GCMP-TT doses distributedworldwide, the vaccine has been well toleratedwith an incidence rate of 0.01% for all the mostcommonly encountered types of adverse events. Aftera catch-up UK vaccination campaign where 5-8year old children were primarily given GCMP-TT, a93% decline in meningococcal disease incidencewas observed. In view of its immunogenicity, safetyand potential suitability for use among infants in reduceddose schedules, GCMP-TT appears to marka major advance over predecessor polysaccharidevaccines for the prevention of meningococcal C disease

NMR assays for carbohydrate-based vaccines.

Antibodies against the cell surface carbohydrates of many microbial pathogens protect against infection. This was initially exploited by the development of purified polysaccharide vaccines, but glycoconjugate vaccines, in which the cell surface carbohydrate of a microbial pathogen is covalently attached to an appropriate carrier protein, are proving the most effective means to generate this protective immunity. Carbohydrate-based vaccines against Haemophilus influenzae Type b, Neisseria meningitidis, Streptococcus pneumoniae and Salmonella enterica serotype Typhi (S. Typhi) are already licensed, and many similar products are in various stages of development. For many of these vaccines, biological assays are not available or are inappropriate and NMR spectroscopy is proving a valuable tool for the characterisation and quality control of existing and novel products. This review highlights some of the areas in which NMR spectroscopy is currently used, and where further developments may be expected.

Antibodies against Haemophilus influenzae type b capsular polysaccharide and tetanus toxoid before and after a booster dose of the carrier protein nine years after primary vaccination with a protein conjugate vaccine.

IgG antibodies against Haemophilus influenzae type b (Hib) capsular polysaccharide (CPS) and tetanus toxoid (TT) were measured for 53 children, 10 years of age, before and 1 month after a booster dose of diphtheria-tetanus vaccine (DT). All children had been vaccinated at 3, 5 and 12 months of age with DT and a Hib-TT conjugate. Geometric mean concentrations of Hib CPS serum IgG antibody were 4.16 and 4.30 microg/mL before and after the DT booster, respectively. The geometric mean concentration of TT IgG antibody increased from 0.09 IU/mL to 4.58 IU/mL (P < 0.001). Hib CPS IgG levels remained well above protective titers for 9 years after 3 doses of Hib-TT appropriately spaced in infancy. A booster dose of TT did not affect Hib CPS antibody concentrations but induced a pronounced IgG response against TT.