Conventional pertussis vaccine prepared from killed whole cell B. pertussis organisms has been in widespread use since the early 1950's. Despite marked reductions in the incidence of pertussis, the use of the vaccine has caused concern because of questions of significant adverse reactions. Whooping cough is not notifiable in South Africa, and there is consequently a paucity of hard data on efficacy; in addition few cases are proven. Incidence, prevalence, severity and transmission of the disease hence remain a matter of conjecture. In order to provide background information and determine baseline data for undertaking further studies, available clinical and epidemiological data on whooping cough (pertussis) in South Africa was collated. It was intended to compare the pattern of disease seen in this country with that known in other parts of the world. Clinical and epidemiological findings from 1525 whooping cough admissions (diagnosed on the basis of clinical criteria) obtained from 6 major infectious disease hospitals around the country for the period 1980-1987/1988 are reported. The data from Durban were available in some detail. Incidence, morbidity and mortality of the disease in South Africa, as elsewhere, was higher in infancy. Infants and young children were predominantly affected, with 31.3% of cases under 12 months of age and 7.2% less than 2 months. Mortality was disproportionately higher in infancy; 53 .2% of deaths were in those younger than 12 months of age. There was a slight female preponderance, both in respect of prevalence and mortality. Patients were admitted with pertussis throughout the year, although there was a peak during the winter months (May to October). The typical whoop accompanied the cough in 55.6% of patients . A raised white cell count was recorded in 66% of patients. The most commonly detected The average duration of hospital stay was between 1 0-13 days. Of those with vaccination records, 26% were unvaccinated, 44% had 1 or 2 doses, and 27% had been fully vaccinated with a whole-cell pertussis vaccine combined with diphtheria and tetanus toxoids. The picture, incomplete though it is, reveals a pattern of pertussis similar to that described in other developing countries. The study reveals huge gaps in our knowledge of this subject in South Africa. More research needs to be done, particularly with respect to improved diagnosis, prevention and treatment; further pertussis should be made a notifiable disease in South Africa. The whole-cell pertussis vaccine currently used in South Africa has not been adequately evaluated for post-vaccination events and immunogenicity. The development of new purified component pertussis vaccines, which appear to be safer than conventional whole-cell preparations and of equal or almost equal efficacy (although optimal vaccine composition remains to be defined), requires that the concept of early vaccination with this vaccine compared with conventional whole-cell vaccine be examined in order to optimise the immune response to these vaccines in infants; more especially since neonates do not appear to benefit from passive immunity. Acellular pertussis vaccine has not been evaluated previously in neonates. In order to address the problem of high morbidity and mortality from pertussis in early infancy; and the incorporation of the vaccine into routine vaccination schedules, a phase 11 trial of acellular and whole-cell vaccines was undertaken in very young infants. The effect of neonatal vaccination with acellular pertussis vaccine on subsequent immunity; and the immunogenicity and shortterm safety and reactogenicity of routine primary vaccination with acellular vaccine compared with conventional whole-cell preparations was investigated. Three hundred and forty-five healthy, full-term African babies were, enrolled in the study at birth; 58% of whom were successfully followed for 9 months. Infants were assigned to 1 of 3 vaccine groups in sequence at birth and received either acellular or whole-cell pertussis vaccine , combined with 0 and T (A-OTP or W-OTP) at 2, 4 and 6 months of age. Groups I and 11 received A-OTP and Group III W-OTP. In addition, at birth, Group I received an additional dose of A-OTP and Group 11, a saline placebo injection. No unvaccinated controls were studied for ethical reasons. Serologic IgG responses to 3 major protective antigens of B. pertussis, filamentous haemagglutinin (FHA), pertussis toxin (PT) and fimbrial agglutinogens 2,3 (AGG2,3), were measured by ELlSA in sera obtained at birth, and before vaccination at 2, 4 and 6 months and at 9 months of age. The incidence and nature of post-vaccination events were recorded for 14 days after each dose. A-OTP induced serum IgG responses to PT and FHA comparable with those reported in other studies, with peak PT titres occurring at 6 months of age after 2 doses in babies vaccinated according to the routine schedule (Group 11). Surprisingly, response to W-OTP was found merely to restore levels of antibody to PT and FHA to those found in cord blood after 3 doses of vaccine, which questions the immunogenicity of the South African product. Four doses of AOTP (Group I) did not produce a better antibody response than the 3-dose schedule. Incidence of all post-vaccination events to both acellular and whole-cell vaccines was low (85.96/1000 doses, 136.36/1000 doses and 76.30/1000 doses in Groups I, 11 and III respectively). Minor symptoms were more common in recipients of A-OTP, although no significant differences in rates were demonstrated. Neurologic post-vaccination events (without sequelae) occurred more frequently hi recipients of W-OTP. No infant vaccinated with A-OTP from 2 months of age (Group 11) experienced a neurologic symptom. The risks of major post-vaccination events cannot however be fully quantified In a study of this small size and diseases. A-DTP vaccination commencing at birth produced final antibody titres to PT and FHA which were superior to those of South African whole-cell vaccine but were considerably lower than when the vaccine was incorporated into routine schedules commencing at 2 months of age. The study findings suggest that acellular pertussis vaccines, whether given from birth or from the age of 2 months, appeared safer and produced a better serologic response than the South African whole-cell product which may have impaired immunogenicity. During the course of the above study, 11 full-term infants with pertussis infection (10 subclinical) were retrospectively diagnosed on the basis of ser~logic evidence. Of the infants with subclinical disease, all 10 had a ~ 4-fold rise in at least 2 different pertussis IgG antibodies and nine had ~ 4-fold rise in all 3 IgG antibodies measured. Seven infants had raised IgA antibodies to PT and FHA and 4 infants had raised IgA antibodies to AGG2,3. Subclinical infection provoked antibody production to multiple antigens to differing degrees. The role of various factors which may have contributed to asymptomatic infection were analysed, viz - household contacts; type of antibody response (clinical vs. subclinical; vaccinated vs. subclinical); maternally acquired antibody levels; vaccination status (number of vaccine doses received); age and gender; and nutritional status. SpeCial features of the study which require emphasis are: pertussis remained subclinical in unvaccinated babies (most of the subjects were unvaccinated). Subclinical infection followed incomplete primary vaccination with either acellular or whole-cell vaccines commencing at 2 months of age. Subjects were 8 months of age or younger and only 1 had completed primary vaccination. Other infections of infancy were commonly detected; 4 infants had upper Likelihood of subclinical infection was related to significantly lower levels of maternallyacquired pertussis IgG-AGG2,3 antibodies but not associated with infants' nutritional status. Subclinical pertussis is described in very young African babies at an age when the disease is most severe, and therefore has implications for infant morbidity and mortality; it is also relevant to disease surveillance and vaccine-efficacy studies . Some perinatal factors influencing vaccination were also explored . In this context we looked at: i. The acquisition of maternal antibodies to B. pertussis in paired mother-infant sera from both well -nourished and SGA full-term and pre-term infants, and infants who subsequently developed pertussis infection, and effect of these maternally-acquired antibodies on subsequent antibody responses to acellular pertussis vaccine administered soon after birth, and to acellular and whole-cell vaccines administered from the age of 2 months. if. The acquisition of maternal antibodies to diphtheria and tetanus (OT) in paired motherinfant sera from full-term and pre-term infants, and the effect of these maternallyacquired antibodies on serologic responses to neonatal OT vaccination followed by whole-cell OTP vaccination at 2, 4 and 6 months. Maternal antibodies were measured since little is known about materno-fetal transfer of pertussis antibodies, especially in African countries where inhibition of placental transfer might occur for a variety of reasons. Furthermore, the effect of peri-natal malnutrition and prematurity on transplacental transfer of diphtheria, tetanus and pertussis antibodies has not been conclusively established in these areas. sera with levels in the latter frequently being higher, Indicating active transplacental transfer of antibodies. The significant pertussis antibody levels in maternal sera were unlikely to be due to the currently used South African whole-cell vaccine (given the poor antibody response to PT and FHA shown in this study). It is assumed that the presence of these antibodies are the end result of natural infection and therefore that pertussis is widespread in the African community. Maternal and cord IgG-PT and AGG2,3 titres were significantly lower (p <0.05) and maternal IgG-FHA marginally lower (p ... O.05) in SGA infants compared to cohorts, although placental transfer was equally efficient in both groups~ This study has demonstrated that the high titres of maternally derived circulating B. pertussis antibodies do not have an inhibitory effect on the subsequent serologic response to acellular vaccine administered in early infancy (2 months) or with the first dose given soon after birth. Protective levels of diphtheria and tetanus antibodies were detected in 100% and 76% of cord sera in pre-term infants and in 85% and 67% of cord sera in full-term infants. Although the number of infants studied was too small to make a definite comment, there did not appear to be 'tolerance' due to neonatal diphtheria-tetanus vaccination of pre-term infants, or to high levels of maternally-acquired antibody. During analysis of the data from the phase 11 study of acellular pertussis vacclnes, 25 infants with protein-energy-malnutritlon (PEM) were detected on the basis of anthropometric indices. Seventeen infants were smaIJ-for-gestatlonal-age (SGA). of whom 9 developed PEM by the age of 9 months. Eight other infants developed post-natal PEM before the completion of the primary vaccination course. and extent of immunological impairment, if any, on the serologic responses to acellular vaccine and to conventional whole-cell OTP in SGA infants, and in infants who developed PEM before the completion of the primary vaccination course. The following indices were evaluated in malnourished infants; (i) anthropometric indices of nutritional status, (ii) intercurrent illnesses including pertussis infection, (iii) post-vaccination events, (iv) serologic responses to vaccination. Results were compared with those obtained in well-nourished (WN) age- and vaccine-matched cohorts. Overall, peak titres and seroconversion data of all 3 antibodies were not significantly different in malnourished infants though final anti-AGG2,3 titres (at 9 months of age) in Group III were significantly lower (p = 0.035). Although peak and final PT and FHA antibody titres in many SGA and malnourished infants were lower than in WN infants and peak responses were attained at a later age, malnutrition did not significantly affect the response to A-OTP. Peak and final AGG2,3 antibody titres were similar in SGA, malnourished and WN infants. Overall malnourished infants responded no less well to pertussis vaccination than did other vaccinees. Incidence of minor local and systemic post-vaccination symptoms was not significantly different in PEM and WN groups although induration at injection site and irritability were more frequently reported in the latter. No major neurologic post-vaccination symptoms to either vaccine were reported in SGA infants or infants with PEM at the time of vaccination. No significant differences was noted in the incidence of major symptoms in PEM as compared with WN infants. One male infant (Group I) who was malnourished at birth and who had been given 2 doses of AOTP, developed clinical signs of pertussis infection between 2 and 4 months of age. Pertussis antibody levels immediately prior to infection were not significantly different from those of un infected age-matched cohorts. The percentage of infants afflicted with common childhood illnesses were similar in PEM and WN groups (46 vs. 43.2%) although the former group incurred significantly more illnesses at an earlier age' (s6 months) (p=O.05, chi square). These findings, albeit preliminary given the small numbers of subjects studied, suggest that acellular pertussis vaccine may be incorporated into routine vaccination schedules followed in developing countries with the expectation that adequate antibody responses will be provoked in SGA infants and in infants who develop post-natal PEM and that the incidence of vaccinerelated adverse effects will be no higher than in WN infants. Further and more extensive studies are indicated before the use of acellular pertussis vaccines can be recommended for routine primary vaccination of infants in preference to whole-cell preparations in developing countries. / Thesis (Ph.D.)-University of Natal, Durban, 1991.

La toxine de pertussis (PTX) est une A-B protéine considérée comme l’un des principaux facteurs de virulence de Bordetella pertussis, l’agent bactérien responsable de la coqueluche. Aujourd’hui, cette maladie représente encore un réel danger pour les nouveaux-nés et les<p>nourrissons non ou partiellement immunisés. Actuellement, la coqueluche provoque encore la<p>mort d’environ 350.000 individus par an. La toxicité de la PTX est liée à l’activité<p>enzymatique de sa sous-unité A capable d’inhiber les voies de signalisation associées aux<p>protéines Gi. La partie B, quant à elle, permet l’entrée de cette sous-unité A dans le<p>cytoplasme des cellules cibles en se liant spécifiquement à son ou ses récepteurs<p>membranaires toujours inconnus de nos jours.<p><p>Des études réalisées chez la souris et chez l’homme ont montré que les vaccins anticoquelucheux combinés à différents antigènes vaccinaux étaient capables de moduler<p>leurs réponses humorales spécifiques. Par ailleurs, la PTX est couramment qualifiée d’agent<p>immunostimulant. En effet, des modèles murins de vaccination permirent d’identifier des<p>propriétés adjuvantes de la PTX coadministrée avec des antigènes non relevants.<p><p>Le travail développé dans ce manuscrit étudie les effets de la PTX sur 2 types cellulaires<p>primordiaux sollicités lors d’une vaccination :la cellule dendritique (DC) et le lymphocyte T<p>CD4+ naïf.<p><p>Les DC sont les seules cellules présentatrices d’antigènes aptes à initier une réponse immune<p>primaire. Dans un premier temps, nous avons montré que la PTX était capable d’activer des<p>DC générées in vitro à partir de monocytes. En effet, elles acquièrent un phénotype mature<p>caractérisé par une augmentation de l’expression membranaire des molécules costimulatrices<p>et du CMH de classe II, démontrant un effet direct et spécifique de la PTX sur les DC<p>myéloïdes. Parallèlement, ces DC produisent du TNF-a, de l’IL-12p40 et de l’IL-12p70 et<p>activent NF-kappaB, un facteur de transcription essentiel au processus de maturation. Nous<p>avons obtenu des résultats similaires avec une toxine génétiquement modifiée qui est<p>enzymatiquement inactive. A partir de sang total incubé avec la PTX, nous avons par ailleurs<p>observé que les DC circulantes du nouveau-né étaient déficientes dans leur maturation et leur<p>sécrétion d’IL-12p70 comparées aux DC de l’adulte.<p><p>D’autre part, il a été décrit précédemment que la PTX exerçait des effets mitogènes sur les<p>lymphocytes T humains et murins. Cependant, le rôle qu’elle joue sur la population des<p>lymphocytes T CD4 naïfs reste peu connu. A l’issue de notre second travail, nous pouvons<p>dès lors affirmer que la PTX est également capable d’activer des lymphocytes T<p>CD4+CD45RA+ naïfs isolés à partir des cellules mononuclées du sang périphérique, et ce<p>indépendamment de son activité enzymatique. En effet, ces lymphocytes T CD4+ naïfs stimulés par la PTX prolifèrent, synthétisent des quantités non négligeables d'ARN messagers<p>codant pour l’IL-2 et le TNF-a, augmentent l’expression membranaire des molécules CD40L,<p>CD69 et CD25 et expriment la protéine Foxp3. Cette activation s’accompagne de la translocation nucléaire de NF-kappaB et NFAT. Parallèlement à l’adulte, la PTX active les lymphocytes T CD4 néonataux. Néanmoins, ceux-ci prolifèrent moins bien et expriment plus faiblement le CD40L à leur surface.<p><p>Enfin, la PTX induit la sécrétion de taux importants d’IFN-g par des T CD4+CD45RA+ naïfs<p>adultes mis en présence de DC autologues.<p><p>Nous terminerons en proposant l’hypothèse suivante :La PTX pourrait exercer ses propriétés<p>adjuvantes par l’intermédiaire de différents mécanismes comprenant notamment la maturation<p>des DC d’origine myéloïde et l’activation des lymphocytes T CD4+CD45RA+ naïfs. Ces 2 populations cellulaires sont en effet les principaux protagonistes impliqués dans la réponse<p>immune primaire. / Doctorat en sciences pharmaceutiques / info:eu-repo/semantics/nonPublished

A imunização materna com a vacina acelular para pertussis (dTpa) é uma intervenção adicional que visa fornecer proteção aos recém-nascidos (RN). No entanto, tem sido relatado que altos níveis de anticorpos adquiridos por transferência placentária podem afetar adversamente a resposta imune desses RN após a imunização ativa, devido ao mascaramento antigênico. Neste estudo, avaliamos a aquisição passiva neonatal de anticorpos específicos para pertussis e sua influência na resposta imune celular dos neonatos. A casuística foi composta por gestantes vacinadas com a vacina dTpa (grupo caso, n=66) ou por gestantes que não receberam a vacina (grupo controle, n=101). As concentrações de anticorpos IgG séricos específicos para Bordetella pertussis total (Bp), toxina pertussis (PT), hemaglutinina filamentosa (FHA) e pertactina (PRN) foram quantificadas em soro materno e de cordão umbilical de seu respectivo RN, e as concentrações de anticorpos IgA específicos para Bp e PT foram dosadas nas amostras de colostro por meio de ensaio imunoenzimático. A responsividade dos linfócitos do sangue neonatal foi avaliada após estimulação ex vivo com Bp inativada por citometria de fluxo com o intuito de detectar a proliferação, produção de citocinas e fenótipo de ativação dos linfócitos T em um contexto de altas concentrações de IgG específicas adquiridas após a vacinação materna. As concentrações de anticorpos IgG anti-Bp, PT, FHA e PRN foram maiores nas amostras de soro materno e de cordão umbilical do grupo caso quando comparadas ao grupo controle (p < 0,0001), com índices de correlação positivos em ambos os grupos para todos os antígenos estudados (p < 0,0001). As vacinações realizadas entre 26 e 31 semanas de gestação foram associadas com as melhores taxas de transferência placentária, embora índices significativamente menores foram detectados no grupo caso (p < 0,01). As concentrações de anticorpos IgA anti-Bp e anti-PT no colostro não foram afetadas pelo estado vacinal da parturiente. Os ensaios de cultura celular revelaram que os RN responderam ao estímulo com Bp, com maior expressão de CD40L, CD69 e proliferação de células T CD4, em comparação com células não estimuladas. Também foi observada uma menor resposta Th1, enquanto a resposta Th2 foi preservada, em comparação com os adultos, mas sem diferenças entre os grupos de neonatos em nenhum dos parâmetros estudados. Nossos resultados indicam que níveis mais altos de anticorpos IgG específicos para B. pertussis no soro dos RN após a vacinação materna não afetam a resposta imune neonatal mediada por células / Maternal immunization with pertussis acellular vaccine (Tdap) is an additional intervention that provides protection to newborns. However, it has been reported that high antibody levels acquired via placental transfer may adversely affect the immune response of newborns after active immunization due to epitope masking. In this study, we evaluated neonatal passive acquisition of pertussis-specific antibodies and their influence on the neonatal cell-mediated immune response. The sample consisted of pregnant women vaccinated with the Tdap vaccine (case group, n=66) or pregnant women who received no vaccine (control group n=101). Whole-cell Bordetella pertussis (Bp), pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (PRN)-specific serum IgG concentrations were quantified in paired maternal-cord sera, and Bp- and PT-specific IgA concentrations were evaluated in colostrum samples by immunoenzymatic assay. Ex vivo neonatal blood lymphocyte responsiveness after inactivated Bp stimulation was assessed using flow cytometry to detect the proliferation, cytokine production and activation phenotype of T lymphocytes in the context of high specific IgG concentrations acquired after maternal vaccination. Anti-Bp, PT, FHA and PRN IgG antibody concentrations in maternal and cord serum samples from case group were higher than those in control group (p < 0.0001), with positive correlation indexes in both groups for all pertussis antigens (p < 0.0001). Vaccinations performed between 26 and 31 gestation weeks were associated with the best placental transfer ratios, although significantly lower ratios were detected in case group (p < 0.01). Anti-Bp and anti-PT IgA concentrations in colostrum were not affected by vaccine status. Cell culture assays revealed that newborns responded to Bp stimulation with higher expression of CD40L CD69 and CD4+ T cell proliferation compared to unstimulated cells. It was also observed a lower Th1 response, while a preserved Th2 response compared to adults, but there were no differences between neonatal groups for any of the studied parameters. Our results indicate that higher pertussis-specific IgG levels in newborn sera after maternal vaccination do not affect the neonatal cell-mediated immune response

A imunização materna com a vacina acelular para pertussis (dTpa) é uma intervenção adicional que visa fornecer proteção aos recém-nascidos (RN). No entanto, tem sido relatado que altos níveis de anticorpos adquiridos por transferência placentária podem afetar adversamente a resposta imune desses RN após a imunização ativa, devido ao mascaramento antigênico. Neste estudo, avaliamos a aquisição passiva neonatal de anticorpos específicos para pertussis e sua influência na resposta imune celular dos neonatos. A casuística foi composta por gestantes vacinadas com a vacina dTpa (grupo caso, n=66) ou por gestantes que não receberam a vacina (grupo controle, n=101). As concentrações de anticorpos IgG séricos específicos para Bordetella pertussis total (Bp), toxina pertussis (PT), hemaglutinina filamentosa (FHA) e pertactina (PRN) foram quantificadas em soro materno e de cordão umbilical de seu respectivo RN, e as concentrações de anticorpos IgA específicos para Bp e PT foram dosadas nas amostras de colostro por meio de ensaio imunoenzimático. A responsividade dos linfócitos do sangue neonatal foi avaliada após estimulação ex vivo com Bp inativada por citometria de fluxo com o intuito de detectar a proliferação, produção de citocinas e fenótipo de ativação dos linfócitos T em um contexto de altas concentrações de IgG específicas adquiridas após a vacinação materna. As concentrações de anticorpos IgG anti-Bp, PT, FHA e PRN foram maiores nas amostras de soro materno e de cordão umbilical do grupo caso quando comparadas ao grupo controle (p < 0,0001), com índices de correlação positivos em ambos os grupos para todos os antígenos estudados (p < 0,0001). As vacinações realizadas entre 26 e 31 semanas de gestação foram associadas com as melhores taxas de transferência placentária, embora índices significativamente menores foram detectados no grupo caso (p < 0,01). As concentrações de anticorpos IgA anti-Bp e anti-PT no colostro não foram afetadas pelo estado vacinal da parturiente. Os ensaios de cultura celular revelaram que os RN responderam ao estímulo com Bp, com maior expressão de CD40L, CD69 e proliferação de células T CD4, em comparação com células não estimuladas. Também foi observada uma menor resposta Th1, enquanto a resposta Th2 foi preservada, em comparação com os adultos, mas sem diferenças entre os grupos de neonatos em nenhum dos parâmetros estudados. Nossos resultados indicam que níveis mais altos de anticorpos IgG específicos para B. pertussis no soro dos RN após a vacinação materna não afetam a resposta imune neonatal mediada por células / Maternal immunization with pertussis acellular vaccine (Tdap) is an additional intervention that provides protection to newborns. However, it has been reported that high antibody levels acquired via placental transfer may adversely affect the immune response of newborns after active immunization due to epitope masking. In this study, we evaluated neonatal passive acquisition of pertussis-specific antibodies and their influence on the neonatal cell-mediated immune response. The sample consisted of pregnant women vaccinated with the Tdap vaccine (case group, n=66) or pregnant women who received no vaccine (control group n=101). Whole-cell Bordetella pertussis (Bp), pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (PRN)-specific serum IgG concentrations were quantified in paired maternal-cord sera, and Bp- and PT-specific IgA concentrations were evaluated in colostrum samples by immunoenzymatic assay. Ex vivo neonatal blood lymphocyte responsiveness after inactivated Bp stimulation was assessed using flow cytometry to detect the proliferation, cytokine production and activation phenotype of T lymphocytes in the context of high specific IgG concentrations acquired after maternal vaccination. Anti-Bp, PT, FHA and PRN IgG antibody concentrations in maternal and cord serum samples from case group were higher than those in control group (p < 0.0001), with positive correlation indexes in both groups for all pertussis antigens (p < 0.0001). Vaccinations performed between 26 and 31 gestation weeks were associated with the best placental transfer ratios, although significantly lower ratios were detected in case group (p < 0.01). Anti-Bp and anti-PT IgA concentrations in colostrum were not affected by vaccine status. Cell culture assays revealed that newborns responded to Bp stimulation with higher expression of CD40L CD69 and CD4+ T cell proliferation compared to unstimulated cells. It was also observed a lower Th1 response, while a preserved Th2 response compared to adults, but there were no differences between neonatal groups for any of the studied parameters. Our results indicate that higher pertussis-specific IgG levels in newborn sera after maternal vaccination do not affect the neonatal cell-mediated immune response