Isotype composition of antibodies to streptococcus group B type III polysaccharide and to tetanus toxoid in maternal,cord blood sera and in breast milk

Neonates are protected against group B streptococcal (GBS) infections and tetanus by transplacentally transferred serum antibodies. Antibodies of the immunoglobulin (Ig) G, IgM and IgA classes and IgG subclasses to the capsular polysaccharide (CPS) of type III group B streptococci (GBS III) and to tetanus toxoid (TT) were measured in sera from healthy women of fertile age and in paired maternal and cord blood sera from term and preterm pregnancies. GBS III CPS antibodies of the IgG class were found in sera from 97 out of 100 women of fertile age, but only 15 of them had antibodies above the proposed protective level (2 g/ml). TT IgG antibodies above the protective level (0.01 units/ml) were found in all sera. The IgG antibodies against GBS III CPS were mainly composed of the IgG2 subclass and to a lesser extent of IgG1. Almost all women had IgG1 antibodies against TT and 40% had IgG4 antibodies. Total IgG and IgG1 antibodies against GBS III CPS were higher in cord blood sera from 37 term neonates than in sera from their mothers whereas IgG2 antibody levels were similar. Total IgG and IgG1 antibodies against TT were also higher in the 20 term neonates tested than in their mothers. In contrast, total IgG and IgG1 to both GBS III CPS and TT and IgG2 to GBS III CPS were lower in cord blood sera from preterm neonates than in sera from their mothers. IgA antibodies to GBS III CPS were detected in 63% of breast milk samples while IgA antibodies against TT were detected in only 4%. In conclusion the study shows important differences in IgG subclass composition of antibodies against a polysaccharide and a protein antigen and in placental transfer of IgG antibodies in term and preterm babies.     

Demonstration of opsonic and protective activity of human cord sera against type III group B streptococcus that are independent of type-specific antibody

In an effort to further understand the host defense against group B streptococcus (GBS), we examined 71 human cord sera for their content of type III GBS IgG antibody by enzyme-linked immunosorbent assay and correlated the results with opsonic and protective activity against type III GBS. Most cord sera (67%) containing greater than 0.1 microgram/ml of type III GBS IgG antibody promoted phagocytosis and killing in vitro and protection against type III GBS in neonatal rats. However, 26% of cord sera containing less than 0.1 microgram/ml of type III IgG antibody exhibited similar activity in vitro and in vivo against type III GBS. This opsonic and protective activity was retained in IgG fraction of whole serum, and was not directly associated with complement activity or with fibronectin. Further studies are needed to understand the mechanisms responsible for the opsonic and protective activity of some cord sera against type III GBS that may be independent of antibody to the type-specific polysaccharide antigen.     

Opsonic activity of human IgG and IgM antibody for type III group B streptococci

We separated IgG and IgM from 10 adult sera containing measurable (greater than or equal to 0.05 micrograms/mL) antibody of both isotypes to the type III polysaccharide of group B streptococci. Ig preparations were used to preopsonize 3H-labeled type III group B streptococci which were added to adherent monolayers of human, monocyte-derived macrophages. Reproducibly significant phagocytosis, measurable by accumulation of radioactivity and confirmed by electron microscopy, required both antibody (from adult serum or Ig preparation) and complement (from cord serum deficient in specific antibody). All adult IgG and IgM preparations were opsonic in the presence of complement. When a cord serum containing IgG but no IgM antibody was separated by the same procedure, the IgG fraction was opsonic but the fraction that would contain IgM was not. The opsonic activity of IgM in adult sera persisted after the removal of contaminating IgG4. These observations indicate that both IgG and IgM antibody in adult sera are opsonic for type III GBS and support the hypothesis that IgM deficiency in newborns may be a contributing factor to certain bacterial infections.     

Neonatal group B streptococcal disease in Finland: a ten-year nationwide study.

BACKGROUND: Group B Streptococcus (GBS) is the most common cause of invasive infections in newborns. GBS bacteria are typed on the basis of capsular polysaccharides or surface-localized proteins. Both polysaccharides and protein antigens have been suggested as potential vaccine candidates. METHODS: A prospective nationwide laboratory-based study of invasive GBS infections in children younger than 3 months of age was conducted in 1985 through 1994. Isolates were serotyped by immunodiffusion in agar gel with HCl extracts and rabbit antisera. Clinical diagnoses and case fatalities were verified from the patient records or the national hospital discharge register. RESULTS: There were 485 cases registered during the 10-year period. The incidence of disease was 0.76/1000 live births. The case fatality rate was 8.0%. Of the 485 cases 398 (83%) were early onset and 87 (17%) late onset infections. The most common clinical diagnosis was bacteremia (77%) without an identified focus of infection. Other diagnoses included meningitis (17%), pneumonia (3%), osteomyelitis or septic arthritis (2%), pyelonephritis or cellulitis. Serotyping of 395 isolates revealed that 47% were of serotype III or III/R, 23% of Ia/c, 11% of Ib, 6% of II/R, 8% of IV, 1% of V and 7% were nontypable. CONCLUSIONS: The clinical picture of GBS disease and serotype distribution are similar to what has been reported from other countries. Serotypes III and III/R dominated (47% of all infections), especially in late onset disease. On the basis of these results a GBS vaccine including at least the Ia, Ib, II and III components would provide coverage against 88% of GBS serotypes causing neonatal disease in Finland.     

Vaccines to prevent neonatal GBS infection

Group B Streptococcus (GBS) remains the leading bacterial cause of neonatal sepsis and meningitis in the United States. Although antibiotic prophylaxis has decreased the infection rate, the best long-term solution lies in the development of effective vaccines. The GBS capsular polysaccharide (CPS) is a major target of antibody-mediated immunity. While antibody to CPS is protective, uncoupled CPS is variably immunogenic in humans, a finding that led to the development of GBS CPS-protein conjugate vaccines. GBS CPS-protein conjugate vaccines of all clinically important serotypes have been produced and tested in animals. Mice and baboons immunized with CPS conjugates transplacentally transferred functionally active GBS-specific IgG to their offspring. Phase 1 and phase 2 clinical trials have shown that GBS conjugate vaccines are safe, well-tolerated and immunogenic in healthy adults. Moreover, human antibodies elicited by the conjugate vaccines are functionally active both in vitro and in animal models of invasive GBS disease.     

Maternally transferred neutralising dengue antibodies in Thai infants: a pilot study

In a dengue-endemic area, sera from 42 mother-infant pairs and sera collected from the infants at follow-up at the ages of 3 months (n =27), 6 months (n =34), 9 months (n =23) and 12 months (n =8) were tested for antibodies to four dengue serotypes using a plaque reduction neutralisation test (PRNT(50)), IgG ELISA and haemagglutination inhibition assay (HAI). The IgG ELISA and HAI tests were less sensitive than PRNT(50) in detecting low levels of antibodies. Levels of maternally transferred dengue neutralising antibodies in the cord sera were very high and identical to those in the mothers. Neutralising antibody prevalences in the newborns were 95% to dengue serotype 1 (DEN-1), 93% to DEN-2 and DEN-3 and 91% to DEN-4. The antibodies decreased with increasing age. At least one dengue serotype neutralising antibody persisted in the infants at ages 3, 6 and 9 months in 92%, 69% and 13%, respectively. No maternally transferred antibody was observed in 12-month-old infants. In endemic areas therefore, where most infants have maternally transferred dengue antibodies, interference with dengue vaccine is likely to be less after 12 months of age than before then.     

The carriage of group B streptococci in Turkish pregnant women and its transmission rate in newborns and serotype distribution

The prevalence of group B streptococci (GBS) colonization was studied in 500 pregnant women and their newborn infants by collecting vaginal and rectal swabs from mothers, and umbilical and throat swabs from their infants. Forty-six isolates of GBS were obtained from mothers' specimens and eight from neonates. Maternal and infant colonization rates were found to be 9.2% and 1.6%, respectively. Vertical transmission rate was 15.2%. Additionally, serotypes and antimicrobial susceptibility of 54 isolates of GBS were determined. Type Ia, II and III were common serotypes among GBS isolates from mothers and infants. When evaluating the factors that affect GBS carriage, age, socio-economic status and education level of pregnant women were important for carriage, while use of intrauterine device and parity were unrelated. No resistance to ampicillin, penicillin, ceftriaxone or vancomycin was found by disk diffusion method. A high level of resistance against tetracycline was noted (91%). Although invasive serotypes are predominant, the rarity of GBS disease in Turkish infants may be due to low rates of maternal carriage or to their possessing protective levels of GBS-specific IgG antibody in their sera.     

Fetal Response to Maternal Ascariasis as Evidenced by Anti Ascaris Lumbricoides IgM Antibodies in the Cord Blood

ABSTRACT. The immune response of the fetus to maternal infection with Ascaris lumbricoides was studied by estimating IgG and IgM antibodies, using ELISA, in 28 paired samples of mother and cord blood. A. lumbricoides adult male, cuticle and unembryonated egg antigen was used. Toxocara canis larva antigen was used as a specificity control. Presence of IgG in the cord blood does not signify fetal response, but the presence of IgM antibodies does. IgM antibodies to Ascaris adult male antigen were present in 27 out of 28 maternal sera and 1 out of 28 cord sera. All maternal sera and only 6 cord sera showed IgM antibodies against Ascaris cuticle and 20 out of 22 maternal sera and 8 out of 22 cord sera tested, showed IgM antibodies to Ascaris unembryonated egg antigen. Sixteen out of 22 maternal sera and none out of 22 cord sera showed IgM antibody against Toxocara canis antigen, ruling out cross reaction and transplacental leak. The results of our study suggest that the Ascaris infection can spread to the fetus and elicit immune response.     

Fetal response to maternal ascariasis as evidenced by anti ascaris lumbricoides IgM antibodies in the cord blood.

The immune response of the fetus to maternal infection with Ascaris lumbricoides was studied by estimating IgG and IgM antibodies, using ELISA, in 28 paired samples of mother and cord blood. A. lumbricoides adult male, cuticle and unembryonated egg antigen was used. Toxocara canis larva antigen was used as a specificity control. Presence of IgG in the cord blood does not signify fetal response, but the presence of IgM antibodies does. IgM antibodies to Ascaris adult male antigen were present in 27 out of 28 maternal sera and 1 out of 28 cord sera. All maternal sera and only 6 cord sera showed IgM antibodies against Ascaris cuticle and 20 out of 22 maternal sera and 8 out of 22 cord sera tested, showed IgM antibodies to Ascaris unembryonated egg antigen. Sixteen out of 22 maternal sera and none out of 22 cord sera showed IgM antibody against Toxocara canis antigen, ruling out cross reaction and transplacental leak. The results of our study suggest that the Ascaris infection can spread to the fetus and elicit immune response.     

Population-based active surveillance for neonatal group B streptococcal infections in Alberta, Canada: implications for vaccine formulation.

BACKGROUND: Knowledge of circulating serotypes of group B Streptococcus (GBS) is important for formulation of vaccines. There are no Canadian data on the serotype distribution of neonatal GBS isolates. METHODS: Using a retrospective laboratory and health record survey between 1993 and 1994 (before introduction of Canadian prevention guidelines) and prospective active laboratory-based surveillance from 1995 to 1999 of all laboratories in Alberta, we identified 168 cases of invasive neonatal GBS infections including stillbirths among 262,398 total births; 118 of 123 (96%) isolates from 1995 to 1999 were serotyped, and the corresponding neonatal health records were reviewed. RESULTS: The average annual incidence was 0.64 of 1000 total births/year. Of these 95 (57%) had early onset disease (EOD), 15 (9%) were still births and 58 (34%) had late onset disease (LOD). Eighty-one percent of EOD cases were caused by serotypes Ia, Ia/c, Ia/c/R, III, III/R and V, V/R, whereas 81% of LOD cases were caused by serotypes III and III/R. GBS serotypes containing the C protein along with serotypes III and V as a group constituted 91% (107 of 118) of all GBS cases in our population. The most common clinical presentation was bacteremia without focus (74%) followed by meningitis (14%) and pneumonia (12%). During 1995 to 1999, in addition to 13 stillbirths, there were 6 of 64 (9%) neonatal deaths among EOD cases and 1 of 46 (2%) neonatal death among LOD cases. CONCLUSIONS: In this population-based study stillbirths account for a proportion of cases that are not routinely counted and represent a group for which intrapartum antibiotics would likely not be effective, but potentially preventable by vaccination. Inclusion of serotypes Ia, III and V in a conjugate vaccine or serotypes III and V conjugated with the C protein in a GBS vaccine could theoretically provide protection against the majority of GBS invasive disease in Alberta neonates.     

Serum and salivary anti-capsular antibodies in infants and children immunized with the heptavalent pneumococcal conjugate vaccine

AIM: To study the ability of seven-valent experimental pneumococcal polysaccharide CRM197 protein conjugate vaccine (PncCRM) to induce antibodies in serum and saliva of infants. METHODS: Sixty Finnish infants received Pnc-CRM vaccine at 2, 4 and 6 months of age and were boosted with PncCRM (n = 30) or pneumococcal polysaccharide (PncPS) (n = 29) vaccine at the age of 15 months. Serum IgG antibody concentrations to vaccine serotypes 4, 6B, 9V, 14, 18C, 19F and 23F were measured by enzyme immunoassay at 2, 4, 6, 7, 15, 16 and 24 months of age. Salivary IgA, IgG and secretory Ig antibody titers at 7 and 16 months of ages were analyzed by enzyme immunoassay against the same serotypes, except 23F. RESULTS: PncCRM induced systemic immune responses and immunologic memory. At 7 months of age 69 to 100% of children, depending on the serotype, had serum IgG antibody concentrations exceeding the value of 1.0 microg/ml. At 15 months the titers were still higher than before the vaccinations. Booster doses of either PncPS or PncCRM induced an increase in antibody concentrations. The titers were still elevated at 24 months of age. Salivary IgA and IgG antibodies were found rarely at 7 months of age, but in up to 80% of samples taken at 16 months of age, depending on the serotype and nature of the booster vaccine. Salivary IgG correlated with IgG in serum, supporting the theory that salivary IgG is derived from serum. Salivary IgA and secretory Ig correlated positively, which indicates that IgA was locally produced. CONCLUSIONS: PncCRM induces both systemic and mucosal immune responses in infants.     

Autoantibodies to Tamm-Horsfall protein associated with urinary tract infections in girls.

Girls with various forms of urinary tract infections and a reference material were analyzed for autoantibodies in serum to the Tamm-Horsfall glycoprotein. Such antibodies could be detected in all sera analyzed. In the control subjects cord blood contained very low IgA and IgM anti-TH, which increased significantly up to the age of 8 months. The IgG anti-TH levels in cord blood correlated with maternal levels. After the age of 2 months the IgG anti-TH followed the anti-TH levels of the other immunoglobulin classes. Among the infants aged 2 to 7 months with acute UTI, no anti-TH increases were found. In girls more than one year of age with acute nonobstructive UTI, IgG and IgA anti-TH levels were significantly higher in those with acute pyelonephritis and reflux, with or without parenchymal reduction, than in those with acute pyelonephritis and normal radiologic findings. The latter group had significantly higher levels of IgG and IgA but not IgM anti-TH than did those with acute cystitits. In contrast, girls with renal parenchymal reduction but no signs of infection at the time of testing had significantly depressed anti-TH levels compared to control values.     

Passive immunity acquisition of maternal anti-enterohemorrhagic Escherichia coli (EHEC) O157:H7 IgG antibodies by the newborn

Enterohaemorrhagic Escherichia coli (EHEC) strains are among the main causes of haemorrhagic colitis (HC) and haemolytic-uremic syndrome (HUS) in industrialised countries. In Brazil, EHEC have been detected in the faeces of patients with non-bloody diarrhoea, though an association between EHEC and HUS has been detected recently. These observations suggest that there is a pre-existing immunity triggered by the contact with EHEC and other categories of bacteria, such as EPEC, that share similar virulence factors and to which our population is highly exposed. Our aim was to evaluate the placental transfer of IgG antibodies reactive to EHEC O157:H7 antigens. We evaluated 28 paired maternal and cord sera for the presence of IgG against EHEC O157:H7 protein antigens and IgG and IgM to O157 LPS employing ELISA and IB technique. Total IgG and IgM level analyses were also made. Anti-EHEC O157:H7 and anti-LPS O157 IgG antibody levels in cord sera were equivalent to those of their maternal sera. A good correlation between the mothers’ anti-LPS O157 IgM and total IgM levels was found. Anti-LPS O157 IgM levels were higher than anti-LPS O157 IgG levels in the same samples, and anti-LPS IgM antibodies were not detected in cord sera. Identical patterns of recognition of bacterial protein antigens by specific IgG were found in the paired samples and the recombinant purified variable region of γ intimin was specifically recognized by one paired maternal and cord sample. In conclusion, although the antibody profile varied among individuals, all paired cord and maternal serum samples showed an identical recognition pattern, indicating an efficient placental transfer of IgG antibodies reactive to EHEC O157:H7 antigens. Dr. Patricia Palmeira and Leonardo Y. Ito contributed equally to this work.     

Maternal-fetal transfer of pneumococcal capsular polysaccharide antibodies

Maternal-fetal transfer of IgG antibodies is an important host defense for newborns, who have an increased incidence of bacterial infections. To study the transfer of specific pneumococcal capsular polysaccharide (PPS) antibodies, we measured the concentrations, in 30 paired maternal and cord serum samples, of IgG and IgM by radial immunodiffusion, of serotype 7F Streptococcus pneumoniae PPS antibodies by radioimmunoassay and enzyme immunoassay, and of opsonic activity to that organism by a radiolabeled bacterial uptake assay. Cord serum had significantly greater total IgG, yet significantly less type 7F PPS IgG antibodies and opsonic activity than maternal serum. Cord serum had low concentrations of total IgM and no IgM type 7F-specific antibodies. Reduced transport of specific IgG antibodies and absent transfer of IgM may contribute to the susceptibility of newborns to bacterial infection.     

Class-specific antibodies to Bordetella pertussis, Haemophilus influenzae type b, Streptococcus pneumoniae and Neisseria meningitidis in human breast-milk and maternal-infant sera

Children under 2 years of age are most susceptible to acute respiratory infections caused by Bordetella pertussis, Haemophilus influenzae type b, Streptococcus pneumoniae and Neisseria meningitidis. We analysed milk samples and sera from mother-infant pairs for specific antibodies that may enhance protection against the bacterial pathogens. The results show that the breast-milk samples contained significant titres of specific IgG and IgA antibodies to the four organisms, although the mean IgG antibody levels were higher in maternal sera than in breast-milk. On the other hand, the mean IgA antibody levels to the four organisms were higher in breast-milk than in both maternal and infant sera. IgM antibodies to these organisms were relatively low or absent in many milk and serum samples. Nevertheless, the significant concentrations of specific IgG and IgA antibodies in milk samples may indicate a protective role for breast-milk against the four infections in early childhood.     

Long term enhancement of the IgG2 antibody response to Haemophilus influenzae type b by breast-feeding

SUBJECTS: Sets of sera were obtained from 30 children <6 years of age with invasive type b (Hib) infection and their mothers. Duration and mode of breast-feeding were monitored. Titers of IgG1, IgG2, IgA and IgM antibodies against Hib capsular polysaccharide were determined in sera taken during the acute illness and during early and late convalescence. RESULTS: Children 18 months or older with longer durations of exclusive breast-feeding (13 weeks or more; mean, 19.3 weeks) had higher Hib antibody concentrations of the IgG1, IgG2, IgA and IgM isotypes than those with a shorter duration of exclusive breast-feeding (<13 weeks; mean, 5.4 weeks). The difference was greatest for the IgG2 isotype. In regression analyses the association between the duration of exclusive breast-feeding and the anti-Hib IgG2 concentration was significant when breast-feeding, type of Hib infection, maternal Hib antibody titer and age were used as explanatory factors. In the group of 14 children <18 months of age no significant differences were noted. DISCUSSION: This study indicates the presence of a long lasting enhancing effect of breast-feeding on the antibody response to Hib in children, in particular on IgG2 Hib antibody production. This may result from the content in the milk of IFN-gamma and IFN-gamma-producing cells and possibly other factors, which can support IgG2 antibody production.     

Prospective study on anti-ganglioside antibodies in childhood Guillain-Barré syndrome.

BACKGROUND: Antiganglioside antibodies have been reported to play a part in the pathophysiology of Guillain-Barré syndrome (GBS). AIMS: To investigate the prevalence and correlation of anti-ganglioside antibodies with clinical data in children with GBS in a multicentre clinical trial. METHODS: Immunoglobin (Ig)G and IgM to GM1, GM1b, GD1a, GalNAc-GD1a, GD1b, GT1a, and GQ1b were measured by ELISA in sera obtained before treatment. In addition, serological testing for Campylobacter jejuni was carried out. In parallel, a group of adults with GBS and a control group of children without GBS or other inflammatory diseases were evaluated. RESULTS: Sera from 63 children with GBS, 36 adults with GBS and 41 children without GBS were evaluated. Four of the children with GBS showed positive IgG to GM1, in one case combined with anti-GalNAc-GD1a and in one with anti-GD1b. Two others showed isolated positive IgG to GD1b and GT1a. One showed increased anti-GalNAc-GD1a IgM. In 5 of the 63 children, serological evidence of a recent infection with C jejuni was found, and this correlated significantly with the raised antibodies (p = 0.001). In the control group without GBS, no child showed positive IgG, but one showed anti-GalNAc-GD1a IgM. Compared with the adults with GBS, the frequency of antibodies in children was insignificantly lower. In our study, patients with positive antibodies did not show a more severe GBS course or worse outcome than those who were seronegative, and we could not show an increased incidence of axonal dysfunction. CONCLUSIONS: In some children with GBS, one can detect raised IgG against various gangliosides, similar to that in adults. A recent infection with C jejuni is markedly associated with the presence of these antibodies. However, in contrast with what has been reported in adults, in this study we were unable to show a negative effect of these findings on the clinical course.     

Recurrent pneumococcal meningitis in a patient with transient IgG subclass deficiency

We report the case of a 3 year old boy who exhibited recurrent serious infections with a transient imbalance of IgG subclass in the second year of life. He suffered from pneumococcal meningitis at 3 months, hepatitis at 9 months, and purulent arthritis at 11 months of age. The second episode of pneumococcal meningitis occurred at 14 months. Serum IgG level was normal for age. Low level of IgG2, undetectable level of IgG4 and negligible level of pneumococcus-specific IgG1-G2 antibodies were found. No other primary immunodeficiency was apparent. Serum IgG2-G4 levels but not pneumococcus-specific IgG1-G2 titers increased by the age of 30 months. At that time, he was inoculated with a polyvalent pneumococcal vaccine along with acellular diphtheria-pertussis-tetanus vaccine. He acquired the immunity against these agents, and had no episodic infections in the following 2 years. This observation stresses the existence of transient IgG subclass deficiency associated with delayed development of the anti-polysaccharide antibody response.     

Functional activity of class-specific antibodies to type III, group B streptococcus

The functional activity of naturally acquired IgG and IgM with specificity for the capsular polysaccharide of type III, group B Streptococcus (III-GBS) was compared. Sera collected during convalescence from 14 infants who had developed specific antibodies following III-GBS infection were employed for separation of IgG from IgM by ion-exchange chromatography. Bactericidal killing of III-GBS was similar for IgG- and IgM-rich samples (37 and 42%, respectively) in reactions containing a mean of 1.0 or 1.9 micrograms/ml of III-GBS specific IgG or IgM antibody. Purified IgA lacked opsonophagocytic activity for III-GBS. These results indicate that III-GBS-specific IgG and IgM antibodies in infant sera promote opsonophagocytosis at low concentrations, and that their functional capacity is comparable.     

Decreased production of specific antibodies to cow's milk proteins in premature infants during the first six months of life

Concentrations of IgG and IgM antibodies to casein, β-lactoglobulin, lactalbumin and bovine serum albumin (BSA) in sera of premature infants of less than 36 weeks gestation, at 5 weeks of age, were less than in age-matched term infants. At 6 months of age IgG antibodies to BSA in preterms were still significantly lower than in term infants.