Induction of apoptosis in equine chorionic gonadotropin (eCG)-primed rat ovaries by anti-eCG antibody

BACKGROUND: Pneumococcal infections are a common cause of morbidity and mortality among elderly people. Protection against pneumococcal infections is mediated by serotype-specific antibodies to capsular polysaccharides. To obtain an estimate of anti-pneumococcal immunity, prevalence and levels of pneumococcal antibodies were studied in an unvaccinated elderly population. METHODS: IgG antibodies to pneumococcal serotypes 3, 6A, and B and to cell wall polysaccharide (C-PS, a common antigen to all pneumococci) were measured by enzyme immuno-assay in 480 subjects aged 64-97 years (206 men, 274 women) who were a random sample (41%) of elderly inhabitants in a semirural community in Finland. RESULTS: An average of 10% of the elderly lacked antibodies to serotypes 3, 6A, and 8, and 62% of the elderly had them in low titres only. Anti-C-PS antibodies were found in 99% of the elderly, and in significantly higher titres than anti-capsular antibodies. Antibody titres to C-PS and to type 6A decreased with age. Elderly women had significantly lower antibody levels than men. Among the men, current smokers had higher antibody titres than non-smokers; in the women, this analysis was not possible because of infrequent history of smoking. The effect of smoking on antibody titres was reversible after cessation of smoking. CONCLUSIONS: A considerable proportion of the elderly lacked protective antibodies to commonly infecting pneumococcal serotypes 3, 6A, and 8. Smoking increased the prevalence and levels of pneumococcal antibodies probably as a consequence of numerous respiratory infections. These observations emphasize the importance of administration of the pneumococcal vaccine among the elderly.     

Antibodies against pneumococcal C-polysaccharide are not protective

The ability of antibodies against C-polysaccharide (C-Ps) to protect against experimental pneumococcal infection was examined in a mouse model. No protection against types 6A and 14 pneumococcal infection could be demonstrated neither with mouse monoclonal antibodies against C-Ps, specific for phosphorylcholine (PC) or for C-Ps backbone, nor for polyclonal rabbit immunsera against C-Ps. The monoclonal antibody with PC-specificity was protective against infection with type 27 pneumococcus, that has PC as part of its capsular polysaccharide. Type-specific mono- and polyclonal antibodies were highly protective against infection with the homologous type. We conclude that no species-specific protection can be achieved against intraperitoneal Streptococcus pneumoniae infection with optimally capsulated bacteria in outbred mice by passive immunization with antibodies to C-Ps.     

Pneumococcal immune complexes in the diagnosis of lower respiratory infections in children

BACKGROUND: In recent years serologic methods have been applied to assess pneumococcal etiology of pneumonia and other respiratory tract infections. Antigen and antibody assays have shown to be insensitive, especially in young children. The aim of this study was to evaluate the usefulness of circulating immune complexes in the diagnosis of pneumococcal lower respiratory infection in children. MATERIAL AND METHODS: Pneumococcal immune complexes (IC) containing antibodies to species-specific C-polysaccharide, to mixtures of type-specific capsular polysaccharides or to a protein antigen, pneumolysin, were studied in the sera of 449 children with lower respiratory tract infection. RESULTS: Circulating ICs were found in 68 (15%) children; 46 (68%) of them were demonstrated in acute and 43 in convalescent serum. In 5 (7%) of the 68 IC-positive patients pneumococcal antigen was present in acute serum; those patients formed 18% of the 28 cases with antigenemia. An antibody response between paired sera to any of the 3 pneumococcal antigens studied was observed in 14 (21%) IC-positive children; they formed 23% of the 60 cases with an antibody response. In total ICs were positive in 51% of all the 134 pneumococcal cases diagnosed by any method. CONCLUSIONS: We conclude that the measurement of circulating ICs is more sensitive than other serologic methods for the diagnosis of pneumococcal lower respiratory infection. In infants, however, it was as insensitive as antigen and antibody assays.     

The chemical structures of the capsular polysaccharides from Streptococcus pneumoniae types 32F and 32A

The structures of the capsular polysaccharides from Streptococcus pneumoniae types 32F and 32A have been determined by means of NMR spectroscopy as the principal method. It is concluded that both polysaccharides are composed of tetrasaccharide repeating units with a phosphorylcholine (PCho) group linked to the 3-position of the 4-substituted beta-L-rhamnose (Rha) residue. Both polysaccharides are substituted with one O-acetyl group at the 2-position of the same beta-L-rhamnose residue. In addition, the type-32A polysaccharide is substituted with another O-acetyl group at the 4-position of the 2,3-disubstituted alpha-D-glucose residue, i.e. the branch-point residue. An unusual detail in the structure is that the side chain is composed of a rhamnosyl phosphate. [chemical structure: see text] In the type-32F polysaccharide R=H, and in the type-32A polysaccharide R=Ac. The structure of C-polysaccharide found in our preparations of type-32F and type-32A capsular polysaccharides is in agreement with that published previously for the pneumococcal common antigen C-polysaccharide [Fischer, W., Behr, T., Hartmann, R., Peter-Katalinic, J. & Egge, H. (1993) Eur. J. Biochem. 215, 851-857; Kulakowska, M., Brisson, J.-R., Griffith, D. W., Young, N. M. & Jennings, H. J. (1993) Can. J. Chem. 71, 644-648].     

Pneumococcal polysaccharide vaccine in children with chronic renal disease: a prospective study of antibody response and duration

We studied the antibody response to pneumococcal serotypes 3 and 14 after pneumococcal polysaccharide vaccine was administered to 41 children with renal disease. One month after vaccination, 76% and 61% of patients achieved at least a twofold titer rise to serotypes 3 and 14, respectively; this finding was comparable to historic control values. One year after vaccination, the majority of patients retained protective antibody levels. Achieving a titer > or = 1.0 microgram/ml IgG at 1 month was highly predictive of retaining a protective antibody level > or = 0.15 microgram/ml at 1 year.     

Pneumococcal vaccination in HIV-1-infected adults in Uganda: humoral response and two vaccine failures

OBJECTIVES: To assess the feasibility of establishing a pneumococcal vaccine trial among HIV-1-infected adults in Uganda and to characterize their responses to 23-valent pneumococcal polysaccharide vaccine. DESIGN: An open-label pilot trial to assess recruitment and compliance of HIV-1-infected adults in Uganda to vaccination and to determine the immunogenicity of the vaccine. SETTING: A community clinic for HIV-1-infected adults in Entebbe, Uganda. METHODS: Levels of capsule-specific IgG to four common vaccine capsular serotypes were measured before vaccination and 1 month after vaccination. Subsequent rates of disease episodes and deaths, and immunologic responses in two vaccine failures, were followed. RESULTS: One month after-vaccination, both HIV-1-infected (n = 77) and seronegative control subjects (n = 10) demonstrated a significant rise in capsule-specific immunoglobulin G (IgG) for three of four serotypes tested, but levels were significantly lower among HIV-1-infected patients. In 149 patient-years of follow-up, two (2.6%) developed pneumococcal pneumonia, one bacteremic with serotype 1 and one non-bacteremic with serotype 13, a non-vaccine serotype; both patients showed inadequate killing of the organism in vitro. In this same follow-up period, 29 (38%) patients died. CONCLUSION: HIV-1-infected adults in Uganda are at high risk of pneumococcal disease and show a significant but suboptimal response to pneumococcal vaccine. Although reliable recruitment and follow-up of vaccinees is feasible, evaluation of vaccine efficacy may be compromised by limited responses to common vaccine serotypes, an unknown incidence of disease with non-vaccine serotypes, and a high rate of mortality unrelated to Streptococcus pneumoniae infection.     

Functional analysis of glycosyltransferases encoded by the capsular polysaccharide biosynthesis locus of Streptococcus pneumoniae serotype 14

Bacteria belonging to the species Streptococcus pneumoniae vary in their capsule. Presently, 90 capsular serotypes are known, all possessing their own specific polysaccharide structure. Little is known about the biosynthesis of these capsular polysaccharides. The cps locus of S. pneumoniae serotype 14 was cloned. So far, 7 open reading frames have been sequenced, cps14B to cps14H. The gene products are similar to proteins involved in bacterial polysaccharide biosynthesis, both of Gram-negative and -positive micro-organisms. Gene-specific mutants were created for cps14D to cps14H by insertional mutagenesis. All mutants no longer agglutinated with a monoclonal antibody against type 14 capsule polysaccharides. The biosynthetic function of cps14E and cps14G was determined by analysis of the intermediates in the synthesis of the oligosaccharide subunit, formed in membrane preparations of the wild-type and mutant strains and in membrane preparations of Escherichia coli expressing the pneumococcal glycosyltransferases. The enzyme encoded by cps14E is a glucosyl-1-phosphate transferase that links glucose to a lipid carrier, the first step in the biosynthesis of the type 14 repeating unit. The gene product of cps14G encodes a beta-1,4-galactosyltransferase, the enzyme responsible for the second step in the subunit synthesis, the transfer of galactose to lipid-linked glucose.     

Characterization of the humoral immune response to Klebsiella species in inflammatory bowel disease and ankylosing spondylitis

This study was carried out to characterize the antibody class response by ELISA to seven Klebsiella pneumoniae serotypes (K2, K3, K17, K21, K26, K36, K50) in five different groups, 40 HLA-B27-positive ankylosing spondylitis (AS) patients, 46 patients with Crohn's disease (CD), 38 patients with ulcerative colitis (UC), 50 patients with active anti-endomysial antibody-positive coeliac disease and 40 healthy controls, using whole bacteria and capsular polysaccharide. IgG antibody levels were significantly elevated in AS patients to K17, K36, K50; IgA to K2, K3, K21, K26, K36 and K50; and IgM to serotype K21 when compared to normal controls. Furthermore, IgG antibody levels were significantly elevated in CD patients to K2, K17, K21, K26, K36 and K50; IgA to K2, K3, K21, K26, K36 and K50; and IgM to K2, K3, K17, K21 and K50. Increased IgG antibody levels in the UC group were limited only to K17, K36 and K50. No antibody class was increased to any of the K. pneumoniae serotypes in the coeliac disease group. The immune responses in AS patients also involve Klebsiella bacteria having capsular serotypes other than K26, K36 and K50. The similarity in the immune responses between CD and AS groups suggests that many AS patients may have occult bowel inflammation.     

Antibody response to pneumococcal polysaccharide vaccine in young, adult and old mice

The anti-pneumococcal antibody response was studied in young (5-week-old) and adult (10-week-old) BALB/c and CBA/J mice and in adult (9-10-week-old) and old (12-, 18- and 24-month-old) AB6F1 and B6D2F1 mice after s.c. immunization with a 23-valent pneumococcal polysaccharide vaccine. Both young and adult mice showed a significant IgM antibody response to the vaccine 6 days after immunization with 1-11 micrograms antigen. There were significant immune responses to serotypes 1, 2, 4 and 7F in contrast to small responses to serotypes 14, 19F and 23F after immunization with the vaccine. One month after immunization, there were only marginal differences in IgM anti-pneumococcal antibody levels to the vaccine (anti-PPS) between immunized and unimmunized BALB/c mice, whereas in CBA/J mice the anti-PPS remained higher in immunized than in unimmunized mice. Immunization of old mice induced a significant IgM antibody response 6 days after immunization, but the anti-PPS thereafter decreased rapidly towards preimmunization values in AB6F1 mice. A significant IgG anti-PPS was not detected in any of the mice studied. The IgA anti-PPS tended to vary over time with no consistent pattern. It is important to carefully consider age and strain of the mice used when studying the immune response to pneumococcal polysaccharide antigens.     

Oligoclonality of serum immunoglobulin G antibody responses to Streptococcus pneumoniae capsular polysaccharide serotypes 6B, 14, and 23F

Serum antibodies (Abs) specific for the capsular polysaccharides of Streptococcus pneumoniae provide protection against invasive pneumococcal disease. Previous studies indicate that Abs to pneumococcal polysaccharide (PPS) serotypes 1 and 6B have limited clonal diversity. To determine if restricted diversity was a feature common to other PPS specificities, we examined the light (L)-chain expression and isoelectric heterogeneity of type 6B, 14, and 23F Abs elicited in 15 adults following PPS vaccination. At the population level, both PPS-6B and PPS-14 Abs expressed kappa and lambda chains, although 6B Abs more frequently expressed lambda chains lambda and 14 Abs more frequently expressed kappa chains. In individual sera, Abs were generally skewed towards either kappa or lambda expression. 23F-specific Abs had predominantly kappa chains. Isoelectric focusing analyses showed that sera contained one or at most a few immunoglobulin G Ab spectrotypes to all three respective capsular serotypes, a result indicative of oligoclonality. A sequence analysis of a purified PPS-14-specific Ab having a single spectrotype gave uniform amino-terminal sequences for both the heavy chain (V(H)III subgroup) and the L chain (kappaIII-A27 V region). From these results we conclude that within individual adults, serum Ab responses to PPS serotypes 6B, 14, and 23F derive from a small number of dominant B-cell clones, and consequently variable-region expression is probably individually limited as well. Oligoclonality appears to be a general characteristic of human PPS-specific Ab repertoires, and we suggest that this property could lead to individual differences in Ab fine specificity and/or functional activity against encapsulated pneumococci.     

Maternal-foetal interaction, antibody formation, and metabolic response in mice immunized with pneumococcal polysacharides

The maternal transfer of pneumococcal polysaccharides to foetus, as well as the antibody formation and metabolic response were studied in mice exposed to pneumococcal polysaccharides during pregnancy. Type 19 and type 57 pneumococcal polysaccharides display cross-placental transfer to foetus. These polysaccharides also transfer through mother's milk to neonates. Maternal immunization of type 19 polysaccharide during pregnancy induced higher antibody formation in the offspring than the group from non-immunized mothers. Young mice, which received a second dose of polysaccharide at 2 weeks of age, showed a higher antibody response than those which did not receive polysacharide. Treatment of mothers with anti-lymphocyte serum, following by administration of polysaccharide, significantly increased the neonatal immune response to the polysaccharide. Treatment of the mother with a high dose of type 19 or type 57 polysaccharide did not cause significant changes in neonatal growth and organ weights. The offspring from mothers treated with high doses of these polysaccharides did not exhibit abnormalities in chemical contents of their tissues.     

Vaccination with protein-conjugated and native type 3 capsular polysaccharide in an ethanol-fed rat model of pneumococcal pneumonia

A chronic ethanol-fed rat model was used to determine the effect of alcohol ingestion on production of antibody to type 3 pneumococcal capsular polysaccharide. Sprague-Dawley rats were fed a liquid diet containing 36% of calories as ethanol (ethanol-fed), an isocaloric diet containing dextrin-maltose (pair-fed) or standard rat chow (chow-fed). After 7 days of feeding, the rats were vaccinated subcutaneously with placebo or with either 25 microg of type 3 pneumococcal capsular polysaccharide (SpnCP) or 5 microg of SpnCP linked to the protein carrier CRM197 (SpnCP/CRM197). Rats given the conjugated vaccine received a booster injection 14 days later. Maximum antibody titers were observed six days postvaccination for rats given SpnCP alone and 21 days postvaccination for rats given SpnCP/CRM197. All rats were infected transtracheally with 2-3 times the expected lethal dose50 for each feeding group of type 3 Streptococcus pneumoniae on the day of peak antibody titers. Mortality was recorded for a 10-day period. Vaccination with SpnCP increased survival of ethanol- and chow-fed, but not pair-fed rats. This protection was only statistically significant in the chow-fed group (p < 0.01). Vaccination with SpnCP/CRM197 moderately increased survival of rats in all three feeding groups, but this was not statistically significant in any of them.     

Immunologic epitope, gene, and immunity involved in pneumococcal glycoconjugate

Pneumococcal infection persists as a major cause of pneumonia, otitis media, and meningitis in infants. Children less than 2 years of age show the highest incidence of pneumococcal diseases. Production of monoclonal antibody (MAb) to polysaccharide (PS) and binding characteristics to PS epitopes were studied. Removal of the O-acetyl group from 9V PS by alkali hydrolysis resulted in a decreased binding with rabbit 9V antiserum (AS). However, the binding reaction with 9V MAb was less affected by the loss of O-acetyl content. Type 9V IgG MAb provided passive protection and enhanced the opsonophagocytic activity of polymorphonuclear (PMN) leukocytes to kill type 9V pneumococci. The pathogenecity of pneumococci is attributed to various virulence factors distributed on the cell surface, including capsular polysaccharide and protein antigens, for example, pneumolysin, autolysin, pneumococcal surface protein A (PspA), pneumococcal surface adhesion (PsaA), and hemin binding protein. Some of these protein antigens may be used as a component to combine with pneumococcal PS vaccine or as a carrier of conjugate vaccine. Clinical trials of pneumococcal conjugate vaccines showed that covalent linkage of capsular PS to protein carriers improved the immunogenicity of the PS. Development of glycoconjugate vaccine for selected pneumococcal types will help solve the problem of poor immunogenecity of PS vaccine in young children used for prevention of pneumococcal infection.     

Potential and limitations of polysaccharide vaccines in infancy

Of infections caused by encapsulated bacteria, those due to Haemophilus influenzae b (Hib) are among the most restricted to infancy and require very early immunisation. Hib capsular polysaccharide (CPS) has the most typical T-cell independent profile. The absence of efficacy of this vaccine in infants triggered development of conjugate vaccines which are so effective that there is now no room for plain polysaccharide Hib vaccines. Pneumococcal infections pose similar problems to Hib, but are more complex. The immunogenicity of the different pneumococcal serotypes varies considerably in infancy. Although the current CPS vaccine provides limited protection in infancy, the burden of pneumococcal infection is so high that its use could be reconsidered should conjugate vaccines be available later than expected. Meningococcal infections are less a specific problem for infants. Again, serogroup immunogenicity varies widely. Group B meningococcal CPS is not immunogenic even in adults, Group C behaves as Hib CPS, whereas Group A is immunogenic as early as 6 months of age. Group A CPS may prove of interest for an infant vaccine, especially in epidemic situations. Typhoid fever is uncommon in infancy; Vi CPS is poorly immunogenic in infancy and is, therefore, of limited interest for use as an infant vaccine.     

Pneumolysin PCR-based diagnosis of invasive pneumococcal infection in children

Blood-based pneumolysin PCR was compared to blood culture and detection of pneumolysin immune complexes, as well as to detection of antibodies to pneumolysin and to C polysaccharide, in the diagnosis of pneumococcal infection in 75 febrile children. Invasive pneumococcal infection was suspected on clinical grounds in 67 of the febrile children, and viral infection was suspected on clinical grounds in 8 of the febrile children. In addition, 15 healthy persons were examined to test the specificity of the PCR assay. Plasma, serum, and leukocyte fractions were analyzed by PCR. The combination of all test results led to the diagnosis of pneumococcal infection in 25 patients. Pneumolysin PCR was positive in 44% of these children, an increase occurred in the pneumolysin antibodies in 39% and in the C polysaccharide antibodies in 30% of the patients; pneumolysin immune complexes were found in convalescent serum in 30%, pneumolysin immune complexes occurred in acute-phase serum samples in 16%, and a positive blood culture was found in 20% of the patients. None of the healthy controls had positive results by PCR. The results suggest that the diagnosis of Streptococcus pneumoniae infection from blood samples necessitates the use of several different assays. Pneumolysin PCR was the most sensitive assay, but its clinical value is reduced by the fact that three blood fractions are needed.     

Infant immunization with pneumococcal CRM197 vaccines: effect of saccharide size on immunogenicity and interactions with simultaneously administered vaccines

Six pentavalent pneumococcal conjugate vaccines (Pn-CRM197) were evaluated among 400 infants. The vaccines differed in saccharide chain length (oligosaccharide [OS] or polysaccharide [PS]) and saccharide quantity (0.5, 2, or 5 microg). Subjects were randomized into groups 1-6 (Pn-CRM197 recipients) or 7 (controls) for immunization at 2, 4, and 6 months of age. Pn-CRM197 were well tolerated and elicited mean antibody concentrations that exceeded those in controls for all 5 capsular serotypes. PS formulations were generally more immunogenic than their OS counterparts. For PS vaccines, a dose-response was documented (5 microg > 2 microg > 0.5 microg), but the differences between the 5- and 2-microg formulations were insignificant. The mean anti-PRP antibody concentration was significantly higher among Pn-CRM197 recipients. It is concluded that PS vaccines are more immunogenic than OS vaccines. The improved immunogenicity from Haemophilus type b oligosaccharide conjugate (HbOC) vaccine when given with Pn-CRM197 suggests that a decreased dose of HbOC vaccine may be sufficient to elicit protection.     

IgG responses to protein-conjugated pneumococcal capsular polysaccharides in persons who are genetically incapable of responding to unconjugated polysaccharides

We have previously shown that the capacity to make IgG to pneumococcal capsular polysaccharides (PCPs) is inherited as an autosomal, mixed codominant trait. The purpose of this study was to determine whether this genetically determined unresponsiveness could be overcome by injection of protein-conjugated pneumococcal vaccines. Seven healthy adults who had failed to produce IgG to five or more of 10 representative PCPs after receiving pneumococcal vaccine and whose parents, siblings, and/or offspring had a similar lack of responsiveness received a series of protein-conjugated polysaccharide vaccines. Excellent IgG responses to most of the PCPs tested were eventually observed in five of the seven subjects after they received octavalent diphtheria toxoid-conjugated vaccine. Administration of certain protein-conjugated PCPs leads to IgG responses in some persons who lack the capacity to respond to unconjugated PCPs.     

Pneumococcal diversity: considerations for new vaccine strategies with emphasis on pneumococcal surface protein A (PspA)

Streptococcus pneumoniae is a problematic infectious agent, whose seriousness to human health has been underscored by the recent rise in the frequency of isolation of multidrug-resistant strains. Pneumococcal pneumonia in the elderly is common and often fatal. Young children in the developing world are at significant risk for fatal pneumococcal respiratory disease, while in the developed world otitis media in children results in substantial economic costs. Immunocompromised patients are extremely susceptible to pneumococcal infection. With 90 different capsular types thus far described, the diversity of pneumococci contributes to the challenges of preventing and treating S. pneumoniae infections. The current capsular polysaccharide vaccine is not recommended for use in children younger than 2 years and is not fully effective in the elderly. Therefore, innovative vaccine strategies to protect against this agent are needed. Given the immunogenic nature of S. pneumoniae proteins, these molecules are being investigated as potential vaccine candidates. Pneumococcal surface protein A (PspA) has been evaluated for its ability to elicit protection against S. pneumoniae infection in mouse models of systemic and local disease. This review focuses on immune system responsiveness to PspA and the ability of PspA to elicit cross-protection against heterologous strains. These parameters will be critical to the design of broadly protective pneumococcal vaccines.     

Nonsteroidal anti-inflammatory drug use and Alzheimer-type pathology in aging

Infant rats were passively immunized to determine the protective capacity of pneumococcal anticapsular antibodies. Animal-passaged strains of Streptococcus pneumoniae serotypes 1, 4, 5, 6b, 7f, 9v, 14, 18c, 19f, and 23f were used as challenge inocula (1-1500 cfu) in a model of pulmonary infection that resulted in bacteremia, meningitis, and death. From untreated control animals, histologic sections of lung demonstrated infiltrative pneumonia and lung homogenate cultures grew S. pneumoniae at concentrations of 10(3)-10(8) cfu per gram of lung tissue. A type-specific anti-capsular antibody serum concentration of 0.1-1.15 microg/mL resulted in a statistically significant reduction in mortality compared with the reduction in untreated controls, except for serotype 14, which required 2.32 microg/mL for a significant reduction in mortality. The serum antibody level that provided 50% reduction in mortality ranged from 0.1-3.5 microg/mL for all serotypes.     

Effects of acute endurance exercise and 8 week training on the production of reactive oxygen species from neutrophils in untrained men

The suboptimal efficacy of the currently available 23-valent pneumococcal vaccine in the growing population of adults >65 years old may be related to the limited immunogenicity of the vaccine polysaccharides in this group. In this study, the majority of elderly outpatients with stable chronic illnesses generated a vigorous IgG response to seven vaccine serotypes comparable to that of healthy young adults at 1, 3, and 16 months after immunization. Moreover, the quality and function of anticapsular antibodies, measured as avidity and in vitro opsonization, were comparable between elderly and young subjects over time. However, a subset (approximately 20%) of elderly outpatients responded to fewer than two of seven serotypes tested 1 and 3 months after immunization, whereas none of the healthy young adults were such poor responders. Thus, despite the adequate mean immune responses of the elderly as a group, a substantial proportion of elderly persons may have poor responses to the currently available pneumococcal vaccine.