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J B Robbins

Publications and source records attributed to J B Robbins.

At least 91 records · Page 5Linked to original sources
PubMed1992

Antibodies elicited by a Cryptococcus neoformans-tetanus toxoid conjugate vaccine have the same specificity as those elicited in infection.

The antibody responses of BALB/c mice to serotype A Cryptococcus neoformans capsular polysaccharide (CNPS) were compared after cryptococcal infection and immunization with a serotype A glucuronoxylomannan-tetanus toxoid conjugate (GXM-TT). Infection rarely resulted in a rise of serum antibody titer to CNPS. In contrast, mice immunized with GXM-TT produced serum IgM and IgG to CNPS. Six IgM and one IgG1 monoclonal antibodies (MAbs) were generated from the spleen of one infected mouse. Nine IgM, 1 IgG3, 16 IgG1, and 7 IgA MAbs were generated from the spleen of one GXM-TT-immunized mouse. All MAbs generated from both mice bound to the GXM fraction of the capsular polysaccharide. For some MAbs, de-O-acetylation of serotype A GXM abolished or greatly reduced MAb binding compared with the native GXM. All MAbs reacted with CNPS from C. neoformans serotypes A-D. MAbs generated from the infected mouse competitively inhibited the binding of MAbs generated from the GXM-TT-immunized mouse. These results indicate that some antibodies elicited by infection with C. neoformans or by immunization with GXM-TT bind to the same antigenic determinant in the GXM.

Animals↗
PubMed1992

Protection of mice against Salmonella typhimurium with an O-specific polysaccharide-protein conjugate vaccine.

Serious infections with salmonellae remain a threat in many human populations. Despite extensive study of salmonella infections in animals and clinical experience with killed cellular vaccines, there are no vaccines against serotypes other than Salmonella typhi licensed for human use. Serum antibodies to the O-specific polysaccharide (O-SP) of salmonellae protect mice against invasive infection. In order to render it immunogenic, we have conjugated the O-SP of Salmonella typhimurium to carrier proteins by various schemes. O-SP conjugated to tetanus toxoid (O-SP-TT) elicited antibodies in outbred mice after three subcutaneous injections without adjuvant. The O-SP alone elicited no detectable antibody. The antibody response to O-SP-TT was boosted by successive doses and consisted of immunoglobulin G (IgG) and IgM. Most mice only produced antibodies specific for the abequose (O:4 factor) region of the O-SP. Occasional animals also produced antibodies to the core oligosaccharide. Immunized mice were protected against intraperitoneal challenge with S. typhimurium, demonstrating a 160-fold increase in the 50% lethal dose. Passive immunization with conjugate-induced IgM or IgG also protected against challenge. These results indicate that an O-SP-TT conjugate, when given by a route and formulation acceptable for human use, protects mice against challenge with S. typhimurium.

Animals↗
PubMed1992

Comparative immunogenicity of conjugates composed of the Staphylococcus aureus type 8 capsular polysaccharide bound to carrier proteins by adipic acid dihydrazide or N-succinimidyl-3-(2-pyridyldithio)propionate.

Staphylococcus aureus type 8 capsular polysaccharide (CP) was conjugated either to diphtheria toxoid or to Pseudomonas aeruginosa recombinant exoprotein A by using adipic acid dihydrazide (ADH) or N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP) as the joining reagent. The polysaccharide/protein ratios of these two pairs of conjugates were similar. The two synthetic schemes bound the linker to the carboxyls of the type 8 CP by carbodiimide-mediated condensation. ADH was bound to the carboxyls of the protein, whereas SPDP reacted with the amino groups of the protein. Intermolecular linking of the carrier protein, caused by the carbodiimide during the conjugation reaction with the type 8 CP derivative, probably accounts for the larger size of the conjugates formed with ADH compared with those formed with SPDP. Both conjugates synthesized with ADH elicited higher levels of CP antibodies, especially after the first immunization, than did those prepared with SPDP. Similar levels of exoprotein A antibodies were elicited by both conjugates. Higher levels of diphtheria toxoid antibodies were elicited by the conjugate prepared with SPDP than by the one prepared with ADH. The basis for the differences in the immunogenicities of these two pairs of S. aureus type 8 CP conjugates is discussed.

ADP Ribose Transferases↗
PubMed1992

Synthesis, characterization, and some immunological properties of conjugates composed of the detoxified lipopolysaccharide of Vibrio cholerae O1 serotype Inaba bound to cholera toxin.

Protection against cholera has been correlated with the level of serum vibriocidal antibodies. The specificity of these vibriocidal antibodies was mostly to the lipopolysaccharide (LPS). We synthesized conjugates of detoxified LPS with cholera toxin (CT) and other proteins in order to elicit serum LPS antibodies with vibriocidal activity. Treatment with hydrazine (deacylated LPS) reduced the endotoxic properties of the LPS to clinically acceptable levels and resulted in a molecule larger and more antigenic than the saccharide produced by acid hydrolysis. More immunogenic conjugates resulted from multipoint compared with single-point attachment of the deacylated LPS to the protein. The conjugates containing CT had low levels of pyrogen and no toxic activity upon Chinese hamster ovary cells and elicited booster responses of vibriocidal and CT antibodies when injected subcutaneously as saline solutions into mice; the vibriocidal titers were similar to those elicited by comparable doses of cellular vaccines. We suggest how serum vibriocidal antibodies might prevent cholera.

Animals↗
PubMed1992

Synthesis of a conjugate vaccine composed of pneumococcus type 14 capsular polysaccharide bound to pertussis toxin.

Type 14 is one of the common types isolated from patients of all ages with infections caused by Streptococcus pneumoniae. Its capsular polysaccharide (Pn14) is composed of a neutrally charged tetrasaccharide repeat unit. Pn14 does not elicit protective levels of antibodies in infants and children and is a less than optimal immunogen of the 23-valent vaccine for adults. Pertussis toxin (PT) is both a virulence factor and protective antigen of Bordetella pertussis: it is not soluble at neutral pH and forms insoluble complexes with acidic polysaccharides. Both Pn14 and PT are potential components of vaccines for infants and children. Accordingly, a synthetic scheme was devised to prepare a conjugate of Pn14 and PT. An adipic acid hydrazide derivative of Pn14 was bound to PT at pH 3.9 by carbodiimide-mediated condensation. The conjugation procedure inactivated the PT as assayed by CHO cell and histamine-sensitizing activity. The Pn14-PT conjugate elicited antibodies in mice to Pn14 at levels estimated to be protective in humans and elicited neutralizing antibodies to PT. We plan to evaluate Pn14-PT clinically.

Animals↗
PubMed1991

Evaluation of monophosphoryl lipid A (MPL) as an adjuvant. Enhancement of the serum antibody response in mice to polysaccharide-protein conjugates by concurrent injection with MPL.

Concurrent injection of monophosphoryl lipid A (MPL) in saline or as an oil-in-water emulsion enhanced both the primary and secondary serum antibody responses to the capsular polysaccharide (CP) components of seven conjugates: the enhanced responses were Ag-specific. In contrast, MPL did not enhance the serum antibody response to five of the six unconjugated CP. MPL and trehalose dimycolate injected concurrently with the unconjugated Vi CP of Salmonella typhi (Vi) enhanced the serum antibody response to that Ag. MPL further enhanced the Vi antibody levels when injected with conjugates of this CP. The serum antibody responses to Pseudomonas aeruginosa exotoxin A, used as the carrier protein for the Staphylococcus aureus types 5 and 8 conjugates, were also enhanced by MPL. MPL in oil-in-water emulsion was generally more effective than when administered in saline.

ADP Ribose Transferases↗
PubMed1991

Antibodies to poly[(2----8)-alpha-N-acetylneuraminic acid] and poly[(2----9)-alpha-N-acetylneuraminic acid] are elicited by immunization of mice with Escherichia coli K92 conjugates: potential vaccines for groups B and C meningococci and E. coli K1.

Meningitis and other systemic infections caused by group B Neisseria meningitidis and Escherichia coli K1 remain important problems. The capsular polysaccharides (CPs) of these pathogens (poly[(2----8)-alpha-N-acetylneuraminic acid] or poly(alpha 2-8NeuNAc] are identical and are virulence factors and protective antigens for both. CP vaccines for these pathogens are not available because poly(alpha 2-8NeuNAc) alone, as a complex or a conjugate, is poorly immunogenic. Because oligomers of poly(alpha 2-8NeuNAc) in fetal brain and other tissues bind antibodies in vitro, it has been suggested that antibodies to this CP might be pathologic. We synthesized conjugates of this CP with tetanus toxoid under conditions that avoid lactone formation. Using this scheme, we also synthesized conjugates of group C meningococcal CP (poly[(2----9)-alpha-N-acetylneuraminic acid] or poly(alpha 2-9NeuNAc] and of E. coli K92 CP [poly(alpha 2-8, alpha 2-9NeuNAc)]. When injected s.c. in saline into mice, conjugates of poly(alpha 2-8NeuNAc) or poly(alpha 2-9NeuNAc) elicited homologous antibodies. E. coli K92 conjugates elicited both poly(alpha 2-8NeuNAc) and poly(alpha 2-9NeuNAc) antibodies. Both components of the conjugates expressed T-dependent immunologic properties under conditions and dosages acceptable for clinical evaluation. Poly(alpha 2-8NeuNAc) antibodies elicited by the homologous or the K92 conjugates had lower binding activities at 37 degrees C than at 22 degrees C. "Natural" poly(alpha 2-8NeuNAc) antibodies were present in almost all matched pairs of human maternal and cord sera; most cord levels were higher than in corresponding maternal sera. These findings suggest that increased levels of poly(alpha 2-8NeuNAc) IgG antibodies elicited by our conjugates will confer protective immunity to group B meningococci and E. coli K1 and will not be pathologic.

Animals↗
PubMed1991

Persistence of serum antibodies elicited by Haemophilus influenzae type b-tetanus toxoid conjugate vaccine in infants vaccinated at 3, 5 and 12 months of age.

Eighty-five children received three injections of a vaccine consisting of Haemophilus influenzae type b (Hib) capsular polysaccharide (CPS) conjugated to tetanus toxoid (TT) (Hib-TT) at 3, 5 and 12 months of age according to the vaccination schedule for Swedish children. Diphtheria-tetanus toxoid vaccine was concurrently injected at another site. Two dosages, 7.5 and 15 micrograms, of Hib CPS were studied. No serious reactions occurred. Hib-TT elicited fewer local reactions than diphtheria-tetanus toxoid vaccine. Significant increases in Hib CPS serum antibodies occurred after all injections in both dosage groups with virtually no differences between the two groups. After the first and second injections geometric mean serum antibody concentrations of both dosage groups combined increased to 0.49 and 3.71 micrograms/ml and 81 and 99% of the vaccinees, respectively, had concentrations greater than 0.15 micrograms/ml. After the third dose geometric mean concentrations increased to 13.7 micrograms/ml and all had concentrations greater than 0.15 micrograms/ml. The geometric mean Hib CPS antibody concentrations decreased to 1.24 micrograms/ml 18 months after the third injection, but 97% still had concentrations greater than 0.15 micrograms/ml. The rise of Hib CPS antibodies was mostly in the IgG class. The most pronounced increase was seen in the IgG1 subclass but there were also increase in IgG2 and IgG3. Protective concentrations of TT antibodies were found in all postimmunization sera. In conclusion Hib-TT is safe and immunogenic in infants and should be protective from 6 to 30 months and probably longer thereafter.

Antibodies, Bacterial↗
PubMed1991

Cryptococcus neoformans serotype A glucuronoxylomannan-protein conjugate vaccines: synthesis, characterization, and immunogenicity.

We synthesized Cryptococcus neoformans serotype A glucuronoxylomannan (GXM) conjugate vaccines under conditions suitable for human use to prevent disseminated cryptococcosis. The purified, sonicated GXM was derivatized with adipic acid dihydrazide through either hydroxyl or carboxyl groups and then covalently bound to tetanus toxoid (TT) or Pseudomonas aeruginosa exoprotein A (rEPA). The immunogenicity of these conjugates was evaluated in BALB/c and general purpose mice by subcutaneous injection in saline. The conjugates elicited higher GXM antibody responses than GXM alone. Booster immunoglobulin G (IgG) and IgM responses were elicited by all conjugates in BALB/c mice. The conjugates prepared through hydroxyl activation (GXM-TT2 and GXM-rEPA) were more immunogenic than the one prepared through carboxyl activation (GXM-TT1). GXM antibody response was enhanced by the administration of monophosphoryl lipid A 2 days following the injection of GXM-TT2 (P less than 0.03). The conjugates also elicited IgG antibodies to the carrier proteins. Gel diffusion tests using conjugate-induced hyperimmune sera and chemically modified GXMs suggested that the specificity of GXM-TT1-induced antibodies was conferred by the O-acetyl groups. Hyperimmune sera generated by GXM-TT2 precipitated with the chemically unmodified and the de-O-acetylated GXMs but not with the carboxyl-reduced and de-O-acetylated GXM. GXM-TT2-induced hyperimmune serum also precipitated with the capsular polysaccharides of C. neoformans serotypes D, B, and C. The conjugate vaccines prepared through hydroxyl activation of the GXM are sufficiently immunogenic and appear to be suitable for clinical evaluation.

Animals↗
PubMed1991

Preparation, characterization, and immunogenicity of conjugates composed of the O-specific polysaccharide of Shigella dysenteriae type 1 (Shiga's bacillus) bound to tetanus toxoid.

The background for developing conjugate vaccines for shigellosis composed of the O-specific polysaccharide (O-SP) bound to a protein is described elsewhere (C. Y. Chu, R. Schneerson, and J. B. Robbins, submitted for publication). Briefly, there is direct evidence for type (lipopolysaccharide [LPS])-specific protection after infection with the wild type or with attenuated strains of shigellae. Prospective studies of Israeli armed forces recruits show a correlation between preexisting serum immunoglobulin G (IgG) LPS antibodies and resistance to shigellosis (D. Cohen, M. S. Green, C. Block, R. Slephon, and I. Ofek, J. Clin. Microbiol. 29:386-389, 1991). In order to elicit IgG LPS-specific antibodies to Shigella dysenteriae type 1, the O-SP of this pathogen was purified and bound to tetanus toxoid (TT) by three schemes. The most immunogenic used a modification of a published method (C. Y. Chu, R. Schneerson, J. B. Robbins, and S. C. Rastogi, Infect. Immun. 40:245-256, 1983). The resultant O-SP-TT conjugates were stable and elicited high levels of IgG O-SP antibodies and booster responses in young mice when injected subcutaneously in saline at 1/10 the proposed human dose. Adsorption onto alum or concurrent administration with monophosphoryl lipid A enhanced both the IgG and IgM antibody responses to the O-SP of the conjugate; both the nonadsorbed and adsorbed conjugates elicited higher rises of IgG than of IgM antibodies. Clinical evaluations of S. dysenteriae type 1 O-SP-TT conjugates are planned.

Animals↗
PubMed1991

Relation between structure and immunologic properties of the Vi capsular polysaccharide.

The Vi capsular polysaccharide of Salmonella typhi is a linear homopolymer of poly-alpha(1----4)GalNAcp variably O acetylated at the C-3 position. Serum antibodies elicited by this antigen confer protective immunity against typhoid fever. The relation between the immunologic properties and structure of Vi was investigated by carboxyl reduction, O deacetylation, and acid hydrolysis. The immunogenicity of Vi was closely related to its degree of O acetylation. Partial O deacetylation slightly increased immunogenicity; complete O deacetylation eliminated the immunogenicity of Vi. O-deacetylated Vi, however, still reacted with antisera prepared by injection of whole bacteria. Carboxyl reduction, in contrast, had a comparatively slight effect upon both the immunogenicity and antigenicity of Vi. Retention levels of antigenicity after acid treatment were greater for both the native and carboxyl-reduced Vi than for the O-deacetylated product. The Courtauld-Koltun space-filling model of a pentamer of Vi demonstrated that the bulky nonpolar O-acetyls, which protrude in rows on both sides, make up most of the surface. The carboxyls are less exposed and are partially shielded by the O-acetyls. The molecular model thus provides an explantation for the dominant role of the O-acetyls, as well as the lesser effect of carboxyl reduction, upon the immunologic properties of Vi.

Acetylation↗
PubMed1991

Identity between polysaccharide antigens of Moraxella nonliquefaciens, group B Neisseria meningitidis, and Escherichia coli K1 (non-O acetylated).

A surface polysaccharide antigen of Moraxella nonliquefaciens, reported to be cross-reactive with the capsular polysaccharides of group B Neisseria meningitidis and Escherichia coli K1 (K. Błvre, K. Bryn, O. Closs, N. Hagen, and L. O. Froholm, NIPH Ann. 6:65-73, 1983), was isolated, purified, and characterized chemically, immunologically, and by nuclear magnetic resonance. This polysaccharide was shown to be a linear homopolymer of alpha (2----8)-linked N-acetylneuraminic acid, identical to the capsular polysaccharide of group B N. meningitidis and O-acetyl-negative variants of E. coli K1.

Animals↗
PubMed1990

Studies on Pneumococcus vaccine alone or mixed with DTP and on Pneumococcus type 6B and Haemophilus influenzae type b capsular polysaccharide-tetanus toxoid conjugates in two- to five-year-old children with sickle cell anemia.

Pneumococcus vaccine, injected alone or mixed with diphtheria-tetanus toxoid-pertussis, did not elicit significant concentrations of pneumococcus type 6 antibodies in 2- to 5-year-old sickle cell anemia patients (n = 22). Reinjection 5 months later failed to elicit a booster response to pneumococcus type 6. We then injected conjugates of pneumococcus type 6B and of Haemophilus influenzae type b (Hib), each bound to tetanus toxoid (TT), alternatively at monthly intervals into sickle cell anemia patients of the same age group (n = 25); most received 3 injections of each vaccine. Pneumococcus vaccine was administered to 19 patients and Hib to 1 at approximately 1 year of age. Blood samples were taken before each and approximately 6 months after the last injection. Infrequent and minimal local reactions and only 6 episodes of fever (3%) occurred after injection of the conjugates. Pneumococcus type 6B-TT elicited a rise in the geometric mean concentration of pneumococcus type 6 antibodies (Ab) from 104 ng of antibody nitrogen (AbN)/ml in preimmunization sera to 385 ng of AbN/ml after the first injection (P less than 0.01). There were further increases after the 2 subsequent injections; 6 months after the third injection, the mean concentration was 940 ng of AbN/ml and 15 of 16 (94%) had greater than 300 ng of AbN/ml. Hib-TT elicited a 160-fold increase of Hib antibodies to a geometric mean concentration of 39.0 micrograms of Ab/ml after the first injection. These levels rose approximately 2-fold following 2 additional injections to 71.7 micrograms/ml and declined to 10.7 micrograms/ml at the 6-month sampling.(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia, Sickle Cell↗
PubMed1990

Synthesis and immunological properties of conjugates composed of group B streptococcus type III capsular polysaccharide covalently bound to tetanus toxoid.

A synthetic scheme for covalently binding group B streptococcus type III to tetanus toxoid (TT), using adipic acid dihydrazide as a spacer, is described. Type III alone or as a conjugate with TT was injected subcutaneously into laboratory mice, and the type-specific and TT antibody responses elicited by these immunogens were assayed. Type III-TT elicited significantly higher levels of type-specific antibodies after each immunization than did the type III alone. These levels were related to the dosage of the conjugate, enhanced by Freund adjuvant, and exhibited booster responses. Type III alone elicited only immunoglobulin M (IgM) antibodies in Swiss albino mice and mostly IgM and low levels of IgG antibodies of the IgG3 subclass in BALB/c mice. Type III-TT conjugates, in contrast, elicited mostly IgG antibodies in both strains of mice. IgA type III antibodies were not detected. The first two immunizations with the conjugates elicited type III antibodies in the IgG1 and in the IgG3 subclasses. Low levels of IgG2a type III antibodies were detected after a third injection of type III-TT. Conjugate-induced antibodies facilitated opsonization of group B streptococcus type III organisms and did not react with the structurally related pneumococcus type 14. TT alone or as a component of type III-TT induced mostly antibodies of the IgG class: IgG1 levels were the highest of the four subclasses. No IgA TT antibodies were detected. The conjugation procedure, therefore, enhanced the immunogenicity of and conferred T-cell dependent properties to the type III while preserving the immunogenicity of the TT component. The T-cell dependent properties of the conjugates were responsible for stimulating IgG type III antibodies which could be boosted. Evaluation of type III-TT conjugates in antibody-negative women of child-bearing age is planned.

Animals↗