Monoclonal antibody to streptococcal group B carbohydrate: applications in latex agglutination and immunoprecipitin assays (original) (raw)
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Journal of Clinical Microbiology
Type-specific antigen was purified from the supernatant of type III group B streptococcal cultures, tyrosylated, and bound to microtiter wells for an enzymelinked immunosorbent assay. The immunological specificity of the antigen and the assay was shown by (i) reaction only with homologous unabsorbed rabbit sera and (ii) inhibition after incubation of human serum with homologous but not heterologous purified antigen. The assay was quantitated by relating optical density readings to absolute amounts of human immunoglobulin G bound to the microtiter wells.
Journal of Clinical Microbiology
A commercially available latex agglutination reagent, Directigen (Hynson, Westcott & Dunning, Div. Becton Dickinson & Co., Baltimore, Md.), in which a murine monoclonal antibody to group B streptococcal (GBS) antigen is the active component, was evaluated by using body fluid specimens from 94 sick infants. Antigen was detected in one or more admission specimens from 18 of 19 (94.7%) infants with symptomatic GBS infection. In 15 patients with GBS meningitis, cerebrospinal fluid, serum, and 10-fold-concentrated urine specimens were positive in 87, 50, and 100%, respectively. GBS antigen was detected in 50% of unconcentrated urines, but in no sera from infants with nonmeningitic GBS sepsis. Among specimens from 27 infants with invasive infection due to organisms other than GBS and from 48 culture-negative sick infants, false-positive latex agglutination reactions occurred in only 4 (9.5%) urine specimens and in no cerebrospinal fluid or serum specimens. The 94.7% sensitivity and specificity of the Directigen GBS test indicate that it is a useful reagent for the rapid diagnosis of invasive GBS infection in young infants.
Microbiological Research, 1997
A Monoclonal antibody (MAb II-T) specific for serotypes II and V of Group E streptococci (GES) was prepared by fusing myeloma cells with spleen cells of mice immunized with whole cells of a serotype II strain. MAb II -T reacted in an enzyme immunoassay (EIA) with whole cells of both serotypes and reacted in gel diffusion test with autoclaved-saline extracts of serotypes II and V. The extract was purified by DEAE-Sephadex A-25, followed by treatment with proteinase K, and further by chromatogniphy with a Sephadex G-200 column. The purified polysaccharide (PS) antigen contained 98.6% carbohydrate and 1.4% protein, but no detectable phosphorus. In hapten inhibition tests using various sugars, D-mannosamine markedly inhibited the precipitin reaction. These results indicated that the antigenic determinant might have a structure similar to D-mannosamine.
Journal of Experimental Medicine, 1988
Group B streptococcal (GBS) infections cause significant mortality and morbidity among infants. Passive antibody immunotherapy has been proposed as treatment for infected infants. To this end, two human mAb-secreting cell lines were produced by EBV immortalization of human B cells. The mAbs were specific for the group B polysaccharide and bound to strains of all five serotypes as demonstrated by ELISA and crossed immunoelectrophoresis. The mAbs reacted and opsonized 100% (132/132) of the clinical isolates tested which represented all four capsule types. Both prophylactic and therapeutic protection with these mAbs were demonstrated in neonatal rats given lethal infections of types Ia and III human clinical isolates. These data indicate that a single human mAb directed against the group B carbohydrate can protect against GBS infections caused by the different serotypes. This antibody may be useful in the passive immunotherapy of infants infected with GBS.
Seroepidemiology of group B streptococcus type II antibody specificity
Epidemiology and Infection, 1988
The specificity of human antibodies for the two major sidechain determinants of the type II group B streptococcal (GBS) polysaccharide was examined in 90 pairs of maternal and cord sera. Using an ELISA system, total antibody was measured against the complete (sialylated) type II antigen and the proportion of antibody against the galactose determinant was estimated by inhibition with free ,3-methylgalactopyranoside. Mothers colonized by type II or by other GBS types had higher levels of total specific antibody (means, 3-3 and 4-7 jug/ml, respectively) than those not colonized (mean, 2-2 ,ug/ml). Cord sera averaged 1-2 ,ug/ml lower than maternal sera. Colonization with GBS was also associated with higher levels against the galactose determinant (mean, 1-5 jug/ml, compared to 0 7 sg/ml for those not colonized). The distribution of specificities favoured antibodies against the sialic acid determinant in maternal but not cord sera. Specificity as well as antibody level may play a role in the epidemiology of GBS type II.
Journal of medical …, 1996
A murine IgM monoclonal antibody (MAb H11) was developed against the type polysaccharide capsular antigen of group B streptococcus (GBS), serotype IV, after intraperitoneal immunisation of BALB/c mice with heat-killed bacteria. MAb H11 reacted in immunodiffusion with the purified polysaccharide in both its sialylated and desialylated form, giving a line of identity, and opsonised type IV GBS strains in an invitro assay. When administered at the time of intraperitoneal lethal challenge with homologous GBS, or 4 h earlier, MAb H11 protected 90% of the mice. Protection was still observed when MAb H11 was given 4 h after the challenge. This MAb was strongly effective in preventing septic arthritis induced by type IV GBS.
Functional properties of anti-group B streptococcal monoclonal antibodies
Clinical immunology and immunopathology, 1982
Group B streptococci (GBS) are frequently recognized as the etiologic agents of sepsis and meningitis during the neonatal period. Using the technique of somatic cell hybridization, we have developed hybridomas which secrete monoclonal antibodies directed against each of the major polysaccharide determinants of the five serotypes of GBS (anti-GBS Iak, Ib, II, and III). We have demonstrated that these monoclonal antibodies agglutinate, fix complement, and opsonize Lancefield reference strains to which they correspond in specificity. In addition, the anti-group B streptococcal monoclonal antibodies specifically protect against lethal infection in Balb/C mice.
Zentralblatt für Bakteriologie, 1995
A monoclonal antibody specific to a cell wall antigen of Streptococcus rattus (S. rattus) was prepared after cell fusion of mouse myeloma cells to the spleen cells of mice immunized with whole cells of strain FAL The monoclonal antibody reacted with a crude and purified polysaccharide antigen of S. rattus in precipitin reactions as well as in a solid phase enzyme assay (EIA). It also reacted in the EIA with whole cells of S. rattus strains, but did not react with any other species of the mutans group or of other oral and streptococcal species. Moreover, among many haptenic sugars and their derivatives tested, D-galactosamine and D-glucosamine strongly inhibited the reaction in a competitive enzyme immunoassay using the purified antigen and whole cells, indicating that the type-specific antigenic determinant of the organism has a structure similar to the amino group of the sugar molecules. Furthermore, immunoelectron microscopy revealed that the antigen epitopes formed an irregular fibrous structure over the entire surface of individual cells.