ABSTRACT
A new monoclonal antibody (5F81A4P1.9), which is specific for subtype 9 antigen of meningococci, was studied. The antibodies were raised against a previously non-typable (NT) serogroup B strain from Brazilian patients and were found to react with the subtype antigen of prototype reference strains for subtype 9 (M982), as well as with those of homologous strains. The subtype 9 epitope was found in 6.8 percent of serogroup B strains among 602 strains of Neisseria meningitidis case isolates, including representative isolates from Brazilian states. Subtype P1.9 was predominantly related to serogroup B in Brazil among the isolates collected during the N. meningitidis epidemic in 1992. No significant differences were observed in the occurrence of subtype P1.9 among strains isolated from several Brazilian states. Fluorescence-activated cell-sorter analysis showed that 5F81A4 MAb recognized a 46 kDa protein on the surface of a homologous strain of N. meningitidis (B:4:P1.9). These results, in association with a bactericidal activity assay for 5F81A4, and with experimental passive protection in mice, demonstrated the importance of subtype 9 class 1 proteins of N meningitidis in Brazil. Serotyping is essential for the development of vaccination strategies.
Subject(s)
Humans , Animals , Mice , Antibodies, Bacterial/biosynthesis , Antibodies, Monoclonal/biosynthesis , Bacterial Outer Membrane Proteins/immunology , Meningococcal Infections/microbiology , Neisseria meningitidis/immunology , Blotting, Western , Electrophoresis, Polyacrylamide Gel , Enzyme-Linked Immunosorbent Assay , Flow Cytometry , Mice, Inbred BALB C , Neisseria meningitidis/classification , SerotypingABSTRACT
Determining the profile of antigen expression among meningococci is important for epidemiologic surveillance and vaccine development. To this end, two new mouse monoclonal antibodies (MAbs) have been derived against Neisseria meningitidis proteins (class 5). The MAbs were reactive against outer membrane antigens and were bactericidal. Selected anti-class 5 MAbs [(5.1)-3E6-2;(5.3)-3BH4-C7;(5.4)-1BG11-C7;(5.5)-3DH-F5G9 also 5FIF4-T3(5.c)], and two new monoclonal antibodies C14F10Br2 (5.8) and 7F11B5Br3 (5.9), were then tested against different meningococcal strains, (63 strains of serogroup A, 60 strains of serogroup C (from 1972 to 1974); and 136 strains of serogroup B (from 1992) meningococci). Our results demonstrated that the expression of class 5 proteins in the N. meningitidis B Brazilian strains studied is highly heterogeneous. The serotypes and subtypes of B:4:P1.15, B:4:P1.9, B:4:P1.7, B:4:P1.3, B:4:p1.14, B:4:P1.16, B:4:NT, and B:NT:NT were detected in N. meningitidis B serogroups. The strains C:2a:P1.2 and A:4.21:P1.9 were dominant in the C and A serogroups, respectively. Serogroup B organisms expressed the class 5 epitopes 5.4 (18 percent), 5.5 (22 percent), 5.8 (3.6 percent), 5.9 (8 percent) and 5c (38 percent). Serogroup C expressed class 5 epitopes 5.1(81 percent), 5.4 (35 percent), 5.5 (33 percent) and 5.9 (5 percent); and serogroup A showed reactivity directed at the class 5 protein 5c (47 percent); and reactivity was present with the new monoclonal antibody, 5.9 (5.5 percent). We conclude that the two new MAbs are useful in detecting important group B, class 5 antigens, and that a broad selection of serogroup B, class 5 proteins would be required for an effective vaccine based on the class 5 proteins.
Subject(s)
Antibodies, Monoclonal , Bacterial Outer Membrane Proteins , Bacterial Vaccines , Flow Cytometry , Meningitis, Meningococcal/epidemiology , Meningitis, Meningococcal/prevention & control , Neisseria meningitidis , Serologic TestsABSTRACT
We describe the production of the potential monoclonal antibodies (MoAbs) using BALB/c mice immunized with vesicular fluid (VF)-Tcra (T. crassiceps) antigen. Immune sera presented anti-VF-Tcra (<20kD) IgG and IgM antibodies with cross-reactivity with T. solium (Tso) antigen (8-12, 14, and 18 kD). After cell fusion, we selected 33 anti-Tcra and anti-Tso reactive IgM-clones and 53 anti-Tcra specific IgG-clones, 5 of them also recognizing Tso antigens. Two clones identified the 8-14 and 18kD peptides of VF-Tcra.
Subject(s)
Animals , Female , Mice , Antibodies, Helminth/biosynthesis , Antibodies, Monoclonal/biosynthesis , Antigens, Helminth/immunology , Taenia/immunology , Cross Reactions , Cysticercosis/immunology , Immunoblotting , Immunoglobulin G/immunology , Immunoglobulin G/isolation & purification , Immunoglobulin M/immunology , Immunoglobulin M/isolation & purification , Mice, Inbred BALB CABSTRACT
The specific antibody responses were compared among susceptible (A/Sn), moderately susceptible (Balb/c) and resistant (C57 BL/lOJ) mice infected with Trypanosoma cruzi (Y strain). Sera obtained during the second week of infection recognized a surface trypomastigote antigen of apparent Mr 80 kDa while displaying complex reactivity to surface epimastigote antigens. Complex trypomastigote antigens recognition was detected around the middle of the third week of infection. No major differences were observed along the infection, among the three strains of mice, neither in the patterns of surface antigen recognition by sera, nor in the titres of antibodies against blood trypomastigotes (lytic antibodies), tissue culture trypomastigotes or epimastigotes. On immunoblot analysis, however, IgG of the resistant strain displayed the most complex array of specificities against both trypo and epimastigote antigens, followed by the susceptible strain. IgM antibodies exhibited a more restricted antigen reactivity, in the three mouse strains studied. Balb/c sera (IgG and IgM) showed the least complex patterns of reactivity to antigens in the range of 30 kDa to 80 kDa. The onset of reactivity in the serum to trypomastigote surface antigens was also dependent on the parasite load to which the experimental animal was subjected