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Group B streptococci (GBS) express strain-variable and surface-localized proteins, which are important serotype markers and targets of protective antibodies. These include the c(alpha) and R4 proteins, one or the other of which is expressed by approximately 75% of clinical GBS isolates. These proteins have been considered vaccine candidates. In this study, the c(alpha) and R4 proteins were extracted by trypsin digestion of GBS and purified by sequential precipitation with trichloroacetic acid and ammonium sulfate followed by gel filtration chromatography. The proteins were used as antigens in an indirect enzyme-linked immunosorbent assay (ELISA) to measure the levels of c(alpha)- and R4-reactive antibodies in sera from pregnant women from Norway (n = 100) and from Zimbabwe (n = 124). Antibody levels in the Norwegian group of women were significantly higher than in the Zimbabwean group, and a higher proportion of the Norwegian women contained appreciable levels of antibodies against both proteins. The antibodies traversed the placental barrier. With individual sera, a significant correlation between the anti-c(alpha) and anti-R4 antibody levels was observed and each of the two protein antigens effectively competed for human serum antibodies both against itself and against the other antigen. Inhibition ELISA results demonstrated specificity for each of the proteins of immune antibodies raised in rabbits. These results demonstrate that (i) the majority of women of childbearing age have antibodies against c(alpha) and R4, (ii) the levels of these antibodies differ among pregnant women in different parts of the world, and (iii) the normal human serum antibodies may target a common c(alpha) and R4 protein site, whereas immune antibodies targeted a different site(s) specific for each protein.

Tularemia was diagnosed in 57 patients during an outbreak in central Norway in 1984 and 1985. Clinical categories of the disease showed seasonal variations. A bacterial microagglutination test and an enzyme-linked immunosorbent assay (ELISA) with class-specific antibodies against Francisella tularensis outer membrane (OM) antigens were evaluated for the early diagnosis of tularemia. ELISA with immunoglobulin G (IgG), IgA, or IgM antibodies and the microagglutination test differed only marginally in diagnostic sensitivity. The OM preparation harbored F. tularensis agglutinogens and contained a variety of proteins, several of which functioned as immunogens in tularemia patients, as shown by Western blotting (immunoblotting). All 12 patients tested produced antibodies against a 43,000-molecular-weight OM protein. Individual variation was noted with regard to antibody response against other OM antigens. The OM is a suitable antigen preparation in ELISA for the diagnosis of tularemia and, presumably, contains antigens important in the immunobiology of tularemia.

Antibodies to Escherichia coli outer membrane proteins in sera from healthy persons and from patients bacteremic with various enteric or nonenteric bacteria were measured by an enzyme-linked immunosorbent assay (ELISA). Outer membranes were prepared from E. coli O55. Serum was absorbed with E. coli O55 lipopolysaccharide and diluted 1:100 for immunoglobulin A (IgA) or IgM and 1:1,000 for IgG antibodies. Paired serum specimens were obtained from the 56 patients included in the study (the first specimen on the day of positive blood culture and the second specimen 8 to 12 days later) and compared with sera from blood donors (n = 50) as controls. On an average, the patients bacteremic with enterobacteria (n = 40) showed increased levels of antibodies of all three immunoglobulin classes in the first serum specimens and significantly higher levels in the second specimens compared with the controls, although with considerable case-to-case variation. Increased levels of IgG antibodies showed the best combination of diagnostic specificity (100%) and sensitivity (53%) for bacteremia caused by enteric bacilli. Mostly, the antibody response was directed against the major E. coli O55 outer membrane proteins at 81,000, 38,500, 33,500, and 7,500 molecular weights as shown by Western blot (immunoblot) analysis. Some of the patients bacteremic with nonenteric bacteria showed increased levels of IgA antibodies, but not of IgG or IgM antibodies. Cross-reactivity of the nonenteric blood culture isolates with the E. coli outer membrane preparation was not demonstrated. The cross-reactivity of the E. coli O55 outer membrane proteins with those of enteric bacilli of other genera was examined by absorption experiments. Western blots with serum absorbed with live E. coli O55 provided evidence that the epitopes of the outer membrane protein at 7,500 molecular weight were available for antibody binding at the bacterial surface, and that at least some of the epitopes of the 38,500- and 33,500-molecular -weight proteins were accessible to antibodies. The results suggest that an ELISA for the measurement of antibodies against cross-reactive outer membrane proteins from enteric bacilli may be useful in the diagnosis of serious infections caused by members of the family Enterobacteriaceae, and that antibodies to the major outer membrane proteins may have an immunobiological function.

Antibodies against a 43,000-molecular-weight Francisella tularensis outer membrane (OM) protein (43K protein) were measured in paired serum specimens from 23 patients with tularemia and matched against antibodies in sera from 25 patients with nontularemic infectious diseases and from 25 blood donors. Antibodies were measured by a competition enzyme-linked immunosorbent assay which tested the ability of human serum to compete with rabbit anti-43K protein antibodies for its binding to the F. tularensis OM coat. The sera from nontularemic patients and from blood donors, in dilutions of 1:16 and 1:64, respectively, showed no or very low levels of antibodies. All of the tularemia patients showed positive tests with the first, the second, or both of the serum specimens examined. For instance, with serum diluted 1:64, each of the serum specimens showed a sensitivity of 95.7% and a specificity of 96%. When used for antibody competition in Western blotting (immunoblotting), the rabbit anti-43K selectivity blocked the binding of human serum antibodies to the 43,000-molecular-weight protein. This protein was immunoaccessible in Formalin-killed F. tularensis. These data indicate an important role of the 43,000-molecular-weight OM protein in the immunobiology of tularemia and emphasize its potential usefulness as an antigen in serodiagnostic tests.

Sera from fifty patients with gonorrhoea, thirty with non-specific urethritis, and eighty blood donors were treated with mercaptoethanol (ME) and examined by the indirect haemagglutination test for antibodies against endotoxin from gonococci. Erythrocytes sensitized with determinant a of endotoxin from Strains 8551, V, and VII, or determinant b from Strain V were used. The percentage of sera active in the haemagglutination test was much higher in the gonorrhoea group than in the controls. The geometric mean titre was also significantly higher in the gonorrhoea group. This applied for all four antigens used. Results obtained in an anti-globulin test indicated that the titre of ME-treated serum was determined by IgG antibodies against the endotoxin. Many sera had titres which varied according to the strain origin of the antigen used in the test. The sensitivity of tests for antibodies was increased by using endotoxin from several different strains of gonococci for the examination of each serum. A simplified procedure for determination of antibodies against endotoxin from different strains of gonococci was elaborated. [ABSTRACT FROM PUBLISHER]

The antigonococcal activity of the quinolone derivative flumequine was evaluated. Of 246 strains examined, 240 (97.5%) strains showed minimum inhibitory concentrations (MICs) of flumequine of less than or equal to 0.4 microgram/ml, including three beta-lactamase-producing strains. The six remaining strains showed MICs from 3.2 to 9.6 micrograms/ml. By disc diffusion tests using 3-micrograms discs of flumequine the zones of growth inhibition correlated well with the MICs of flumequine. The effect of treatment with flumequine was compared in 239 patients with uncomplicated gonorrhoea. A single dose regimen of 1200 mg flumequine orally, a two-dose regimen of 1200 and 800 mg, and a three-dose regimen of 1200, 800, and 800 mg (six hours apart) were given. With a single dose of flumequine the failure rate was 26%. The two-dose and three-dose regimens were equally effective with an overall cure rate of 95.4%. In patients harbouring beta-lactamase-producing gonococci the infection was cured. The failures (10 men) included all of the six patients infected with flumequine-resistant gonococci. Side effects were noted by 14.6% of the patients and were mostly described as dizziness. [ABSTRACT FROM PUBLISHER]