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PubMed1975

Factors affecting the molecular structure and the agglutinating ability of concanavalin A and other lectins.

Ultracentrifugation analyses were performed on lectins under varying conditions of pH, ionic strength and temperature. It has been demonstrated that the phytohemagglutinin from Phaseolus vulgaris, the wheat germ agglutinin and the soybean agglutinin are stable when these parameters are varied, whereas the concanavalin A molecule exhibits a striking reversible dimer-tetramer transition with variation in pH (from 6.0 to 7.2) and temperature (from 4 degrees up to 37 degrees C). It has also been demonstrated that, in agglutination experiments undertaken at different temperatures, cells do eventually aggregate with the first three lectins provided that incubation time is sufficient, whereas the concanavalin-A-induced agglutination was previously found to be temperature-sensitive. These results strongly suggest that the effect of temperature on agglutination by lectins may essentially be due to a structural transition of the lectin itself and nott only to modification of cell surface properties.

Agglutination↗

PubMedDate not supplied

Is low titre agglutination seen when testing male sera for antisperm antibodies an immunological phenomenon?

The gelatin agglutination test (GAT) and the tray slide agglutination test (TAT) for antisperm antibodies may yield equivocal titres in a number of cases when sera from infertile men are tested. The question is whether these equivocal titres represent true immunological activity or whether other factors such as beta-spermagglutinins are responsible. The sera from 24 infertile men with moderate or equivocal titres were tested using the TAT after absorption with protein A-producing staphylococci to remove IgG. Only two of the 24 sera showed activity which may have been due to beta-spermagglutinins; the majority of the sera showed no activity following absorption. These results mean that even at low titres the GAT and TAT are detecting immunological agglutination when male sera are tested and by inference that antisperm antibodies in male sera only become clinically significant at higher titres, as it is well known that men may father children in the presence of lower or equivocal serum GAT or TAT titres.

Absorption↗

PubMedDate not supplied

Modification of the slide agglutination test for the detection of sperm-agglutinins.

We have modified the slide agglutination test (SAT) in order to make it available for the routine detection and titration of sperm agglutinins. Serum and seminal plasma samples of 156 subfertile patients were tested by the modified slide agglutination test (MSAT) in two trials. Fifteen per cent of serum and 7.5% of siminal plasma samples gave positive results and MSAT showed excellent reproducibility: a highly significant statistical correlation between the positive titres in the two determinations was observed. One hundred and ten samples were tested simultaneously by the MSAT and the tray agglutination test (TAT). The two tests showed a similar sensitivity with a significant statistical correlation between the positive titres. Using the MSAT the reading of results was easier and more precise. Therefore we propose the MSAT for the routine detection and titration of sperm-agglutinins.

Humans↗

PubMedDate not supplied

White piedra and Trichosporon species in equatorial Africa. III. Identification of Trichosporon species by slide agglutination test.

Fifty-two Trichosporon strains isolated from Gabonese female patients 15-60 years, were studied. The identity of these strains was established by two different methods: the method proposed by Guého et al. (1992), based on mycological criteria, and a slide agglutination method performed with monospecific antisera prepared in our laboratory. The final results show a perfect correlation between the two methods, which allowed us to identify 25 strains of T. mucoides, 21 strains of T. inkin and seven strains of T. asahii. The results of the agglutination tests performed with 24-h-old subcultures grown on Sabouraud glucose agar are available in less than 15 mins. In the light of these results, it appears that this method, which is rapid and easy to perform and reproduce, may readily be used in hospital laboratories. In addition, this method allowed us to verify the presence of antigens common to the genera Cryptococcus and Trichosporon, which were easily shown by the use of crude sera. The fact that the anti-Trichosporon monospecific sera lose their capacity to agglutinate Cryptococcus neoformans proves their high specificity.

Adolescent↗

PubMed1987

A fertile man with a high sperm agglutination titer in the seminal plasma: a case report.

A fertile man had sperm-agglutinating activity in his serum (titers 1:16-1:128) and in his seminal plasma (titers 1:128-1:2048). The antibodies in the seminal plasma could be absorbed with anti-IgA antiserum but not with anti-IgG antiserum. A fresh ejaculate showed strong auto-agglutination of the spermatozoa. With mixed antiglobulin reaction tests (MART) and/or immunobead tests (IBT), IgA and IgG were detected on almost all motile spermatozoa; the erythrocytes, in the MART, and the latex spheres, in the IBT, adhered mainly to the tip of the tail. After mixing the fresh semen with cervical mucus, only 40% of the spermatozoa were locally shaking. The spermatozoa showed excellent penetration of cervical mucus in vitro. This case shows that IgA coating of the tails of the spermatozoa does not necessarily lead to adherence of these spermatozoa to the micelles of the cervical mucus and that the sperm cervical mucus contact test has a better predictive value than the sperm agglutination titer in the seminal plasma.

Adult↗

PubMed1977

Thermostable Neisseria gonorrhoeae antigens examined by a bacterial agglutination test.

Rabbit antisera against three different N. gonorrhoeae isolates agglutinated heated gonococci (100 degrees C, 2 h) before and after treatment with periodate or pronase, but this was not the case with gonococci exposed to the combined action of the reagents. All agglutinins could be removed by absorption of antiserum with untreated or heat-treated gonococci or with a heat extract of the bacteria. Antiserum absorbed with the lipopolysaccharide still agglutinated the heated gonococci both before and after exposure of the bacteria to periodate or pronase. The results of cross-absorption experiments indicated strain variation of thermostable antigenic determinants involved in the agglutination reaction.

Agglutination Tests↗

PubMed1979

Diagnosis of Salmonella bacteria: antibodies against synthetic Salmonella O-antigen 8 for immunofluorescence and co-agglutination using sensitized protein A-containing staphylococci.

An antiserum against the synthetic disaccharide abequose 1 leads to 3 alpha rhamnose (AR), representative of Salmonella O-antigen 8, coupled to bovine serum albumin (BSA) was used for diagnosis of Salmonella bacteria by indirect immunofluorescence (IFL) and by co-agglutination (COA) using sensitized protein A-containing staphylococci. Among the 1150 enteric bacteria tested in IFL, the antiserum correctly identified all 99 Salmonella serogroup C2 and C3 bacteria with O-antigen 8. No fluorescence was seen with 484 Salmonella bacteria belonging to other serogroups or 567 non-Salmonella enteric bacteria. The anti-AR-BSA serum was favourable as compared to a conventional Salmonella factor O8 serum as regards both titre and specificity. In the COA test, all 22 Salmonella serogroup C2 and C3 strains agglutinated strongly and within seconds, whereas no agglutination could be seen when 93 Salmonella bacteria representing other serogroups were tested.

Agglutination Tests↗

PubMed1984

Interaction of human serum transferrin with Neisseria gonorrhoeae, demonstrated by agglutination and precipitation.

Human sera show non-immune precipitation with ultrasonically disrupted bacteria of the N. gonorrhoeae strain 8551. A human serum was resolved by DEAE cellulose chromatography and immune absorption to isolate the serum component involved in the precipitation. Testing of the final product against antisera to various serum proteins and analysis by SDS-PAGE revealed only serum transferrin. This preparation and transferrin obtained commercially produced precipitation in agar gel against the gonococcal extract. The bacterium was agglutinated by transferrin in solution or when carried by latex particles, and particles sensitized with the bacterial extract were agglutinated by transferrin. Four out of 26 gonococcal strains examined showed reactivity with transferrin in the precipitation and agglutination tests.

Agglutination Tests↗

PubMed1983

Classification of Bacteroides nodosus by agglutination tests.

One thousand two hundred and sixty seven isolates of Bacteroides nodosus from 292 sheep in 58 flocks were examined. Of these, 1260 could be classified by slide agglutination into 8 serogroups designated A to H. Up to 6 serogroups were detected in individual flocks, with up to 4 serogroups being detected in a single foot. Of the 292 sheep examined, 38 (13%) carried mixed serogroup infections. Determination of the range of serological types infecting a flock frequently required the examination of a number of isolates from each of a number of sheep. Cross-tube agglutination tests carried out on 44 isolates and their antiserums indicated that members of some serogroups could be divisible into subgroups or serotypes. These results suggested that 16 or more serotypes of B. nodosus might exist. The nature of the antigens responsible for both slide and tube agglutination reactions needs to be determined.

Agglutination Tests↗

PubMed1989

[The c protein fractions of group B streptococci: its distribution and relation to heat-labile antigens for the agglutination method].

Distribution of the c protein fractions of group B streptococci and relation to heat-labile antigens for agglutination were investigated. The results were summarized as follows: 1. Analysis of antigenicity of the c protein in group B streptococcal strains isolated revealed that 74% of the type Ia/c strains carried only alpha antigen, and 76% of the type Ib/c strains contained both alpha and beta antigens. Component of the c protein fractions in most of type Ia/c strains isolated was different from that in reference strains. 2. Of 37 Ia/c alpha strains, 45.9% were determined non-typable, 32.4% were Ia/W, 13.5% were Ia/S, and 8.1% were Ia/Q in the agglutination for heat-labile antigens. Of 8 Ia/c alpha beta strains, 87.5% were Ia/Q, and 12.5% were Ia/SW. Of 5 Ia/c beta strains, 60% were Ia/Q, and 40% were Ia/QW. Of 19 Ib/c alpha beta strains, 68.4% were Ib/-, and 31.6% were Ib/S. Of 5 Ib/c alpha strains, 60% were Ib/-, and 40% were Ib/S. One Ib/c beta strain was Ib/-. 3. Because trypsin-sensitive portions of the beta antigens were lost, preparation of antigens for agglutination by pancreatic digestion could not exactly reflect results of the precipitation method.

Agglutination Tests↗

PubMed1975

Cell rigidity: Effect on concanavalin A-mediated agglutinability of fibroblasts after fixation.

A quantitative hemadsorption assay distinguishes the effects of membrane fixation on concanavalin A-mediated agglutinability of fixed cells with unfixed cells. We observed undiminished adherence of unfixed erythrocytes to glutaraldehyde-fixed normal and virus-transformed hamster fibroblasts coated with concanavalin A. Fixation of the erythrocytes abolished agglutination with fixed fibroblasts. The agglutinability of fixed cells is more likely related to increased cell rigidity than to decreased membrane fluidity.

Agglutination↗

PubMed1972

Concanavalin A agglutination of intestinal cells from the human fetus.

Concanavalin A markedly agglutinated isolated epithelial cells from the intestine of the human fetus but not from the intestine of the adult. Wheat germ agglutinin only moderately agglutinated cells from the intestine of an adult. These results extend the studies of concanavalin A agglutination of embryonic cells to human tissue, and they suggest that concanavalin A may be reacting with a common antigen on the fetal cell membrane.

Age Factors↗

PubMed1988

Autologous red cell agglutination assay for HIV-1 antibodies: simplified test with whole blood.

An antibody detection procedure based on agglutination of autologous red cells has been developed for samples of whole blood. A nonagglutinating monoclonal antibody to human red blood cells conjugated to a synthetic peptide antigen (in this case residues 579 to 601 of the HIV-1 envelope precursor, Arg-Ile-Leu-Ala-Val-Glu-Arg-Tyr-Leu-Lys-Asp-Gln-Gln-Leu-Leu-Gly-Ile-Trp- Gly-Cys - Ser-Gly-Lys) permitted the detection of antibodies to the human immunodeficiency virus type 1 (HIV-1) in 10 microliters of whole blood within 2 minutes. Agglutination was specifically inhibited by addition of synthetic peptide antigen but not by unrelated peptides. The frequency of false positive results was 0.1% with HIV-1 seronegative blood donors (n = 874). The false negative results were approximately 1% (n = 81). The autologous red cell agglutination test is potentially suitable for simple, rapid, qualitative screening for antibodies to a variety of antigens of medical and veterinary diagnostic significance.

Agglutination Tests↗

PubMed1971

Microagglutination procedures for febrile agglutination tests.

Febrile agglutination tests were done by using as antigens Brucella abortus, Salmonella group D, Proteus OX19, and Pasteurella tularensis. Comparison of results from 23 sera showed that the microtechnique, rapid slide, and test tube methods gave similar titers, although those from the microtechnique were generally higher. The sensitivity of the microtechnique depended upon the concentration of antigen, and, to obtain reproducible results, the optimal concentration of antigens had to be determined by preliminary titrations against specific, positive control antisera. Readability of reactions in the microtechnique was enhanced by adding the dye Safranin O to diluent for antigen and by use of V-type, rather than U-type, microtiter plates. Tests were also done to determine the effects of dye and salt concentrations, pH, and temperature of incubation upon the titer of agglutinations by the microtechnique. Our results indicated that the microtechnique could be used for agglutination tests involving febrile antigens. The procedure is less time-consuming than the tube method and requires less antigen and serum than the latter method or the rapid slide method.

Agglutination Tests↗

PubMed1972

Effects of carbohydrates in growth medium on agglutination of several species of Salmonella with polyvalent H antiserum.

The effect of various carbohydrates in the growth medium on agglutination of salmonellae with polyvalent H antiserum was studied. There appeared to be a relationship between fermentation of the carbohydrate by the organism and resultant agglutination with the antiserum. It is recommended that the tube test for flagellar antigens be allowed to remain in a water bath for 2 hr before the final observation is made. Sorbitol, dulcitol, mannose, maltose, rhamnose, or trehalose, when included in the growth medium for Salmonella, yielded high percentages of positive agglutinations with all conditions of the experiment.

Agglutination Tests↗

PubMed1996

Production of agglutinating monoclonal antibody against antigen 8 specific for Cryptococcus neoformans serotype D.

A hybridoma (clone CRND-8) that produced agglutinating monoclonal antibody (MAb) against Cryptococcus neoformans serotype D was established by using a soluble capsular polysaccharide-keyhole limpet hemocyanin conjugate for immunization. The isotype was immunoglobulin M(kappa). Specificity was determined by cell slide agglutination and enzyme-linked immunosorbent assay (ELISA). In both tests, the MAb reacted to serotypes D and A-D but not to serotypes A, B, and C. Furthermore, the specificity of the MAb determined by ELISA was the same as that of polyclonal antibody factor serum (PAb factor) 8, which showed high-level reactivity with serotypes D and A-D. These results supported the deduced specificity of the PAb-based antigenic factor 8. A total of 15 isolates of serotypes D and A-D but no serotype A isolates reacted with the MAb in cell slide agglutination tests. CRND-8 MAb can be used in place of PAb factor 8 for serotyping C. neoformans isolates and for the analysis of the antigen 8 epitope.

Agglutination Tests↗

PubMed1998

A modified agglutination test for Neospora caninum: development, optimization, and comparison to the indirect fluorescent-antibody test and enzyme-linked immunosorbent assay.

Current serologic tests used to detect antibodies to Neospora caninum require species-specific secondary antibodies, limiting the number of species that can be tested. In order to examine a wide variety of animal species that may be infected with N. caninum, a modified direct agglutination test (N-MAT) similar to the Toxoplasma gondii modified direct agglutination test (T-MAT) was developed. This test measures the direct agglutination of parasites by N. caninum-specific antibodies in serum, thus eliminating the need for secondary host-specific anti-isotype sera. The N-MAT was compared to the indirect fluorescent-antibody test (IFAT) and the enzyme-linked immunosorbent assay (ELISA) with a "gold standard" serum panel from species for which secondary antibodies were available (n = 547). All positive samples tested were from animals with histologically confirmed infections. Up to 16 different species were tested. The N-MAT gave a higher sensitivity (100%) and specificity (97%) than the ELISA (74 and 94%, respectively) and had a higher sensitivity but a lower specificity than the IFAT (98 and 99%, respectively). The reduced specificity of the N-MAT was due to false-positive reactions in testing fetal fluids with particulate matter or severely hemolyzed serum. Overall, the N-MAT proved to be highly sensitive and specific for both naturally and experimentally infected animals, highly reproducible between and within readers, easy to use on large sample sizes without requiring special equipment, and useful in testing serum from any species without modification.

Abortion, Veterinary↗

PubMed1977

Macrophage-agglutinating factor produced in vitro by BCG-sensitized lymphocytes.

Supernatant fluids from cultures of BCG-sensitized rabbit lymph node and spleen cells contained a factor that strongly agglutinated normal rabbit alveolar macrophages within 3 min at room temperature. In contrast, fluids from nonsensitized cell cultures did not agglutinate normal rabbit alveolar macrophages. This factor was designated macrophage-agglutinating factor (MAgF) because it is similar to the previously described factor found in lung lavages of rabbits exhibiting a BCG-induced pulmonary delayed hypersensitivity reaction. The kinetics of MAgF production in vitro by sensitized lymph node cells and its inhibition by puromycin and actinomycin D suggest active synthesis; sensitized spleen cells exhibited kinetics resembling release rather than synthesis. Studies on purified lymphocyte and macrophage populations from sensitized spleen and lymph nodes indicated that lymphocytes are responsible for MAgF production. However, MAgF production was not induced in normal cells incubated in vitro with concanavalin A or phytohemagglutinin. Fractionation of cell culture supernatant fluids in Sephadex G-100 or Ultrogel AcA-34 clearly separated MAgF from migration inhibition factor; MAgF was present in the void volume of the eluates, suggesting a molecular weight of over 400,000, whereas migration inhibition factor was recovered in the same peak as albumin. The role of MAgF in vivo is unknown, but it is postulated that it may cause the adherence of macrophages during granuloma formation.

Agglutination↗