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PubMed1963

Suppression of blood group agglutinability of human erythrocytes by certain bacterial polysaccharides.

Erythrocytes coated with bacterial capsular polysaccharides, notably the Vi antigen, were no longer agglutinated by antibodies directed against the various antigens native to the red cell surface. These effects could not be attributed to prevention of antibody uptake even though in some systems the uptake of antibody was diminished. In fact, agglutination by Rh-incomplete antibody was brought back to the original titer only after the sensitized Vi-coated cells had been subjected to ten alternating exposures to globulin and antiglobulin. Hemagglutination by Newcastle, mumps, and influenza viruses was also suppressed. Erythrocytes coated with Vi polysaccharide assumed the distinctive physicochemical attributes of this acidic polymer which results in a stabilization of the erythrocyte suspension as manifested by increased electrophoretic mobility and a striking decrease in the rate of sedimentation. Among the possible models for explaining the nature of the Vi effect on immune agglutination, the data favor interference with lattice formation.

Antibodies↗
PubMed1999

Diagnosis of pneumococcal pneumonia in epidemiological studies: evaluation in Kenyan adults of a serotype-specific urine latex agglutination assay.

A serotype-specific tube latex agglutination assay for 10 pneumococcal serotypes was evaluated with use of urine samples from 72 Kenyan adults with pneumonia whose blood or lung aspirate cultures were positive for Streptococcus pneumoniae, 203 patients with pneumonia whose cultures were negative for S. pneumoniae, and 101 afebrile controls. Detection thresholds for purified capsular polysaccharide in normal urine ranged from 0.33 to 10 ng/mL. The sensitivity of the assay for the 10 pneumococcal serotypes was 0.57 (95% confidence interval, 0.44-0.70) and was unaffected by human immunodeficiency virus seropositivity, prior antibiotic use, and bacteremic or nonbacteremic status but varied significantly by serotype. Of the pneumococci obtained by culture, 81% were of serotypes (1, 4, 5, 6, 7, 9, 12, 14, 19, and 22) that were included in the antigen assay. Strong simultaneous agglutinations against two different serotypes were found in urine samples from two patients. The specificity of the assay was 0.98 (lower 95% confidence limit, 0.95). Subjective reading of agglutination results introduced variation in specificity that may be inapparent if not formally measured. The assay extended the diagnostic yield in pneumococcal pneumonia by a factor of 2.2 (from 54 diagnoses established by blood culture to 119 established by both methods) and may therefore prove useful in reducing the sample size of epidemiological studies of pneumococcal pneumonia in adults.

Adolescent↗
PubMed1980

Comparison of enzyme immunoassay and latex agglutination methods for detection of Cryptococcus neoformans antigen.

An enzyme immunoassay for the measurement of cryptococcal capsular polysaccharide in human body fluids is described. The enzyme immunoassay detects cryptococcal capsular polysaccharide at a concentration of 6 ng/ml, compared with 35 ng/ml detectable by the latex agglutination test. The enzyme immunoassay detects cryptococcal capsular polysaccharide in body-fluid specimens that are negative by the latex agglutination test. Titers by enzyme immunoassay are generally higher and persist longer into the treatment period than those determined by latex agglutination. No cryptococcal capsular polysaccharide is detected by the enzyme immunoassay procedure in fluids from subjects not known to have cryptococcosis. The enzyme immunoassay procedure presented here provides earlier detection of cryptococcal material in body fluids, and thereby diagnosis and treatment of cryptococcosis can be made earlier in the course of disease.

Antigens, Fungal↗
PubMed1981

Detection of cryptococcal antigen. Comparison of two latex agglutination tests.

The detection of cryptococcal antigen by means of the agglutination of antibody-coated latex particles is an important aid in the diagnosis of cryptococcosis. A commercially available latex agglutination test (IBL kit) was compared with the latex agglutination test from the Center for Disease Control in regard to sensitivity, specificity, and height of antigen titer. Over a 13-month period, 335 specimens were tested with both kits. There was one false-positive reaction with both kits (0.4%) and one false-negative reaction only with the CDC kit, among 18 patients who had meningitis or disseminated infection due to Cryptococcus neoformans. Sera from patients who had localized pulmonary cryptococcosis showed negative results with both kits. The antigen titers measured by the two kits were the same or within two dilutions in 22 of 26 specimens of cerebrospinal fluid or serum from patients who had proved cryptococcosis. Overall, the IBL kit compared favorably with the CDC kit for the detection of cryptococcal antigen in cerebrospinal fluid or serum.

Antigens, Fungal↗
PubMedDate not supplied

Rapid diagnosis of streptococcal pharyngitis in two pediatric offices using a latex agglutination kit.

The diagnostic accuracy and practicality of a latex agglutination test for the rapid diagnosis of streptococcal pharyngitis directly from throat swabs were evaluated in two private pediatric practices. Compared with anaerobic throat culture the latex agglutination method had a sensitivity of 93.4%, a specificity of 90.2% and an overall accuracy of 91.8%. Even used as a while-you-wait test, the rapid method fit easily into the routine of busy office practice. Latex agglutination testing for the rapid diagnosis of streptococcal pharyngitis may prove to be a valuable adjunct to the office microbiology laboratory.

Child↗
PubMed1986

Serotyping of campylobacters by co-agglutination on the basis of heat-stable antigens.

A new and simple method of serotyping campylobacters has been developed which utilises co-agglutination to detect the presence of heat-stable antigens. Campylobacters are heated at 75 degrees C for 30 min to destroy antigenic protein and allowed to react on a glass slide with staphylococci coated with antibody. Of 74 isolates, 67 gave the same result by co-agglutination and the previously described passive haemagglutination method. The co-agglutination technique may be used as a rapid screening test before serotyping by passive haemagglutination.

Antigens, Bacterial↗
PubMed1988

Light Affects Flagellar Agglutinability in Chlamydomonas eugametos by Modification of the Agglutinin Molecules.

The effect of light on the sexual competence of a light-sensitive mating type minus strain (mt(-)) of Chlamydomonas eugametos obtained by crossing a light-sensitive mating type plus strain (mt(+)) with a light-insensitive mt(-) strain is described. As previously demonstrated for the mt(+) parent, this study of one of the mt(-) offspring shows that (a) a light-sensitive mechanism affects flagellar agglutinability in a rapid process that does not require protein synthesis; (b) only the activity of the flagellar agglutinins (glycoproteins responsible for agglutination) is susceptible to light while agglutinins on the cell body surface are not affected by light. We further demonstrate that (a) membrane vesicles naturally released from nonagglutinable dark gametes remain inactive. Extracts of these vesicles also remain inactive even though they contain agglutinin-like components; (b) inactive mt(-) agglutinin is present in extracts of flagella from nonagglutinable dark gametes by comparison of its chromatographic, electrophoretic, and immunogenic properties with those of active agglutinin. When purified of all other flagellar proteins, it remains inactive; (c) a monoclonal antibody directed against the sexual agglutination site of the mt(-) agglutintin discriminates between active and inactive agglutinins when present in a native state on the flagellar surface, but is unable to discriminate between them when they are denatured in sodium dodecyl sulfate-electrophoresis gels and blotted onto nitrocellulose. Taken collectively these observations suggest that light activation involves the chemical modification of the agglutinins in situ on the flagellar surface.

Journal Article↗
PubMed1979

Cycles of agglutination-disagglutination induced by ristocetin in thrombasthenic platelets.

An oscillatory pattern of platelet agglutination-disagglutination in response to Ristocetin (R) at narrow concentration ranges was observed in citrated platelet rich plasma (PRP) of 10 patients with Glanzmann's thrombasthenia. The cyclic pattern decreased in intensity over time, was reproducible, and was not pH dependent. Formalin-fixed thrombasthenic platelets agglutinated with R but did not show a cyclic pattern. Incubation with 2.5 microM ADP inhibited R oscillation response, but small increases in R dose overcame this inhibition. The addition of ATP or creatine phosphate/creatine phosphokinase to thrombasthenic platelets inhibited by ADP restored the R oscillation response. In the platelets of a single patient, intracellular levels of ADP and ATP were shown to diminish during an oscillation response to R. There was an increase in AMP levels during the same period of time. The changes in these three intracellular nucleotides were gradual over time and did not vary with phases of the oscillation. Acetyl salicylic acid (ASA), at concentrations shown to block cyclooxygenase activity in control platelets, enabled thrombasthenic platelets to respond to R with full agglutination without oscillations. Lower concentrations of ASA in the PRP gave a return of the oscillation response. Our data suggest that the disagglutination phase of the R response of thrombasthenic platelets is not a function of the known glycoprotein membrane defect, but depends on materials originating in the platelet whose release is blocked by ASA.

Adenosine Diphosphate↗
PubMed1984

The agglutination of human platelets by botrocetin: evidence that botrocetin and ristocetin act at different sites on the factor VIII molecule and platelet membrane.

Botrocetin caused a factor VIII (FVIII) dependent platelet agglutination which was associated with a reduction in the plasma levels of all FVIII parameters as a result of specific binding of FVIII to the platelets. The site of binding of FVIII to the platelet in response to ristocetin or botrocetin involves the glycoprotein I complex. This is suggested by the inability of chymotrypsin treated platelets or platelets from patients with the Bernard-Soulier syndrome to agglutinate in response to ristocetin. These platelets responded to botrocetin , but this was greatly reduced compared to normal. Crossed immunoelectrophoretic analysis indicated that in the presence of botrocetin most multimetric forms of FVIII bound to the platelet, whereas ristocetin caused binding of high and intermediate molecular weight forms. The antibiotic vancomycin inhibited platelet agglutination by ristocetin but had no effect on that caused by botrocetin . Assays of FVIII von Willebrand factor (VIII:vWf) using botrocetin compared well with those obtained using ristocetin in plasmas from normal individuals and from patients with classical von Willebrand disease (vWd). However, a patient with variant vWd demonstrated 100% botrocetin cofactor activity and 0% ristocetin cofactor activity. This suggested that the site of interaction on the FVIII molecule for botrocetin and ristocetin are different. Therefore the diagnosis of some von Willebrand variants cannot be excluded on the basis of a normal botrocetin cofactor assay.

Blood Platelets↗
PubMed1993

BCSH-NIBSC anti-D reference reagent for antiglobulin tests: the in-house assessment of red cell washing centrifuges and of operator variability in the detection of weak, macroscopic agglutination. British Committee for Standards in Haematology. National Institute for Biological Standards and Control.

A batch of an anti-D preparation, reference 91/608, has been prepared for the preparation of red cells weakly sensitized with IgG that can reveal inhibition of the antiglobulin test by one volume of human serum, diluted 1:1000. The preparation provides an objective assessment of red cell washer efficacy and the confidential, in-house assessment of operator variability in detecting weak but definite macroscopic agglutination by blind, replicate tests. Red cell washer efficacy and poor operator reading procedures causing disruption of weak agglutination are two major causes of false-negative antiglobulin tests; neither are adequately detected by the common quality-control procedure of adding strongly IgG-sensitized red cells ('Coombs control cells') to apparently negative antiglobulin tests. However, weakly IgG-sensitized red cells do offer a valuable control function that can detect some degree of cell washer inefficiency and reading errors although such cells are not a substitute for the more sensitive replicate testing. Test protocols are provided to assess the efficacy of cell washing machines and operator skills in the detection of weak but definite macroscopic agglutination.

Artifacts↗
PubMed1975

A correction to the autoanalyzer data for quantitative agglutination measurements.

The AutoAnalyzer was used for quantitative measurements of antibody agglutinating activity by a Polybrene agglutination technique. Since the continuous flow system introduces an experimental error to the determination of true agglutination percentage, it is necessary to apply a correction factor. The experimental method of correction is described.

Autoanalysis↗
PubMed1984

A mouse monoclonal antibody with anti-A,(B) specificity which agglutinates Ax cells.

A hybridoma (ES-15) was obtained by fusing the NS-1 cell line with spleen cells from a mouse immunised with soluble blood group A2 substance. The cloned hybridoma culture supernatant was shown to contain an IgM class antibody which strongly agglutinates group A cells and weakly agglutinates group B cells. The serological specificity of this antibody is described as anti-A,(B) in this report. The abilities of unconcentrated monoclonal anti-A,(B), a commercial human polyclonal anti-A,B (group O serum) and a commercial monoclonal anti-A reagent to detect 15 examples of Ax cells were compared by both slide and tube techniques. Using a slide technique monoclonal anti-A,(B) agglutinated 14 examples of Ax cells, human anti-A,B 2 examples, while monoclonal anti-A failed to detect any of the Ax cells tested. Similar differences in the reactivity of the three antibodies were observed using a tube technique. Data are also presented which show that a 1:1 (v/v) mixture of monoclonal anti-A,(B) with a monoclonal anti-B reagent is an effective replacement for human anti-A,B in ABO grouping procedures.

ABO Blood-Group System↗
PubMed1990

Agglutination of red blood cells from patients with diabetes mellitus by a polyclonal human antibody specific for D-glucose.

We have previously described an antibody which will agglutinate red blood cells which had been incubated in vitro in D-glucose. This antibody is specific for the ring form of glucose, beta-D-glucopyranose. The current report demonstrates that without prior in vitro incubation with glucose, red blood cells from 36 of 38 patients with diabetes mellitus, and 7 of 70 patients not diagnosed as diabetic were agglutinated by this antibody. Strength of agglutination of red blood cells from diabetic patients correlated with both glucose (r = 0.61; p less than 0.001) and hemoglobin A1c levels (r = 0.50; p less than 0.01) in simultaneously obtained samples. This reactivity could be reversed by incubating red blood cells from diabetics for several hours in saline. This report suggests that red blood cells from diabetic patients have membrane-bound glucose that can be detected immunologically. Reversibility of the reaction and rapidity of in vitro glycosylation suggests short-term binding of glucose. To our knowledge, this is the first report documenting immunological detection of in vivo short-term reversible binding of glucose to cellular membranes.

Antibodies↗
PubMed1993

Direct agglutination of weak D red cells by tetramolecular complexes containing monoclonal IgG anti-D.

The capacity of blood group antibodies to agglutinate red cells suspended in saline is largely dependent on the antibody isotype. The immunological cross-linking of IgG antibodies has previously been described as a means to increase the reactivity of IgG in many situations. We have prepared anti-D-containing complexes by blending a human IgG anti-D monoclonal antibody (mAb) and a murine anti-human IgG mAb. In standard red cell serology assays, the anti-D complexes exhibited a very high avidity and could agglutinate weak D-positive red cells in direct saline testing. These results indicate that potent saline hem-agglutinating reagents of RhD and eventually of other blood group specificities can be prepared from IgG mAbs.

Animals↗
PubMed1997

Inhibitory effects of nucleoside 5'-alkylphosphates on sexual agglutination in Saccharomyces cerevisiae.

Among various nucleoside 5'-alkylphosphates, uridine 5'-hexadecylphosphate (UMPC16) and adenosine 5'-hexadecylphosphate (AMPC16) inhibited the sexual agglutination between a and alpha haploid cells of Saccharomyces cerevisiae. The effect of AMPC16 accompanied severe growth inhibition of the yeast cells but it was not observed with UMPC16. Sexual agglutination was not inhibited by the presence of UMPC16 or AMPC16 when the yeast cells had been pretreated with the mating pheromone. UMPC16 was characterized as a specific inhibitor of sexual agglutination without direct influence on the agglutinin function, being distinguishable from any of those ever known.

Adenine Nucleotides↗
PubMed1983

A rotavirus staphylococcal co-agglutination test.

A simple and rapid staphylococcal co-agglutination (SA) test for detection of rotavirus in human faecal specimens is described. A suspension of protein A-containing staphylococci coated with a rabbit hyperimmune serum against the rotavirus strain of calf diarrhoeae virus was used as reagent. Before the SA test, the faecal specimens were absorbed with a suspension of uncoated staphylococci. 34 of 36 rotavirus immune electron microscopy (IEM) positive samples showed a positive SA test, whereas none of 41 IEM negative specimens agglutinated the staphylococcal reagent. The SA test was as sensitive as an enzyme-linked immunosorbent assay (Rotazyme) and in our hands more sensitive than a latex agglutination test (Rotalex).

Antibodies, Viral↗
PubMed1998

The development of a semi-automated latex agglutination test for the detection of antibodies to Anaplasma marginale using a cell culture-derived antigen.

Serologic diagnosis of anaplasmosis is currently done by the complement-fixation, ELISA, and card agglutination tests. These tests have utilized A. marginale harvested from bovine erythrocytes as antigen which is often contaminated with erythrocyte stroma. We are currently testing A. marginale propagated in a Ixodes scapularis cell line as antigen for serologic tests. In this study, we report the use of the cell culture-derived A. marginale as antigen for development of a rapid, semi-automated latex agglutination test. Diluted serum and latex (polystyrene microspheres), sensitized with cell culture-derived A. marginale proteins, were dispensed into 96-well microtiter plates. An initial reading of light transmission was recorded by a computer-interfaced scanning autoreader. After 30 minutes, the plates were mixed and read a second time, recording the delta % light transmittance. The sensitized latex microspheres (latex) agglutinated in the presence of A. marginale antibodies, thus producing an increase in light transmittance. In preliminary tests, 724/977 of the sera were positive for A. marginale antibodies with an apparent agreement of 83.3% when compared with the complement-fixation test. Sensitization and sera dilution buffers were shown to have a marked effect on the sensitivity and specificity of this assay. Results will be presented on the optimization of buffers and the testing of sera from experimentally and field-infected cattle.

Anaplasma↗
PubMed1996

Latex agglutination test for canine parvovirus.

Canine parvovirus (CPV) was detected in faeces from dogs with diarrhoea by a specific slide agglutination test using latex particles coated with anti-CPV monoclonal antibody (LA-anti-CPV). The agglutination of LA-anti-CPV with CPV on a glass slide was evident macroscopically within 2 min. The sensitivity of the latex agglutination (LA) test was similar to that of the hemagglutination test. The LA test is available for the rapid diagnosis of CPV infection at an animal hospital.

Animals↗