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Study of the staphylococcal affinity to fibrinogen by passive hemagglutination: a tool for the Staphylococcus aureus identification.

Cadness-Graves et al. used a slide agglutination reaction with human plasma to identify Staphylococcus aureus. The clumping factor (CF) is responsible for this reaction by reacting directly with the fibrinogen. To increase the sensitivity and the specificity of the reaction and the taxonomic value of the test based on the CF detection, a passive hemagglutination has been developed and applied on 580 staphylococcal strains. Formolized sheep red cells were sensitized with human fibrinogen. This reaction has been compared to the classic plasma slide test. The hemagglutination test is more suitable and more precise than the plasma slide test. The detection of staphylococcal affinity to fibrinogen using the passive hemagglutination reaction is a method which is simple and specific, and therefore of obvious interest in taxonomic studies.

Coagulase↗

[Evaluation of the indirect hemagglutination inhibition and radial immunodiffusion tests as methods of quantitative immunoglobulin determination].

In comparison with the radial immunodiffusion method, the sensitivity of the indirect hemagglutination test in determining the concentration of immunoglobulins G, M and A in various biological substrates (blood serum, saliva, cerebrospinal fluid, feces) was 35--100 greater. Under the action of proteolytic enzymes immunoglobulin fragmentation led to increase in the concentration of the Ig indices (according to the data of radial immunodiffusion) and produced no effect on the indices of the indirect hemagglutination test; The latter should be used to determine the immunoglobulins in the external secretions characterized by a low content of the given proteins and a marked probability of their proteolytic splitting. In assessing the results of the indirect hemagglutination test it should be remembered that it was less precise and less reproducible than the radial immunodiffusion method.

Feces↗

Screening of pig sera for antibodies to Japanese encephalitis virus using a dot enzyme immunoassay and IgM capture ELISA: comparison with the hemagglutination inhibition and plaque reduction neutralization tests.

A dot enzyme immunoassay for determination of antibodies to Japanese encephalitis virus was designed for use as a field technique for the surveillance of Japanese encephalitis virus activity among domestic pigs. The test was compared with the neutralization test and the hemagglutination inhibition test and found to be more sensitive than the hemagglutination inhibition test and comparable to the neutralization test in sensitivity but more simple to perform than either the neutralization or the hemagglutination inhibition tests. An IgM capture ELISA for the determination of JEV specific porcine IgM was also utilized to determine current infection rates in pigs. The tests which do not involve the determination of specific IgM are better used for testing sentinel animals for providing clues as to the rate of transmission of JEV among pigs. IgM tests determining acute infection are less likely to be useful unless animals are tested very frequently or if a great number of animals are tested at any one time.

Animals↗

Comparative sensitivity of two hemagglutination inhibition immunoassays for fibrinolytic degradation products in human serum.

A new modification of hemagglutination inhibition immunoassay for measuring fibrinogen/fibrin degradation products (FDP) using glutaraldehyde as a coupling reagent was introduced. This method was compared with the tanned-red-cell hemagglutination inhibition immunoassay (TRCHII). Sheep erythrocytes (SRBC) were sensitized with fragment D or E, respectively. The procedure of sensitizing SRBC is simple and can be achieved within 2 hrs. The sensitized SRBC stored at 4 degrees C for 6 months did not lose their activities. The sensitivities for assaying D and E relative FDP were 0.32 mug/ml, respectively, which were slightly better than those of TRCHII. This represents the first adaptation of glutaraldehyde erythrocyte hemagglutination inhibition immunoassay (GEHII) for the estimation of FDP employing either microtiter plate or test tube. The microtechnique and test tube method were found to be essentially equivalent. The FDP level in the sera of normal individuals and patients suspected of elevation of FDP were assayed by both TRCHII and GEHII. By linear least squares analysis, the results show a significant correlation between these two methods. These results indicate GEHII is a simple, rapid and sensitive immunoassay for FDP in human serum.

Erythrocytes↗

Improvement of the slide hemagglutination test for rapid Chagas' disease screening in epidemiological surveys.

A slide hemagglutination test, here called SHAT, which is practical and economical for seroepidemiological surveys was standardized. This is an improved modification of the rapid hemagglutination test (RHA) which utilizes a short-lived reagent prepared with fresh blood cells. The reagent and conditions of the test were considerably modified and, most importantly, an alkaline-solubilized Trypanosoma cruzi epimastigote antigen reagent is proposed. The stability of the SHAT reagent was at least one year at 4 degrees C, in an appropriate liquid suspension. The SHAT was applied to 71 serum samples from patients with Chagas' disease and from 235 clinically healthy blood donors. Sensitivity, specificity and positive and negative predictive values for the selected cutoff titer corresponding to 1:4 dilution were 0.972 (0.903-0.992), 0.983 (0.957-0.993), 0.945 (0.867-0.979) and 0.991 (0.969-0.998), respectively. These values were comparable to those found for the RHA, immunofluorescence (IFT), indirect hemagglutination (IHAT) and complement fixation (CFT) tests. These data suggest that the SHAT should be useful for seroepidemiological surveys conducted at public health laboratories in developing countries.

Chagas Disease↗

[Monoclonal anti-idiotypic antibodies, imitating the antigenic determinant of hemagglutination site of Venezuelan equine encephalomyelitis virus glycoprotein E2].

A panel of 9 mouse hybridomas producing monoclonal antibodies (MAb-2) to determinants of rat MAb 4H5 (MAb-1) was prepared. MAb-1 blocked hemagglutination caused by different alphaviruses. The specificity of paratopes of MAb-2 was studied by competitive enzyme immunoassay and they were divided into 2 groups: 1) interacting with isotypic and/or allotypic determinants of molecules of MAb 4H5 (5 hybridomas) and 2) specific to idiotypic determinants of MAb 4H5 molecules (4 hybridomas). The antigenic structure of paratopes of 3 antiidiotypic MAb (1C2, 1F9, and 6C8) was specific to the idiotopes localized in the active MAb 4H5 center interacting with the hemagglutination domain of VEE virus glycoprotein E2. These antiidiotypic MAb can agglutinate goose red cells, this indicating that the antigenic structure of their paratopes mimicks the functional determinant of the hemagglutination domain of VEE virus glycoprotein E2.

Animals↗

[Comparative data on the formation of complement-binding and hemagglutinating antibodies to penicillin].

Comparative data on production of complement-binding and hemagglutinating antibodies in the process of the antigenic effect of benzylpenicillin under experimental conditions are presented. 30 rabbit antisera and 3 sera of intact animals were studied. The hemagglutinating antibodies were determined in 19 antisera, high and reliable titers of the antipenicillin hemagglutinating antibodies being found only in 8 antisera. The antipenicillin complement-binding antibodies using complex antibiotic antibodies were also found in 19 antisera. The process of antibody production was more pronounced in the complement-binding reaction (CBR). Both types of the antibodies were detected simultaneously in 14 antisera. It is concluded that the CBR with the use of the penicillin complex antigenes on the stroma of the erythrocytes and in combination with the blood serum is a rather sensitive reaction for detection of antipenicillin antibodies.

Animals↗

Further evaluation of a rubella passive hemagglutination test.

Clinical experience with the Rubacell passive hemagglutination (PHA) test over a one-year period has shown the test to be a rapid, reliable, and economical method for determining antibody to rubella. The data from two separately administered rubella proficiency surveys showed 100% correlation between the PHA and the hemagglutination inhibition (HI) qualitative results with 24 reference specimens. Also, the PHA titers appeared to be generally higher than the HI in these specimens and in the sera of immune individuals. The efficacy of detecting HI antibody in the absence of PHA antibody as an indication of recent infection was compared to the HI paired sera method and to a rubella-specific immunoglobulin M (IgM) test based on protein A absorption. From the results obtained with the sera of 76 rubella patients, the efficacy of the three diagnostic methods was of the following order: protein A IgM test greater than positive HI/negative PHA greater than HI paired sera method.

Antibodies, Viral↗

Isolated HE-protein from hemagglutinating encephalomyelitis virus and bovine coronavirus has receptor-destroying and receptor-binding activity.

Bovine coronavirus (BCV) and hemagglutinating encephalomyelitis virus (HEV) from swine were found to grow to high titers in MDCK I cells, a subline of Madin Darby canine kidney cells. Virus grown in these cells was used to isolate and purify the HE-protein. This protein has been shown recently to have acetylesterase activity and to function as the receptor-destroying enzyme of BCV. Here we show that HEV contains this enzyme, too. The glycoproteins were solubilized by treatment of virions with octylglucoside. Following centrifugation through a sucrose gradient the surface proteins S and HE (hemagglutinin-esterase) were obtained in purified form. After removal of the detergent by dialysis, HE formed rosettes as shown by electron microscopy. The purified HE protein retained acetylesterase activity and was able to function as a receptor-destroying enzyme rendering red blood cells resistant against agglutination by both coronaviruses. HE protein released from the viral membrane failed to agglutinate red blood cells. However, it was found to recognize glycoconjugates containing N-acetyl-9-O-acetylneuraminic acid as indicated by a binding assay with rat serum proteins blotted to nitrocellulose and by its ability to inhibit the hemagglutinating activity of BCV, HEV, and influenza C virus. The purified enzyme provides a useful tool for analyzing the cellular receptors for coronaviruses.

Acetylesterase↗

Hemagglutination by Pasteurellaceae isolated from rodents.

Pasteurellaceae notably P. pneumotropica, have been associated with severe outbreaks of respiratory disease in several species of rodents. Host-specific parasitism of Pasteurellaceae in rodents has hardly been studied. Since host tropism in many bacteria involves adhesive mechanisms, we examined the hemagglutinating (HA) properties of 44 isolates from different rodent species (mouse (15) rat (8), hamster (9), gerbil (10) and Mastomys (2)). Only 13 mouse isolates and the 2 Mastomys isolates hemagglutinated human (type O Rh+) and canine red blood cells (RBCs). No HA was found using RBCs from 10 other animal species. HA was not inhibited by simple sugars and glycoconjugates, but was completely inhibited by heating of bacterial cells for 10 min at 80 or 100 degrees C, partially inhibited by glutaraldehyde and inhibited in a dose-dependent mode by NaIO4, suggesting the involvement of bacterial polysaccharide structures in the HA process. Enrichment procedures did not reveal the presence of HA- subpopulations in HA+ isolates or the presence of HA+ subpopulations in HA- isolates. Electron microscopy revealed the presence of fimbriae both in HA+ and HA- isolates. A regularly structured (RS) layer was detected on cells of part of the HA+ isolates only. Our results suggest that Pasteurellaceae of mice and Mastomys may be related and differ from isolates isolated from other rodent species.

Animals↗

Preparation of an inhibitor of viral hemagglutination from human erythrocytes.

A material, derived from human erythrocytes and believed to be identical with the receptor site for the myxoviruses, has been obtained in homogeneous form. The method of preparation involves pH adjustment of the stroma, hot phenolic extraction, chloroform-methanol treatment, and ultracentrifugation. The material so obtained possesses a high inhibitory titer to viral hemagglutination (45,000 to 60,000 inhibitory units/mg. against 4 hemagglutination units of Lee strain of influenza virus) and appears to be a glycoprotein containing 22 to 24 per cent sialic acid, 12 per cent hexose, 12 per cent hexosamine, 1 per cent fucose in addition to at least eleven amino acids. The sialic acid probably occupies a terminal position in an oligosaccharide chain extending from the protein peptide chain. The molecular weight is near 30,000-an unusually low value for substances possessing this biological activity. M and N blood group activity also seems to be associated with this protein.

Binding Sites↗

Canine herpesvirus 47 kD and mutated 41 kD glycoproteins are responsible for hemagglutination.

Monoclonal antibodies (MoAbs) were used to identify the hemagglutinin of canine herpesvirus (CHV). The inhibition of viral hemagglutination (HA) activity was observed with MoAbs against 41 kD glycoprotein, while no hemagglutination-inhibition (HI) activity was observed with those against 145/112 kD and 80 kD glycoproteins, suggesting that the 41 kD glycoprotein is the hemagglutinin of plaque-selected virus of CHV YP11 strain used as immunogen for MoAb production. All of the HI MoAbs also showed HI activities against HA antigens which were prepared from cells infected with other CHV strains, namely, F-205 V and Glasgow CHV2 reference strains, eight Japanese isolates, and the original YP11 strain. However, on immunoblotting analysis, a 47 kD protein band was detected in these strains by the HI MoAbs. These data suggest that the 47 kD glycoprotein is the common molecule of the hemagglutinin among CHV strains and the plaque-selected virus of YP11 strain appears to be a mutant whose molecular weight of the hemagglutinin changed into 41 kD.

Animals↗

Biological properties of mengovirus: characterization of avirulent, hemagglutination-defective mutants.

Biological properties of two mengovirus mutants, 205 and 280, were compared to those of wild-type virus. The mutants exhibited alterations in plaque morphology, hemagglutination, and virulence in mice, but were not temperature-sensitive. Agglutination of human erythrocytes by mengovirus was dependent on the presence of sialic acid on the erythrocyte surface; however, free sialic acid failed to inhibit hemagglutination. Glycophorin, the major sialoglycoprotein of human erythrocyte membranes, exhibited receptor specificity for wild-type virus, but not for mutants 205 or 280. Cross-linking studies indicated that glycophorin exhibited binding specificity for the alpha (1 D) structural protein. The LD50 titers for wild-type mengovirus were 7 and 1500 plaque forming units (PFU) in mice infected intracranially (IC) and intraperitoneally (IP), respectively. However, mice infected IC or IP with 10(6) or 10(7) PFU of mutant 205 or 280 did not exhibit symptoms indicative of virus infection. Revertants were isolated from the brains of mice infected with mutant 205, but not from the brains of mice infected with mutant 280. The biological characterization of the revertants indicated that hemagglutination and virulence may be phenotypically-linked traits.

Animals↗

Demonstration of non-infectious hemagglutinating particles of rabies virus and isolation of the hemagglutinin by disruption of the virion with Nonidet P-40.

Non-infectious hemagglutinating particles of rabies virus accumulated in the fluid phase of chick embryo cell cultures at 6 days post-infection, though they were undetectable at 4 days. They were characterized as looped filaments resembling viral envelope as revealed by electron microscopy. Another form of hemagglutinin (HAnin) was obtained by solubilization of partially purified virions with Nonidet P-40 (NP-40) followed by successive high speed and CsCl density gradient centrifugations. The density of the isolated HAnin averaged 1.28 g/cm3. SDS-polyacrylamide gel electrophoresis of the HAnin demonstrated that it was mainly composed of a glycoprotein (G) with a molecular weight of 83,000. Electron microscopically, it differed from the above non-infectious hemagglutinating particles, being much smaller in size and showing a star- or rosette-like appearance with a diameter of about 25 nm, composed of a central particle surrounded by particles resembling envelope-spikes. Virus-neutralizing (VN) and hemagglutination inhibiting (HI) antibodies were produced in rabbits immunized with the HAnin isolated from virions.

Animals↗

Crossreactivity of hemolytic and hemagglutinating proteins in the coelomic fluid of lumbricidae (Annelida).

Oligospecific antisera against the hemolytic and hemagglutinating compounds of the coelomic fluid (CF) of the earthworm species Eisenia fetida, Lumbricus terrestris and Aporrectodea caliginosa were prepared. The proteins were bound to the membranes of erythrocytes and injected into rabbits. By the use of these antisera the following results were obtained: 1) The antisera RaL T and RaAC reached a titer of 1:64,000, the detection limit of RaEF was 1:512,000. RaEF was demonstrated to be oligospecific only against three hemolytic proteins by Western blotting. 2) RaEF is able to inhibit the biological activity not only of hemolysins (E. fetida, A. caliginosa) but also of hemagglutinins (L. terrestris, L. rubellus, D. rubidus). 3) Complex carbohydrates, but not simple sugar compounds, are able to inhibit hemolytic and agglutinating activities in the CF of the investigated species. Fet. and alpha 1ac. GP were demonstrated to be strong inhibitors both of the hemolytic and of the hemagglutinating activity, whereas N-acetylglucosamine was only able to inhibit the hemagglutinating activity. 4) The investigated compounds were shown to crossreact in ELISA experiments. 5) By the use of Western blotting, the crossreacting molecules in the CF of the investigated lumbricid species were identified.

Animals↗

Monomeric inhibitors of influenza neuraminidase enhance the hemagglutination inhibition activities of polyacrylamides presenting multiple C-sialoside groups.

BACKGROUND: Influenza viruses use hemagglutinin (HA) arrays to bind to sialic acid moieties on the surface of cells; crosslinking of erythrocytes by this mechanism leads to hemagglutination. A number of synthetic polymers containing multiple sialic acid (Neu5Ac) groups as side chains are potent inhibitors of this process. Inhibition may be due to two mechanisms: polyvalent binding of the inhibitor's multiple Neu5Ac side chains to multiple HA sites on the viral surface, or steric stabilization of the viral particle by a layer of the adsorbed, water-swollen polymer, which prevents adhesion to the erythrocyte. The balance between these two effects is not yet known. RESULTS: Polyacrylamides with multiple C-sialosides (PA(Neu5Ac)) were 2-20 fold more effective as inhibitors of virally mediated hemagglutination when assayed in the presence of Neu2en-NH2, a potent monomeric inhibitor of influenza neuraminidase (NA). The ability of monomeric inhibitors of NA to enhance the inhibition of hemagglutination in this assay correlated with the affinity of the monomer for NA. CONCLUSIONS: We propose that inhibitors of NA act by competing with the C-sialosides of PA(Neu5Ac) for binding to the active sites of the NA. Competitive displacement of Neu5Ac causes an expansion of the layer of polymeric gel absorbed to the virus, enhancing its inhibitory effect. This study provides an example of synergy between two ligands directed toward the active sites of two different proteins, and reinforces the conclusion that steric stabilization is important for the activity of polyvalent inhibitors.

Acrylic Resins↗

The galactosyl-(alpha 1-4)-galactose-binding adhesin of Streptococcus suis: occurrence in strains of different hemagglutination activities and induction of opsonic antibodies.

The occurrence of the galactose-(alpha 1-4)-galactose-specific adhesin in Streptococcus suis, a pig and human pathogen causing sepsis, meningitis, and other serious infections, was studied. Poly- and monoclonal anti-bodies to the purified adhesin, as well as pigeon ovomucoid, a specific probe for the adhesin activity, detected one single protein band in extracts of S. suis. The adhesin was detected in all 23 strains studied, representing pathogenic serotypes (1, 2, 4, 5, 7, 8, and nontypeable) and including several weakly hemagglutinating or nonhemagglutinating strains and phase variants. The amount of adhesin detected was not correlated with the hemagglutination activity of the intact bacteria. Extraction of cells showing no binding of pigeon ovomucoid by ultrasonic treatment resulted in extracts with pigeon ovomucoid binding activity, suggesting that the adhesin was not accessible to the probe on the intact cells. Analysis of the amount of capsular polysaccharide revealed an inverse relationship between the hemagglutination activity and expression of capsular polysaccharide, thus suggesting a factor influencing adhesin accessibility. The purified adhesin was highly immunogenic and induced in preliminary experiments bactericidal activity in mice. Thus, the adhesin, with its specific binding mechanism to host cells and a proposed pathogenic role, is widely expressed among strains of different serotypes and therefore appears to represent a novel promising candidate for the development of a vaccine against S. suis.

Adhesins, Bacterial↗