Showing papers on "Hemagglutination published in 2003"

Characterization of an outer membrane protein associated with haemagglutination and adhesive properties of enteroaggregative Escherichia coli O111:H12.

Abstract: Summary Diarrhoeagenic Escherichia coli strains of serotype O111:H12 are characterized by their aggregative pattern of adherence on cultured epithelial cells and thus are considered enteroaggregative E. coli (EAEC). We have previously shown that these EAEC strains lack the genes encoding the aggregative fimbriae I and II described in other heterologous EAEC strains. In this paper, we show compelling data suggesting that a plasmid-encoded outer membrane 58 kDa protein termed aggregative protein 58 (Ap58) produced by EAEC O111:H12 strains, is associated with the adherence capabilities and haemagglutination of animal red blood cells. This conclusion is supported by several lines of evidence: (i) adherent O111:H12 strains are able to produce Ap58; (ii) non-adherent O111:H12 strains are unable to produce Ap58; (iii) antibodies raised against Ap58 inhibited adherence and haemagglutination of epithelial and bovine red blood cells, respectively; (iv) a non-adherent E. coli K-12 host strain containing the ap58 gene determinant on plasmid pVM15 displayed abundant adherence to cultured HEp-2 cells; and (v) the purified Ap58 bound specifically to HEp-2 and bovine red blood cells. Our findings indicate that the aggregative adherence in the O111:H12 strains may be also mediated by non-fimbrial adhesins. We believe our data contribute to the understanding of the adherence mechanisms of these organisms.

Involvement of a Sialic Acid-Binding Lectin with Hemagglutination and Hydrophobicity of Flavobacterium psychrophilum

Abstract: Strains of Flavobacterium psychrophilum were studied for their ability to adhere and cause agglutination of erythrocytes and yeast cells. Strains of the serotype Th showed low or no hemagglutinating (HA) properties toward human, avian, bovine, and rainbow trout erythrocytes, whereas strains of serotype Fd and FpT exhibited distinct HA properties. None of the strains was able to cause agglutination of yeast cells. Greater adherence specificity toward rainbow trout blood cells was seen for the HA-positive strains. Growth at 5°C, compared to that at 15°C, induced an increase in the hemagglutination of some strains. HA activities of F. psychrophilum were inhibited only by sialic acid (N-acetyl-neuraminic acid), heat treatment at 65°C, and proteinase K treatment and not by any of seven other carbohydrates, periodate oxidation, or treatment with trypsin. The supernatant from washed bacterial cells also showed some HA properties. All strains were shown to be highly hydrophobic by the hydrophobic interaction chromatography test, although some contradictions to the results of the salt aggregation test (showing some strains as less hydrophobic) were seen. These results indicate that the aggregation of F. psychrophilum and erythrocytes depend on a lectin present on the surface of HA-positive F. psychrophilum strains and absent on HA-negative strains. This lectin reacts specifically with sialic acid. The adhesion differences observed for F. psychrophilum strains do not appear to correlate with the virulence but still provide insights into the interaction of F. psychrophilum and rainbow trout.

Chagas' disease diagnosis: comparative analysis of recombinant ELISA with conventional ELISA and the haemagglutination test.

Abstract: Background and Objectives Serological screening for Chagas’ disease in the blood banks of South America is carried out by using two different assays that generally show a high number of inconclusive results. To establish a combination of two tests that can minimize the number of inconclusive results, we compared a recombinant enzyme-linked immunosorbent assay (ELISA) with two conventional tests. Materials and Methods Serum samples from chagasic patients (n = 112), from non-chagasic individuals (n = 143) and from patients with other diseases (n = 32) were tested using three assays: recombinant ELISA (Rec-ELISA); conventional ELISA (Con-ELISA); and the indirect haemagglutination (IHA) test. Results When we evaluated the data by matching the Rec-ELISA and the IHA test, 52 inconclusive results were obtained. When Rec-ELISA and Con-ELISA were matched, only four inconclusive results were observed. Conclusions Our investigation indicates that the use of two ELISAs with different antigen preparations provides an effective test combination for blood bank screening of Chagas’ disease.

Identification of a 19.3-kDa protein in mrha-positive Edwardsiella tarda: putative fimbrial major subunit

Abstract: The hemagglutinating properties of Edwardsiella tarda isolated from fish were investigated. Hemagglutination of E. tarda was not inhibited by D-mannose but was strongly inhibited by fetuin and N-acetylneuraminic acid. Extraction of hemagglutinating activity from bacterial cells was achieved using n-octyl-beta-D-thioglucoside (NOTG), and the NOTG extracts were fractionated by sucrose density gradient ultracentrifugation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the fractions revealed that a 19.3-kDa protein band appeared in the fractions exhibiting highest hemagglutinating activity. In an immunoblot analysis of NOTG extracts from 18 strains of E. tarda, the 19.3-kDa protein was detected only in the extracts possessing hemagglutinating activity. The predicted amino acid sequence of a 534-bp gene encoding the 19.3-kDa protein was identical to fimbrial subunit (FimA) of E. tarda by FASTA homology search. These findings suggest that fimbriae are implicated in the hemagglutination of E. tarda.

Purification and characterization of a sialic acid specific lectin from the hemolymph of the freshwater crab Paratelphusa jacquemontii.

Abstract: A naturally occurring hemagglutinin was detected in the serum of the freshwater crab, Paratelphusa jacquemontii (Rathbun). Hemagglutination activity with different mammalian erythrocytes suggested a strong affinity of the serum agglutinin for horse and rabbit erythrocytes. The most potent inhibitor of hemagglutination proved to be bovine submaxillary mucin. The lectin was purified by affinity chromatography using bovine submaxillary mucin-coupled agarose. The molecular mass of the purified lectin was 34 kDa as determined by SDS/PAGE. The hemagglutination of purified lectin was inhibited by N-acetylneuraminic acid but not by N-glycolylneuraminic acid, even at a concentration of 100 mm. Bovine submaxillary mucin, which contains mainly 9-O-acetyl- and 8,9 di-O-acety-N-acetyl neuraminic acid was the most potent inhibitor of the lectin. Sialidase treatment and de-O-acetylation of bovine submaxillary mucin abolished its inhibitory capacity completely. Also, asialo-rabbit erythrocytes lost there binding specificity towards the lectin. The findings indicated an O-acetyl neuraminic acid specificity of the lectin.

Whole-Blood Agglutination Assay for On-Site Detection of Human Immunodeficiency Virus Infection

Abstract: Simple and rapid diagnostic tests are needed to curtail human immunodeficiency virus (HIV) infection, especially in the developing and underdeveloped nations of the world. The visible-agglutination assay for the detection of HIV with the naked eye (NEVA HIV, which represents naked eye visible-agglutination assay for HIV) is a hemagglutination-based test for the detection of antibodies to HIV in whole blood. The NEVA HIV reagent is a cocktail of highly stable recombinant bifunctional antibody fusion proteins with HIV antigens which can be produced in large quantities with a high degree of purity. The test procedure involves mixing of one drop of the NEVA HIV reagent with one drop of blood sample on a glass slide. The presence of anti-HIV antibodies in the blood sample leads to clumping of erythrocytes (agglutination) that can be seen with the naked eye. Evaluation with commercially available panels of sera and clinical samples has shown that the performance of NEVA HIV is comparable to those of U.S. and European Food and Drug Administration-approved rapid as well as enzyme-linked immunosorbent assay kits. The test detects antibodies to both HIV type 1 (HIV-1) and HIV-2 in a single spot and gives results in less than 5 min. The test was developed by keeping in mind the practical constraints of testing in less developed countries and thus is completely instrument-free, requiring no infrastructure or even electricity. Because the test is extremely rapid, requires no sample preparation, and is simple enough to be performed by a semiskilled technician in any remote area, NEVA HIV is a test for the hard-to-reach populations of the world.

Uropathogenic Escherichia coli--a preliminary study.

Abstract: Urinary isolates of Escherichia coli were studied for presence of haemolysin, adhesins, serum resistance and O serotype prevalence. Of the 144 isolates studied, 72 exhibited hemolysin, 7 were resistant to bactericidal effect of serum and 50 strains showed Mannose resistant Haemagglutination (MRHA). O101,O68,O04 and O25 were the commonest serotypes in this study.

Haemagglutinating activity of canine parvovirus

Abstract: Haemagglutination is an important characteristic of non-defective parvovirus. The HA test is simple, convenient and comparatively more accurate. The present study was aimed to standardize the HA test using erythrocytes of different species, and to analyze the effect of different incubation temperatures, buffers and pH on the HA reaction. The porcine erythrocytes when used at an incubation temperature of 4oC gave best results. Highest HA titer was obtained using PBS, PBSS and PBS with 0.1 % BSA as diluent in the pH range of 4-6. Also its specificity was ascertained by haemagglutination inhibition test and a HI titer of 3120 was obtained. Using the standardized reagents, HA test was used to detect CPV in the fecal samples from clinical cases and experimentally infected pup.

A cost-effective particle agglutination assay to detect viral antibodies in dried blood spots: a simple solution to HIV and HCV screening

Abstract: Objectives: To conduct a serological survey of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) in Gabon and Ga-Rankuwa South Africa. A secondary objective was to test a novel simple inexpensive agglutination assay for anti-HIV IgG and anti-HCV IgG from blood samples stored as sports dried onto filter paper. Design: Blood from heel pricks was dried onto filter paper and stored. Blood was eluted from the spots and serum antibody was then assayed using a modified agglutination assay -- blood was added to gelatin agglutination beads that had been sensitised with viral antigen. A positive result showed as an agglutination pattern while a negative result appeared as a tight bead. Subject: This was a hospital-based study involving 271 neonates at Ga-Rankuwa Hospital South Africa and 856 patients ranging in age from three months to over 50 years who attended clinics in Gabon. Results: Seroprevalence to HIV was determined in Ga-Rankuwa to be just under 14% (13.8%). Antibodies to HCV were not detected. In Gabon the prevalence to HIV was just under 1% (0.82%) with a relatively high incidence of HCV nearing 4% (3.79%). Conclusion: The sensitivity of the agglutination assay compared favourably to enzyme immune assay (ELA) with respect to sensitivity simplicity and cost. This assay may be useful in sero-epidemiological assays in developing countries. (authors)

Isolamento do vírus Parainfluenza bovino tipo 3 no Rio Grande do Sul, Brasil

Abstract: The isolation of bovine parainfluenza virus type 3 (bPI-3) from a case of mild respiratory disease in a calf is described. Identification was carried out by virus isolation in cell cultures and confirmed by hemagglutination, hemagglutination inhibition, hemadsorbtion and direct imunofluorescence. This is the first report on the isolation of bPI-3 in Rio Grande do Sul, Brazil.

Establishment of human heterohybridoma and lymphoblastoid cell lines specific for the Rh D and C antigens.

Abstract: Human monoclonal antibodies specific for the D antigen of the Rh system are valuable tools for blood group typing and prevention of erythroblastosis. In this study, peripheral blood lymphocytes obtained from an Rh-negative woman immunized with Rh-positive fetuses were immortalized with Epstein-Barr virus (EBV), and transformed lymphoblastoid cell lines (LCLs) secreting antibodies to Rh antigens were generated. The presence of specific antibody was assessed by direct haemagglutination using Rh-positive, papain-treated red blood cells (RBCs), and the production of human antibody was assayed by enzyme-linked immunosorbent assay (ELISA). Specificities of the antibodies were determined by a panel of RBCs of known Rh phenotypes. Five LCLs produced antibody specific for the D antigen, and one LCL showed specificity towards the C antigen of the Rh blood group system. High-titre anti-Rh antibody-producing LCLs were subsequently selected and fused with a human x mouse heteromyeloma cell line. A hybridoma line producing human antibody of the immunoglobulin M (IgM) isotype, which strongly reacted with the D antigen, was established. The hybridoma was cloned, and the monoclone has been stable for growth and antibody production during 8 months of continuous culture, with a mean antibody concentration of 11.5 microg mL-1 and haemagglutination titre of 1/20 480. This antibody was not able to agglutinate a sample of native weak D RBCs (Du); however, agglutination was achieved with papain-treated Du RBCs. Immunoprecipitation of the D antigen by this antibody, followed by Western blot analysis, did not reveal any immobilized D-specific polypeptide. As this human antibody readily agglutinates D+ RBCs in saline, it has the potential to be used as an efficient reagent in routine blood group typing.

Inhibition of Helicobacter pylori adhesion by acidic polysaccharide isolated from Artemisia capillaris

Abstract: Helicobacter pylori specifically adhere to host cells through a number of putative receptors and ligands, mainly based on carbohydrate-protein interactions. Polysaccharide fractions isolated from the leaves of Artemisia capillaris showed different inhibitory activities against H. pylori adhesion by using hemagglutination assay. Among these fractions, an acidic polysaccharide fraction F1A showed highly effective inhibitory activity, and its minimum inhibition concentration was 0.63 mg/ml. The inhibition results by the hemagglutination assay were consistent with those obtained by the enzyme- linked glycosorbent assay, which was developed by the conjugation of horseradish peroxidase with fetuin, a sialic acid-containing glycoprotein which was specific to H. pylori adhesion. F1A contained the highest carbohydrate content among polysaccharide fractions, and no protein was detectable when further purified by gel filtration FPLC. Sugar composition analysis using GC revealed the highest amount of galacturonic acid among sugars, which suggests that F1A contains essentially acidic polysaccharides. Our data suggest that acidic polysaccharides may play an important role in the inhibition of H. pylori adhesion to host cells.

Tuberculosis altering erythrocyte membrane topology - a lectin haemagglutination study

Abstract: Background: A factor of great importance in the inflammatory process is the physical interaction between the circulating cells and the blood vessel endothelium. This critical association is mediated by an array of cellsurface adhesion molecules.Glycoconjugates play important roles in cellular functions such as antigen presentation and cell adhesion which may be modulated in patients with lung disease due to alteration in cell membrane glycoproteins. Methods: Because carbohydrate residues can be recognized by specific lectins, Pedilanthus tithymaloides agglutinin-lectin(PTA-lectin) haemagglutination titres obtained from patients were compared with the PTAlectin binding properties of erythrocytes from healthy volunteers. Results: Haemagglutination titres from tuberculosis patients were significantly higher than healthy subjects. Compared with untreated patients, the treated patients showed statistically significant shifting of the final titres towards values in healthy persons. Our finding shows that in tuberculosis, pathologically altered erythrocytes membrane determinants differ from the normal cell membrane determinants, in their carbohydrate contents, as reflected by haemagglutination titre against galactose specific PTA-lectin. Conclusion: Altered expression of surface carbohydrate residues of erythrocytes caused by the inflammatory process in tuberculosis may be due to either the unmasking of galactose residues, non-enzymatic glycosylation, absorption of bacterial polysaccharides on erythrocyte membrane or the effect of toxins from the tubercle bacillus.

The Determination of Human-ABO Blood Groups in Captive Cynomolgus Macaques (Macaca fascicularis)

Abstract: In human, we can determine the ABO blood group by hemagglutination of red blood cell (RBC) with anti-A and anti-B antibodies due to the expression of antigen A/B on the surface of RBC. However, in non-human primate, except for apes, the RBC does not express the antigen A/B on the surface, but synthesize and secrete the antibody A/B into the serum. Therefore, in order to determine the human-ABO blood type in non- human primate, the agglutination of human A and/or B red blood cells with the antibody in monkey sera under the light microscope is observed. In this study, the aim is to determine the human-ABO blood groups in cynomolgus macaques (Macaca fascicularis), one species among other non- human primates that do not express antigen A/B on the RBC surface. Seventy-two cynomolgus macaques (8->20 years old) reared at the Primate Research Unit, Faculty of Science, Chulalongkorn University, were used. The result showed that the ratio of O:A:B:AB of ABO blood group was 1.0:1.2:3.5:1.5 in 43 female monkeys, 1.0:1.6:6.0:1.0 in 29 male monkeys, and 1.0:1.3:4.3:1.3 in all monkeys. From this study, it can be concluded that most of cynomolgus macaques in our laboratory have type-B blood group.

Diagnosis of canine parvovirus by rapid immunomigration on a membrane.

Abstract: Rapid immunomigration on a membrane was applied to the diagnosis of canine parvovirus (CPV) in 128 samples of faeces containing four strains of parvovirus (two CPV-2a strains, including one vaccine strain, and two CPV-2b strains). The results were compared with the results of haemagglutination and ELISA sandwich techniques. The new test was quick and easy to use, and made it possible to identify both the CPV-2a and CPV-2b strains. Its detection thresholds per gram of faeces corresponded to specific haemagglutination titres of between 320 and 640 and a virus titre of between 10(4) and 10(5) CCID50 (dose required to infect 50 per cent of cell cultures).

Resistance to Isatia indigotica Fort Lectin Inhibit Influenza Virus

Abstract: The Isatia indigotica Fort lectin is a bioative nonimmune proteinThe lectin extracted from Isatia indigotica Fort rootsThe lectin^s hemagglutination activity was tested to estimate the role of inhibition on influence virus(A_(1)/Jing Fang/97-53H_(1)N_(1) and A_(1)/Jing Fang/262/95)The results showed that the lectin(453mg/mL)had a function of remarkable killing,treatment and prevention influenza virus,and the hemagglutination activity of the lectin in different breeds had a remarkable difference in inhibition on influenza virus,and the hemagglutination activity of the lectin was in proportin to inhibition on influenza virus

Hemagglutination and antigenic comparison of rabbit hemorrhagic disease virus.

Abstract: The hemagglutinating activity and serological properties of three strains of rabbit hemorrhagic disease virus, Chinese, Korean and Shizuoka, which was first isolated in Japan, were examined by hemagglutination (HA) and cross hemagglutination inhibition (HI) test with human erythrocytes. Similar results were observed between the Chinese and Korean strains, both of which gave positive HA at 4 degrees C with O, A, B and AB, and at 22 degrees C with B and AB blood groups. In the Shizuoka strain, positive HA was observed at 4 degrees C with O, A, B and AB, at 22 degrees C with A, B And AB, and at 37 degrees C with B blood group. In experimentally infected rabbits, HI antibody in these animals showed a titer of 16,384 or 32,768 at 4 weeks after inoculation. No serological difference was observed in three strains by cross HI test.

Patterns and Properties of Haemagglutinins Expressed by Shigella Serogroups in Lagos, Nigeria

Abstract: Forty-five strains of Shigella were screened for haemagglutinin production and broad-spectrum haemagglutination reaction. Mannose-sensitive haemagglutinin (MSHA) was found in 22 strains [Shigella flexneri (7), S. dysenteriae (7), S. sonnei (3), and S. boydii (5)]. Eighteen strains harboured mannose-resistant haemagglutinin (MRHA), and 8 strains were observed to be non-haemagglutinating to guinea pig erythrocyte. With the exception of human erythrocytes (O, A, B, and AB), the observed MSHA and MRHA also agglutinated the erythrocytes of rabbit, sheep, rat, chicken, and horse, suggesting a broad-spectrum haemagglutinating property. Haemagglutinins of S. flexneri and S. dysenteriae elicited a relatively stronger haemagglutinating activity with agglutinability to chicken and rabbit erythrocytes enhanced by trypsinization. Haemagglutination reaction with guinea pig erythrocyte was generally inhibited by sialic acid, while simple sugars, such as D-glucose, D-galactose, N-acetylgalactosamine, N-acetylglucosamine, and D-rhamnose, elicited no inhibitory effect. The results of the study revealed broad-spectrum haemagglutinin expression by circulating Shigella strains in Nigeria.

The Effects of Newcastle Disease Virus (NDV) On Breast Cancer Cell Lines

Abstract: Three Newcastle disease virus (NDV) isolates namely; F, Ijuk and 0l/C were tested for their anticancer properties against two breast cancer cell lines, MCF-7 and MDA-MB-231. Each virus strain was propagated in 10-day old embryonated eggs. Purification was carried out by density gradient centrifugation using sucrose. The titer of each virus strain was determined by hemagglutination (HA) test. Screening of NDV strains for anticancer properties on breast cancer cells was performed by a colorimetric cytotoxic assay using tetrazolium salt (MTT). F strain displayed cytotoxic activity on both breast cancer cells with an IC50 value of 8 HAU for MDA-MB-231 cells and 2048 HAU for MCF-7 cells. Meanwhile Ijuk showed cytotoxic activity against MDA-MB-231 cells only with an IC50 value of 8.6 HAD. Strain 01/C did not exhibit any cytotoxic activity towards both breast cancer cells. Inactivation of the virus at 100°C for 30 minutes destroyed its ability to kill the breast cancer cells. Positive control experiment involved treatment of the cells with tamoxifen, an estrogenic antagonist agent. Negative control experiment was carried out by infecting the virus onto normal mouse fibroblasts (3T3 cell). No cytotoxic activity was observed on 3T3 cells following infection at low virus titer. However, infection at higher virus titer resulted in 50% inhibition of cell growth. Infection of the virus displayed clear evidence of apoptosis which was detected as a ladder-like pattern on agarose gel electrophoresis. This was further confirmed by TEM which provided ultrastructural changes of the infected cells. The role of sialic acid receptor was also studied based on neuraminidase (NA) and sialyllactose (SLL) treatment. Treatment of the cells with NA did not destroy the ability of the virus to cause apoptosis. Meanwhile a reduction in the ability of the virus to cause apoptosis was observed in the treatment of SLL. However there was no significant difference between the SLL-treated virus (27.05%) and untreated virus (30.87%). Based on the results obtained, this study showed that NDV strains, F and ljuk have the potential to be developed as an anticancer agent. Mechanisms by which the virus infects and kills the cells need further studies. The role of sialic acid receptors in NDV-induced oncolytic effects requires further studies.

Analysis on the aetiology of influenza in children in Tianjin

Abstract: OBJECTIVE To analyse the pathogen of child patients with influenza in Tianjin area. METHODS The influenza virus isolation was performed by MDCK cells and embryonated eggs. The identification of the isolates was carried out with hemagglutination (HA) and hemagglutination inhibition (HI) tests. RESULTS Two hundred and thirty-eight throat swab specimens from children with influenza-like illness were collected in Tianjin area from Oct. 2001 to Mar. 2002 and 64 strains (26.9%) of influenza virus were isolated. Data showed that there were 42 strains (65.6%) of A (H3N2) subtype, 13 strains (20.3%) of A (H1N1) subtype and 9 strains (14.1%) of B type in these positive isolates. All the isolated viruses grew very well in MDCK cells and hemagglutinated with human "O" red blood cells, and most (62/64 strains) of them were able to multiply in embryonated chick eggs. However, there were only 3 isolates with HA positive in inoculating embryonated eggs with the specimens. Meanwhile, it was revealed that out of 55 strains of A type viruses, 53 strains (96.4%) were from O to D phase, 2 strain of A (H3N2) were D phase characters and all B type isolated viruses being D phase properties. CONCLUSION There were three endemic types of influenza viruses-A (H3N2), A (H1N1) and B type in Tianjin area, with A, the main type.

Characteristics of the pathogenic isolates from the SARS patients in Guangzhou

Abstract: To investigate the pathogenic isolates from clinical specimens of the SARS patient. Throat swabs, throat washings and autopsy tissues collected from the SARS patients were inoculated into cell lines of HL、MDCK and Hep 2 for culture under 37℃ and 34℃. The specimens and the culture medium of the cell with cytopathic effect also inoculated into the amniotic and allantoid cavities of 9-day-old embryonated eggs. The urines and amnia fluids collected 3 days later to undergo hemagglutination test(HA) with 1% chicken, 0.75% guinea pig red blood cells, human “O” type red blood cell and the partridge red blood cells. The cells with cytopathic effect were tested through absorbed test with 0.2% guinea pig red blood cells. Immunofluorenscent stain was performed to test the antibody of the patient's convalescent phase serum. The lung tissues from the SARS bodies were examined by the electronic microscope and the isolated pathogen were identified through RT-PCR.

Analysis of Factors Affecting the Hemagglutination and Hemagglutination-inhibition Test for Detection of Antibody to Rabbit Hemorrhagic Disease Virus

Abstract: Objective\ To explore the factors that affect the hemagglutination and hemagglutination\|inhibition test. Method\ Hemagglutination and hemagglutination\|inhibition test in different dilution and different serum treatments and 7 kind of reactive plates were compared. Result\ The test condition of clear image, regular and stable result was obtained. Conclusion\ The results provided some experimental data for fine instructions of the national standard.

A passive haemagglutination test for rabies antibodies using rabies glycoprotein coupled erythrocytes.

Abstract: The presently recommended tests for assaying rabies antibodies like mouse neutralization test (MINT) and rapid fluorescent focus inhibition test (RFFIT) are either time consuming or expensive and are generally performed in reference laboratories. There is a need to develop a specific and rapid method for detection of rabies antibodies that can be used to monitor sero-conversion after pre-or post-exposure vaccination. In this study, we have developed a passive haemagglutination (PHA) using purified rabies virus glycoprotein coupled to sheep erythrocytes using chromium chloride (0.04%) as a coupling agent. Two hundred and fifty five serum samples from people vaccinated with different rabies vaccines, 16 paired serum and CSF samples from autopsy confirmed cases of paralytic rabies, and serum samples from 65 normal healthy controls were tested and evaluated in comparison to standard MNT. Among the vaccinees, 250 samples were positive both by MNT and PHA but 5 samples were negative by PHA and positive by MNT. The titres obtained by PHA were lower compared to MNT, but there was significant correlation between the two (r=0.885). The specificity of the test was 99.7% and sensitivity was 100% as compared to MNT. Thus this PHA test promises to be a rapid and specific test for assaying rabies antibodies and may be useful in screening large number of serum samples for sero conversion after vaccination. It may also assist in rapid laboratory confirmation of paralytic rabies cases, based on detection of antibodies in CSF and serum.