Simplified method for the rubella haemagglutination inhibition screening test.

A modification of the rubella haemagglutination inhibition (HAI) test in which both pretreatment and serum titration are carried out in wells of the same microtitre plate saves time, labour, and materials and gives results comparable to a conventional HAI procedure.     

Anti-immunoglobulin G in the haemagglutination inhibition test for Newcastle disease virus antibody assays

The effect of incorporation of species-specific anti-immunoglobulin G (anti-IgG) antisera into the haemagglutination-inhibition (HI) test for antibodies to Newcastle disease viruses (NDV) was investigated. Experiments were made on the specificity of the rise in titre and on the reproducibility of results, and routine examinations of sera were carried out. A special object was to scrutinize the specificity of low titres in conventional tests and to investigate the possibility of eliciting measurable titres from sera negative by conventional methods by adding anti-IgG. Despite the good accuracy and the acceptable reproducibility of the anti-immunoglobulin G haemagglutination-inhibition test, only 66% of sera positive in conventional haemagglutination-inhibition test yielded a rise of titres. Neither age nor 2-mercaptoethanol-sensitivity of haemagglutination-inhibiting antibodies seemed to be responsible for this property. A possible reason why not every serum that is positive in the normal test shows an increase in titre might be the physico-chemical properties of avian antiviral sera or immunoglobulins. The findings did not achieve the expectations mentioned earlier. If it were possible, however, to determine the reasons for the differences in the behaviour of NDV-antisera, the anti-IgG test could be of value in the understanding of the HI-test and for the further study of Newcastle disease serology.     

Some observations on the value of the infectious bronchitis haemagglutination inhibition test in the field

The response of commercial broilers vaccinated against infectious bronchitis (IB) in a conventional manner was examined by the IB haemagglutination inhibition (HI) test and correlated with the clinical picture. On this basis, differences in serum titres were observed which were significant in the diagnosis of clinical disease. Results in vaccinated broiler breeders indicated similar differences in titre patterns which were related to the clinical history of the flock, but some evidence of titre variation due to cycling of vaccine virus in the flocks made interpretation more difficult. The test is a rapid and simple serological aid to diagnosis of IB.     

Use of formalinized human cord blood erythrocytes in the haemagglutination inhibition test for rubella

The use of formalinized human cord blood erythrocytes in the haemagglutination inhibition test for rubella is proposed. These cells retain their sensitivity to rubella virus haemagglutinin for several months and give serum titres comparable with those obtained with fresh cord blood erythrocytes.     

Avian mycoplasmosis: Comparative study of the plate agglutination test, haemagglutination inhibition test and metabolic inhibition test for detection of antibody against Mycoplasma gallisepticum

This study was performed with the use of the MG/S6 strain of Mycoplasma gallisepticum, reference sera, sera from vaccinated chickens (given at inactivated vaccine) and sera from infected turkeys in the field. Titres of antibody detected were well correlated for the three tests. However, the plate agglutination test (PAT) allowed the earliest detection, and metabolic inhibition test (MIT) was as sensitive and specific as the haemagglutination inhibition test (HIT). MIT allowed a good repeatability of results, and discriminated very well between positive and negative sera. Serological studies with MIT using a constant dilution of sera gave results comparable with titration by MIT, with a valuable saving of time and material. PAT was found to be one of the best techniques for mass serological screening. Results with MIT and HIT confirmed the PAT results, but MIT was more easily interpreted, particularly with sera taken during the late phase of antibody decrease.     

Procedures for the haemagglutination and the haemagglutination inhibition tests for avian infectious bronchitis virus

Various aspects of production, storage and stability of the haemagglutination (HA) activity of infectious bronchitis virus (IBV) were studied. From the results obtained, a standard procedure for the production of IBV, HA and the HA and haemagglutination inhibition (HI) tests is suggested. The main points of the suggested procedure are: (1) the virus should be concentrated but not purified; (2) the virus should be treated with phospho-lipase C type 1 (PLC), at a final concentration of one unit/ml, for two hours at 37 degrees C; (3) the virus should be stored at 4 degrees C after PLC treatment; (4) HA and HI test plates should be kept at 4 degrees C and read 45-60 min after the addition of chicken red blood cells. Using the recommended standard procedure the HA and HI tests for IBV were as reproducible as the HA and HI tests for Newcastle disease virus.     

Comparison of the haemagglutination inhibition test and the serum neutralisation test in tracheal organ cultures for typing infectious bronchitis virus strains

Five strains of infectious bronchitis (IB) virus, which had been compared antigenically by the serum neutralisation (SN) test in tracheal organ cultures (OC), were arbitarily coded and then compared by the haemagglutination inhibition (HI) test. Their antigenic relationships were found to be similar by the two methods but, because of the high and variable cross reactions found in the HI test, the differences between the strains were less clear by that method. It was concluded that the HI test, in its present state of development, is considerably less type-specific than the SN test in OC, and cannot be recommended for defining antigenic relationships between strains of IB virus. However, it retains its value for diagnosing IB or for monitoring the vaccinal status of flocks.     

Preliminary evaluation of the haemagglutination and haemagglutination inhibition tests for avian infectious bronchitis virus

Four of the 9 strains of infectious bronchitis virus which were concentrated and treated with phospholipase C type 1 showed haemagglutination activity. These strains, Holte, Massachusetts 41 (M41), H120 and Connecticut, were distinguishable by the haemagglutination inhibition (HI) test but showed much closer relationships than could be detected by the plaque reduction (PR) test. The four haemagglutinating strains were used to compare the HI and PR titres of 17 anti sera prepared against reference and field virus strains. In most cases titres were similar although there was a tendency for the HI titres to be higher than the PR titres especially with M41 antigen. HI titrations of the pooled sera from 20 birds infected with M41 showed a peak of activity at 14 days after infection which was not detected by serum neutralisation or complement fixation tests. HI titres of individual sera from birds infected 21 days previously with M41 virus compared favourably with serum neutralisation titres but showed little relationship to the complement fixation titres.     

Rapid slide haemagglutination test in urinary candidiasis

Quick diagnosis of urinary candidiasis was done by rapid slide haemagglutination test (SHA) and its efficacy was compared with countercurrent immunoelectrophoresis. This method was found to be much easier, less time consuming and an economical technique. Sera of 50 patients with urinary candidiasis were included for the present study and 50 control cases were also taken. The present study revealed that SHA test was more sensitive and specific than Countercurrent immunoelectrophoresis (the percentage of positive cases being 68% and 56% respectively).     

Modification of the indirect haemagglutination test for amoebiasis

Optimal conditions for carrying out the indirect haemagglutination test with sheep erythrocytes were studied using the microtitre system. The age of the erythrocytes, concentration of reagents, time and temperature of tanning, sensitization, and incubation are described with reference to replication of titres. Sera from patients with amoebic colitis were used to evaluate the test conditions.     

A haemagglutination test for staphylococcal anti-leucocidin

A haemagglutination test using tanned erythrocytes sensitized with the fast and slow moving components of the Panton-Valentine staphylococcal leucocidin is described. From the results obtained it is suggested that this test could be useful in the diagnosis of deep-seated staphylococcal lesions.     

Plasminogen assay by a haemagglutination inhibition technique

Formaldehyde or gluteraldehyde cells treated with tannic acid were coated with plasminogen. These cells are agglutinated by plasminogen antiserum and this reaction can be quantitatively inhibited by purified plasminogen, plasma, and euglobulin. Correlation between this haemagglutination assay and a caseinolytic method is good. The sensitivity of the technique is high and compares favourably with other immunological methods and is approximately 10 times more sensitive than caseinolytic assays. The merits of this type of assay are discussed.     

Sensitized chick cells in the indirect haemagglutination test for echinococcosis

An indirect haemagglutination (IHA) test was performed with chick red blood cells (RBC) on sera from 26 confirmed cases of echinococcosis and 45 control sera. The results were compared with those obtained in an IHA test with sheep RBC on the same batches of sera; both tests were equally sensitive. The chick cells settled quickly and the results could be determined within 30-45 min. Heterophilic antigen was not a problem. This study also showed that chick cells stabilised by the double-aldehyde method, could be sensitised with the antigen and then stored at 4 degrees C for up to 31 days before use in the IHA test without loss of sensitivity. The use of sensitised double-aldehyde stabilised (DAS) chick cells in IHA tests provides a rapid diagnostic test in echinococcosis.     

The value of complement fixation and haemagglutination inhibition tests in the diagnosis of influenza A.

Antibody response of 133 influenza A patients from three outbreaks since 1972-73 was analyzed by complement fixation (CF) and haemagglutination inhibition (HI) methods. During the first outbreak, a significant response was more often measured by CF than by HI. During the last outbreak HI appeared more useful than CF for routine serological diagnosis; 23% of cases verified by HI were missed by CF. The poor response of CF antibodies was associated with the high level of pre-infection antibodies.     

Comparison of enzyme-linked immunosorbent assay and haemagglutination inhibition test for the detection of Newcastle disease virus antibodies in human sera.

A comparison of haemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA) techniques for the detection of antibodies against Newcastle disease virus in sera from persons working in poultry farms and veterinary vaccine institutes and from the general population revealed that 22% more sera were positive by ELISA compared to HI. No samples were negative by ELISA but positive by HI. While HI titres of positive sera were found in the range 8-64, ELISA titres were between 16 and 512. It was interesting that though 78% sera had concordant results by the two tests, titres obtained by ELISA were nearly six times higher than those by HI.