Hemagglutinin Inhibition Test Research Articles

Humoral Response to Influenza Vaccination in HIV-Infected Patients

Objective: To assess the humoral response in HIV-infected adults immunised against influenza in Poland in the epidemic season 1997/98. Patients and Methods: The study was carried out in 34 HIV-infected patients in different stages of the disease, vaccinated with a single 0.5ml dose of subunit vaccine (‘Influvac’, Solvay Pharmaceuticals BV). Antihaemagglutinin (HI) antibody levels were measured by the haemagglutinin inhibition test before immunisation and then after one and six months. Results: One month after vaccination HI antibody titres significantly increased from 1.5 to 5.5 times. After six months HI antibody levels were higher than those before vaccination and also higher than those determined one month after vaccination. Before immunisation the number of patients with HI antibody titres ≥l:40 ranged from 2.9 to 50%. After vaccination, protection rates increased and ranged from 17.6 to 79.4% one month after vaccination, and from 20.6 to 82.4% six months after vaccination. Response rate values remained at similar levels during the whole study and were between 9.4 and 14.7%. No statistically significant differences were found in humoral response between patients with different CD4 counts nor between AIDS patients and those not suffering from AIDS. Significantly higher antibody titres were recorded during the whole study for the A/Wuhan/359/95 (H3N2) influenza strain than for the A(H1N1) and B strains. Conclusions: The results of this study indicated that in HIV-infected patients humoral response to influenza vaccination was poor compared with healthy people. However, in some HIV-infected patients the vaccine induced the production of HI antibodies in titres that were considered high enough to protect against the infection.

Immunogenicity of subunit trivalent influenza vaccine in children with acute lymphoblastic leukemia.

The aim of this study was to assess humoral response to influenza vaccine in children with acute lymphoblastic leukemia. Studies were performed in 25 patients previously vaccinated against influenza (Group A) and in 20 children who had never been immunized before (Group B). In Autumn, 1996, they were vaccinated with subunit trivalent influenza vaccine containing 15 microg of hemagglutinin of A/Singapore/6/86, A/Wuhan/359/95 and B/Beijing(184/93. Antihemagglutinin (HI) and antineuraminidase antibody titers were determined before immunization and 3 weeks and 6 months after vaccination by the hemagglutinin inhibition test and the neuraminidase inhibition test. All results were presented as the geometric mean titer of antibodies, mean fold increase of antibody titer, protection rate and response rate. In Group A mean fold increase of HI antibodies ranged from 17.2 to 26.7 three weeks after vaccination and from 22.1 to 38.2 six months after vaccination, while in Group B it ranged from 15.7 to 22.6 and from 30.3 to 39.3, respectively. In the case of neuraminidase, mean fold increases for Group A varied from 9.2 to 13.2 three weeks after immunization and from 15.6 to 21.1 six months after vaccination, whereas for Group B they varied from 5.5 to 8.3 and from 14.4 to 23.4, respectively. Six months after vaccination the proportion of subjects with HI antibodies > or = 1:40, as well as those with at least 4-fold increase of HI antibody titers, ranged from 68 to 100% in Group A and from 90 to 100% in Group B. No vaccinated child was infected with the influenza virus; the vaccine was well-tolerated and did not cause any adverse reactions. The results obtained in this study indicate that influenza vaccine is immunogenic in patients with acute lymphoblastic leukemia, despite their serious disease.

Efficacy of Recombinant Fowl Poxvirus Vaccine in Protecting Chickens against a Highly Pathogenic Mexican-Origin H5N2 Avian Influenza Virus

Internationally and nationally, governments and the poultry industries have used various strategies to control avian influenza (AI), ranging from a minimum of living with mildly pathogenic AI virus (AIV) infections to the other extreme of implementing a total quarantine-slaughter approach for eradication of highly pathogenic (HP) forms of the disease. However, recent economic considerations in various countries have prompted a broader reevaluation of vaccination as one of several tools to be used in AI control programs, including H5 and H7 HP AI. In the current study, 1-day-old chickens were immunized with a recombinant fowl poxvirus vaccine containing a hemagglutinin gene insert (Vector-HA) from an H5 AIV. Vector-HA- and negative control (vector-control)-vaccinated chicks were challenged with a HP H5N2 AIV isolated from chickens in Mexico. All immunized chickens were antibody negative on the agar gel precipitin test, indicating that vaccination would not interfere with routine AI serologic surveillance programs in the United States. However, in the hemagglutinin-inhibition test, a few immunized chickens (8%) had low serologic titers. Protection against illness (90-100%) and death (90-100%) was provided by the vector-HA vaccine from 3 wk of age to the end of the 20-wk study. The number of chickens shedding the challenge AIV from their enteric tracts was significantly reduced (50-75%) and the quantity of challenge AIV shed from respiratory and enteric tracts was significantly reduced (10(1)-10(2.1) mean embryo lethal dose/ml) in most vector-HA vaccine groups when compared with vector-control groups. Furthermore, vector-HA vaccination reduced in contact transmission of HP AI challenge virus to both vector-HA- and vector-control-vaccinated chickens. These findings indicate the recombinant fowl poxvirus vaccine can be a useful tool in an AI control program by preventing illness and death in chickens and reducing intestinal and respiratory shedding of H5 AIV. However, for an AI control program to be successful, enhanced biosecurity and surveillance must be practiced, and the vaccine's use must be controlled by an industry and/or government task force.

Pathogenicity and Diagnosis of H5N2 Mexican Avian Influenza Viruses in Chickens

Chickens were inoculated with one of five H5N2 Mexican-origin avian influenza virus (AIV) isolates to determine their pathogenicity for chickens and to determine the ability of routine virologic and serologic tests to detect infections. In laboratory infections, three AIVs, H5/94, M5/94, and J12/94, produced sporadic illness and death and were categorized as mildly pathogenic. Q1/95 produced illness and death in all inoculated chickens and was categorized as highly lethal and highly pathogenic (HP). P11/94B commonly produced clinical illness, but deaths were infrequent. During the presence of clinical signs, oropharyngeal swabs were superior for isolation of AIV, but cloacal swabs were more successful after disappearance of clinical signs. Agar gel precipitin (AGP) serologic test was superior for detecting AIV infection during the clinical phase, but AGP and hemagglutinin inhibition tests were equally effective in detecting infections after recovery from clinical illness. Passage of P11/94B parent stock and selected 14-day-embryo-passed AIVs in adult hens resulted in emergence of some HP AIV derivatives. The hemagglutinin of Q1/95 and P11/ 94B parent stock and derivative AIVs had an identical proteolytic cleavage site of.... Pro-Gln-Arg-Lys-Arg-Lys-Thr-Arg-Gly, consistent with AIVs of high pathogenicity. However, no consistent differences were identified in the sequence of the hemagglutinin gene to explain the discrepancy in lethality patterns of the P11/94B AIVs. This suggests that genes other than the hemagglutinin impact the full expression of high lethality of Mexican-origin AIV infections in chickens.

Influenza vaccine strain selection: equivalence of two antigenically distinct haemagglutinin variants of 1989 H3N2 influenza A virus in protection of mice

Precise antigenic analysis with haemagglutinin-inhibition (HI) tests of 1989 H3N2 influenza A viruses with polyclonal ferret, rabbit and mouse antisera has shown, first, significant differences among 1989 wild-type isolates, second, antigenic differences between two high-yield vaccine candidate reassortant viruses, third, significant antigenic differences of one reassortant (X-105) from the wild-type virus (A/Guangdong A/39) from which it was derived, and fourth, dependence of antigenic characterization of viruses upon the host species used in immunization. Nevertheless, the two reassortant viruses (only 43% similar by HI test) were equally protective in preventing homovariant or heterovariant infection in either previously unimmunized or infection-primed mice. These results not only confirm the known antigenic heterogeneity of influenza A viruses, but raise questions about the adequacy of current methods of antigenic characterization of influenza viruses and the basis for decisions on vaccine strain selection.

Studies of the pathology of velogenic Newcastle disease: Virus infection in non‐immune and immune birds

The pathology of velogenic viscerotropic Newcastle disease virus infection was compared in 7-and 20-week-old groups of non-immune birds and birds with two levels of immunity as determined by the haemagglutinin inhibition test. In non-immune birds the bursa at 7 and 20 weeks was the only lymphoreticular organ to show sustained reticular and lymphoid cell reactions until death took place. Caecal tonsil and spleen were extensively necrotized on day 4 after contact exposure, and similar changes occurred in lung and proventriculus. There was evidence of lymphoid recovery in birds which survived for 18 days. In immune birds the spleen showed two main responses. The first, acute reticular cell response around the ellipsoids indicated that renewed exposure to antigen was often associated with localized cell degeneration. The second, immunological, reaction was rapid formation of germinal centres which occurred somewhat earlier in 20-week-old birds (4-5 days). Especially from the second week, reticular (dendritic) cell and lymphoid hyperplasia occurred diffusely in the bursal medulla of both age groups although marked atrophy and cellular depletion, probably of physiological origin, was a feature of 20-week-old birds with high antibody levels. In the gastro-intestinal tract, germinal centre formation was most marked in the caecal tonsils at 20 weeks. With the Indonesian ITA strain of ND virus, degenerative and inflammatory changes in the brain were mild in all groups up to day 18 irrespective of immune status.

Immunogenicity of trivalent subunit and split influenza vaccines (1989–90 winter season) in volunteers of different groups of age

Trivalent split or subunit influenza vaccines [A/Shangai/11/87 (H3N2), A/Singapore/6/86 (H1N1) and B/Yamagata/16/88] recommended for the 1989–90 winter season and licensed in Italy, were administered to 149 volunteers of three different age groups (elderly, middle-aged and young). Antibody production was determined in pre- and postvaccination sera by haemagglutinin inhibition test and the results were evaluated as protection and response rates. The split vaccine was more immunogenic than the subunit preparation, especially against the B virus strain. Age had no obvious impact on the degree of responsiveness to vaccination.

Two Doses of Measles Mumps Rubella (MMR) Vaccine

A schedule of two doses of measles mumps rubella vaccine (MMR) at an interval of six weeks was tried in children aged between 12 and 48 months. One hundred percent seroconversion was attained in the measles HI (hemagglutinin inhibition) test, rubella HI test, and mumps ELISA test in both groups of children who received NIH (National Institute of Health, Japan) MMR lot B-30 and Kitasato MMR lot TV-1. The possibility of vaccine failure with one dose of measles vaccine is not negligible [1], and the frequency of vaccine failure increases if three vaccines are combined in the form of MMR. Our observations revealed that a few of the children who had received one dose of MMR remained seronegative with regard to measles HI antibody and rubella HI antibody, and that some of the children remained seronegative with regard to mumps ELISA antibody. A schedule of two doses of MMR was shown to be helpful in reinforcing immunity in children who did not respond satisfactorily to one dose of MMR. We concluded that two doses of MMR are preferable to control measles, mumps and rubella infections.

Specificity of purified protein derivative extracts from ten species of Mycobacteria killed with phenol in the haemagglutination and haemagglutination inhibition test

The specificity of purified protein derivative (PPD) extracts from 10 species of Mycobacteria killed with phenol was evaluated using the haemagglutinin (HA) and haemagglutination inhibition (HI) tests. The HA test showed many cross-reactions with homologous and heterologous antisera. In the HI test, many antisera cross-reacted with most PPD extracts. The PPD extracts from Mycobacterium foruitum and M. smegmatis were the most specific. It was concluded that PPD extracted from unheated bacilli was not sufficiently specific for use in HI tests.

Dengue Haemorrhagic Fever in Cuba. I. Serological confirmation of clinical diagnosis

Serological studies by the haemagglutinin inhibition test to confirm a clinical diagnosis of dengue were done on 406 patients during the dengue 2 epidemic in Cuba in 1981. 49% of the cases were serologically positive; of these 64% was classified as primary and 36% as secondary. The frequency of symptoms is described: the most frequent were fever, headache, malaise and vomiting. Haemorrhagic manifestations predominated significantly in the secondary cases. The white race and female sex were found to predominate in the positive cases.

α-LACTOSE BINDING HEMAGGLUTININS FROM THE ASCIDIANPHALLUSIA MAMILLATA(CUV.)

The carbohydrate binding specificities of Phallusia mamillata anti-rabbit and anti-human (A, B, O) hemagglutinins were determined by hemagglutinin inhibition tests. Both these molecules bind α-lactose, while only anti-HE hemagglutinins bind lactulose. In spite of this difference, absorption experiments did not show two distinct agglutinins for rabbit and human erythrocytes. Since both sugars are oligosaccharides which present a D-galacto-configuration, isolation by affinity chromatography with Sepharose was performed. The D-galactose-eluted fraction, investigated by PAGE and SDS-PAGE, appears to be the more anodal serum glycoprotein which consists of 2 subunits: the larger has a molecular weight of approximately 61-65,000 Daltons and the second one was 4000 Daltons smaller than the first. Gel filtration on Sephadex G 200 suggests that hemagglutinins represent a population of molecules in which the larger molecules (<200,000 Daltons) represent the greatest fraction.

Canine kidney cell line for isolation of respiratory viruses

By means of a continuous canine kidney cell line (MDCK), influenza viruses were rapidly isolated from specimens collected from patients with respiratory disease. The cell line proved more sensitive than either eggs or rhesus monkey cells for currently circulating influenza A and B strains. Influenza viruses caused a distinct cytopathology within 5 days of inoculation if trypsin-ethylenediamine-tetraacetic acid was incorporated into the medium. Sufficient hemagglutinin was produced on the initial tissue culture passage to allow direct identification of isolates by hemagglutinin inhibition tests. A variety of other respiratory viruses replicated in MDCK, and over a 10-month period 211 of 600 specimens (35%) yielded viruses.

Antibody response in non-haemorrhagic smallpox patients

SUMMARYTwo hundred and sixteen sera from 151 patients suffering from smallpox (non-haemorrhagic) were examined for antibody by precipitation in agar gel, by haemagglutinin inhibition (HI), complement fixation (CF) and neutralization tests. Most of the patients were adults and the majority had been vaccinated earlier in life. HI and neutralizing antibodies showed rising titres from the 6th day of illness while the majority showed precipitins and CF antibodies from the 8th day. The results of the precipitation-in-agar-gel tests are in marked contrast to the findings in healthy vaccinated and revaccinated individuals, none of whose sera gave a positive result for antibody by this technique. In unvaccinated patients the antibody response was frequently delayed and the titres lower than those attained by the previously vaccinated patients. There was no exact correlation in antibody titres obtained by the four methods of measurement, HI antibody, in particular, reaching in some cases relatively high titres when other tests showed low titres. It is suggested that with the methods and materials used, a positive precipitation test in agar gel, a CF titre of 1/20 or more and an HI titre of 1/80 or higher in a single specimen of serum would be suggestive of recent smallpox infections. Such a result might be of special value in the retrospective diagnosis of missed cases and in the detection of minimal or subclinical infections.This investigation was supported in part by Public Health Service Grant AI–1632–16 VR from the National Institute of Allergy and Infectious Diseases, by the World Health Organization and by the Marcus T. Reynolds III Fund.

Rubella-neutralizing and haemagglutinin-inhibiting antibodies in children of different ages.

Rubella neutralization and haemagglutinin-inhibition tests were used to determine the incidence of rubella antibodies in the sera of 235 children and adolescents aged 1 month to 20 years. The tests showed good agreement in the detection of rubella antibodies resulting from acute infection. Maternal antibodies became undetectable within six months after birth. The proportion of children possessing rubella antibodies was found to be about 23% by the age of 5 years, rising sharply to 80% in the 6-12 years age group and 83% in the 13-20 years age group. Results indicate that the incidence of rubella infection may be higher in females than in males. The correlation between statements concerning a past history of rubella and immune status was poor, particularly in the older age groups. Any policy for vaccination against rubella must take into account the difficulties of identifying nonimmune persons in a large population.

風疹ウイルスの研究

Cytopathic effect in Vero cultures caused by the two representative laboratory strains of rubella virus was investigated from the point of view whether the CPE is virus specific or not. Serologically, the CPE was neutralized by rubella convalescent patients' sera to high titers whereas no neutralization was observed by various kinds of heterologous virus antisera. Rabbit immune sera prepared in this laboratory against the Vero-grown rubella viruses did not neutralize heterologous viruses covering various groups except HVJ against which the preimmunization rabbit sera were found to be neutralizing, too. Hemagglutinin against goose erythrocytes was produced in the infected Vero cultures. Using this hemagglutinin hemagglutinin-inhibition tests were performed on the rubella patients' paired sera, anti-rubella virus sera obtained from other laboratories and the above-mentioned homologous and heterologous immune sera in parallel tests with BHK-21 produced hemagglutinin. Comparable results were obtained with both HA antigens, so that specificity of the hemagglutinin produced in Vero was acceptable.Neither cytoplasmic nor intranuclear inclusion bodies were found in the hematoxylin-eosin stained preparations of infected Vero cells. No hemadsorption of guinea pig erythrocytes was observed in the infected cultures. No production of hemagglutinin for chicken red blood cells in allantoic fluid occurred after allantoic inoculation of embryonated chicken eggs with the Vero grown viruses. New born mice survived without showing any symptoms after intracerebral inoculation with the agent. Sensitivity to chloroform and RNA type of the agent as determined by IUDR inhibition test of virus growth were also proved. Filtration tests using Millipore membranes gave suggestive results of around 50mμ diameter of particle size of the CPE agents. Rapid inactivation by 1:4000 formalin at 37°C was demonstrated with the Vero grown viruses as tested in Vero cultures for residual infectivity.These results do not contradict the reported properties of rubella virus and can exclude a wide range of heterologous viruses as the CPE-causing agent for Vero cells or as contaminating viruses in the virus stocks tested by us. If follows that the cell line, Vero, can be used as one of the suitable CPE system for rubella virus study.

THE EPIDEMIOLOGY OF LOUPING ILL IN AYRSHIRE: THE FIRST YEAR OF STUDIES IN SHEEP.

1. Following an epizootic of louping ill on certain farms in south-west Ayrshire in 1960, a long-term study of several farms was initiated.2. The flocks on two hirsels of one farm were studied during spring and early summer of 1961. Although only one lamb death was confirmed as due to louping ill, the infection rates in sentinel hoggs on the two hirsels were 50–60. and 11% respectively. The difference between the hirsels is probably attributable to the difference in the amount of tick habitat on them.3. The ewes were bled in March and June and their lambs in June. Haemagglutinin inhibition (HI) and neutralization tests revealed that the HI antibody is much shorter lasting than neutralizing antibody. Many ewes, therefore, had neutralizing but not HI antibody. Otherwise agreement between the tests was good. In March almost all the ewes aged 3 years or more had antibody. Of the gimmers (2-year-olds) about two-thirds on one hirsel and one-third on the other had antibody in March: by June almost all the former and about half of the latter had antibody.4. About two-thirds of the lambs had the same antibody status as their mothers in June and almost all the rest had less antibody than their mothers. Serological evidence suggestive of louping ill without recognizable clinical disease was found in six lambs and a further lamb recovered from clinical disease.5. Revaccination of two-thirds of the flock failed to cause any detectable change in antibody status.6. The epidemiology and pathogenesis are discussed in relation to immunity and infection rates, and to the design of control measures.We are greatly indebted to the late Mr James Murdoch at Dalmellington, Mr John Murdoch at Dalcairnie Farm, and Mr David Murdoch at Knockgray Farm for permission to work on their farms and for all the help they gave us during the study.

Hemagglutinin inhibition with ether-treated antigen as a more sensitive method to measure the immunological response to an Asian influenza virus vaccine.

The appearance of antibodies in the sera of 31 adults receiving a monovalent formalin-inactivated Asian influenza virus vaccine, in August-September 1957, has been studied by complement fixation (CF) and hemagglutinin-inhibition (HI) tests.

A localized outbreak of dengue fever in Kuala Lumpur: serological aspects.

1. Sera from an outbreak of about forty cases of dengue fever due to dengue-1 virus have been studied using the neutralization, haemagglutinin-inhibition, and complement-fixation tests.2. The neutralization test was the most specific and the complement-fixation test the least so.3. The neutralization test is essential for clear identification of the causal virus by serological means, and serial serum specimens from each patient must be examined.4. The haemagglutinin-inhibition test can be used to screen patients in outbreaks where some cases have been fully identified by neutralization tests.5. Homologous neutralizing antibodies persist in high titre for at least 30 weeks after infection, while heterologous antibodies have disappeared by that time.6. Both haemagglutinin-inhibiting and complement-fixing antibodies to homologous and heterologous viruses usually persist for at least 30 weeks, although the homologous titres tend to be highest.7. The implications of these findings in serological surveys are discussed.8. Some evidence suggesting the occurrence of inapparent infections during the epidemic is presented.I am greatly indebted to my staff for help with this work: especially to my senior technician, Che Ali bin Mohamed Amin, and to Che Mohamed bin Omar who drew the figures.