Homologous Hemagglutination Inhibition Research Articles

AS03-adjuvanted H7N9 inactivated split virion vaccines induce cross-reactive and protective responses in ferrets

Human infections with avian H7N9 subtype influenza viruses are a major public health concern and vaccines against H7N9 are urgently needed for pandemic preparedness. In early 2013, novel H7N9 influenza viruses emerged in China that caused about 1600 human cases of infection with a high associated case fatality rate. In this study, two H7N9 split virion vaccines with or without AS03 adjuvant were tested in the naive ferret model. Serological analyses demonstrated that homologous hemagglutination inhibition and microneutralization antibody titers were detectable in the ferrets after the first immunization with the AS03-adjuvanted vaccines that were further boosted by the second immunization. In addition, heterologous antibody titers against older H7 subtype viruses of the North American lineage (H7N7, H7N3) and newer H7 subtype viruses of the Eurasian lineage (H7N9) were detected in the animals receiving the AS03-adjuvanted vaccines. Animals receiving two immunizations of the AS03-adjuvanted vaccines were protected from weight loss and fever in the homologous challenge study and had no detectable virus in throat or lung samples. In addition, microscopic examination post-challenge showed animals immunized with the AS03-adjuvanted vaccines had the least signs of lung injury and inflammation, consistent with the greater relative efficacy of the adjuvanted vaccines. In conclusion, this study demonstrated that the AS03-adjuvanted H7N9 vaccines elicited high levels of homologous and heterologous antibodies and protected against H7N9 virus damage post-challenge.

The type of adjuvant in whole inactivated influenza a virus vaccines impacts vaccine-associated enhanced respiratory disease

Influenza A virus (IAV) causes a disease burden in the swine industry in the US and is a challenge to prevent due to substantial genetic and antigenic diversity of IAV that circulate in pig populations. Whole inactivated virus (WIV) vaccines formulated with oil-in-water (OW) adjuvant are commonly used in swine. However, WIV-OW are associated with vaccine-associated enhanced respiratory disease (VAERD) when the hemagglutinin and neuraminidase of the vaccine strain are mismatched with the challenge virus. Here, we assessed if different types of adjuvant in WIV vaccine formulations impacted VAERD outcome. WIV vaccines with a swine δ1-H1N2 were formulated with different commercial adjuvants: OW1, OW2, nano-emulsion squalene-based (NE) and gel polymer (GP). Pigs were vaccinated twice by the intramuscular route, 3 weeks apart, then challenged with an H1N1pdm09 three weeks post-boost and necropsied at 5 days post infection. All WIV vaccines elicited antibodies detected using the hemagglutination inhibition (HI) assay against the homologous vaccine virus, but not against the heterologous challenge virus; in contrast, all vaccinated groups had cross-reactive IgG antibody and IFN-γ responses against H1N1pdm09, with a higher magnitude observed in OW groups. Both OW groups demonstrated robust homologous HI titers and cross-reactivity against heterologous H1 viruses in the same genetic lineage. However, both OW groups had severe immunopathology consistent with VAERD after challenge when compared to NE, GP, and non-vaccinated challenge controls. None of the WIV formulations protected pigs from heterologous virus replication in the lungs or nasal cavity. Thus, although the type of adjuvant in the WIV formulation played a significant role in the magnitude of immune response to homologous and antigenically similar H1, none tested here increased the breadth of protection against the antigenically-distinct challenge virus, and some impacted immunopathology after challenge.

Efficacy of seasonal live attenuated influenza vaccine against virus replication and transmission of a pandemic 2009 H1N1 virus in ferrets

In March 2009, a swine origin influenza A (2009 H1N1) virus was introduced into the human population and quickly spread from North America to multiple continents. Human serologic studies suggest that seasonal influenza virus vaccination or infection would provide little cross-reactive serologic immunity to the pandemic 2009 H1N1 virus. However, the efficacy of seasonal influenza infection or vaccination against 2009 H1N1 virus replication and transmission has not been adequately evaluated in vivo. Here, ferrets received one or two doses of the US licensed 2008–2009 live attenuated influenza vaccine (LAIV) intranasally. An additional group of ferrets were inoculated with the A/Brisbane/59/07 (H1N1) virus to model immunity induced by seasonal influenza virus infection. All vaccinated and infected animals possessed high titer homologous hemagglutination-inhibition (HI) and neutralizing antibodies, with no demonstrable cross-reactive antibodies against 2009 H1N1 virus. However, in comparison to non-immune controls, immunized ferrets challenged with pandemic A/Mexico/4482/09 virus displayed a significant reduction in body temperature and virus shedding. The impact of single-dose LAIV inoculation on 2009 H1N1 disease and virus transmission was also measured in vaccinated ferrets that were challenged with pandemic A/Netherlands/1132/09 virus. Although a single dose of LAIV reduced virus shedding and the frequency of transmission following homologous seasonal virus challenge, it failed to reduce respiratory droplet transmission of 2009 H1N1 virus. The results demonstrate that prior immunization with seasonal LAIV or H1N1 virus infection provides some cross-protection against the 2009 H1N1 virus, but had no significant effect on the transmission efficiency of the 2009 H1N1 virus.

An Evaluation of Avian Influenza Diagnostic Methods with Domestic Duck Specimens

Monitoring of poultry, including domestic ducks, for avian influenza (AI) virus has increased considerably in recent years. However, the current methods validated for the diagnosis and detection of AI virus infection in chickens and turkeys have not been evaluated for performance with samples collected from domestic ducks. In order to ensure that methods for the detection of AI virus or AI virus antibody will perform acceptably well with these specimens, samples collected from domestic ducks experimentally infected with a U.S. origin low pathogenicity AI virus, A/Avian/NY/31588-3/00 (H5N2), were evaluated. Oropharyngeal (OP) and cloacal swabs were collected at 1, 2, 3, 4, 5, 7, 10, 14, and 21 days postinoculation (PI) for virus detection by virus isolation, which was considered the reference method, and real-time RT-PCR. In addition, two commercial antigen immunoassays were used to test swab material collected 2-7 days PI. Virus isolation and real-time RT-PCR performed similarly; however, the antigen immunoassays only detected virus during the peak of shed, 2-4 days PI, and both kits detected virus in fewer than half of the samples that were positive by virus isolation. Cloacal swabs yielded more positives than OP swabs with all virus detection tests. To evaluate AI virus antibody detection serum was collected from the ducks at 7, 14, and 21 days PI and was tested by agar gel immunodiffusion (AGID) assay, a commercial blocking enzyme-linked immunosorbent assay (ELISA), and homologous hemagglutination inhibition (HI) assay, which was used as the reference method. Results for the ELISA and HI assay were almost identical with serum collected at 7 and 14 days PI; however, by 21 days PI 100% of the samples were positive by HI assay and only 65% were positive by ELISA. At all time points AGID detected antibody in substantially fewer samples than either ELISA or HI assay.

An Adjuvanted, Low‐Dose, Pandemic Influenza A (H5N1) Vaccine Candidate Is Safe, Immunogenic, and Induces Cross‐Reactive Immune Responses in Healthy Adults

To protect a naive global population against pandemic influenza, pandemic vaccines should be effective at low antigen doses, because of limited manufacturing capacity. In a multicenter, randomized, blind-observer phase 1 trial, groups of 50 healthy young adults received 2 doses, 21 days apart, of influenza A/Vietnam/1194/2004 NIBRG-14 (H5N1) vaccine containing 1.9, 3.8, 7.5 or 15 microg of hemagglutinin with oil-in-water emulsion adjuvant or 7.5 microg of hemagglutinin without adjuvant. Safety was monitored to day 42. Homologous hemagglutination-inhibition (HI) and microneutralization titers were determined after each vaccination. Cross-reactivity against A/Indonesia/05/2005 RG2 was tested after the second vaccination. No vaccine-related significant or serious adverse events occurred. Injection site reactions, but not systemic reactions, were more frequent with adjuvant than without. Even with only 1.9 microg of hemagglutinin plus adjuvant, 72% of subjects had HI titers >or=1:32 after 2 doses. This proportion was 81%-89% with higher adjuvanted doses but was only 34% without adjuvant. Adjuvanted vaccine induced cross-neutralizing antibodies in 39%-65% of samples, versus 7% without adjuvant. The emulsion-adjuvanted pandemic influenza vaccine candidate was safe, immunogenic, and induced cross-reactive antibodies. This adjuvanted 1.9-microg candidate is the lowest effective dose tested to date. This could have a major impact on prepandemic vaccination strategies with stockpiled batches of vaccine. ClinicalTrials.gov identifier: NCT00457509 .

A comparison of antibody responses to admune inactivated influenza vaccin in serum and respiratory secretions of healthy non-smokers, healthy cigarette-smokers and patients with chronic bronchitis

Admune inactivated influenza vaccine was administered intramuscularly to 31 healthy subjects (18 non-smokers and 13 cigarette smokers) and 30 patients with chronic bronchitis. Homologous haemagglutination inhibition (HI) antibody titres were measured in serum and respiratory secretions over a three-month post-vaccination period. Clinical reactions to the vaccine were recorded during the week following vaccination. Among healthy subjects cigarette smoking did not influence HI antibody responses in serum and nasal secretion following vaccination. Chronic bronchitics produced at least as much serum and nasal antibody as healthy subjects and their sputum and nasal secretion antibody responses were comparable. Clinical reactions to the vaccine were mild and well tolerated in all groups but seven patients with chronic bronchitis (23%) experienced increased respiratory symptoms during the week following vaccination.

Resistance of chickens to challenge with the virulent Herts 33 strain of Newcastle disease virus induced by prior infection with serologically distinct avian paramyxoviruses

Results indicate that some degree of protection from challenge by Newcastle disease virus (NDV)/Herts 33 was conferred on chickens by prior infection with PMV/turkey/Wisconsin/68, PMV/turkey/Ontario/6661/68, PMV/Netherlands/449/75 and PMV/parakeet/England/39/78 viruses, all of which are serologically related but distinguishable from NDV. Except for one bird which survived challenge three weeks after infection with Robin/Hiddensee/19/75, no protection was seen in chickens infected with other unrelated avian paramyxoviruses. In contrast to infection with NDV-B1, birds protected by infection with avian paramyxoviruses showed large increases in NDV haemagglutination inhibition (HI) titres after challenge. In these birds considerable increases in the homologous HI titres were also seen after challenge.

Haemagglutination and haemagglutination inhibition with Mycoplasma synoviae

A haemagglutinating antigen prepared from cultures of M synoviae WVU 1853 successfully detected homologous haemagglutination inhibition (HI) in sera of fowls and turkeys inoculated with M synoviae. Nonspecific HI was encountered with normal fowl sera but this was removed by treatment with receptor destroying enzyme. It is suggested that M synoviae. HA antigen will be a useful reagent for the diagnosis of M synoviae infection.

Influenza antihemagglutinin and antineuraminidase activity of IgG and IgM in reference chicken antisera. 1.

SummaryChicken antisera prepared against recombinants possessing the hemagglutinin (H3) and the neuraminidase (N2) of the A/Hong Kong/8/68 (H3N2) strains were fractionated and the homologous and heterologous [A/Japan/305/57 (H2N2)] antibody activity of the 2 major immunoglobulin classes (IgG and IgM) was determined. Homologous hemagglutination inhibition (HI) and neuraminidase inhibition (NI) titers of whole sera were found to be predominantly IgG. Heterologous HI and NI titers of whole sera were associated with IgG, IgM, or both.The authors thank Mrs. Judy Galphin for her technical assistance.

The serological reactions in yellow fever.

Summary and Conclusions 1) The serological responses of 29 cases of human yellow fever infection were studied by hemagglutination-inhibition (HI), complement-fixation (CF) and neutralization (N) tests. 2) The cases were divided into two groups, chiefly according to the pattern of CF antibodies to a variety of Group B agents. The 17 cases in the first group are considered to be primary infections of yellow fever; the 12 cases in the second are considered to be infections of yellow fever in individuals who had previously been infected with another Group B virus. 3) In primary infections of yellow fever specific HI antibodies appear first, followed rapidly by antibodies to other Group B viruses. The titers of homologous HI antibodies are always as high as, or higher than, the titers of heterologous antibodies. 4) In primary infections there is great variation in the time after onset at which CF antibodies become demonstrable. Complement-fixing antibodies are produced over a long period and may still be increasing when HI antibodies are diminishing. The pattern of CF antibodies is remarkably specific. Overlaps with other antigens occur only when the homologous CF antibodies are high. 5) In primary infections the development of N antibodies as determined by the standard intracerebral test is quite specific. Heterologous N antibodies are developed to a limited extent. 6) In cases of secondary infection, the production of HI and CF antibodies is both massive and very rapid. There is no suggestion of specificity in the patterns developed and, in fact, as a rule the highest HI and CF antibodies were heterologous. Furthermore, in secondary infections the production of heterologous N antibodies is stimulated to a greater extent than in primary infections. In the present 12 cases, the heterologous response was so great that in all but one of the cases accurate diagnosis of the current illness by N test was impossible.