Had Hemagglutination Inhibition Research Articles

Inactivated influenza virus vaccines expressing COBRA hemagglutinin elicited broadly reactive, long-lived protective antibodies

ABSTRACT The influenza viruses cause seasonal respiratory illness that affect millions of people globally every year. Prophylactic vaccines are the recommended method to prevent the breakout of influenza epidemics. One of the current commercial influenza vaccines consists of inactivated viruses that are selected months prior to the start of a new influenza season. In many seasons, the vaccine effectiveness (VE) of these vaccines can be relatively low. Therefore, there is an urgent need to develop an improved, more universal influenza vaccine (UIV) that can provide broad protection against various drifted strains in all age groups. To meet this need, the computationally optimized broadly reactive antigen (COBRA) methodology was developed to design a hemagglutinin (HA) molecule as a new influenza vaccine. In this study, COBRA HA-based inactivated influenza viruses (IIV) expressing the COBRA HA from H1 or H3 influenza viruses were developed and characterized for the elicitation of immediate and long-term protective immunity in both immunologically naïve or influenza pre-immune animal models. These results were compared to animals vaccinated with IIV vaccines expressing wild-type H1 or H3 HA proteins (WT-IIV). The COBRA-IIV elicited long-lasting broadly reactive antibodies that had hemagglutination-inhibition (HAI) activity against drifted influenza variants.

Identification of novel E347Q and G362K amino acid substitutions in HN neutralization epitope and major antigenic difference in novel sub-genotype VIIj isolates.

Hemagglutinin-neuraminidase (HN) protein of Newcastle disease virus (NDV) plays a crucial role in induction of immune response against Newcastle disease infection. Mutation in residues 347 and 362 of HN linear antigenic site has been identified to be responsible for antigenic variations. Hence we studied antigenic difference between sub-genotype VIIj isolates and vaccine strains by the use of polyclonal serum against LaSota strain in hemagglutination inhibition test. Furthermore, epitope patterns of the isolates under study were analyzed and compared to HN sequences in GenBank. The results demonstrated that new Newcastle disease isolates (Mazandaran and Behshahr) had hemagglutination inhibition (HI) titer three and five, respectively while LaSota strain titer was eight. In addition, observation of sequences and epitope patterns revealed three unique amino acid substitutions (D144N, E347Q and G362K) in HN protein. E347Q and G362K mutations were located in neutralization antigenic site. Thus, we suggest that, these two novel amino acid substitutions in major linear epitope might be responsible for antigenic variation and decrease of HI activity.

Antibody responses to influenza a H1N1 vaccine compared to the circulating strain in influenza vaccine recipients during the 2013/2014 season in North America

BackgroundInfluenza strain A/California/07/2009 H1N1 (H1N1-09) reemerged in 2013/2014 as the predominant cause of illness. We sought to determine if antigenic drift may have contributed to the decreased responses to influenza vaccine. MethodsFifty adults who received trivalent inactivated influenza vaccine (IIV3) and 56 children who received live attenuated quadrivalent influenza vaccine (LAIV4) had hemagglutination inhibition (HAI) and microneutralizing (MN) antibodies measured in plasma against H1N1-09 and H1N1 2013/2014 (H1N1-14) influenza. Partial sequencing of the hemagglutinin gene (nt 280–780) was performed on 38 clinical isolates and the vaccine prototype. ResultsIn IIV3 recipients, HAI and MN titers against H1N1-14 were significantly lower than against H1N1-09 (p<0.0001 and 0.04, respectively). In LAIV4 recipients, only MN titers were significantly lower (p=0.02) for H1N1-09 compared with H1N1-14. A combined analysis showed significantly lower HAI and MN titers for H1N1-14 compared with H1N1-09 (p=0. 016 and 0.008, respectively). All 38 clinical isolates encoded the HA gene K166Q non-synonymous substitution; other non-synonymous substitutions were observed in <10% of the clinical isolates. Conclusions2013/2014 IIV3 and LAIV4 recipients had consistently lower MN antibody titers against H1N1-14 compared with H1N1-09. The HA K166Q mutation, located in a neutralizing epitope, probably contributed to these findings.

Vaccine Efficacy Against a New Avian Influenza (H9N2) Field Isolate from the Middle East (Serology and Challenge Studies)

Avian influenza subtype H9N2 is endemic in many countries in the Middle East. The reported prevalence of infection was variable between countries and ranged from 28.7% in Tunisia to 71% in Jordan. Several commercial killed whole-virus vaccine products are used as monovalent or bivalent mixed with Newcastle disease virus. Recently, we have noticed that many of the vaccinated broiler flocks did not show a production advantage over nonvaccinated flocks in the field. A new avian influenza field virus (H9N2) was isolated from these vaccinated and infected broiler flocks in 2013. This virus had 89.1% similarity of its hemagglutinin (HA) gene to the classical virus used for manufacturing the classical vaccine. Inactivated autogenous vaccine was manufactured from this new field isolate to investigate its serological response and protection in specific-pathogen-free (SPF) and breeder-male chickens compared to the classical vaccine. Oropharyngeal virus shedding of vaccinated breeder-male chickens was evaluated at 3, 9, 10, and 14 days postchallenge (DPC). Percentage of chickens shedding the virus at 3 DPC was 64%, 50%, and 64% in the classical vaccine group, autogenous vaccine group, and the control challenged group, respectively. At 7 DPC percentage of virus shedding was 42%, 7%, and 64% in the classical vaccine group, autogenous vaccine group, and the control challenged group, respectively. At 10 DPC only 9% of classical vaccine group was shedding the virus and there was no virus shedding in any of the groups at 14 DPC. There was statistical significance difference (P < 0.05) in shedding only at 7 DPC between the autogenous vaccine group and the other two groups. At 42 days of age (14 DPC), average body weight was 2.720, 2.745, 2.290, and 2.760 kg for the classical vaccine group, autogenous vaccine group, control challenged group, and control unchallenged group, respectively. Only the control challenged group had significantly (P < 0.05) lower average body weight. In another experiment, vaccinated SPF chicks had hemagglutination inhibition (HI) geometric mean titers (GMTs), with classical antigen, of 8.7 and 3.1 log 2 for classical and autogenous vaccine groups, respectively. When the autogenous antigen was used for HI, GMTs were 6.0 and 8.1 log 2, respectively. Both vaccines protected against body weight suppression after challenge. However, autogenous vaccine elicited significantly higher HI titer and reduced viral shedding at 7 DPC. In conclusion, it is important to revise the vaccine virus strains used in each region to protect against and control infection from new field strains. Further field experiments are needed to demonstrate the efficacy of new vaccines under field conditions.

Significant cross reactive antibodies to influenza virus in adults and children during a period of marked antigenic drift.

BackgroundLittle is known about the development of cross-reactive antibodies following natural exposure to pathogens. Such knowledge is critical in the development of new universal influenza vaccines.MethodsTo study the possibility of the presence of cross-reactive antibodies to influenza viruses which underwent a major antigenic drift between the years 1999 and 2007 sera from samples of 80 children and 400 adults were selected at random from the Israeli national serum bank. The sera was obtained in 2002 and in 2007, two time points that followed a major drift in the infectious H3N2 influenza virus strain (A/Panama/2007/99 to A/Wisconsin/67/2005).ResultsIn the summer of 2002, 13% of the children had Hemagglutination Inhibition (HI) antibody titers of at least 40 and these antibodies recognized both A/Panama/2007/99 and A/Wisconsin/67/2005, where the latter strain only began to circulate in Israel in 2006. In 2007, 29% of the children had HI antibody titers of at least 40 directed against both A/Wisconsin/67/2005 and A/Panama/2007/99, even though they had never been exposed to the latter virus. Anti-A/Panama/2007/99 antibodies were detected in 58% and 68% of the 2002 and 2007 adult samples, respectively, while 8% and 39% had antibodies against A/Wisconsin/67/2005, respectively.ConclusionsThe presence of naturally occurring cross-reactive influenza virus antibodies in a significant percentage of children has important implications for the development of a universal influenza vaccine.

A clinical study to assess the immunogenicity and safety of a monovalent 2009 influenza A (H1N1) vaccine in an area with low-level epidemics of pandemic influenza

We conducted a multi-center, randomized, laboratory-blinded clinical trial in 185 healthy adults (<60 years) and 107 elders (>60 years) to examine the immunogenicity and safety of different doses of an inactivated, monovalent, non-adjuvanted, split vaccine against the 2009 pandemic influenza A (H1N1) virus. The 186 adults were assigned to three treatment groups, i.e., one 15 μg hemagglutination (HA) antigen dose, two 15 μg or 30 μg HA doses in 3 weeks apart, and the 107 elders were treated with two 15 μg or 30 μg doses in 3 weeks apart. Prior to the vaccination, 4.8% subjects had hemagglutination-inhibition (HAI) antibody titers of 1:40 or more. By day 21 post-vaccination of one dose of 15 μg HA, the seroprotective rate was 95.1% and 75.5% in subjects <60 and >65 years of age, respectively; by day 21 post the second 15 μg HA dose, the seroprotective rates were 93.2% and 73.1%, respectively. The seroprotective rates for recipients of 30 μg HA antigen by day 21 were 95.2% for subjects <60 years and 81.1% for subjects >65 years of age, that was boosted to 98.3% and 80.4%, respectively with a second dose of 30 μg HA antigen. No vaccine-related serious adverse events occurred. The data indicated a single 15 μg HA dose of the vaccine induced a protective immune response in most adults, including the elders >60 years of age, and a booster dose at the third week did not render a higher level of antibody response.

Cross-reactive Antibodies against Avian Influenza Virus A (H5N1)

Cross-reactive Antibodies against Avian Influenza Virus A (H5N1)

A Trivalent Virus-Like Particle Vaccine Elicits Protective Immune Responses against Seasonal Influenza Strains in Mice and Ferrets

There is need for improved human influenza vaccines, particularly for older adults who are at greatest risk for severe disease, as well as to address the continuous antigenic drift within circulating human subtypes of influenza virus. We have engineered an influenza virus-like particle (VLP) as a new generation vaccine candidate purified from the supernatants of Sf9 insect cells following infection by recombinant baculoviruses to express three influenza virus proteins, hemagglutinin (HA), neuraminidase (NA), and matrix 1 (M1). In this study, a seasonal trivalent VLP vaccine (TVV) formulation, composed of influenza A H1N1 and H3N2 and influenza B VLPs, was evaluated in mice and ferrets for the ability to elicit antigen-specific immune responses. Animals vaccinated with the TVV formulation had hemagglutination-inhibition (HAI) antibody titers against all three homologous influenza virus strains, as well as HAI antibodies against a panel of heterologous influenza viruses. HAI titers elicited by the TVV were statistically similar to HAI titers elicited in animals vaccinated with the corresponding monovalent VLP. Mice vaccinated with the TVV had higher level of influenza specific CD8+ T cell responses than a commercial trivalent inactivated vaccine (TIV). Ferrets vaccinated with the highest dose of the VLP vaccine and then challenged with the homologous H3N2 virus had the lowest titers of replicating virus in nasal washes and showed no signs of disease. Overall, a trivalent VLP vaccine elicits a broad array of immunity and can protect against influenza virus challenge.

Immunogenicity and safety of intradermal versus intramuscular route of influenza immunization in infants less than 6 months of age: A randomized controlled trial

We aimed to explore intradermal influenza vaccination in infants <6 months. One hundred twenty-six infants 2–3 months of age were randomized to receive either two doses, 1 month apart, of 0.25ml of a trivalent inactivated influenza vaccine (7.5μg of hemagglutinin per strain) via the intramuscular (IM) route or 0.1ml of the same vaccine (3μg of hemagglutinin per strain) via the intradermal (ID) route. The vaccine was well tolerated. Only four infants had hemagglutination inhibition (HAI) titer <40 against ≥1 vaccine-covered antigen pre-vaccination. There was no difference in fold-rise of HAI titer response between those in the IM or ID group. We documented maintenance of HAI titers above seroprotective levels against all three vaccine antigens in 97.6% of subjects regardless of vaccination methods over a time of waning maternal antibodies.

Antibody responses after dose-sparing intradermal influenza vaccination

Reduced-dose intradermal (ID) influenza vaccination is an attractive approach to increase availability of vaccine supply in an event of vaccine shortage. We conducted a randomized open-label study, in which 500 subjects were randomly assigned to receive an ID injection of 0.1 ml dose of inactivated split-virion influenza vaccine or an IM injection of 0.5 ml dose. The subjects who had hemagglutination inhibition (HI) antibody titer of at least 1:40 at day 28 post-vaccination in ID and IM groups were 93.3% versus 98.0% for influenza A(H1N1) virus, 86.3% versus 95.0% for A(H3N2) virus, and 43.5% versus 57.0% for influenza B virus. Subjects in the ID group had an increase in geometric mean titer by a factor of 16 for the H1N1 strain, 8 for the H3N2 strain, and 2 for the B strain on day 28, as compared with respective increase in the IM group of 31, 20, and 3. Local reactions were significantly more frequent among subjects in the ID group than those in the IM group, but the reactions were mild and transient. In this study, ID administration of one-fifth dose of influenza vaccine elicited significantly lower levels of antibody response as compared to full-dose IM injection. However, the antibody responses elicited by the ID vaccination were still sufficiently high to meet the requirement guidelines of the European Committee for Proprietary Medicinal Products (CPMP) for the annual relicensure of influenza vaccines.

Serum Antibody Responses after Intradermal Vaccination against Influenza

If found to be safe and immunogenic, reduced doses of influenza vaccine given by the intradermal route could increase the number of available doses of vaccine. In an open-label study, we randomly assigned 119 subjects to receive an intradermal injection of trivalent inactivated influenza vaccine, containing 6 mug of hemagglutinin for each antigen (40 percent of the usual dose), and 119 to receive an intramuscular injection of the standard dose of 15 mug of hemagglutinin for each antigen. The two groups were subdivided according to age (18 to 60 years and older than 60 years). Among subjects who were 18 to 60 years of age, serum antibody responses were vigorous and did not differ significantly between the intradermal and intramuscular groups, and all subjects had hemagglutination-inhibition (HAI) titers of at least 1:40. Although the subjects who were older than 60 years of age also had a vigorous antibody response, there was a trend toward a better response in the intramuscular route, but this finding was significant only for antigen to the H3N2 strain. Nevertheless, 100 percent of older subjects in the intramuscular group and 93 percent of such subjects in the intradermal group had an HAI antibody titer to the H3N2 strain of more than 1:40, and 100 percent in each group had a titer of this level for both the H1N1 and B strains. Local pain was significantly more common in the intramuscular group than in the intradermal group among subjects who were 18 to 60 years of age but not among subjects who were over 60 years old. Signs of local inflammation were significantly more common among subjects in the intradermal group than among those in the intramuscular group, in both age groups. As compared with an intramuscular injection of full-dose influenza vaccine, an intradermal injection of a reduced dose resulted in similarly vigorous antibody responses among persons 18 to 60 years of age but not among those over the age of 60 years.

Antigenic variation among human strains of influenza C virus detected with monoclonal antibodies to gp88 glycoprotein

Antigenic variation among influenza C virus strains was investigated with monoclonal antibodies against gp88 glycoprotein. Seven monoclonal antibodies obtained were tentatively classified into two groups, A and B. The group A antibodies had hemagglutination inhibition (HI), hemolysis inhibition and neutralization activities whereas the group B antibodies possessed none of them. A comparison of antigenicity among 15 human strains with these antibodies in radioimmunoprecipitation and HI tests showed that the regions recognized by the group A antibodies undergo considerable changes, whereas those by group B are conserved among the strains.

A Historical Account of the Diagnosis and Characterization of Strains of Mycoplasma gallisepticum of Low Virulence

Numerous chicken flocks were studied beginning in 1970 because of questionable results on their serologic tests for Mycoplasma gallisepticum (MG). Typically a low number of hens in the flocks were positive reactors to the rapid serum plate test and rarely had hemagglutination-inhibition (HI) titers over 1:80. Usually no clinical signs were observed. Isolates of MG eventually were cultured from most of the flocks that exhibited that type of marginal serologic pattern. In the laboratory, the MG isolates were frequently less virulent and less pathogenic than the typical field isolates recovered in previous years. Most isolates produced airsacculitis of varying severity when broilers were exposed to the MG cultures as aerosols following exposure to infectious bronchitis virus. They became positive on the rapid serum plate test and developed moderate to high HI titers. Egg-transmission appeared to be the most likely means of transmission, even though the infected progeny rarely showed clinical signs of disease.

Surveillance of arbovirus activity in Iowa, USA, 1978-1980.

Considerable information pertaining to the epidemiology of mosquito-borne viruses in Iowa, USA, has been acquired during a continuing arbovirus surveillance program. Virus isolation results indicate that Culex tarsalis is the primary vector of St. Louis encephalitis (SLE) and western equine encephalomyelitis (WEE) viruses in Iowa, but that Culex spp. ( Cx. pipiens, Cx. restuans, or Cx. salinarius ) may contribute to the amplification of SLE virus. Also, Aedes trivittatus may be important in the natural maintenance of WEE virus in Iowa. From 1978 through 1980, a total of 243 isolations of viruses such as Flanders and trivittatus were made from various species of mosquitoes in Iowa. Many of the wild-bird bloods tested had hemagglutination-inhibition (HI) antibodies (titer ≥ 20) to WEE virus, and a few had antibodies to SLE in Council Bluffs, where a human case occurred in 1980. Eighteen human cases of La Crosse encephalitis occurred in Iowa in 1978, and a 3-year-old girl who lived near the Iowa state line died from the effects of this virus. La Crosse virus was isolated from a pool of Aedes triseriatus collected in Dubuque, where a human case occurred in 1979 and a 2nd case occurred in 1980.

Monoclonal antibodies distinguish between wild and vaccine strains of yellow fever virus by neutralization, hemagglutination inhibition, and immune precipitation of the virus envelope protein

Nineteen monoclonal antibodies were produced to the 17D strain of yellow fever virus (17D YF). Virus-specific structural and nonstructural proteins were identified for 17D YF and for the parent wild Asibi YF by radioimmunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Fourteen of the monoclonal antibodies were directed against the envelope glycoprotein, E, and five against the nonstructural protein gp 48. The E protein of 17D YF was resolved as a double complex whereas the E protein of Asibi YF appeared as a single band of slightly lower molecular weight. The only IgM anti-E antibody obtained precipitated and neutralized 17D YF specifically with no activity against Asibi YF. This antibody also distinguished clearly by neutralization (N) between the 17D-204 derived vaccine strain to which the animal had been immunized and 17D YF strains of different origin. All 13 IgG anti-E monoclonal antibodies had hemagglutination-inhibition (HI) activity to 17D YF and all but one neutralized Asibi YF; however, only 3 of the 13 neutralized 17D YF. Four anti-E antibodies cross-reacted with other flaviviruses by HI or HI and N. Three of the five anti-gp 48 antibodies had complement-fixation (CF) titers against 17D YF and Asibi YF but none had N or HI activity.

Frequency of Antibody to Adenovirus 127 in Domestic Ducks and Wild Waterfowl

SUMMARY Nearly 90% of sera from breeder ducks had hemagglutinationinhibition (HI) titers to adenovirus 127, and 50-70% of ducklings had positive titers. Most titers ranged from 8 to 32; the most frequent titer was 16. Only 3.7%o of sera from mallard ducks and 14.7% of the sera from Canada geese were positive for HI antibody to adenovirus 127. The distribution of titers was sporadic, with lower titers in wild-goose sera than in the mallard-duck sera. Sera with HI antibody were also positive in the serum-neutralization test. The data support the view that adenovirus 127 infection is enzootic in commercial duck flocks. The sporadic occurrence in wild waterfowl suggests that they are not the primary source of the infection in domestic ducks.

Relationship Between Homogeneous IgG Fractions and Measles Virus Antibody Activities in Subacute Sclerosing Panencephalitis Brain

Cellulose acetate and agarose gel electrophoresis of pH 7.4 brain extracts from three patients with subacute sclerosing panencephalitis (SSPE) revealed two to three homogeneous bands in the gamma-globulin region. The IgG concentration in the brain extracts ranged from 6 to 8.5% of the total protein. The IgG was isolated by passing each brain extract twice through gel filtration on Sephadex G-200 column. The Sephadex-isolated IgG preparations, at a concentration of 1 mg/ml, had hemagglutination inhibition (HI) titers ranging from 512 to 800, complement fixation (CF) titers of 64 to 100, and neutralizing titers of 400 to 1024 when tested against envelope, nucleocapsids, and while measles virus, respectively. These IgG preparations were further separated into several fractions by isoelectric focusing (IEF) technique and the reactivities of these eluted fractions were examined against differnt specific measles virus components and against whole virus. The results showed that both slow and fast moving homogeneous IgG had high HI and neutralizing titers. However, CF antibodies were present only in specific IEF-eluted fractions and their profiles differed somewhat from one brain to another. The IgG fractions reacted with both kappa-and gamma-chain antisera, but the reactivity varied from one brain to another. When the polyacrylamide gel electrophoretic (PAGE) patterns of heavy (H) and light (L) chains of SSPE IgG were compared to those of IgG from controls, the H chain patterns of both groups were identical whereas the SSPE brain IgG demonstrated two distinct bands in L chain as compared to a single diffuse band observed in controls. These latter results, in addition to homogeneous bands and selective CF antibody activity in IEF eluted IgG fractions from SSPE brain, fulfill some of the criteria of monoclonality.

Measles (rubeola) susceptibility among elementary schoolchildren.

Measles (rubeola) immunity among 479 elementary schoolchildren from suburban Minneapolis was serologically surveyed in December 1971. Of the 479 children, 25 (5.2%) had hemagglutination-inhibition (HI) titers less than 2. These children were considered susceptible to measles. For the 233 immunized children with no measles history, 13 (5.6%) had rubeola HI titers less than 2 while 5 (5.1%) of the 98 youngsters with a history of clinical measles had rubeola HI titers less than 2. Of the 454 immune children, 73 (16%) had measles HI titers between 2 and 8. These findings confirm durable immunity and a low rate of vaccine failure following live attenuated measles vaccination but demonstrate the importance of testing sera beginning at a dilution of 2 in order to detect children with low antibody levels. This survey also suggests that maternal antibody interferes with the active immune response in youngsters immunized when less than 1 year of age because this group of children had significantly lower geometric mean titers and significantly more susceptibles than the children immunized when greater than or minus 2 years.