Hemagglutination Inhibition Method Research Articles

Serological baseline, antibody stability and efficacy of different types of avian influenza (H5) vaccines.

Evaluating Iran's national highly pathogenic avian influenza (HPAI) control program can inform vaccine selection, optimize immunization duration, guide exit strategies, and assess hemagglutination inhibition (HI) and serum neutralization (SN) methods. To establish a serological baseline, assess antibody stability, and compare the efficacy of three HPAI (H5) vaccines. We analyzed over 9,000 blood samples and 6,420 swabs from approximately 1.5 million birds up to 64 weeks old. HI (β, α), RT-PCR, and SN tests were conducted, with statistical analysis performed using two-way ANOVA. The serological baseline (GM titer) using H5N8 antigens from A/Chicken/Iran/162/2016 varied. The Re6+Re8 vaccine produced higher and more stable HI β titers than the H5N3 and baculovirus vaccines. Serum HI α neutralization ability was similar for Re6+Re8 and H5N3 vaccines, both 100 times greater than the baculovirus vaccine. Neutralization indices for H5N3, Re6+Re8, and baculovirus vaccines were 4.7, 4.5, and 4.2 (log2), respectively. After two vaccinations, Re6+Re8 exhibited the most stable HI β antibody response, while H5N3 had the highest neutralization index, surpassing Re6+Re8 by 0.2 and the baculovirus vaccine by 0.5. These findings highlight discrepancies between HI β and SN test results, with SN being a stronger indicator of protective titers due to its in vivo methodology, compared to the in vitro HI assay.

Mesenchymal stem cells prevent H7N9 virus infection via rejuvenating immune environment to inhibit immune-overactivity

BackgroundInfluenza is a clinically important infectious disease with a high fatality rate, which always results in severe pneumonia. Mesenchymal stem cells (MSCs) exhibit promising therapeutic effects on severe viral pneumonia, but whether MSCs prevent virus infection and contribute to the prevention of influenza remains unknown. MethodsICR mice were pretreated with human umbilical cord (hUC) MSCs and then infected with the influenza H7N9 virus. Weight, survival days, and lung index of mice were recorded. Serum antibody against influenza H7N9 virus was detected according to the hemagglutination inhibition method. Before and after virus infection, T cell and B cell subtypes in the peripheral blood of mice were evaluated by flow cytometry. Cytokines in the supernatants of MSCs, innate immune cells, and mouse broncho alveolar lavage fluid (BALF) were determined by enzyme-linked immunosorbent assay (ELISA) or Luminex Assay. ResultsPretreatment with MSCs protected mice against influenza H7N9 virus infection. Weight loss, survival rate, and structural and functional damage to the lungs of infected mice were significantly improved. Mechanistically, MSCs modulated T lymphocyte response in virus-infected mice and inhibited the cGAS/STING pathway. Importantly, the protective effect of MSCs was mediated by cell-to-cell communications and attenuation of cytokine storm caused by immune overactivation.

H3N2 influenza hemagglutination inhibition method qualification with data driven statistical methods for human clinical trials.

Hemagglutination inhibition (HAI) antibody titers to seasonal influenza strains are important surrogates for vaccine-elicited protection. However, HAI assays can be variable across labs, with low sensitivity across diverse viruses due to lack of standardization. Performing qualification of these assays on a strain specific level enables the precise and accurate quantification of HAI titers. Influenza A (H3N2) continues to be a predominant circulating subtype in most countries in Europe and North America since 1968 and is thus a focus of influenza vaccine research. As a part of the National Institutes of Health (NIH)-funded Collaborative Influenza Vaccine Innovation Centers (CIVICs) program, we report on the identification of a robust assay design, rigorous statistical analysis, and complete qualification of an HAI assay using A/Texas/71/2017 as a representative H3N2 strain and guinea pig red blood cells and neuraminidase (NA) inhibitor oseltamivir to prevent NA-mediated agglutination. This qualified HAI assay is precise (calculated by the geometric coefficient of variation (GCV)) for intermediate precision and intra-operator variability, accurate calculated by relative error, perfectly linear (slope of -1, R-Square 1), robust (<25% GCV) and depicts high specificity and sensitivity. This HAI method was successfully qualified for another H3N2 influenza strain A/Singapore/INFIMH-16-0019/2016, meeting all pre-specified acceptance criteria. These results demonstrate that HAI qualification and data generation for new influenza strains can be achieved efficiently with minimal extra testing and development. We report on a qualified and adaptable influenza serology method and analysis strategy to measure quantifiable HAI titers to define correlates of vaccine mediated protection in human clinical trials.

Anti-Influenza Virus Potential of Probiotic Strain Lactoplantibacillus plantarum YML015 Isolated from Korean Fermented Vegetable

Lactic acid bacteria are one of the potential natural remedies used worldwide, commonly known as probiotics. Here, the aim of this research investigation was to isolate a probiotic Lactobacilli strain, YLM015, from the popular Korean fermented vegetable “Kimchi” and to evaluate its anti-viral potential against influenza virus A (IFVA) H1N1 using the MDCK cell line in vitro, and in embryonated eggs in ovo. The YML015 strain was selected from among the 1200 Lactobacilli isolates for further studies based on its potent anti-viral efficacy. YML015 was identified and characterized as Lactoplantibacillus plantarum YML015 based on the 16S rRNA gene sequencing and biochemically with an API 50 CHL Kit. In ovo assay experienced with embryonated eggs and the hemagglutination inhibition method, as well as cytopathogenic reduction assay, was performed individually to observe anti-influenza viral activity of YML015 against influenza virus A H1N1. Additionally, YML015 was classified for its non-resistance nature as safe for humans and animals as confirmed by the antibiotic susceptibility (MIC) test, cell viability, and hemolysis assay. The heat stability test was also experienced by using different heat-treated cell-free supernatant (CFS) samples of YML015. As a result, YML015 showed highly potent anti-viral activity against influenza virus A H1N1 in vitro in the MDCK cell line. Overall findings suggest that anti-influenza viral activity of L. plantarum YML015 makes it a potential candidate of choice for use as an influential probiotic in pharmacological preparations to protect humans and animals from flu and viral infection.

Susceptibility to Plasmodium falciparum Malaria: Influence of Combined Polymorphisms of IgG3 Gm Allotypes and Fc Gamma Receptors IIA, IIIA, and IIIB.

The binding of immunoglobulin (Ig) to Fc gamma receptors (FcgR) at the immune cell surface is an important step to initiate immunological defense against malaria. However, polymorphisms in receptors and/or constant regions of the IgG heavy chains may modulate this binding. Here, we investigated whether polymorphisms located in FcgR and constant regions of the heavy chain of IgG are associated with susceptibility to P. falciparum malaria. For this purpose, a clinical and parasitological follow-up on malaria was conducted among 656 infants in southern Benin. G3m allotypes (from total IgG3) were determined by a serological method of hemagglutination inhibition. FcgRIIA 131R/H and FcgRIIIA 176F/V genotypes were determined using the TaqMan method and FcgRIIIB NA1/NA2 genotypes were assessed by polymerase chain reaction using allele-specific primers. Association analyses between the number of malaria infections during the follow-up and polymorphisms in IgG G3m allotypes and FcgR were studied independently by zero inflated binomial negative regression. The influence of combinations of G3m allotypes and FcgRIIA/FcgRIIIA/FcgRIIIB polymorphisms on the number of P. falciparum infections, and their potential interaction with environmental exposure to malaria was assessed by using the generalized multifactor dimensionality reduction (GMDR) method. Results showed that individual carriage of G3m24 single allotype and of G3m5,6,10,11,13,14,24 phenotype was independently associated with a high risk of malaria infection. A risk effect for G3m6 was observed only under high environmental exposure. FcgRIIIA 176VV single genotype and combined carriage of FcgRIIA 131RH/FcgRIIIA 176VV/FcgRIIIB NA1NA2, FcgRIIA 131HH/FcgRIIIA 176FF/FcgRIIIB NA1NA1, FcgRIIA 131HH/FcgRIIIA 176VV/FcgRIIIB NA2NA2 and FcgRIIA 131HH/FcgRIIIA 176VV/FcgRIIIB NA1NA2 genotypes were related to a high number of malaria infections. The risk was accentuated for FcgRIIIA 176VV when considering the influence of environmental exposure to malaria. Finally, the GMDR analysis including environmental exposure showed strengthened associations with a malaria risk when FcgRIIA/FcgRIIIA/FcgRIIIB genotypes were combined to G3m5,6,11,24 and G3m5,6,10,11,13,15,24 phenotypes or G3m10 and G3m13 single allotypes. Our results highlight the relevance of studying IgG heavy chain and FcgR polymorphisms, independently as well as in combination, in relation to the individual susceptibility to P. falciparum infection. The intensity of individual exposure to mosquito bites was demonstrated to impact the relationships found.

Evaluation for Efficacy of Commercially Available Vaccines Against Challenge with Newcastle Disease Virus Genotype VII in Broilers

The study evaluated the protective efficacy of commercially available live and inactivated Newcastle Disease Virus (NDV) vaccines. Moreover, study also highlighted the implementation of genotypically-matched NDV vaccines to the currently circulated velogenic genotype VII strain in commercial broilers vaccination regimes in Egypt. Serum antibodies level was assessed by Haemagglutination Inhibition method .Efficacy of Newcastle Disease killed and live vaccine was also determined using challenge test. Group A immunized with live attenuated and inactivated NDV vaccines genotype VII homologous to challenge virus provided non-significant protection against mortality .It proved 20 % as compared to 15 % mortalities in group B immunized with live attenuated and inactivated NDV vaccines genotype II heterologous to challenge virus. Meanwhile, group Aredult proved a significant reduction in viral shedding by cloacal swabs in compared with group B ,7 days post-challenge. Final Results of the present work concluded that live and inactivated NDV genotype VII vaccines antigenically matched to currently epidemic NDV genotype VII providing better control on virus shedding if compared with different genotype II vaccines. However, both vaccines provided good protection against likely virulent challenge in commercial broilers.

Influenza A H1N1 Virus 2009 Synthetic Hemagglutinin and Neuraminidase Peptides for Antibody Detection

Influenza serologic diagnosis is mainly based on hemagglutination inhibition and microneutralization methods, both methods require handling living viruses under an enhanced biosafety level. The current study was performed for developing an ELISA using synthetic peptides to detect influenza A H1N1 virus 2009 specific antibodies in serum and saliva. Alignments were made with H1N1 hemagglutinin and neuraminidase (HA and NA, respectively) sequences; only conserved sites were used for antigenicity prediction. Two synthetic peptides were assayed; one of neuraminidase (NA15) and one of hemagglutinin (HA-15) and used in ELISA for detecting IgG and IgA antibodies. A cross-sectional study was performed in three municipalities of Mexico City, using negative samples collected before the 2009 influenza outbreak, samples of people who became ill during the outbreak, and samples of the participants in the epidemiological study with or without symptoms. The determination of serum IgG antibodies with both peptides allowed differentiating between the post outbreak groups with respect to all others. No differences were found in IgA determination in saliva against both peptides. The frequency of positive participants for NA-15 was 9.5 and 8.8% for HA-15 in serum IgG; whereas the frequency of positive participants for NA-15 was 11%, and for HA-15 was 8.6% for saliva IgA. Synthetic peptides of the neuraminidase and hemagglutinin proteins can be used in ELISA for the determination of IgG and IgA antibodies against the influenza A H1N1 virus2009.

Salivary and plasma inflammatory mediators and secretory status in preterm delivery women with periodontitis - a cross sectional study

Bacground/Aim. Preterm birth is defined as a delivery prior to the completed 37th week of gestation. Literature data suggested that periodontal processes may influence to the feto-placental unit and induce preterm delivery. The degree of the periodontal disease is influenced by secretor status. Pro-inflammatory cytokines are involved in periodontitis as well as in delivery. The combined influence of these factors on the risk of preterm birth has not been explored. The aim of our study was to investigate the associations between periodontal diseases, secretor status, and interleukin- 1-? (IL1-?) and prostaglandine E2 (PGE2) levels in women delivered preterm. Methods. The study included 56 preterm delivery women and 56 women delivered at term as a control group, aged between 17 and 41 years. Periodontal examination, blood and saliva sampling were performed within 48 hours following delivery. Secretor phenotype was determined by hemagglutination inhibition method. The concentrations of IL1-? and PGE2 were measured by high sensitivity Enzyme-linked Immunosorbent Assay (ELISA). Results. In the pre-term birth group there were 66.1% of women with periodontitis, while in the control one there were 12.5% (p &lt; 0.01). Concentrations of IL1-? and PGE2 in plasma were significantly higher in the non-secretor group of women who gave birth pre-term and had periodontitis comparing to other groups. There was a significant correlation between salivary and plasma levels of PGE2 and IL1-? in the preterm birth group (R = 0.416, p = 0.017 and R = -0.592, p &lt; 0.001, respectively). There were no such correlations in women who delivered at term. Conclusion. Our results support the hypothesis that non-secretor phenotype and periodontitis are at least in part responsible for pathogenesis of preterm birth. This probability of negative impact of non-secretor status cannot be ignored. These findings support the need for additional research into the biology of human parturition.

Serological Investigation of H9N2 Avian Influenza Virus in Slaughtered Water Buffaloes (Bubalus bubalis) in Khuzestan, Iran.

The aim of the present was to evaluate the prevalence of H9N2-specific antibodies among water buffaloes (Bubalus bubalis). To this end, blood samples were obtained from 80 randomly selected water buffaloes, 40 cases of which were obtained in the winter months, and 40 cases were sampled in the spring months. The presence of H9N2-specific antibody was determined by hemagglutination inhibition method. The antibody was diagnosed in 14 buffaloes (i.e., 10 males and 4 females). There were no significant differences between the two genders and between different age groups in terms of antibody prevalence. The presence of the antibody had a seasonal pattern; in this regard, all positive cases were found in the winter months (P&amp;lt;0.01). Detection of antibody against H9N2 in water buffaloes suggests the presence of an avian-water buffalo cycle of H9N2 virus. Additional research is needed for the detection of the probable epidemiologic role of buffaloes in the interspecies transmission and pathogenesis of H9N2 avian influenza viruses.

COMPARATIVE STUDY OF DIFFERENT VACCINATION ROUTES AGAINST NEWCASTLE DISEASE IN LAYER CHICKENS

In the present study, a trail to evaluate of Newcastle Disease (ND) antibodies levels after different vaccination programs was conducted on layer chickens. A total of 200 one day-old layer chicks (White Lohmann) were divided into five groups A, B, C, D and E. Birds in groups A, B and C were vaccinated with live vaccine by intraocular, intranasal and drinking water methods , respectively. On the other hand, groups D and E were kept as unvaccinated control groups. Vaccination performed at days 5, 18 and 28 by different routes for mentioned groups. Hemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA) methods were used for assessment of antibodies titer at days 15, 25, 37 and 45. Results of HI and ELISA tests indicated that, the intranasal and the intraocular method have highest antibodies titers compared with the drinking water method. In this study, maternally derived antibodies specific to Newcastle Disease Virus (NDV) (IgY) were extracted by dextran sulfate method from collected eggs of vaccinated laying chickens . Antibodies specific to NDV (IgY) were detected in the egg yolk using HI test . Data revealed that antibodies specific to NDV (IgY) were presented in high titers that confer protection during early weeks of life for hatching chicks. Data concluded that extraction of maternally derived specific antibodies from egg yolk will facilitate accurate monitoring of ND vaccination programmes.

Serological surveillance of avian influenza virus and canine distemper virus in captive Siberian Tigers in Northeastern China.

In order to understand infection of avian influenza A virus (AIV) and canine distemper virus (CDV) in the Siberian Tiger in Northeast China, 75 Siberian Tiger serum samples from three cap- tive facilities in northeastern China were collected. AIV and CDV antibody surveillance was test- ed by using hemagglutination inhibition and serum neutralization methods. The results showed that the seroprevalence of H5 AIV, H9 AIV and CDV was respectively 9.33% (7/75), 61.33% (46/75) and 16% (12/75). In the 1⟨years ⟨2 and > 5 year-old group, the seroprevalence of the H9 AIV was 24% and 80% (P ⟨ 0.01), and the CDV seroprevalence was 6% and 36% (P ⟨ 0.01), respectively. It was demonstrated that 3 (4%) out of 75 serum samples were AIV+CDV seropos- itive, with 2.67% (2/75) in H9+AIV and 1.33% (1/75) in H5+H9+AIV. To our knowledge, this is the first report of AIV and CDV seroprevalence in Siberian Tigers in China, which will provide base-line data for the control of AIV and CDV infection in Siberian Tigers in China.

Seroepidemiology of arbovirus in communities living under the influence of the lake of a hydroelectric dam in Brazil

Abstract Introduction The arbovirus proposes an important problem of public health in Brazil, especially in the Amazon, due to its capacity to cause outbreaks with high levels of morbidity-mortality in humans as well as in animals. Objective This paper had the objective to estimate the prevalence of antibodies to arbovirus in communities that live under the influence of the artificial lake of UHE Tucuruí in the State of Pará, Brazil. Method The analytical transversal study has selected 657 blood serum samples of individuals over 18, both genders, residents at the Sustainable Development Reserves (SDR) in the region of the lake of UHE Tucuruí. The epidemiological information has been registered in an instrument especially designed for such a study and the blood samples were collected in two periods of high and low tide of the lake. The blood serum tests were performed by the method of hemagglutination inhibition (HI). Results The results revealed a prevalence of positive antibodies to arbovirus of 85.0%, being 84.1% related to Flavivirus (vaccine strain of YFV), 25.5% related to Alphavirus and 34.6% to Bunyavirus. The results of serum prevalence to arbovirus between the periods of high tide and low tide have revealed significance amongst the Alphavirus, not observed in the other families. Conclusion In general, the data from this paper have suggested that the anthropoid actions on the environment of the lake have become determinant factors for the prevalence of arboviral antibodies.

Intranasal Immunization Using Mannatide as a Novel Adjuvant for an Inactivated Influenza Vaccine and Its Adjuvant Effect Compared with MF59.

Intranasal vaccination is more potent than parenteral injection for the prevention of influenza. However, because the poor efficiency of antigen uptake across the nasal mucosa is a key issue, immunostimulatory adjuvants are essential for intranasal vaccines. The immunomodulator mannatide or polyactin (PA) has been used for the clinical treatment of impaired immunity in China, but its adjuvant effect on an inactivated trivalent influenza vaccine (ITIV) via intranasal vaccination is unclear. To explore the adjuvant effect of PA, an inactivated trivalent influenza virus with or without PA or MF59 was instilled intranasally once a week in BALB/c mice. Humoral immunity was assessed by both the ELISA and hemagglutination inhibition (HI) methods using antigen-specific antibodies. Splenic lymphocyte proliferation and the IFN-γ level were measured to evaluate cell-mediated immunity. The post-vaccination serum HI antibody geometric mean titers (GMTs) for the H1N1 and H3N2 strains, antigen-specific serum IgG and IgA GMTs, mucosal SIgA GMT, splenic lymphocyte proliferation, and IFN-γ were significantly increased in the high-dose PA-adjuvanted vaccine group. The seroconversion rate and the mucosal response for the H3N2 strain were significantly elevated after high-dose PA administration. These adjuvant effects of high-dose PA for the influenza vaccine were comparable with those of the MF59 adjuvant, and abnormal signs or pathological changes were not found in the evaluated organs. In conclusion, PA is a novel mucosal adjuvant for intranasal vaccination with the ITIV that has safe and effective mucosal adjuvanticity in mice and successfully induces both serum and mucosal antibody responses and a cell-mediated response.

The prevalence of secretor status and co-expression of lewis antigen in voluntary blood donors

Background: Blood group substances are present in soluble form in a majority of individuals in secretion such as saliva and body fl uids. Secretor status refers to the presence (SeSe and Sese) or absence (sese) of secretor gene which secrete ABH soluble substances. Secretor status can be used to resolve ABO discrepancies of people whose blood group cannot be identified by routine blood grouping and it can also help in identifying patients who may be a high risk group for getting certain diseases. Aims and Objectives:Our aim and objectives of the study is to fi nd out the Prevalence of Secretor Status and Co-expression of Lewis Antigens among the Voluntary Blood Donors.Materials and Methods:This study was conducted in sixty volunteers and the method used to determine the secretor status was hemagglutination inhibition method. Their blood was used to detect the type of Lewis (Le) antigen since the type of Lewis antigen correlated with the secretor status of the individual.Results:Among the sixty subjects tested, forty fi ve of them were found to be secretors and fifteen of them were Non-secretors. The number of Lewis (a+b-) individuals were twelve, Lewis (a-b+) were thirty nine and Lewis (a-b-) were nine.Conclusion:The prevalence of secretors was 75% and non-secretors were 25% respectively. We found 65 % of the volunteers were found to be Le (a-b+) positive, 20% were Le (a+b-) and the remaining 15% were Le (a-b-) which correlated with the ABH antigen secretor status.Asian Journal of Medical Sciences Vol.7(5) 2016 93-96

Molecular basis of Bombay phenotype in Mashhad, Iran: identification of a novel FUT1 deletion.

Bombay phenotype is characterized by the lack of H substance both on red blood cell (RBC) surface and in body secretions. Mutations of fucosyltransferase 1 (FUT1) and fucosyltransferase 2 (FUT2) genes are resulted in this rare phenotype. Five unrelated patients were tested by hemagglutination and adsorption/elution techniques for the presence of ABH antigens. The saliva specimens were analysed by hemagglutination inhibition method. The exons 6 and 7 of ABO gene were sequenced to determine ABO genotype. The coding fragments of FUT1 and FUT2 were amplified and sequenced by specific primers. Serologic investigation confirmed Bombay phenotype in all individuals. FUT1 molecular analysis revealed a novel large deletion. Also two novel homozygous mutations were detected; one was a missense mutation (392T>C, L131P) and the other a three nucleotide deletion (668_670delACT, Y224del). FUT2 sequencing showed one reported null allele (428G>A, W143X) and one homozygous deletion of FUT2. Although FUT2 deletion has been reported, this is the first report of FUT1 deletion. Finding two FUT1 novel alleles in Iranian people is indicative of mutation diversity in this gene.

Synthesis and immunogenicity evaluating of a discontinuous B-cell epitope predicted from influenza virus A/H5N1 HA antigen

To develop vaccine with stable efficiency against easily transforming virus such as influenza A/H5N1 virus, bioinformatic tools have been used to predict conserved epitopes from viral antigens to be used as materials for the development of polyvalent vaccine against this virus. Using this approach, we have successfully predicted one discontinuous B-cell epitope, a peptide of 14 aminoacids on conserved domains of HA antigen from H5N1 influenza A virus. In this study, we report results of the preparation of this discontinuous B-cell epitope as the recombinant fusion form with H:1,2 flagellin from Salmonella typhimurium to increase the immunogenicity of this epitope using genetic manipulating techniques with Escherichia coli as host cell. The immunogenicity of the chemically synthesized predicted epitope and the recombinant epitope was examined by immunization of each of these epitopes to mice. Using hemagglutination inhibition (HI) method, we successfully demonstrated that both anti-sera from mice immunized either with chemically synthesized peptide or with recombinant flagellin H:1,2 fused epitope could recognize and inhibit the agglutination of inactivated influenza H5N1 virus strains, such as A/H5N1/ Chicken13/ Vietnam/LA/2006 and A/Vietnam/CL26/2004 (H5N1) isolated from infected chicken and human in Vietnam.

Examination of some biological properties of glycoprotein subunits of PHY-LMV.42 strain of Newcastle disease virus

The objective of our work was to investigate some biological characteristics of purified glycoprotein subunits of Newcastle disease virus strain PHY-LMV.42 isolated from pigeons for the purpose of vaccine production. PHY-LMV.42 strain of Newcastle disease virus was multiplied by successive passages in embryonated eggs and identified by the methods of Reverse transcriptase PCR and Real-Time PCR along with F gene sequencing. Proving the presence of HN and F antigene in the virus subunits samples was carried out by hemagglutination inhibition method with referent immune sera. Biochemical characterization of glycoprotein subunits was performed by SDS-PAGE method as well as liquid chromatography with mass spectrometry (LC ESI-TOF-MS/MS). Testing for the virus subunits immunogenicity was carried out in biological experiment on 75 laying hens Tetra-SSL and 25 chickens Isa Brown by inducing an artificial infection with Hertz 33 strain of the virus. Low concentrations of the virus antigens of 0.36 mg/ml along with glycoprotein fractions of 77 i 58 kDa manifested a strong hemagglutination activity of 4096 HJ/0,1ml. The subunit vaccines of 256 and 128 HJ/0.5 ml induced a protective immune response in all the vaccinated animals. Based on the obtained results it can be concluded that low concentrations of purified virus subunits of PHY-LMV.42 strain can be used for preparing of effective vaccines.

A seroepidemiological study of pandemic A/H1N1(2009) influenza in a rural population of Mali

The swine-origin H1N1 influenza A virus (pH1N1(2009)) started to circulate worldwide in 2009, and cases were notified in a number of sub-Saharan African countries. However, no epidemiological data allowing estimation of the epidemic burden were available in this region, preventing comprehensive comparisons with other parts of the world. The CoPanFlu-Mali programme studied a cohort of 202 individuals living in the rural commune of Dioro (southern central Mali). Pre-pandemic and post-pandemic paired sera (sampled in 2006 and April 2010, respectively) were tested by the haemagglutination inhibition (HI) method. Different estimates of pH1N1(2009) infection during the 2009 first epidemic wave were used (increased prevalence of HI titre of ≥ 1/40 or ≥ 1/80, seroconversions) and provided convergent attack rate values (12.4-14.9%), the highest values being observed in the 0-19-year age group (16.0-18.4%). In all age groups, pre-pandemic HI titres of ≥1/40 were associated with complete absence of seroconversion; and geometric mean titres were <15 in individuals who seroconverted and >20 in others. Important variations in seroconversion rate existed among the different villages investigated. Despite limitations resulting from the size and composition of the sample analysed, this study provides strong evidence that the impact of the pH1N1(2009) first wave was more important than previously believed, and that the determinants of the epidemic spread in sub-Saharan populations were quite different from those observed in developed countries.

Chronic psychosocial stress: does it modulate immunity to the influenza vaccine in Hong Kong Chinese elderly caregivers?

Previous studies evaluated the effects of psychosocial stress on influenza vaccine responses. However, there were methodological limitations. This study aims to determine whether chronic stress is associated with poorer influenza-specific immune responses to influenza vaccines in Hong Kong Chinese elderly people. This is a prospective study with a 12-week follow-up. Subjects were recruited from government general out-patient clinics, non-government organizations, and public housing estates in Hong Kong. Participants include 55 caregivers of spouses with chronic conditions that impaired their activities of daily living and 61 age- and sex-matched non-caregivers. A single-dose trivalent influenza vaccine was given to all subjects by intramuscular ingestion. Blood samples were collected before vaccination, at 6 weeks, and at 12 weeks after vaccination. Influenza vaccine strain-specific antibody titers were measured by the hemagglutination inhibition method. Lymphocyte subsets were analyzed for ratios and absolute counts, and cytokine concentration were measured by flow cytometry. Validated scales were used to assess psychological (depressive symptoms, perceived stress, and caregiver strain), social (multidimensional social support scale), and lifestyle factors (physical exercise, cigarette smoking, and alcohol consumption) at baseline prior to vaccination. Demographic and socioeconomic variables were also collected. Albumin levels were measured as an indicator for nutritional status in subjects. Caregivers had statistically significant (p < 0.05) lower cell-mediated immune responses to influenza vaccination at 12 weeks when compared with those of the controls. No differences in humoral immune response to vaccination were observed between caregivers and controls. Hong Kong Chinese elderly who experience chronic stress have a significantly lower cell-mediated immune response to influenza vaccination when compared with non-caregivers.

Influence of morinda citrifolia, L Fruit extract as adjuvant on IG-Y production raised in laying chickens against avian influenza vaccine

Immunized avian with vaccine, produces specific antibody in the serum as well as in the egg yolk. An adjuvant is used to augment the effects of a vaccine by stimulating the immune response. Morinda citrifolia, L., especially the fruit contains of some chemical compounds such as polysaccharide, scopoletin, damnacanthal, proxeronine and proxeroninase. All those of active compounds, are soluble in different solvents and have different activities. Some of those compounds have adjuvant activity. The aim of our study was to observe the capability of M.citrifolia fruit extracts as adjuvant to enhance the specific antibody (IgY) production in immunized laying chickens Lohmann strain (28 weeks old) with a commercially available avian influenza (H5N2) vaccine. To the groups (@6) of laying chickens were orally administered once a day, through out of the study, with n-hexane (group I; divided ino 3 sub groups), ethanolic (group II; divided into 3 subgroups) and aqueous extract (group III; divided into 3 subgroups) of M.citrifolia (prepared in capsules) on dose of 29 mg; 58 mg; and 116 mg/chicken/day, respectively, and group IV as plasebo control and group V as normal control. All of the groups were induced with avian influenza vaccine, except the normal control. Eggs of 3, 6, and 10 weeks after immunized, were collected. Isolation of IgY was performed by repeated polyethylene glycol 6000 precipitation steps. IgY obtained was analyzed by indirect ELISA method. The serum was tested for antibody specificity against the influenza H5N2 virus by hemagglutination-inhibition (HI) method. The result of this study showed that the dose of 58 mg/chicken/day of aqueous extract of M.citrifolia fruit had an optimal capability to enhance specific antibody (IgY) as well as IgG serum production against avian influenza (H5N2) vaccine . Key words: Adjuvant, extract, Morinda citrifolia, L., H5N2 vaccine, immunoglobulin yolk (IgY)