Proposed attributes of national wildlife health programmes.

Wildlife health is important for conservation, healthy ecosystems, sustainable development and biosecurity. It presents unique challenges for national programme governance and delivery because wildlife health not only crosses jurisdictional responsibilities and authorities but also inherently spans multiple sectors of expertise. The World Organisation for Animal Health (OIE) encourages its Members to have wildlife disease monitoring and notification systems. Where national wildlife health surveillance programmes do exist, they vary in scope and size. Evidence-based guidance is lacking on the critical functions and roles needed to meet the OIE's recommendations and other expectations of a national programme. A literature review and consultation with national wildlife health programme leaders identified five key attributes of national programmes: 1) being knowledge and science based; 2) fostering cross-nation equivalence and harmonisation; 3) developing partnerships and national coordination; 4) providing leadership and administration of national efforts; and 5) capacity development. Proposed core purposes include: 1) establishment and communication of the national wildlife health status; 2) leading national planning; 3) centralising information and expertise; 4) developing national networks leading to harmonisation and collaborations; 5) developing wildlife health workforces; and 6) centralising administration and management of national programmes. A national wildlife health programme should aim to identify, effectively communicate and manage the risk to or from a country's wildlife populations. It should generate the appropriate knowledge required to improve the effectiveness of wildlife policies and systems, including identifying and assessing emerging priorities, thus facilitating early warning, preparedness and preventive actions.

La santé de la faune sauvage a un impact important sur la préservation des espèces et d'écosystèmes sains, sur le développement durable et sur la biosécurité. Les défis sont nombreux et complexes pour les programmes nationaux de gouvernance et de mise en oeuvre car les responsabilités et les compétences juridictionnelles sont croisées et les secteurs d'expertise sont multiples. L'Organisation mondiale de la santé animale (OIE) encourage ses Membres à mettre en place des systèmes de notification et de surveillance des maladies de la faune sauvage. Les programmes existants sont de tailles et de compétences variables et les orientations prises concernant les fonctions indispensables pour répondre aux recommandations de l'OIE et à ce qui est attendu d'un programme national ne sont pas toujours déterminées sur une base scientifique. Une revue de la littérature et des consultations auprès de responsables des programmes nationaux de santé de la faune sauvage ont permis d'identifier cinq attributs à proposer pour ces programmes nationaux. Ces programmes doivent :1) fonctionner sur la base de données scientifiques ; 2) favoriser l'équivalence et l'harmonisation transnationales ; 3) développer des partenariats et une coordination à l'échelle nationale ; 4) encadrer et administrer les efforts nationaux ; et 5) assurer le renforcement des capacités. Les missions essentielles sont : 1) déterminer et rendre publique la situation sanitaire de la faune sauvage dans le pays ; 2) encadrer le plan national ; 3) centraliser l'information et l'expertise ; 4) développer les réseaux nationaux d'harmonisation et de collaboration ; 5) former des personnels compétents dans le domaine de la faune sauvage ; et 6) centraliser l'administration et la gestion des programmes nationaux. Les objectifs d'un programme national de santé de la faune sauvage sont d'identifier, de rendre publics et de gérer les risques pour les populations d'animaux sauvages ainsi que les risques générés par ces mêmes populations. Ces programmes doivent promouvoir les connaissances nécessaires pour améliorer l'efficacité des politiques et des systèmes applicables à la faune sauvage, en particulier l'identification et l'évaluation des nouvelles priorités afin de faciliter la mise en oeuvre de systèmes d'alerte précoce, de préparation aux urgences et d'action préventive.

La salud de los animales silvestres, tan importante para la conservación del medio, el buen funcionamiento de los ecosistemas, el desarrollo sostenible y la seguridad biológica, presenta singulares dificultades desde el punto de vista de la gobernanza y aplicación de programas nacionales, dado que la fauna silvestre no solo toca a múltiples responsabilidades y atribuciones jurisdiccionales sino que, por su propia naturaleza, convoca a una plétora de especialidades técnicas. La Organización Mundial de Sanidad Animal (OIE) alienta a sus Miembros a que se doten de sistemas de vigilancia y notificación de enfermedades de la fauna silvestre. Allí donde existen, los programas nacionales en la materia son muy variopintos en cuanto a sus dimensiones y alcance. Faltan pautas científicamente sólidas sobre las funciones y atribuciones básicas que se requieren para cumplir las recomendaciones de la OIE y otras expectativas a las que pueda responder un programa nacional. Tras efectuar un estudio bibliográfico y consultar a los directivos de programas nacionales en la materia, los autores determinaron cinco atributos clave que debe reunir todo programa nacional: 1) estar basado en el saber y la ciencia; 2) favorecer la equivalencia y la armonización entre naciones; 3) crear alianzas y mecanismos de coordinación nacional; 4) encabezar y administrar las actividades a escala nacional; y 5) desarrollar los medios de acción del país. Los objetivos básicos propuestos son: 1) determinar y dar a conocer la situación sanitaria de la fauna silvestre del país; 2) dirigir las labores de planificación a escala nacional; 3) centralizar la información y las competencias especializadas; 4) instituir redes nacionales que propicien la armonización y las iniciativas de colaboración; 5) desarrollar los recursos humanos dedicados a la sanidad de la fauna silvestre; y 6) centralizar la gestión y administración de los programas nacionales. Todo programa nacional de sanidad de la fauna silvestre debe responder a la finalidad de detectar, comunicar eficazmente y gestionar los riesgos que amenacen a las poblaciones de animales silvestres del país o que provengan de ellas. A tal efecto debe generar el conocimiento adecuado y necesario para conferir más eficacia a las políticas y sistemas tocantes a la fauna silvestre, lo que supone, entre otras cosas, determinar y evaluar las nuevas prioridades, facilitando con ello la alerta anticipada y las labores de preparación y prevención.

Network analysis of wildlife translocations in New Zealand.

AIMS: To identify network measures with relevance to disease spread in a network of movements derived from the Department of Conservation (DOC) translocation records from 1970 to mid-2014, and to identify conservation sites that should be prioritised for surveillance activities and improvements to data collection to make the best use of network analysis techniques in the future. METHODS: Data included the source and destination of translocated specimens, the species and the dates the translocations were expected to occur. The data were used to construct a directed, non-weighted network in which a translocation event represented a tie in the network. Network density, in-degree (movements entering a node of interest) and out-degree (movements leaving a node of interest) and reciprocity were calculated. RESULTS: The data analysed consisted of 692 unique translocations between 307 sites, with the majority (518; 73%) being for birds. The constructed network for bird, reptile and frog translocations comprised 260 nodes, with 34/260 (13%) having two-way movements and 47/260 (18%) non-reciprocal movements. The median degree score (sum of in- and out-degree) was two (min 0, max 36) with a mean of 3.5 in a right skewed distribution. Most sites acted as receivers or senders of consignments with only a few having both high in- and high out-degree, and thus had characteristics that made them sites of interest for surveillance activities. These included the National Wildlife Centre at Mount Bruce, Tiritiri Matangi Island and Te Kakahu (Chalky Island). CONCLUSIONS: The presence of linking sites that join larger clusters within the network creates the potential for rapid disease spread if a pathogen were to be introduced. The important sites that supply or receive specimens for translocations are already well recognised by those performing translocations in New Zealand, and this paper provides further information by quantifying their role within the network.

Incidental learning and task boundaries.

For skill learning processes to be effective, they must encode associations that are inherent to the current task and avoid those that are spurious or particular to training conditions so that learning can transfer to novel situations. Some everyday contexts even require grouped responding to simultaneously presented stimuli. Here we test whether learning of these grouped responses depends on overlap in stimulus and/or response modality or on the conceptualization of the stimulus and response streams as belonging to a common task. In the present experiments, participants made 2 responses to 2 simultaneously presented stimuli, and learning was assessed by comparing performance on response combinations that had been practiced throughout training to performance on combinations that had been withheld. Experiments 1-4 paired the same visual-manual task with a 2nd task that differed in terms of the stimulus modality, the response modality, neither modality, or both modalities. Combination-specific learning was only observed when both the stimulus and response modalities were the same for the 2 tasks. However, Experiments 5 and 6 showed that combination-specific learning could occur with nonoverlapping stimulus modalities or response modalities if the 2 tasks were conceptually related. The results suggest that task representations provide top-down constraints on skill learning processes.

Surveillance for avian influenza virus subtypes H5 and H7 in chickens and turkeys farmed commercially in New Zealand.

AIM: To determine the status of avian influenza (AI) virus sub-types H5 and H7 of New Zealand's commercial chicken and turkey farms. METHODS: A cross-sectional serological survey, stratified by production sector, used a sample frame defined by those farms registered with the Poultry Industry Association of New Zealand (PIANZ) or the Egg Producers Federation of New Zealand (EPF). Sectors included were chicken broiler, caged/barn layer, free-range layer, pullet rearer and turkey broiler. The survey used a between- and within-farm design prevalence of 5% (95% confidence for chickens, 99% confidence for turkeys) and 30% (95% confidence), respectively, of AI virus subtypes H5 and H7. The epidemiological unit was the farm for the free-range layer sector, and the individual shed/barn for the other sectors. Serum samples were screened using a commercial generic influenza A indirect ELISA; positive samples were subjected to haemagglutination-inhibition (HI) testing for AI virus subtypes H5 and H7. A comprehensive investigation, that included widespread serological and antigenic screening, was carried out on all farms identified with serum reactors to either the H5 or H7 virus subtype. RESULTS: A total of 4,180 blood samples from 167 chicken and 10 turkey farms were collected and tested using ELISA. Positive ELISA results were returned from 26 farms, comprising 10 caged/barn layer, 14 free-range layer and two turkey (shed-raised) broiler farms. HI testing of ELISA-positive sera for the H7 subtype virus identified no positive sera in any sector. Reactors to the H5 subtype virus were limited to three free-range layer chicken farms; each farm returned a single serum reactor. Follow-up investigations on these free-range farms identified evidence of historic exposure to the H5 subtype virus on one farm, and concluded that the serum reactors identified in the initial sampling round on the other two farms were non-specific (false-positive) reactions. CONCLUSIONS: The survey found no evidence of active infection with notifiable AI viruses, and provided evidence of absence of exposure to AI virus subtypes H5 and H7 in the chicken broiler, caged/barn layer, turkey broiler and pullet-rearer sectors at a between- and within-farm prevalence of 5% and 30%, respectively, with 95% confidence. The results established commercial free-range layer farms as a risk sector for exposure to notifiable AI virus.

Contamination by persistent organic pollutants in dumping sites of Asian developing countries: implication of emerging pollution sources.

In Asian developing countries, large amounts of municipal wastes are dumped daily in open dumping sites without proper management. This practice may cause several adverse environmental consequences and increased health risk to local communities. To elucidate contamination by persistent organic pollutants (POPs)--including dichloro-diphenyl-trichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), chlordanes, hexachlorobenzene (HCB), and polychlorinated biphenyls (PCBs)--in such dumping sites, soil samples were collected from open dumping sites and respective control sites in Cambodia, India, and Vietnam from 1999 through 2001. Our results demonstrated that DDTs, PCBs, and HCHs were dominant contaminants in the dumping sites. However, the contamination pattern was not consistent, showing higher HCHs in India than in Cambodia and Vietnam. Interestingly, in all of the countries, extremely higher levels of POPs were observed in the dumping sites compared with those in the respective control sites, suggesting significant amplification of POP contamination in the dumping sites of Asian developing countries. Mean concentrations of DDTs and PCBs were 350 and 140 ng/g dry weight, respectively, in the dumping sites of Cambodia and 26 and 210 ng/g, respectively, in India. These residue levels were hundreds to thousands times higher than those in general soils, implying possible risk to human health of the local communities, especially to the rag pickers, including children who work in these sites to collect recyclable materials. Composition of DDT compounds suggested their recent use in populated areas, which in turn might have caused increased levels of DDTs in the open dumping sites. In addition, composition of HCH isomers revealed their different use pattern in different countries.

Two unusual cases of Anderson-Fabry disease in a Japanese family.

A 16-year-old Japanese girl was admitted to our hospital on February 27, 2001, for acute renal failure. She had not shown proteinuria or hematuria in any school examination through 2000. The first renal biopsy specimen showed focal segmental glomerulosclerosis and tubulointerstitial change. Electron microscopy showed numerous myeloid bodies in the glomerular epithelium suggesting the diagnosis of Anderson-Fabry disease. After electron microscopy, we measured WBC alpha-galactosidase A, which was slightly decreased to 36.1 nmol/mg P/h (normal: 49.8 - 116.4). WBC alpha-galactosidase A levels for other family members were 74.3 for the mother, 4.8 for the father, 45.6 for the elder sister, and 16.3 for the younger sister. During the follow-up, she had two episodes of nephrotic syndrome, which responded well to steroid therapy. Both second and third renal biopsy showed numerous myeloid bodies by electron microscopy. A 52-year-old man, the father of the case one patient, was admitted for renal biopsy because of proteinuria and low levels of WBC alpha-galactosidase. Biopsy specimen showed typical changes under light microscopy and typical myeloid bodies by electron microscopy. Our cases underscore the importance of electron microscopy when examining the biopsy specimen and suggest that undiagnosed Anderson-Fabry disease may be present, in particular on chronic dialysis.

Dioxins and related compounds in human breast milk collected around open dumping sites in Asian developing countries: bovine milk as a potential source.

In this study, concentrations of dioxins and related compounds (DRCs)--such as polychlorinated dibenzo- p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls--were found in human breast milk from women living near dumping sites of municipal waste and reference sites in India, Cambodia, Vietnam, and the Philippines during 1999 to 2000. DRCs were detected in all human breast milk samples analyzed, demonstrating that residents in these Asian developing countries have been exposed to these contaminants. In India, the concentrations of DRCs in human breast milk from women living near the investigated dumping site were notably higher than those from women living near reference sites and from women in other Asian developing countries. Toxic equivalent quantity (TEQ) levels of DRCs were comparable with or higher than those reported in the general populations of developed countries since 1990. In contrast, levels of these contaminants in human breast milk in women from Cambodia and Vietnam were not significantly different between milk from women living near the dumping and reference sites. These results indicate that significant pollution sources for DRCs are present in Indian dumping sites and that residents there have been exposed to relatively higher levels of these contaminants. TEQ levels in human breast milk from the dumping site in India tended to decrease with an increase in the number of previous deliveries by mothers, whereas no significant relationship was observed in Cambodia, Vietnam, or the Philippines. This suggests that mothers who have been exposed to relatively high levels of DRCs transfer greater amounts of these contaminants to the first infant than later ones through breast-feeding, which in turn implies that the first children of these mothers might be at higher risk from DRCs. When the residue levels of DRCs in bovine milk collected from the Indian dumping site and reference sites were examined, TEQ levels in bovine milk from the dumping site were higher than those from reference sites. This result suggests that bovine milk is a potential source of DRCs for residents living near the dumping site in India. To our knowledge, this is the first comprehensive study on exposure to DRCs of residents living in proximity to open dumping sites of municipal waste in Asian developing countries.

Angiotensin-converting enzyme (ACE) insertion/deletion polymorphism and survival in a cohort of chronic hemodialysis patients.

BACKGROUND: There are conflicting reports regarding the relationship between the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and the initiation and progression of cardiovascular disease. Moreover, there is no report regarding the relationship between the ACE I/D polymorphism and the prognosis of chronic dialysis patients. METHODS: We examined the frequency of the ACE I/D polymorphism in 727 chronic hemodialysis patients in Okinawa, Japan, and observed the prognosis over 2 years in 407 men and 320 women with mean age (SD) of 55.5 (13.9) years with a mean duration of dialysis of 84.3 (66.6) months. RESULTS: Genotype frequencies were 42.1% for II, 43.2% for ID, and 14.7% for DD. The relative risks of death were examined by Cox-proportional hazards analysis after adjusting for age, sex, age at the start of dialysis, presence of diabetes mellitus and hypertension and total cholesterol and serum albumin levels. The adjusted hazard ratio (95% confidence interval) was 1.03 (0.38 - 2.85) for DD genotype and 1.50 (0.83 - 2.70) for DD+ID genotype when compared to II genotype. CONCLUSION: ACE I/D polymorphism appears to have no relation to the short-term prognosis in chronic hemodialysis patients.

Comparative analysis of HLA restriction and cytokine production in hepatitis B surface antigen-specific T cells from low- and high-antibody responders in vaccinated humans.

It is well known that individuals with low, or lack of, antibody production in response to hepatitis B surface antigen (HBsAg) exist in the human population. We have previously reported that HLA class I and class II genes are both involved in antibody production to HBsAg, and that specific alleles of HLA are associated with low and high antibody production. To elucidate further the mechanisms by which the diversity of antibody production to HBsAg is generated in humans, a total of 146 T-cell clones specific for HBsAg were produced from six healthy vaccinees (three low- and three high-antibody responders) and were examined for cytokine production and HLA restriction. It was found that the majority of the T-cell clones from the low-antibody responders were Th1- or Th0-like T cells (62% or 19%, respectively), whereas the majority of T-cell clones from the high-antibody responders were Th2-like T cells (77%), suggesting predominant expansion of Th1/Th0- and Th2-like T cells specific for HBsAg in the low- and high-antibody responders, respectively. This is the first evidence that the diversity of the response to HBsAg in humans is controlled by the activation of functionally distinct CD4+ T-cell subsets, i.e., Th0, Th1, or Th2 T cells.

Family history of hypertension and blood pressure in a screened cohort.

We sought to determine whether a family history of hypertension is quantitatively associated with the prevalence of hypertension and blood pressure in a screened cohort. Clinical data and family (parents and siblings) histories regarding hypertension were collected from 9,914 individuals (probands) who were interviewed and examined during a one-day clinic by the Okinawa General Health Maintenance Association in 1997. We used logistic analysis to calculate odds ratios with adjustments for age, sex, body mass index, total cholesterol, presence of diabetes mellitus, alcohol use, cigarette smoking, and status of physical exercise. The age- and sex-adjusted hypertension prevalences in probands were 29.0% for those with 1 family member with a history of hypertension (n=2,112), 37.6% for those with 2 hypertensive family members (n=374), and 47.3% for those with 3 or more hypertensive family members (n=68). In contrast, only 16.4% of probands who reported no family history of hypertension (n=7,360) were hypertensive themselves. The trend of the prevalence according to the number of family members with a history of hypertension was significantly positive (p=0.003). The adjusted odds ratios (95% confidence interval) of hypertension were 2.74 (2.43-3.10) for 1 member, 4.62 (3.62-5.90) for 2 members, and 6.04 (3.51-10.4) for 3 or more members with a history of hypertension. In patients without antihypertensive medication (n=9,009), systolic/diastolic blood pressure (mean +/- SD) was 121 +/- 17/75 +/- 11 for 1 member, 124 +/- 18/77 +/- 12 for 2 members, and 127 +/- 17/78 +/- 11 for 3 or more members with a history of hypertension. In contrast, the mean systolic/diastolic blood pressure of probands who reported no family history of hypertension (n=7,360) was 119 +/- 15/74 +/- 10 mmHg, which was significantly (p<0.05) lower than that of any of the groups with hypertensive family members. In conclusion, an increase in the number of family members with hypertension was associated with an increasing prevalence of hypertension and blood pressure in the probands, independent of conventional risk factors for hypertension. Family members of hypertensive subjects may need to be treated in primary prevention efforts related to hypertension.

Multiple risk factor clustering of hypertension in a screened cohort.

OBJECTIVE: A family history of hypertension, obesity, diabetes mellitus, hypercholesterolaemia and hypertriglyceridaemia have all been associated with the risk for hypertension. We evaluated whether the clustering of these risk factors increases the risk for hypertension or whether the accumulation of risk factors is associated with the blood pressure level in non-hypertensive subjects. METHODS AND SUBJECTS: We assessed the clinical data and family history of hypertension (in parents and siblings) for 9914 individuals (6163 men and 3751 women, 18-89 years old) who were screened in Okinawa, Japan, in 1997. RESULTS: In 9914 subjects (2465 hypertensive and 7449 non-hypertensive subjects), all the five factors were positively associated with hypertension. The odds ratios (95% confidence interval) for the number of risk factors were 1.88 (1.62-2.18) for one risk factor, 3.06 (2.62-3.57) for two, 5.25 (4.37-6.30) for three, 8.71 (6.48-11.72) for four and 24.48 (8.49-70.56) for five, after adjusting for age, sex, alcohol consumption, cigarette smoking and physical exercise habits. In non-hypertensive subjects, multivariate regression analyses showed that the number of risks was positively correlated with blood pressure; the regression coefficient was 1.96 (P < 0.0001) for systolic blood pressure, and 1.47 (P < 0.0001) for diastolic blood pressure after adjusting for age and sex. CONCLUSIONS: Clustering of risk factors was significantly associated with hypertension. The number of risk factors positively correlated with the blood pressure levels in nonhypertensive subjects. The accumulation of risk factors may play an important role in the pathogenesis of hypertension, and thus the aggregation of risk factors may need to be addressed in primary prevention efforts related to hypertension.

Magnitude of structural changes of the T-cell receptor binding regions determine the strength of T-cell antagonism: molecular dynamics simulations of HLA-DR4 (DRB1*0405) complexed with analogue peptide.

In our model system, we generated T cell clones specific for the HLA-DR4 (DRB1*0405)-index peptide (YWALEAAAD) complex. Based on response patterns of the T cell clones, analogue peptides containing single amino acid substitutions of the index peptide were classified into three types, agonists, antagonists or null peptides (non-agonistic and non-antagonistic peptides). Subtle structural changes induced by the antagonists in the T-cell receptor (TCR) binding regions have already been explained using the root mean square (r.m.s.) deviations from the DR4-index peptide complex in the molecular dynamics (MD) trajectory. In this work, we performed additional MD simulations at 300 K with explicit solvent molecules to reveal the structural character of the HLA-DR4 complexed with the analogue peptides. We examined the r.m.s. deviations of the TCR-binding sites and the exposed areas of the bound peptides. Remarkable differences of the r.m.s. deviations among the DR4-antagonist complexes, together with our previous data, suggest that the magnitude of structural changes of TCR-binding regions would determine the strength of TCR antagonism. The simulations also indicate that TCR could discriminate null peptides from other ligands mainly through the changes of exposed side chains of the bound peptide, rather than the conformational changes of TCR-binding surfaces on HLA molecule.

An HLA-binding-motif-aided peptide epitope library: a novel library design for the screening of HLA-DR4-restricted antigenic peptides recognized by CD4+T cells.

Susceptibility to a series of autoimmune diseases is strongly associated with particular HLA class II alleles. Identification of T cell clones and antigenic epitopes bound by HLA class II molecules involved in autoimmune diseases is critical to understanding the etiology of these HLA class II-associated diseases. However, establishment of T cell clones in autoimmune diseases is difficult because the antigenic peptides are unknown. Peptide library methods which include all possible peptide sequences offer a potentially powerful tool for the detection of cross-reactive antigenic peptides recognized by T cells. Here, we reduced the number of peptides per mixture by utilizing the known binding motifs of peptides for the HLA-DRB1*0405 molecule and evaluated the effectiveness of this library design. Each library mixture evoked a strong proliferative response in the unprimed peripheral blood lymphocytes (PBL) from HLA-DRB1*0405-positive donors but little or no response in the PBL from HLA-DRB1*0405-negative donors. The library also detected antigenic peptides that activated three antigen-specific T cell lines restricted by HLA-DRB1*0405, with different specificities. The motif-based approach thus presents a powerful method for monitoring T cells in large, heterogeneous T cell populations and is useful for the identification of the mimic peptide epitopes of T cell lines and clones.

MHC class I bound peptides of a colon carcinoma cell line, a Ki-ras gene-targeted progeny cell line and a B cell line.

MHC class I associated peptides on cancer cells represent potential targets for CD8+ cytotoxic T cell activity against tumor cells. We eluted the naturally bound MHC class I peptides of a colon carcinoma cell line and compared them to peptides isolated from a B cell line and a slow-growing activated Ki-ras-disrupted colon cancer cell line. While we failed to detect any significant differences in class I associated peptides due to the presence or absence of activated Ki-ras in colon cancer cell lines, the colon cancer cell lines and B cell line presented vastly different peptide repertoires in the context of HLA-A*0201 molecules.

Molecular dynamics simulations of HLA-DR4 (DRB1*0405) complexed with analogue peptide: conformational changes in the putative T-cell receptor binding regions.

The specific recognition of foreign peptide bound to the major histocompatibility complex (MHC) molecule by T-cell receptor (TCR) leads to T-cell activation. We found that analogue peptides containing single amino acid substitutions at the third amino acid position (p3), p5, p7 and p8 of the index peptide (YWALEAAAD) induced different response patterns of T cell clones specific for the index peptide in the context of the human MHC class II molecule HLA-DR4. Analogue peptides were classified into three types, agonists, antagonists or null peptides (non-agonistic and non-antagonistic peptides). A molecular basis for how these slight changes lead to such different consequences for T cells has not been described. To explore the mechanistic basis of these observations, molecular dynamics simulations at 300 K of 300 ps duration were carried out for the DR4-index peptide, DR4-agonist, and DR4-antagonist complexes. The simulations showed that the DR4-antagonist complexes were distinguished from the DR4-index peptide and DR4-agonist complexes by relatively higher deviations of C(alpha) atoms in proposed TCR-binding regions, suggesting that subtle changes of the exposed framework of the peptide binding groove by the antagonist peptides could induce the TCR antagonistic activities.

Contribution of HLA class I and class II alleles to the regulation of antibody production to hepatitis B surface antigen in humans.

The HLA multigene family consists of HLA class I (HLA-A, B and C) and class II (HLA-DR, DQ and DP) genes, and plays a central role in the regulation of immune response. To investigate how each HLA gene and each HLA allele contribute to the human immune response, we immunized 339 healthy Japanese medical students with recombinant hepatitis B surface antigen (rHBsAg) and determined the HLA types of all vaccinated subjects at the DNA level. The anti-HBs antibody titers showed a log-normal distribution, implying that the immune response to HBsAg in humans is a multifactorial and continuous trait. A stepwise multiple regression analysis demonstrated the alleles at the HLA-class I (HLA-A and B) and class II (HLA-DRB1, DQA1, DQB1, DPA1 and DPB1) loci significantly contributed to antibody production to HBsAg. The predicting equation of anti-HBs antibody levels for individuals with any HLA phenotype was proposed based on a multiple regression analysis. The multiple correlation coefficient of antibody production to HBsAg with the HLA-DRB1 locus was highest (0.34) among all of the HLA loci, whereas those with whole HLA class I or class II loci were 0.36 or 0.44 respectively. The incorporated correlation coefficient of the presence of all HLA gene families with antibody production became 0.50, suggesting that HLA class I and class II loci within the HLA multigene family are dynamically involved in regulation of the immune response to HBsAg.

Identification of an epitope for T-cells correlated with antibody response to hepatitis B surface antigen in vaccinated humans.

Two antigenic T-cell epitopes of HBsAg, designated HBs 16-31 and HBs 81-99, were identified using synthetic peptides and HBsAg-specific T-cell lines. HBs 16-31 was recognized by five HBsAg-specific T-cell lines from vaccinees with both high and low antibody titers, whereas HBs 81-99 was recognized by two T-cell lines derived from vaccinees with high antibody titers. The antibody titer against HBsAg was correlated significantly with the proliferation of vaccinee's PBLs in response to HBs 81-99 (r = 0.47) but not to HBs 16-31, suggesting that HBs 81-99 plays a critical role in anti-HBs antibody production in humans vaccinated with HBsAg.

[Two siblings with adult-onset sialidosis type I (cherry-red spot-myoclonus syndrome)].

Cases of two Japanese siblings with adult-onset sialidosis type I are reported. A 38-year-old man had gradually developed involuntary movement of the extremities from the age of 31. On admission, he had no skeletal abnormalities and hepatosplenomegaly, but showed myoclonus of the extremities and dyskinesia in the perioral region. We found cherry-red spots and a giant potential in a somatosensory evoked potential (SEP) study. Then, the diagnosis of sialidosis type I was confirmed by low activity of white blood cell sialidase. MRI (SE, TR 2,000/TE 100, 40) of the brain revealed a small high intensity are in the cerebral white matter adjacent to the posterior horn of the right cerebral ventricle. To our knowledge, no report on MRI findings of the brain in sialidosis type I has been reported. So far, it is uncertain whether or not such a lesion is caused by sialidosis. He was treated with clonazepam, sodium valproate, diphenylhydantoin, or haloperidol. The former two improved the symptoms, but SEP findings did not change. The subject's 43-year-old brother had also myoclonus and epilepsy since the age of 31, and low activity of sialidase. Their mother had no symptoms, but her sialidase activity level was as low as that of a carrier. These two are the eighth and ninth cases of sialidosis type I in Japan to be confirmed by enzyme activity.