Different immune responses to three different vaccines following H6N1 low pathogenic avian influenza virus challenge in Taiwanese local chicken breeds.

BACKGROUND: H6N1 low pathogenic avian influenza virus (LPAIV) are frequently isolated in Taiwan and lead to significant economic losses, either directly or indirectly through association with other infectious diseases. This study investigates immune responses to three different vaccines following a H6N1 challenge in different local breeds. METHODS: Experimental animals were sampled from six local chicken breeds maintained at the National Chung-Hsing University, namely Hsin-Yi, Ju-Chi, Hua-Tung (Taiwan), Quemoy (Quemoy Island), Shek-Ki (China), Nagoya (Japan) and a specific pathogen free (SPF) White Leghorn line. A total number of 338 chickens have been distributed between a control and a challenge group, H6N1 challenge was performed at 7 weeks of age; vaccination against Newcastle Disease (ND), Infectious Bursal Disease (IBD) and Infectious Bronchitis (IB) was performed at 11 weeks. The anti-H6N1 LPAIV antibody titers were measured by ELISA at days 0, 7, 14 and 21 after challenge, and the anti-ND, anti-IBD and anti-IB antibody titers were measured by inhibition of hemagglutination test and ELISA at days 0, 14, 28 after vaccination. RESULTS: There was no effect of the H6N1 LPAIV challenge at 7 weeks of age on the subsequent responses to ND and IBD vaccine at 11 weeks of age, but, surprisingly, the H6N1 LPAIV challenge significantly affected antibody levels to IB vaccine in some breeds, since IB0 and IB14 antibody titers were lower in the challenge groups. However, there was no significant difference in IB28 antibody titers among the experimental groups. CONCLUSIONS: Local breeds have different immune response to H6N1 LPAIV challenge and subsequent vaccines. Differences dealt mainly with kinetics of response and with peak values. Quemoy exhibited higher antibody levels to H6N1, ND and IBD. The negative effect of the H6N1 LPAIV challenge on IB vaccine response may be related to the fact that both viruses target the lung tissues, and the type of local immune response induced by LPAIV challenge may not be favourable for birds to make optimum IB-specific antibody response.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

A high-density SNP panel reveals extensive diversity, frequent recombination and multiple recombination hotspots within the chicken major histocompatibility complex B region between BG2 and CD1A1

Background: The major histocompatibility complex (MHC) is present within the genomes of all jawed vertebrates. MHC genes are especially important in regulating immune responses, but even after over 80 years of research on the MHC, much remains to be learned about how it influences adaptive and innate immune responses. In most species, the MHC is highly polymorphic and polygenic. Strong and highly reproducible associations are established for chicken MHC-B haplotypes in a number of infectious diseases. Here, we report (1) the development of a high-density SNP (single nucleotide polymorphism) panel for MHC-B typing that encompasses a 209,296 bp region in which 45 MHC-B genes are located, (2) how this panel was used to define chicken MHC-B haplotypes within a large number of lines/breeds and (3) the detection of recombinants which contributes to the observed diversity. Methods: A SNP panel was developed for the MHC-B region between the BG2 and CD1A1 genes. To construct this panel, each SNP was tested in end-point read assays on more than 7500 DNA samples obtained from inbred and commercially used egg-layer lines that carry known and novel MHC-B haplotypes. One hundred and one SNPs were selected for the panel. Additional breeds and experimentally-derived lines, including lines that carry MHC-B recombinant haplotypes, were then genotyped. Results: MHC-B haplotypes based on SNP genotyping were consistent with the MHC-B haplotypes that were assigned previously in experimental lines that carry B2, B5, B12, B13, B15, B19, B21, and B24 haplotypes. SNP genotyping resulted in the identification of 122 MHC-B haplotypes including a number of recombinant haplotypes, which indicate that crossing-over events at multiple locations within the region lead to the production of new MHC-B haplotypes. Furthermore, evidence of gene duplication and deletion was found. Conclusions: The chicken MHC-B region is highly polymorphic across the surveyed 209-kb region that contains 45 genes. Our results expand the number of identified haplotypes and provide insights into the contribution of recombination events to MHC-B diversity including the identification of recombination hotspots and an estimation of recombination frequency

Correlation in chicken between the marker LEI0258 alleles and Major Histocompatibility Complex sequences

<p>Abstract</p> <p>Background</p> <p>The LEI0258 marker is located within the B region of the chicken Major Histocompatibility Complex (MHC), and is surprisingly well associated with serology. Therefore, the correlation between the LEI0258 alleles and the MHC class I and the class II alleles at the level of sequences is worth investigating in chickens. Here we describe to which extent the LEI0258 alleles are associated with alleles of classical class I genes and non-classical class II genes, in reference animals as well as local breeds with unknown MHC haplotypes.</p> <p>Methods</p> <p>For the class I region, in an exploratory project, we studied 10 animals from 3 breeds: Rhode Island Red, White Leghorn and Fayoumi chickens, by cloning and sequencing <it>B-F1</it> and <it>B-F2</it> cDNA from exon 1 to 3’UTR. For the class II region, we reconstructed haplotypes of the 8.8 kb genomic region encompassing three non-classical class II genes: <it>B-DMA</it>, <it>B-DMB1</it> and <it>B-DMB2</it>, for 146 animals from more than 50 breeds including wild species of jungle fowls.</p> <p>Results</p> <p>Overall we found that the LEI0258 marker genotypes gave good indications of the MHC haplotypes, and a very good predictions (>0.95) of the heterozygosity of an animal at the MHC locus.</p> <p>Conclusions</p> <p>Our results show that the LEI0258 alleles are strongly associated with haplotypes of classical class I genes and non-classical class II genes, unravelling the reasons why this marker is becoming the reference marker for MHC genotyping in chickens.</p

Chicken domestication: From archeology to genomics

 Current knowledge on chicken domestication is reviewed on the basis of archaeological, historical and molecular data. Several domestication centres have been identified in South and South-East Asia. Gallus gallus is the major ancestor species, but Gallus sonneratii has also contributed to the genetic make-up of the domestic chicken. Genetic diversity is now distributed among traditional populations, standardized breeds and highly selected lines. Knowing the genome sequence has accelerated the identification of causal mutations determining major morphological differences between wild Gallus and domestic breeds. Comparative genome resequencing between Gallus and domestic chickens has identified 21 selective sweeps, one involving a non-synonymous mutation in the TSHR gene, which functional consequences remain to be explored. The resequencing approach could also identify candidate genes responsible of quantitative traits loci (QTL) effects in selected lines. Genomics is opening new ways to understand major switches that took place during domestication and subsequent selection

Improved Basic Cytogenetics Challenges Holocentricity of Butterfly Chromosomes

Mitotic chromosomes of butterflies, which look like dots or short filaments in most published data, are generally considered to lack localised centromeres and thus to be holokinetic. This particularity, observed in a number of other invertebrates, is associated with meiotic particularities known as “inverted meiosis,” in which the first division is equational, i.e., centromere splitting-up and segregation of sister chromatids instead of homologous chromosomes. However, the accurate analysis of butterfly chromosomes is difficult because (1) their size is very small, equivalent to 2 bands of a mammalian metaphase chromosome, and (2) they lack satellite DNA/heterochromatin in putative centromere regions and therefore marked primary constrictions. Our improved conditions for basic chromosome preparations, here applied to 6 butterfly species belonging to families Nymphalidae and Pieridae challenges the holocentricity of their chromosomes: in spite of the absence of primary constrictions, sister chromatids are recurrently held together at definite positions during mitotic metaphase, which makes possible to establish karyotypes composed of acrocentric and submetacentric chromosomes. The total number of chromosomes per karyotype is roughly inversely proportional to that of non-acrocentric chromosomes, which suggests the occurrence of frequent robertsonian-like fusions or fissions during evolution. Furthermore, the behaviour and morphological changes of chromosomes along the various phases of meiosis do not seem to differ much from those of canonical meiosis. In particular, at metaphase II chromosomes clearly have 2 sister chromatids, which refutes that anaphase I was equational. Thus, we propose an alternative mechanism to holocentricity for explaining the large variations in chromosome numbers in butterflies: (1) in the ancestral karyotype, composed of about 62 mostly acrocentric chromosomes, the centromeres, devoid of centromeric heterochromatin/satellite DNA, were located at contact with telomeric heterochromatin; (2) the instability of telomeric heterochromatin largely contributed to drive the multiple rearrangements, principally chromosome fusions, which occurred during butterfly evolution

Biodiversité des petits Mammifères terrestres du Jardin des Plantes (Paris)

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Eugenics and medicalized reproduction Conceptual, historical, medical, and ethical considerations

Memo by the Inserm Ethics Committee. Embryo and Developmental Group. Written by: Bernard Baertschi and Pierre Jouannet.The classic eugenics of the late 19th century sought to improve the human race by relying on the coercive power of the state. This practice has been discredited, but it is sometimes argued that “liberal” or “private” eugenics has outlived it, particularly in the context of medically assisted reproduction (MAR). Indeed couples can resort to in vitro fertilization (IVF) when they wish to have a child who does not have certain serious genetic diseases in the name of reproductive freedom and the interest of the unborn child.“Liberal” or “private” eugenics is currently the subject of much debate. The main arguments underlying the current thinking are as follows: (a) even if the aim (not having a child with a serious genetic disease) is laudable, not all means of achieving it are necessarily so; (b) by choosing which embryo(s) to transfer, a choice is made as to the people who deserve to exist; (c) there is a risk of applying arbitrary or even immoral selection criteria; (d) some MAR practices involve the transmission of genetic mutations or chromosomal abnormalities (dysgenics); (e) the practice of genetic testing with the aim of choosing embryos without genetic diseases expresses a stigmatizing attitude towards people with disabilities (expressivist argument); (f) couples and the medical institution have a moral duty not to transfer an embryo carrying a deleterious gene; (g) couples are under a great deal of pressure to undergo testing, a pressure that could undermine their autonomy and their ability to choose freely; (h) the good of the child, a cardinal ethical and legal consideration, could be threatened by “private” eugenics; and (i) an alternative to embryo selection could be germline gene therapy, which is currently prohibited.Today, genetic testing and criteria can be used in a wide variety of ways whenreproduction is medicalized. These may include genetic factors sought in gamete and embryo donors to avoid the transmission to the child of a genetic pathology when the risk is known; chromosomal analysis of embryos to avoid transferring into the uterus those that will not develop to term; a preimplantation diagnosis on the embryos to avoid transmitting to the offspring genetic characteristics of the future parents that are likely to seriously harm the health of the unborn child; selection of embryos on the basis of polygenic scores to detect those less at risk of developing a pathology after birth; and selection of the child’s sex without any medical indication.Male sterility, for example, may be due to a chromosomal factor (Y-chromosome microdeletion) or a genic factor (mutations of the CFTR gene or genes involved in spermatogenesis). When spermatozoa can be used in ICSI, sterility can be bypassed, but chromosomal or genic modifications can be transmitted to offspring and cause sterility in boys. If no spermatozoa are available, an in vitro correction of the defective gene by genomic engineering in germ cells could be considered for the treatment of male infertility.As classical eugenics has been unanimously discredited, labeling a practice as eugenist is tantamount to condemning it. The law is currently doing the same. However, this was not always the case: before World War II, it was often viewed positively.The notion of eugenics was therefore devised at a time when genetics, in the sense of determinism and the process of transmitting inheritable traits, was not yet understood. Nowadays, a return to “genetic determinism” or “genetic program” sometimes resurfaces, often simplistically or erroneously based on the most recent data from knowledge acquired in genetics.The cumulative effect of couples’ decisions has some effect on the composition of future generations, albeit quantitatively minimal. However, there is no eugenist intention as such. A distinction must therefore be made between eugenics as a consequence and intentional eugenics. The first is not truly eugenics, so the term “eugenist” should be used only for interventions that promote the deliberate, intentional transmission of genetic traits or characteristics to offspring

Note « L'eugénisme et la procréation médicalisée. Considérations conceptuelles, historiques, médicales et éthiques »

Memo by the Inserm Ethics Committee. Embryo and Developmental Group. Written by: Bernard Baertschi and Pierre Jouannet.L’eugénisme classique de la fin du XIXe siècle voulait améliorer le genre humain en misant sur le pouvoir coercitif de l’État. Cette pratique a été discréditée, mais il est parfois avancé qu’un eugé-nisme « libéral » ou « privé » lui a survécu, notamment dans le cadre de l’assistance médicale à la procréation (AMP). En effet, au nom de la liberté procréative et de l’intérêt de l’enfant à naître, les couples peuvent recourir à la fécondation in vitro (FIV) quand ils désirent avoir un enfant qui ne soit pas atteint de certaines maladies génétiques graves.L’eugénisme « libéral » ou « privé » est actuellement fortement discuté. Les principaux ar-guments alimentant la réflexion actuelle sont les suivants: (a) même si le but visé (ne pas avoir d’enfant atteint de maladie génétique grave) est louable, tous les moyens de l’atteindre ne le sont pas nécessairement; (b) en choisissant quel(s) embryon(s) transférer, on sélectionne les personnes qui méritent d’exister; (c) on risque d’appliquer des critères de choix arbitraires, voire immoraux; (d) certaines pratiques d’AMP impliquent la transmission de mutations génétiques ou d’anomalies chromosomiques (le dysgénisme); (e) la pratique des tests génétiques dans le but de choisir des em-bryons non affectés par une maladie génétique exprime une attitude stigmatisante vis-à-vis des per-sonnes handicapées (argument expressiviste); (f) les couples et l’institution médicale ont le devoir moral de ne pas transférer un embryon porteur d’un gène délétère; (g) les couples sont soumis à une forte pression qui les pousse à recourir à des tests, pression qui pourrait mettre à mal leur autonomie et leur capacité à choisir librement; (h) le bien de l’enfant, considération cardinale pour l’éthique et le droit, pourrait être menacé par l’eugénisme « privé »; et (i) une alternative à la sélection des embryons pourrait être la thérapie génique germinale, actuellement interdite.À l’heure actuelle, l’utilisation de tests et de critères génétiques peut intervenir de manière très variée quand la procréation est médicalisée. Il peut s’agir de facteurs génétiques recherchés chez les donneurs de gamètes et d’embryons pour éviter la transmission à l’enfant d’une pathologie génétique quand le risque est connu; d’une analyse chromosomique des embryons pour éviter de transférer dans l’utérus ceux dont on sait qu’il ne se développeront pas jusqu’à terme; d’un diagnostic préimplantatoire sur les embryons pour éviter de transmettre à la descendance des caractères génétiques dont les futurs parents sont porteurs et qui sont susceptibles de porter gravement atteinte à la santé de l’enfant à naître; de sélectionner les embryons sur la base de scores polygéniques pour détecter ceux qui seraient moins à risque de développer une pathologie après la naissance; de choisir le sexe de son enfant en dehors de toute indication médicale.La stérilité masculine, par exemple, peut être due à un facteur chromosomique (micro-délé-tion du chromosome Y) ou génique (mutations du gène CFTR ou de gènes impliqués dans le bon déroulement de la spermatogenèse). Quand des spermatozoïdes peuvent être utilisés par ICSI, la stérilité peut être contournée, mais les modifications chromosomiques ou géniques peuvent être transmises à la descendance et être responsables de stérilité chez les garçons. Si aucun spermato-zoïde n’est disponible, une correction in vitro du gène défaillant par ingénierie génomique au ni-veau des cellules germinales pourrait être envisagée pour traiter l’infertilité masculine.L’eugénisme classique étant unanimement discrédité, taxer une pratique d’eugéniste revient à la condamner. Le droit fait actuellement de même. Mais cela n’a pas toujours été le cas: avant la 2e guerre mondiale, il était souvent considéré positivement.La notion d’eugénisme a donc été forgée à une époque où la génétique, au sens du détermi-nisme et du processus de transmission des caractères héritables, n’était pas encore comprise et de nos jours, un retour du « tout génétique » ou du « programme génétique » refait parfois surface, en s’appuyant le plus souvent de manière simpliste ou erronée sur les données les plus récentes des connaissances acquises en génétique.L’effet cumulé des décisions des couples a un certain effet sur la composition des générations futures, quoique quantitativement minime. Il n’y préside toutefois aucune intention eugéniste pro-prement dite. Il faut donc distinguer l’eugénisme en conséquence et l’eugénisme intentionnel. Le premier n’est pas véritablement un eugénisme, si bien que le terme « eugéniste » ne devrait être employé que pour les interventions favorisant la transmission délibérée et intentionnelle de traits ou caractères génétiques à la descendance