排序方式: 共有46条查询结果,搜索用时 15 毫秒
1.
Residue 3 of β2-microglobulin affects binding of class I MHC molecules by the W6/32 antibody 总被引:4,自引:0,他引:4
Previous studies of class I MHC molecules have shown that the owl monkey (Aotus) possesses at least two variants of the β2-microglobulin (β2m) protein. These two variants have different isoelectric points, and exhibit differential reactivity with the monoclonal
antibody W6/32. We report cDNA sequences of the B2m gene, from W6/32-positive and W6/32-negative Aotus cell lines. The two β2m variants we identified exhibit a single amino acid difference at position three. An arginine residue at position 3 was correlated
with W6/32 reactivity, whereas histidine was associated with non-reactivity. W6/32 reactivity was conferred to a W6/32-negative
Aotus cell line when it was transfected with the B2m from the W6/32-positive cell line. Residue 3 of β2m is located at the surface of the class I molecule. It is also close to position 121 of the MHC class I heavy chain, which
has previously been shown to influence W6/32 antibody binding. We conclude that W6/32 binds a compact epitope on the class
I molecule that includes both residue 3 of β2m and residue 121 of the heavy chain. We examined the distribution of the two β2m motifs in a sample Aotus population using an allele-specific polymerase chain reaction assay. The pattern of β2m segregation we observed matches that which was defined previously by serology. Additionally, we identified laboratory-born
hybrid animals who possess both variants of β2m.
Received: 1 April 1998 / Received: 3 July 1998 相似文献
2.
Flávio C. Canavez John J. Ladasky José A. P. C. Muniz Héctor N. Seuánez P. Parham 《Immunogenetics》1998,48(2):133-140
Nucleotide sequences for the three exons of the β2-microglobulin (β2m) gene (B2m) were determined for 135 animals representing 37 species and all 16 genera of neotropical primates (Platyrrhini). Twenty-eight
different nucleotide sequences, encoding for 26 different proteins, were obtained. In comparison with those of other primate
species, the β2-microglobulins of the Platyrrhini form a distinct clade. Individual genera of neotropical primates have distinctive B2m sequences, but within a genera species can have either the same or different B2m sequences. B2m polymorphism was found within three of the species sampled: Callicebus personatus, Saguinus midas, and Aotus azarae. Of these only the polymorphism in A. azarae has an effect upon the mature, functional β2m protein: residue 4 being either alanine or threonine. The A. azarae B2m allele encoding alanine at position 4 is shared with another species of Aotus (A. infulatus). In pairwise comparison the mature β2m proteins of neotropical primates differ by 1–9 amino acid substitutions which can occur at 18 positions within the sequence.
The substitutions are distributed throughout the primary structure but are more commonly found in loops rather than β strands
of the tertiary structure. Of 17 residues of β2m which hydrogen-bond with the class I heavy chain in human MHC class I molecules, 13 are conserved in the neotropical primates.
The overall pattern of sequence variation in the B2m genes of the Platyrrhini is consistent with an evolution by successive selectively neutral events.
Received: 13 November 1997 / Revised: 12 January 1998 相似文献
3.
This paper is a response to Gray MM, Sutter NB, Ostrander EA, Wayne RK: The IGF1 small dog haplotype is derived from Middle Eastern grey wolves. BMC Biology 2010, 8:16. 相似文献
4.
Paulo FP Pimenta Alessandra S Orfano Ana C Bahia Ana PM Duarte Claudia M Ríos-Velásquez Fabrício F Melo Felipe AC Pessoa Giselle A Oliveira Keillen MM Campos Luis Martínez Villegas Nilton Barnabé Rodrigues Rafael Nacif-Pimenta Rejane C Sim?es Wuelton M Monteiro Rogerio Amino Yara M Traub-Cseko José BP Lima Maria GV Barbosa Marcus VG Lacerda Wanderli P Tadei Nágila FC Secundino 《Memórias do Instituto Oswaldo Cruz》2015,110(1):23-47
In the Americas, areas with a high risk of malaria transmission are mainly located in
the Amazon Forest, which extends across nine countries. One keystone step to
understanding the Plasmodium life cycle in Anopheles species from the Amazon Region
is to obtain experimentally infected mosquito vectors. Several attempts to colonise
Ano- pheles species have been conducted, but with only short-lived success or no
success at all. In this review, we review the literature on malaria transmission from
the perspective of its Amazon vectors. Currently, it is possible to develop
experimental Plasmodium vivax infection of the colonised and field-captured vectors
in laboratories located close to Amazonian endemic areas. We are also reviewing
studies related to the immune response to P. vivax infection of Anopheles aquasalis,
a coastal mosquito species. Finally, we discuss the importance of the modulation of
Plasmodium infection by the vector microbiota and also consider the anopheline
genomes. The establishment of experimental mosquito infections with Plasmodium
falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide
interesting models for studying malaria in the Amazonian scenario is important.
Understanding the molecular mechanisms involved in the development of the parasites
in New World vectors is crucial in order to better determine the interaction process
and vectorial competence. 相似文献
5.
BACKGROUND: Biochemical testing for pheochromocytoma by measurement of fractionated plasma metanephrines is limited by false positive rates of up to 18% in people without known genetic predisposition to the disease. The plasma normetanephrine fraction is responsible for most false positives and plasma normetanephrine increases with age. The objective of this study was to determine if we could improve the specificity of fractionated plasma measurements, by statistically adjusting for age. METHODS: An age-adjusted metanephrine score was derived using logistic regression from 343 subjects (including 33 people with pheochromocytoma) who underwent fractionated plasma metanephrine measurements as part of investigations for suspected pheochromocytoma at Mayo Clinic Rochester (derivation set). The performance of the age-adjusted score was validated in a dataset of 158 subjects (including patients 23 with pheochromocytoma) that underwent measurements of fractionated plasma metanephrines at Mayo Clinic the following year (validation dataset). None of the participants in the validation dataset had known genetic predisposition to pheochromocytoma. RESULTS: The sensitivity of the age-adjusted metanephrine score was the same as that of traditional interpretation of fractionated plasma metanephrine measurements, yielding a sensitivity of 100% (23/23, 95% confidence interval [CI] 85.7%, 100%). However, the false positive rate with traditional interpretation of fractionated plasma metanephrine measurements was 16.3% (22/135, 95% CI, 11.0%, 23.4%) and that of the age-adjusted score was significantly lower at 3.0% (4/135, 95% CI, 1.2%, 7.4%) (p < 0.001 using McNemar's test). CONCLUSION: An adjustment for age in the interpretation of results of fractionated plasma metanephrines may significantly decrease false positives when using this test to exclude sporadic pheochromocytoma. Such improvements in false positive rate may result in savings of expenditures related to confirmatory imaging. 相似文献
6.
Reinout Raijmakers Joyce JBC van Beers Mahmoud El-Azzouny Natasja FC Visser Borut Bo?i? Ger JM Pruijn Albert JR Heck 《Arthritis research & therapy》2012,14(3):R114-10
Introduction
Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation of the joints and the presence of autoantibodies directed against proteins containing the non-standard arginine-derived amino acid citrulline. The protein fibrinogen, which has an essential role in blood clotting, is one of the most prominent citrullinated autoantigens in RA, particularly because it can be found in the inflamed tissue of affected joints. Here, we set out to analyze the presence of citrullinated endogenous peptides in the synovial fluid of RA and arthritic control patients.Methods
Endogenous peptides were isolated from the synovial fluid of RA patients and controls by filtration and solid phase extraction. The peptides were identified and quantified using high-resolution liquid chromatography-mass spectrometry.Results
Our data reveal that the synovial fluid of RA patients contains soluble endogenous peptides, derived from fibrinogen, containing significant amounts of citrulline residues and, in some cases, also phosphorylated serine. Several citrullinated peptides are found to be more abundantly present in the synovial fluid of RA patients compared to patients suffering from other inflammatory diseases affecting the joints.Conclusions
The increased presence of citrullinated peptides in RA patients points toward a possible specific role of these peptides in the immune response at the basis of the recognition of citrullinated peptides and proteins by RA patient autoantibodies. 相似文献7.
Comparison of chimpanzee and human leukocyte Ig-like receptor genes reveals framework and rapidly evolving genes. 总被引:2,自引:0,他引:2
F Canavez N T Young L A Guethlein R Rajalingam S I Khakoo B P Shum P Parham 《Journal of immunology (Baltimore, Md. : 1950)》2001,167(10):5786-5794
The leukocyte receptor complex (LRC) on human chromosome 19 contains related Ig superfamily killer cell Ig-like receptor (KIR) and leukocyte Ig-like receptor (LIR) genes. Previously, we discovered much difference in the KIR genes between humans and chimpanzees, primate species estimated to have approximately 98.8% genomic sequence similarity. Here, the common chimpanzee LIR genes are identified, characterized, and compared with their human counterparts. From screening a chimpanzee splenocyte cDNA library, clones corresponding to nine different chimpanzee LIRs were isolated and sequenced. Analysis of genomic DNA from 48 unrelated chimpanzees showed 42 to have all nine LIR genes, and six animals to lack just one of the genes. In structural diversity and functional type, the chimpanzee LIRs cover the range of human LIRs. Although both species have the same number of inhibitory LIRs, humans have more activating receptors, a trend also seen for KIRs. Four chimpanzee LIRs are clearly orthologs of human LIRs. Five other chimpanzee LIRs have paralogous relationships with clusters of human LIRs and have undergone much recombination. Like the human genes, chimpanzee LIR genes appear to be organized into two duplicated blocks, each block containing two orthologous genes. This organization provides a conserved framework within which there are clusters of faster evolving genes. Human and chimpanzee KIR genes have an analogous arrangement. Whereas both KIR and LIR genes can exhibit greater interspecies differences than the genome average, within each species the LIR gene family is more conserved than the KIR gene family. 相似文献
8.
Juliana M Sousa-Canavez Flavio C Canavez Kátia RM Leite Luiz H Camara-Lopes 《Genetic vaccines and therapy》2008,6(1):1-7
Background
Electroporation is an established technique for enhancing plasmid delivery to many tissues in vivo, including the skin. We have previously demonstrated efficient delivery of plasmid DNA to the skin utilizing a custom-built four-plate electrode. The experiments described here further evaluate cutaneous plasmid delivery using in vivo electroporation. Plasmid expression levels are compared to those after liposome mediated delivery.Methods
Enhanced electrically-mediated delivery, and less extensively, liposome complexed delivery, of a plasmid encoding the reporter luciferase was tested in rodent skin. Expression kinetics and tissue damage were explored as well as testing in a second rodent model.Results
Experiments confirm that electroporation alone is more effective in enhancing reporter gene expression than plasmid injection alone, plasmid conjugation with liposomes followed by injection, or than the combination of liposomes and electroporation. However, with two time courses of multiple electrically-mediated plasmid deliveries, neither the levels nor duration of transgene expression are significantly increased. Tissue damage may increase following a second treatment, no further damage is observed after a third treatment. When electroporation conditions utilized in a mouse model are tested in thicker rat skin, only higher field strengths or longer pulses were as effective in plasmid delivery.Conclusion
Electroporation enhances reporter plasmid delivery to the skin to a greater extent than the liposome conjugation method tested. Multiple deliveries do not necessarily result in higher or longer term expression. In addition, some impact on tissue integrity with respect to surface damage is observed. Pulsing conditions should be optimized for the model and for the expression profile desired. 相似文献9.