排序方式: 共有54条查询结果,搜索用时 15 毫秒
1.
Sibylle Bernard-Stoecklin Céline Gommet Aurélien B. Corneau Sabrina Guenounou Claire Torres Nathalie Dejucq-Rainsford Antonio Cosma Nathalie Dereuddre-Bosquet Roger Le Grand 《PLoS pathogens》2013,9(12)
The mucosal events of HIV transmission have been extensively studied, but the role of infected cells present in the genital and rectal secretions, and in the semen, in particular, remains a matter of debate. As a prerequisite to a thorough in vivo investigation of the early transmission events through infected cells, we characterized in detail by multi-parameter flow cytometry the changes in macaque seminal leukocytes during SIVmac251 infection, focusing on T cells, macrophages and dendritic cells. Using immunocytofluorescence targeting SIV proteins and real-time quantitative PCR targeting SIV DNA, we investigated the nature of the infected cells on sorted semen leukocytes from macaques at different stages of infection. Finally, we cocultured semen CD4+ T cells and macrophages with a cell line permissive to SIV infection to assess their infectivity in vitro. We found that primary infection induced strong local inflammation, which was associated with an increase in the number of leukocytes in semen, both factors having the potential to favor cell-associated virus transmission. Semen CD4+ T cells and macrophages were productively infected at all stages of infection and were infectious in vitro. Lymphocytes had a mucosal phenotype and expressed activation (CD69 & HLA-DR) and migration (CCR5, CXCR4, LFA-1) markers. CD69 expression was increased in semen T cells by SIV infection, at all stages of infection. Macrophages predominated at all stages and expressed CD4, CCR5, MAC-1 and LFA-1. Altogether, we demonstrated that semen contains the two major SIV-target cells (CD4+ T cells and macrophages). Both cell types can be productively infected at all stages of SIV infection and are endowed with markers that may facilitate transmission of infection during sexual exposure. 相似文献
2.
Sarah Kutscher Claudia J. Dembek Simone Deckert Carolina Russo Nina K?rber Johannes R. Bogner Fabian Geisler Andreas Umgelter Michael Neuenhahn Julia Albrecht Antonio Cosma Ulrike Protzer Tanja Bauer 《PloS one》2013,8(10)
Polyfunctional CD4 or CD8 T cells are proposed to represent a correlate of immune control for persistent viruses as well as for vaccine mediated protection against infection. A well-suited methodology to study complex functional phenotypes of antiviral T cells is the combined staining of intracellular cytokines and phenotypic marker expression using polychromatic flow cytometry. In this study we analyzed the effect of an overnight resting period at 37°C on the quantity and functionality of HIV-1, EBV, CMV, HBV and HCV specific CD4 and CD8 T-cell responses in a cohort of 21 individuals. We quantified total antigen specific T cells by multimer staining and used 10-color intracellular cytokine staining (ICS) to determine IFNγ, TNFα, IL2 and MIP1β production. After an overnight resting significantly higher numbers of functionally active T cells were detectable by ICS for all tested antigen specificities, whereas the total number of antigen specific T cells determined by multimer staining remained unchanged. Overnight resting shifted the quality of T-cell responses towards polyfunctionality and increased antigen sensitivity of T cells. Our data suggest that the observed effect is mediated by T cells rather than by antigen presenting cells. We conclude that overnight resting of PBMC prior to ex vivo analysis of antiviral T-cell responses represents an efficient method to increase sensitivity of ICS-based methods and has a prominent impact on the functional phenotype of T cells. 相似文献
3.
Neurotoxins from snake venoms act as potent antagonists on the nicotinic acetylcholine receptors (nAChRs). Alpha-neurotoxins such as alpha-bungarotoxin (alpha-Btx) selectively bind to the skeletal muscle nAChRs among other subtypes, causing failure of the neuromuscular transmission. Through evolution, some species including snakes and mongoose have developed resistance to alpha-neurotoxins via specific amino acid substitutions in their muscle-type nAChR alpha1 subunit, which constitutes most of the toxin-binding site. Here we analyze these sequence variations in the context of our recent crystal structure of the extracellular domain of the mouse nAChR alpha1 bound to alpha-Btx. Our structure suggests that alpha-Btx has evolved as an extremely potent antagonist of muscle nAChR by binding the receptor tightly, blocking its ligand site, and locking its conformation in a closed state. Conversely, most toxin-resistant mutations occur at the alpha-Btx binding interface on nAChR alpha1 but away from the agonist binding site. These mutations can interfere with the binding of alpha-Btx without having deleterious effect on the gating function. These analyses not only help understand the structural determinants for neurotoxin sensitivity in muscle-type nAChR, but also shed light on its gating mechanism. 相似文献
4.
Nicoletta Archidiacono Clelia T. Storlazzi Cosma Spalluto Angela S. Ricco Rosalia Marzella Mariano Rocchi 《Chromosoma》1998,107(4):241-246
We have investigated, by fluorescence in situ hybridization (FISH), the cytogenetic evolution of the Y chromosome in primates
using 17 yeast artificial chromosomes, representative of the Y-specific euchromatic region of the human chromosome Y. The
FISH experiments were performed on great apes (Homo sapiens, Pan troglodytes, Gorilla gorilla and Pongo pygmaeus pygmaeus), and on two Old World monkeys species as an outgroup (Cercopitecidae Macaca fascicularis and Papio anubis). The results showed that this peculiar chromosome has undergone rapid and unconstrained evolution both in sequence content
and organization.
Received: 16 January 1998; in revised form: 29 May 1998 / Accepted: 24 June 1998 相似文献
5.
6.
7.
8.
Michael G Anderson Richard T Libby Mao Mao Ioan M Cosma Larry A Wilson Richard S Smith Simon WM John 《BMC biology》2006,4(1):20-11
Background
DBA/2J (D2) mice develop an age-related form of glaucoma. Their eyes progressively develop iris pigment dispersion and iris atrophy followed by increased intraocular pressure (IOP) and glaucomatous optic nerve damage. Mutant alleles of the Gpnmb and Tyrp1 genes are necessary for the iris disease, but it is unknown whether alleles of other D2 gene(s) are necessary for the distinct later stages of disease. We initiated a study of congenic strains to further define the genetic requirements and disease mechanisms of the D2 glaucoma. 相似文献9.
10.