RESUMO
Macrophages are recognized cellular compartments involved in HIV infection; however, the extent to which precursor monocytes are infected in vivo and its significance remains poorly understood. Our aim was to analyze the contribution of monocytes to HIV infection in vivo. PCR assays did not detect HIV-1 proviral DNA in monocytes of HAART-suppressed patients. Monocyte-derived macrophages from individuals under suppressive HAART did not show evidence of harboring HIV, thereby, minimizing the possibility of infection by the integration of sequestered virus after differentiation. These results suggest that the infection of permissive monocytes is directly related to the success of HAART (p<0.001). HIV-1 env was characterized from patients under sub-optimal HAART and hence, with infected monocytes. Sequence analyses showed a consistent relationship between monocytes and plasma virus. Altogether, we found that in suppressive HAART, neither monocytes nor Monocyte-derived macrophages-harbored HIV.
Assuntos
Fármacos Anti-HIV/uso terapêutico , Terapia Antirretroviral de Alta Atividade , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , HIV-1/classificação , Monócitos/virologia , Células Cultivadas , DNA Viral/genética , HIV-1/genética , HIV-1/isolamento & purificação , Humanos , Macrófagos/virologia , Dados de Sequência Molecular , Filogenia , Plasma/virologia , Reação em Cadeia da Polimerase , Provírus/genética , Análise de Sequência de DNA , Homologia de Sequência , Produtos do Gene env do Vírus da Imunodeficiência Humana/genéticaRESUMO
To understand the interaction between lipopolysaccharide (LPS) and proteins in molecular detail, a molecular genetic approach has been employed, using phage as a model system. The phage epsilon(34) is a Salmonella phage whose tailspike protein (TSP) uses the host LPS as its initial host cell receptor. Previous studies indicated that there was a similarity between the well-studied tail protein of Salmonella phage P22 and the epsilon(34). This study reports the identification of the gene for the epsilon(34) TSP as well as its initial characterization. In addition, some aspects of the structure of the epsilon(34) TSP have been deduced.
Assuntos
Fagos de Salmonella/genética , Proteínas da Cauda Viral/genética , Sequência de Aminoácidos , Sequência de Bases , Dados de Sequência Molecular , Salmonella enterica/genética , Salmonella enterica/virologiaRESUMO
OBJECTIVES: The goals of these studies were to characterize the interaction of the P22 phage particle with the Salmonella cell surface and to determine the phage elements involved in this interaction by mutational analysis. BACKGROUND: The phage P22 has been characterized extensively. The gene and protein for the phage P22 tailspike, which is the phage adsorption organelle, have been intensively studied. The kinetics of the interaction of the tailspike protein with the cell surface has been studied in detail, surprisingly no mutational analysis has ever been reported that has defined these components and their interaction between themselves and the cell surface. The main and perhaps only component needed for this cell surface interaction is the tailspike protein. METHODS: Adsorption to the cell surface has been measured in the wild type phage and in mutant derivatives, isolated in this study. Phage mutants have been isolated after hydroxylamine mutagenesis. RESULTS: The adsorption of P22 to the cell surface is a temperature-independent event. Forty putative phage adsorption mutants have been isolated. A sample of them have been further analyzed. These divide the adsorption process into at least two stages. One stage contains mutants that absorb with essential wild type phage kinetics to the cell surface while the other stage with delayed adsorption kinetics. CONCLUSIONS: The interaction of the phage P22 with the Salmonella cell surface has been shown to be a complicated one which is temperature-independent and multi-stage. Mutants isolated in this study may help dissect this process even further.
Assuntos
Adsorção , Bacteriófago P22/metabolismo , Salmonella typhimurium/virologia , Bacteriófago P22/ultraestrutura , Humanos , Lipopolissacarídeos/metabolismo , Salmonella typhimurium/metabolismo , Salmonella typhimurium/ultraestrutura , Temperatura , Proteínas da Cauda Viral/metabolismoRESUMO
This brief report describes the isolation and initial characterization of revertants to the most severe temperature sensitive folding mutant known. The revertants or suppressors may describe amino acid interactions that occur during the folding of the P22 tailspike polypeptide chain. Results indicate that several different types of suppressors may have been obtained.
Assuntos
/genética , Genes Supressores/genética , Glicosídeo Hidrolases/genética , Mutação , Dobramento de Proteína , Proteínas da Cauda Viral/genéticaRESUMO
This review describes the use of a simple genetic system that has provided important insight into the process of folding and, of its flipside, that of protein aggregation. These studies make use of the tail protein of the bacterial virus P22 which infects Salmonella typhimurium. This folding system serves as a model for a number protein structural elements and may also provide important insights into disease-related protein folding defects at a time when an increasing number of diseases are being shown to be due to protein folding alterations