RESUMO
Transmissible spongiform encephalopathy (TSE) agents have contaminated human tissue-derived medical products, human blood components, and animal vaccines. The objective of this study was to determine the potential susceptibility to infection of 5 cell lines used or proposed for manufacture of biological products, as well as other lines. Cell lines were exposed to the infectious agents of sporadic and variant Creutzfeldt-Jakob disease and bovine spongiform encephalopathy (BSE). Exposed cultures were tested for TSE-associated prion protein (PrP(TSE)) and TSE infectivity by assay in rodents and nonhuman primates. No PrP(TSE) or infectivity has been detected in any exposed cell line under study so far. Animals inoculated with BSE brain homogenate developed typical spongiform encephalopathy. In contrast, animals inoculated with cells exposed to the BSE agent remained asymptomatic. All cell lines we studied resisted infection with 3 TSE agents, including the BSE agent.
Assuntos
Contaminação de Medicamentos , Doenças Priônicas/transmissão , Vacinas/isolamento & purificação , Animais , Bioensaio , Células CHO , Bovinos , Técnicas de Cultura de Células , Linhagem Celular , Chlorocebus aethiops , Doenças Transmissíveis Emergentes/transmissão , Síndrome de Creutzfeldt-Jakob/transmissão , Cricetinae , Cricetulus , Modelos Animais de Doenças , Cães , Encefalopatia Espongiforme Bovina/transmissão , Células HEK293 , Humanos , Camundongos , Camundongos Transgênicos , Príons/isolamento & purificação , Príons/patogenicidade , Saimiri , Scrapie/transmissão , Células VeroRESUMO
Mouse CD1d1 molecules present endogenous glycolipids to NKT cells. Although glycolipid presentation requires CD1d1 transport through the endocytic pathway, the processing requirements for such endogenous Ag presentation by CD1d1 molecules are undefined. We examined CD1d1 Ag presentation to NKT cells by disrupting endocytic trafficking and function in cells expressing normal and mutated CD1d1 expressed by recombinant vaccinia viruses. Consistent with previous studies, we found that preventing CD1d1 localization to endosomes by altering its cytoplasmic targeting sequences abrogated recognition by Valpha14Jalpha281(+) NKT cells without affecting recognition by Valpha14(-) NKT cells. Increasing the pH of acidic compartments by incubating cells with chloroquine or bafilomycin A1 blocked CD1d1 recognition by Valpha14(+) (but not Valpha14(-)) NKT cells without reducing levels of cell surface CD1d1. Similar results were obtained with primaquine, which interferes with the recycling of cell surface glycoproteins. These results suggest that the loading of a subset of glycolipid ligands onto CD1d1 molecules entails the delivery of cell surface CD1d1 molecules and an acidic environment in the endocytic pathway.
