ABSTRACT
Ralstonia pickettii is a rare pathogen and even more rare in healthy individuals. Here we report a case of R. pickettii bacteremia leading to aortic valve abscess and complete heart block. To our knowledge this is the first case report of Ralstonia species causing infective endocarditis with perivalvular abscess.
ABSTRACT
Human herpesvirus 8 (HHV8) infection leads to potent activation of nuclear factor kappa B (NFκB) in primary and transformed cells. We used recombinant HHV8 (rKSHV.219) expressing green fluorescent protein under the constitutive cellular promoter elongation factor 2α and red fluorescent protein under an early HHV8 lytic gene promoter T1.1 to monitor replication during infection of human foreskin fibroblasts (HF), noting changes in NFκB activity. In primary HF, NFκB levels do not affect the ability of HHV8 to establish infection or maintain latency. Furthermore, there was no effect on the percent of cells undergoing reactivation from latency, and there were similar numbers of released and cell-associated HHV8 viral particles following reactivation in the presence of inhibitors. Reactivation of HHV8 in latently infected HF in the presence of NFκB inhibitors resulted in production of viral particles that did not efficiently establish infection, due to deficiencies in binding and/or entry into normally permissive cells. Exogenous expression of glycoprotein M, an envelope protein involved in viral binding and entry, was able to partially overcome the deficiency induced by NFκB inhibitors. Our data indicate that in primary cells, NFκB is not required for infection, establishment of latency, or entry into the lytic cycle, but is required for the expression of virion associated genes involved in the initial steps of virion infectivity. These studies suggest that strategies to inhibit NFκB may prevent HHV8 spread and should be considered as a potential therapeutic target for preventing HHV8 associated diseases.
ABSTRACT
We tested a strategy for engineering recombinant mammalian reoviruses (rMRVs) to express exogenous polypeptides. One important feature is that these rMRVs are designed to propagate autonomously and can therefore be tested in animals as potential vaccine vectors. The strategy has been applied so far to three of the 10 MRV genome segments: S3, M1, and L1. To engineer the modified segments, a 5' or 3' region of the essential, long ORF in each was duplicated, and then exogenous sequences were inserted between the repeats. The inner repeat and exogenous insert were positioned in frame with the native protein-encoding sequences but were separated from them by an in-frame "2A-like" sequence element that specifies a cotranslational "stop/continue" event releasing the exogenous polypeptide from the essential MRV protein. This design preserves a terminal region of the MRV genome segment with essential activities in RNA packaging, assortment, replication, transcription, and/or translation and alters the encoded MRV protein to a limited degree. Recovery of rMRVs with longer inserts was made more efficient by wobble-mutagenizing both the inner repeat and the exogenous insert, which possibly helped via respective reductions in homologous recombination and RNA structure. Immunogenicity of a 300-aa portion of the simian immunodeficiency virus Gag protein expressed in mice by an L1-modified rMRV was confirmed by detection of Gag-specific T-cell responses. The engineering strategy was further used for mapping the minimal 5'-terminal region essential to MRV genome segment S3.
