Parvovirus B19 outbreak in a developmental center.

Of 49 employees serving developmentally disabled persons, 13 (27%) were found to have parvovirus B19 infection on the basis of serum positivity for parvovirus B19 IgM by enzyme-linked immunosorbent assay. Two employees had severe peripheral symmetric polyarthropathy lasting longer than 6 months. Infection control measures are described.

Coexpression of truncated human cytomegalovirus gH with the UL115 gene product or the truncated human fibroblast growth factor receptor results in transport of gH to the cell surface.

The gH glycoprotein of herpesviruses is located on the cell surface in viral-infected cells but is retained in the endoplasmic reticulum (ER) when expressed separately from a recombinant expression vector. These observations suggested the requirement for either a viral function or a viral-induced cellular function which facilitates surface expression of gH. gL fulfills this role in the herpes simplex virus (HSV)-infected cell (J. Virol. 66, 2240-2250, 1992). We have identified the gene product of the UL 115 open reading frame (ORF) as the functional homologue of HSV gL in the human cytomegalovirus (CMV) genome. In addition, we have demonstrated that a cellular gene, the human basic fibroblast growth factor receptor (FGFr) will also facilitate some transport of CMV gH to the cell surface. Coexpression in Chinese hamster ovary cells of the gene product of the UL115 ORF or soluble FGFr with C-terminally truncated gH enhanced levels of secreted gH. These studies suggest that the coexpressed molecules act to mask an ER retention signal(s) exposed when recombinant gH is expressed outside of the context of the viral-infected cell.

Primary chimpanzee skin fibroblast cells are fully permissive for human cytomegalovirus replication.

Cytomegaloviruses generally display a host range restricted to differentiated cell types from the species they infect. For human cytomegalovirus (HCMV) this has meant that with few exceptions tissue culture systems have relied on the use of primary foreskin fibroblast (HF) cells or primary human embryonic lung cells to study gene expression and virus replication functions. We have observed that primary skin fibroblast (CF) cells derived from the chimpanzee (Pan troglodytes) support the replication of a laboratory strain (Towne) of HCMV. The kinetics of gene expression of the Towne strain grown in CF or HF cells appeared to be equivalent. Titres of progeny virions grown in CF cells appeared to be reduced 10-fold relative to those of virus grown in HF cells. In contrast, replication of the Towne virus was not supported by growth in WES cells (ATCC no. CRL 1609), a chimpanzee skin fibroblast cell line transformed by an adenovirus 12-simian virus 40 hybrid. This study shows that HCMV is less parochial in its host range than previously thought.

Mechanism of glucocorticoid-induced increase in pancreatic amylase gene transcription.

To determine the mechanism(s) responsible for glucocorticoid-induced increases in amylase content in pancreatic acinar AR42J cells, we examined the effects of dexamethasone on amylase protein biosynthesis, steady-state mRNA levels, and gene transcription. Dexamethasone treatment led to a dose-dependent increase in amylase synthesis which was one-half maximal at 2 nM and maximal at 100 nM where a 6-fold increase was achieved. This dexamethasone-induced increase in amylase synthesis was detectable after 12 h, one-half maximal after 19 h, and approached maximal after 72 h. Dexamethasone treatment also increased amylase mRNA levels in a time- and dose-dependent manner in parallel with the changes in amylase synthesis. Nuclear RNA transcript elongation (run-on) assays indicated that amylase gene transcription was also increased in a time- and dose-dependent manner. Glucocorticoid enhancement of amylase gene transcription occurred relatively slowly, with a 6-fold increase occurring after 48 h of treatment with 100 nM dexamethasone. Thus, the effects of glucocorticoids on pancreatic amylase gene transcription fully accounted for the increased levels of amylase mRNA, synthesis, and content. However, due to the slow time course of dexamethasone induction of amylase gene expression we evaluated the possibility of glucocorticoid induction of a regulatory protein. We found that inclusion of cycloheximide or puromycin during dexamethasone treatment blocked the induction of amylase mRNA. These data suggest that the glucocorticoid-induced increase in amylase gene transcription requires induction of an unidentified regulatory protein(s).