Basic Biological Sciences

Cytomegaloviruses undergo the classical morphologic stages of replication in hedgehog submandibular gland duct cells. A profound cytomegaly is associated with the infection. These features indicate that the hedgehog may be an excellent model in which to study the biology of cytomegalovirus-salivary gland interactions.

[Cytomegalovirus. Pathological-anatomical manifestations and detection methods]

Human cytomegalovirus, a double-stranded DNA virus, is a member of the Herpesviridae family with high rates of transmission. Primary infection is often asymptomatic and leads to life-long latency. Reactivation may induce different organ manifestations, particularly in the setting of immunosuppression. Histopathologically, the virus can be detected by light microscopy. Different cell populations in different organs are transformed into"owl's eye" cells, which are pathognomonic. Immunohistochemistry and electron microscopy can be applied as complementary methods. Various PCR approaches in molecular pathology including nested PCR, capture probe ELISA-PCR and real time PCR confer HCMV tests high sensitivity and specificity. The present article discusses the methods of pathological diagnostic approaches and describes organ manifestations of HCMV.

Animal models of congenital cytomegalovirus infection: an overview of progress in the characterization of guinea pig cytomegalovirus (GPCMV)

BACKGROUND

The strict species-specificity of cytomegalovirus (CMV) precludes preclinical evaluation of human CMV (HCMV) vaccines in animal models and necessitates the study of nonhuman CMVs. Among the CMVs of small mammals, the guinea pig cytomegalovirus (GPCMV) has unique advantages, due to its ability to cross the placenta, causing infection in utero. OBJECTIVE AND STUDY DESIGNS: Progress in GPCMV studies has been hampered by a lack of detailed molecular characterization of the viral genome. Therefore, recent efforts have been undertaken to characterize the GPCMV genome, and apply this information to in vivo subunit vaccine studies.

RESULTS

Progress in the sequencing of the GPCMV genome has revealed the presence of both highly conserved as well as novel open reading frames (ORFs). Cloning of GPCMV vaccine candidates, such as the glycoprotein B (gB) and UL83 proteins, has facilitated subunit vaccine evaluation. Protein vaccines and DNA vaccines have shown evidence of protection in pregnancy/challenge experiments. In addition, the GPCMV genome has proved amenable to cloning as a bacterial artificial chromosome (BAC) in Escherichia coli, and BAC-derived recombinants retain the ability to replicate in vivo.

CONCLUSIONS

Progress has been made in molecular characterization of GPCMV. Insights from these studies should prove germane to the understanding of the correlates of protective immunity for the fetus in vaccine studies, and should assist in prioritization of vaccine strategies in HCMV vaccine trials.

New endogenous herpesvirus of guinea pigs: biological and molecular characterization

Two known guinea pig herpesviruses, guinea pig cytomegalovirus (GPCMV) and guinea pig herpes-like virus (GPHLV), and well characterized. A third herpesvirus (GPXV) was originally isolated from leukocytes of healthy strain 2 guinea pigs. Growth of GPXV in guinea pig embryo fibroblastic cells produced a characteristic cytopathic effect. Electron microscopy of guinea pig cells infected with GPXV revealed the morphological development of a herpesvirus. Cross-neutralization tests and immunoferritin electron microscopy demonstrated that GPXV, GPCMV, and GPHLV were serologically distinct herpeviruses of guinea pigs. To confirm the distinction between these three herpesviruses, DNA genomes were compared by CsCl equilibrium buoyant density measurements and restriction endonuclease cleavage analysis. 32P-labeled viral DNA ws obtained from nucleocapsids isolated from virus-infected cells, and the buoyant density of GPXV DNA differed from that of GPCMV and GPHLV. Cleavage of viral DNAs with restriction endonucleases followed by gel electrophoresis revealed distinct patterns for each virus.

Ultrastructural development and persistence of guinea pig cytomegalovirus in duet cells of guinea pig submaxillary gland

Salivary glands from Hartley guinea pigs were experimentally infected with guinea pig cytomegalovirus (GPCMV) and examined by light and electron microscopy at different time intervals. Characteristic intranuclear and intracytoplasmic viral inclusions were observed in duct cells of infected animals. Viral inclusion counts and infectivity titers in the salivary gland reached maximum levels by 3 to 4 weeks after infection; infectivity persisted, though at reduced levels, for at least 30 weeks. Electron microscopic examination of viral inclusions revealed several developmental events including nucleocapsid assembly, envelopment of nucleocapsids at the inner nuclear membrane and their enclosure by a thin vacuolar membrane. While contained within cytoplasmic vacuoles, enveloped virions acquired surface spikes. Cytoplasmic vacuoles containing virions subsequently coalesced and discharged mature virions at the cell surface into the lumen of the salivary gland duct. The data indicate that the ultrastructural development of GPCMV in the guinea pig salivary gland shows many similarities to that of human cytomegalovirus in humans. The salivary gland may provide a primary locus for virus shedding and horizontal transmission of cytomegalovirus.

Inclusion disease in childhood

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