Human cytomegalovirus infection of caco-2 cells occurs at the basolateral membrane and is differentiation state dependent

Epithelial cells are known to be a major target for human cytomegalovirus (HCMV) infection; however, the analysis of virus-cell interactions has been difficult to approach due to the lack of in vitro models. In this study, we established a polarized epithelial cell model using a colon epithelial cell-derived cell line (Caco-2) that is susceptible to HCMV infection at early stages of cellular differentiation. Infection of polarized cells was restricted to the basolateral surface whereas virus was released apically, which was consistent with the apical and not basolateral surface localization of two essential viral glycoproteins, gB and gH. HCMV infection resulted in the development of a cytopathology characteristic of HCMV infection of colon epithelium in vivo, and infection did not spread from cell to cell. The inability of HCMV to infect Caco-2 cells at late stages of differentiation was due to a restriction at the level of viral entry and was consistent with the sequestration of a cellular receptor for HCMV. These observations provide the first evidence that restriction of HCMV replication in epithelial cells is due to a receptor-mediated phenomenon.

Clinical and electrophysiologic recovery in Arnold-Chiari malformation

The case of a 16-year-old boy with occipital headache, diplopia, ataxia, and weakness in the lower extremities of 1-month duration is reported. Slowness of mentation, speech, and motor action was also present. Massive chronic hydrocephalus was indicated by an enlarged head. The prominent clinical features suggested involvement of the brainstem, and contrast studies showed compression of the brainstem and a filling defect posteriorly at C1-2. Brainstem auditory evoked potential latency suggested bilateral lesions of the brainstem. Posterior fossa decompression confirmed the presence of an Arnold-Chiari malformation, with the cerebellar tonsils as low as C-3. The fourth ventricle was microdissected and opened. Remarkable clinical and evoked potential recovery ensued over several months. Clinical-anatomic and anatomic-physiologic correlations in Arnold-Chiari malformation are discussed.