Jay A. Nelson

HIV and HCMV coinfect brain cells in patients with AIDS

Direct interactions at the cellular level in vitro have been reported which suggest that opportunistic viruses may reactivate latent human immunodeficiency virus (HIV) in cells. The significance of these findings depends on whether coinfection of the same cell with these two different types of viruses occurs in vivo. Using various double-labeling techniques, we present evidence that human cytomegalovirus (HCMV) and HIV can coinfect the same cell in vivo in central nervous system tissue from AIDS patients. These observations indicate that direct cooperation at the single cell level could occur between HCMV and HIV. This new finding in the context of reports that herpesviruses can increase HIV transcription in vitro, suggest the possibility of a direct role for herpesviruses in the pathogenesis of AIDS.

Localization of cytomegalovirus proteins and genome during fulminant central nervous system infection in an AIDS patient.

Approximately one-half of autopsied acquired immune deficiency syndrome (AIDS) patients demonstrate probable human cytomegalovirus (CMV) infection of the central nervous system (CNS). Because CMV in brain tissue or cerebrospinal fluid is difficult to culture, we used antisera, and radioactive probes to diagnose CMV infection in the brain of an autopsied AIDS patient, who died of a fulminant CNS and systemic infection with CMV, suggesting a complete seeding of the ependymal regions possibly followed by a uniform ventriculofugal spread of the virus deep into the parenchyma. Cytomegalic cells were observed in optic nerve, retina, ependymal and subependymal regions of the brain and in the motor (but not sensory) root-CNS junctions. Immunocytochemistry demonstrated viral antigen predominantly in cytomegalic cells, which also stained positively for glial fibrillary acidic protein, S-100, or neuron-specific enolase, but not a common leukocyte antigen. Virions were visible in these cells examined by electron microscopy. No viral replication was observed in pineocytes, pituicytes or the choroid plexus. Morphologically normal cells that were CMV antigen-negative proved to be infected after in situ hybridization with well-defined human CMV DNA fragments. Hence, morphologically normal glia and neurons show restricted replication of CMV, indicating that such cells may be latently infected.

Parotid gland enlargement and xerostomia associated with labial sialadenitis in HIV-infected patients

Infection with human immunodeficiency virus (HIV) may be associated with enlargement of the major salivary glands or symptoms of dry mouth. We term this condition HIV-associated salivary gland disease (HIV-SGD). In this report we describe 12 patients with HIV-SGD. Nine patients (one child, eight adults) had enlargement of the parotid glands, and three had xerostomia alone. Symptoms of dry mouth, dry eyes or arthralgia occurred in 11, five and five patients, respectively. Salivary flow rates were normal or slightly reduced in seven patients and severely reduced in five. Labial salivary gland (LSG) biopsy specimens from patients contained lymphocytic infiltrates in focal and other patterns, whereas specimens from three HIV-infected patients without salivary gland symptoms did not. The inflammatory infiltrates in LSG specimens showed a preponderance of T8-positive cells and a tissue T4/T8 average ratio of 0.66. The mean T4/T8 ratio of peripheral blood lymphocytes was 0.4. Serum antinuclear antibodies were present in one patient, but rheumatoid factor, SS-A, and SS-B antibodies were absent in all. Search for Epstein-Barr virus and cytomegalovirus in the LSG tissue of the six patients tested did not reveal evidence of antigens or DNA. HIV-SGD patients show a number of similarities to and differences from patients with Sjögrens syndrome (SS). The similarities include the oral and salivary features, histopathology and possibly changes in other organs. The differences include the lower salivary gland T4/T8 ratio and the absence of autoantibodies in serum. The causes of HIV-SGD as well as of Sjögrens syndrome are unknown.

Regulation and Tissue-Specific Expression of Human Cytomegalovirus

Human cytomegalovirus (HCMV) establishes a lifelong latent state after primary infection, as do the other members of the human herpesvirus family. The site of latency and the molecular mechanisms involved in the establishment and maintenance of latent virus in the cell are unknown for HCMV. In this chapter, we will discuss experimental approaches to identifying cell types naturally infected in the human host by HCMV. We will examine cell culture systems and transcription factor interactions in vitro which may identify HCMV-host cell interactions that regulate expression of the virus.

Human immunodeficiency virus (HIV) and JC virus in acquired immune deficiency syndrome (AIDS) patients with progressive multifocal leukoencephalopathy

SummaryOf the 93 acquired immune deficiency syndrome (AIDS) patients autopsied between 1983 and 1986, 27 had evidence of viral encephalitis of which 3 had progressive multifocal leukoencephalopathy (PML), confirmed by electron microscopy. Using in situ hybridization with biotinylated JC virus probes, paraffin sections from the brains of these 27 patients were examined. JC virus was found only in those patients with histologically proven PML, while no evidence of JC virus was detected in the brains of the other 24 AIDS patients despite the presence of white matter pathology. Brain biopsies of the PML patients demonstrated human immunodeficiency virus (HIV)-infected macrophages infiltrating regions of demyelination. When the patients died (2 to 6 months after diagnosis of PML), many more macrophages contained HIV antigens and some had fused to form multinucleated giant cells. These findings suggest that in AIDS patients, papovaviruses not only cause damage by directly infecting oligodendroglia but causes additional damage by eliciting the ingress of macrophages latently infected with HIV. As was seen with other infections (e.g., cytomegalovirus) of the CNS this might be a general mechanism of HIV entry into the brain.

Cultured human brain capillary endothelial cells are permissive for infection by human cytomegalovirus.

Human cytomegalovirus (HCMV) infection is associated with a variety of systemic and neurologic diseases. In vitro HCMV growth is usually studied in fibroblasts, while in vivo HCMV growth is frequently observed in a wide variety of cell types including glia, neurons, and human brain capillary endothelial (HBCE) cells. To examine the biology of HCMV in HBCE cells, we have established a procedure for isolating these cells from human brain temporal lobectomies. Greater than 99.0% of these cultured cells were identified as HBCE cells on the basis of positive staining for factor VIII-related antigen-Von Willebrands factor (F VIII) and Ulex Europaeus agglutinin I (UEA I). HCMV antigens were detected by immunocytochemistry in HBCE cells after infection with strain AD 169. Intracellular virions were observed in infected cells by electron microscopy and infectious virus was released from HBCE cells. In addition, infected cells were confirmed as endothelial cells by double staining with antibodies to F VIII and HCMV.

Does HIV cause salivary gland disease

HIV-associated salivary gland disease (HIV-SGD) is characterized by enlargement of the major salivary glands and/or xerostomia. HIV does not appear to play a direct role in this disease since it was detected by immunohistochemistry in only occasional lymphocytes in labial salivary glands in two out of six patients; it was not found in the salivary gland epithelial cells. Moreover, HIV was not found in any of 21 saliva samples from seven patients. We conclude that HIV-SGD is not caused by direct infection of the salivary glands with HIV.

Transcription Factors and Viral Regulatory Proteins as Potential Mediators of Human Cytomegalovirus Pathogenesis

The mechanism(s) of pathogenesis caused by persistent viruses such as the human cytomegalovirus (HCMV) are strongly associated with the control of transcription. In this chapter we explore in vitro systems which suggest the interplay of both viral and cellular regulatory factors as major determinants in controlling the expression state of HCMV. Importantly, we address the issue of both cellular transcription factors and viral regulatory proteins as possible mediators in the pathogenesis associated with HCMV infection.

Plasmodium falciparum: cytoadherence of malaria-infected erythrocytes to human brain capillary and umbilical vein endothelial cells--a comparative study of adhesive ligands.

The cytoadherence of Plasmodium falciparum-infected erythrocytes (FCR-3 line) to human brain capillary endothelial cells (HBEC), C32 amelanotic melanoma cells, and human umbilical vein endothelial cells (HUVEC) was studied. The adhesion of infected red cells was HBEC > amelanotic melanoma > HUVEC. The presence or absence of the adhesive ligands ICAM-1 (CD54 or intercellular adhesion molecule 1), ICAM-2, and CD36 (= glycoprotein IV) was determined for each of these cells by indirect immunofluorescence using the monoclonal antibodies RR1/1, 6D5, and OKM 5/OKM 8, respectively. It appeared that a major ligand for the FCR-3 line of P. falciparum with amelanotic melanoma cells and HBECs was CD36. Binding to HUVECs was very low, presumably due to their lack of expression of CD36. HBECs, because of their ease of in vitro propagation, long-term maintenance of cytoadherent properties, and their high degree of adhesiveness, will be useful for in vitro studies of adherence.

Interactions between cellular regulatory proteins and a unique sequence region in the human cytomegalovirus major immediate-early promoter

Transcription from the human cytomegalovirus major immediate-early promoter is dependent on host-cell regulatory proteins. The interactions between cellular nuclear proteins and a unique sequence located from nucleotide position -660 to -540 was investigated. The unique region presents a defined target for multiple distinct DNA-binding proteins which appear, in part, to have overlapping binding sites. A minimum of five sequence-specific DNA-binding activities that interact with sequences between -632 and -602, -602 and -557, -602 and -590, -563 and -540, and -602 and -582 were detected. Evidence is presented to suggest that the -632 to -602 site, a previously characterized nuclear factor 1 binding site, does not bind NF1 but strongly interacts with a distinct cellular factor. The binding of cellular proteins to the unique sequence region was shown to be important in directing transcription from the major immediate-early promoter.