Infection of highly differentiated human and guinea pig astrocytes with herpes simplex and measles viruses

Abstract

The morphogenesis of type I herpes simplex virus and measles virus (Edmonston strain) is studied in primary cultures of highly differentiated human and guinea pig astrocytes. It is shown that astrocytes are involved in infection. Under varied conditions of inoculation, herpes simplex virus causes acute infection, while measles virus induces both acute and chronic infection. Chronic infection is associated with impaired assembly of virions, accumulation of thickened ribonucleoproteins (25-37 nm in diameter) in the cytoplasm, and budding of "empty" viral particles into the extracellular space. Persisting measles virus reactivates 78_+9.4% of cells, which is accompanied by hypertrophy and hyperproduction of the glial fibrillar acid protein. Key Words: primary cultures; human and guinea pig astrocytes; herpes simplex virus; measles virusRecent neuroimmunological studies show that antigen-activated astrocytes are capable of phagocytosis, production of tumor necrosis factor, intefleukins-la, -113, -6, and aj-interferon, and expression of I and II class proteins of the major histocompatibility complex, which led to reconsideration of the role of astrocytes in the pathogenesis of encephalomyelitis and slow degenerative processes in the central nervous system (CNS) [4,6,8,9]. However, evaluation of the significance of astroglia in the maintenance-of infectious process in the CNS and in its chronization was hampered for a long time by the absence of adequate in vitro models.In the present study we compared the sensitivity of primary cultures of highly differentiated human and guinea pig astrocytes to measles virus (MV) and Byelorussian Institute of Epidemiology and Microbiology, Byelorussian Ministry of Health, Minsk; Minsk State Medical Institute type I herpes simplex virus (HSV-1) with a parallel investigation of morphology, cytoarchitectonics, and expression of the glial fibrillar acid protein (GFAP) by these cells. MATERIALS AND METHODSPrimary confluent cultures of human and guinea pig astrocytes were obtained as described elsewhere [5]. Astrocytes were identified by indirect immunofluorescence using anti-GFAP antiserum (Serva) and specific ultrastructural characteristics [3]. Measles virus (strain Edmonston) and HSV-1 were added to lst-2nd passage cultures in dose ranges 0.01-0.1 and 1-10 TCDJml during logarithmic growth. Virus accumulation was assessed by adding 10-fold serial dilutions of growth medium (from lif t to 10 .9 ) and cell lysates to test-systems: chick embryo fibroblasts for HSV-1 and L-41 for MV. The expression of viral