R. D. Sheppard

Ultrastructure of Measles Virus in Cultures of Hamster Cerebellum

Summary Heating adenovirus types 8 and 12 for 2 to 3 min. at 56° simultaneously reduced both interferon-inducting capacity and infectivity. In contrast, virus inactivated by u.v.-irradiation effectively stimulated interferon production in chick cells. Chick cells infected with adenovirus type 12 and incubated at 25°, 35° or 40° produced about the same amount of interferon but the kinetics of interferon production differed, i.e. at the higher temperatures interferon formation commenced earlier. The possibility that the penton antigen may be responsible for interferon induction by human adenoviruses in chick cells is discussed.

FURTHER ULTRASTRUCTURAL OBSERVATIONS OF VIRUS MORPHOGENESIS AND MYELIN PATHOLOGY IN JHM VIRUS ENCEPHALOMYELITIS

Fleury H.J.A., Sheppard R.D., Bornstein M.B. & Raine C.S. 1980 Neuropathology and Applied Neurobiology 6,165–179

Immunocytochemical studies for the localisation of measles antigens in multiple sclerosis plaques and measles virus-infected CNS tissue.

Actively demyelinating central nervous system (CNS) lesions from a patient with acute multiple sclerosis (MS) were tested for measles antigens using peroxidase-conjugated antimeasles antibody. No evidence of measles antigens was found. Similarly reacted tissue from 2 patients with chronic MS also revealed no evidence of measles antigens. Identically treated and simultaneously tested measles-infected CNS cultures and human SSPE brain tissue stained strongly for measles antigens. The possible reasons underlying the failure to detect measles antigens in MS are discussed.

Virus-host cell relationships in measles-infected cultures of central nervous tissue.

Cultures of hamster cerebellum were infected with the Edmonston strain of measles virus for up to 72 days and studied both virologically and ultrastructurally. The yield of infectious virus was maximal between 10 and 30 days PI. Significant amounts could still be detected after 68 days PI. Ultrastructurally, it could be seen that neurons degenerated early in the course of infection. Demyclination and oligodendroglial cell death followed. A mat of fibrous astrocytes persisted at 72 days PI which still synthesized infectious virus. With the exception of active replication, viral appearances essentially mimicked those described in related, naturally occurring conditions, namely, measles encephalitis, SSPE, and canine distemper. In addition, the pathologic changes evoked by measles infection in vitro shared much in common with those seen in measles affected CNS tissue in situ. The pathogenesis of measles virus infection of the central nervous system (CNS) has gained considerable attention in recent years (9). The recent recovery of measles virus from brain tissue of patients with subacute sclerosing paneneephalitis (SSPE) (7, 11, 17, 19) confirmed the previous immunological evidence indicating its presence (8). These data gave impetus to the study of other diseases, in which the involvement of measles virus has been suspected on the basis of immunological studies, e.g., multiple selerosis (2). These suspicions have led to a series of studies on virus-host cell relationships in measles-infected CNS tissue. Measles virus morphogenesis in infected cultures of hamster cerebellum and dorsal root ganglion has been previously investigated (22, 23). Measles-infected hamster cerebellum was studied for periods up to 39 days post-inoculation (PI) and electron microscopic examination of these cultures documented the development of intranuclear and intracytoplasmic viral nucleocapsid material. Budding viral particles were also observed after 5 days PI and persisted for the entire period of study. Intranuclear structures seen in measles-infected hamster nervous tissue were very similar to those observed in SSPE brain biopsy material (5, 18, 24, 26). Budding viral particles have been dcscribcd in neurons in mcaslcs-infectcd dorsal root ganglion cultures where viral morphogenesis mas observed up to 63 days PI. The purpose of the present study was to maintain mcaslcs virus-infectcd CNS tissue for longer periods antl to delineate further thc virus-host cell relationships. In addition, tlic synthesis of virus in CNS tissue was documented. A preliminary rcport of this study was presented at thc 47th annual meeting of tlic American Association of Neuropathologists.

Observations on uptake of Herpes simplex virus in organized cultures of mammalian nervous tissue

SummaryThe uptake of Herpes simplex virus Type I in outgrowing axons of rat spinal cordin vitro was studied by examining the cultures ultrastructurally after inoculation with high titer material. It was found that the virus was taken up both at enlarged axonal regions and along the course of the axons. After attachment of the virus particles to the axons, invaginations of the plasma membrane were formed which were coated on the cytoplasmic side by a filamentous material. This mode of uptake into coated vesicles is similar to the mechanism by which other macromolecular substances, such as protein tracers, may by incorporated into axons bothin vitro andin vivo. Whether the viruses taken up in this way are infectious to the neuron could be determined from this morphological study.

The effects of measles virus and various strains of SSPE virus on organotypic cultures of nervous tissue

SummaryThe neurotropic effects, virologic behaviors and morphologic appearances of 4 strains of subacute sclerosing panencephalitis (SSPE) virus have been examined in organotypic cultures of hamster cerebellar tissue and have been compared with the Edmonston strain of measles virus in the same system. While measles virus caused extensive damage to nervous tissue, the SSPE strains, in general, exerted a less deleterious effect. All of the SSPE viruses replicated in this tissue. The SSPE strains showed morphologic variation ranging from normal measles-type virions to apparently nucleocapsid deficient forms. It is speculated that some of these differences between measles and SSPE virus may account for the differences in the in vivo conditions with which they are associated.