Characterization of virus-specific RNAs from subacute sclerosing panencephalitis virus-infected CV-1 cells

Autologous and allogeneic antibody responses to canine distemper virus isolates from dogs with chronic neurological diseases

We describe the antibody responses to three strains of canine distemper virus (CDV) isolated from dogs with chronic neurological disease in the Los Angeles area using the naturally occurring sera and cerebrospinal fluids (CSFs) of these animals as probes for comparison. CDV/CDE-2 was derived from a dog with chronic distemper encephalitis, and CDV/ODE-8 and CDV/ODE-10 were derived from dogs with old dog encephalitis. Sera and CSFs were used in autologous (same dog) and allogeneic (different dog) combinations to immune precipitate the [35S]-methionine-labelled H, P, NP, F1, and M polypeptides of the virus-infected cell cultures. The polypeptides were separated by SDS-PAGE and detected by fluorography. There was decreased recognition by the CSF and sera of the polypeptides of the viral isolates in several autologous as well as allogeneic combinations. It is concluded that the immune responses to the CDV strains are not identical, and it is likely that viral mutations occurred after the animals were infected. Some mutations may have contributed to the pathogenesis of distemper encephalitis in these animals and some may have occurred during subsequent passage of the viruses in cell culture. This may explain the decreased recognition of the polypeptides of the viral isolates by the CSF and sera.

A comparative analysis of measles virus RNA by oligonucleotide fingerprinting

Isolates from two cases of acute measles, one case of acute measles encephalitis and three patients with subacute sclerosing panencephalitis were compared. This comparison was based upon the electrophoretic analysis of T1 oligonucleotides from single-stranded, full-length RNA isolated from cytoplasmic nucleocapsids. Although all viruses have oligonucleotides in common, each isolate generated a unique pattern of oligonucleotides. However, no group of oligonucleotides was observed which would allow a differentiation between viruses isolated from acute infections and those isolated from CNS diseases; indicating that probably all measles viruses differ in their nucleotide sequence, regardless of origin.

Characterization of an RNA-dependent RNA polymerase activity associated with measles virus

An RNA-dependent RNA polymerase activity has been found copurifying with measles virus infectivity and complement-fixing antigen in three Vero cell-grown variants of measles virus: the attenuated Edmonston B strain, the natural non-attenuated Edmonston strain, and a subacute sclerosing panencephalitis isolate, IP-3. Incubation of purified measles virions with immunoglobulin G derived from sera of monkeys hyperimmunized against measles specifically removes activity sedimenting in the density region of measles virions. The requirements of the reaction, which is RNase sensitive, are similar to those reported for other paramyxovirus-associated activities, including detergent, divalent cation, ribonucleoside triphosphates, and a reducing agent. The size classes of RNA synthesized correspond to those found in measles-infected cells, including 50, 35, and 16 to 20S. The product RNA of the Edmonston B virus-stimulated reaction was rendered RNase resistant by annealing with RNA extracted from purified Edmonston B virions. RNA from uninfected Vero cells was ineffective in the annealing reaction.

Measles virus and its associated diseases

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Slow Infections of the Central Nervous System

This review describes the recent advances in slow infections of the nervous system emphasizing the pathogenetic aspects of these diseases. A theoretical model for the pathogenesis of subacute sclerosing panencephalitis (SSPE) is proposed, illustrating the factors that may affect host response to the measles virus and allow it to persist and produce the panencephalitis. The isolation of an oncogenic virus from progressive multifocal leukoencephalopathy (PML) has implications in the consideration of a viral etiology for some brain tumors. The agent responsible for the transmissibility of kuru and Creutzfeldt-Jakob disease (CJD) remains uncharacterized despite recent interest in viroids and abnormalities in replication of cell membranes. The epidemiological data on multiple sclerosis suggests an exposure to an infectious agent at an early age of life modified by the host response. No specific agent has been consistently associated with multiple sclerosis. Amyotrophic lateral sclerosis (ALS), Parkinson’s disease, Mollare’s meningitis and Behcet’s disease are other examples where a virus is suspect but unproven. The ability of viruses to persist in the host for months to years has linked many chronic neurologic diseases to an infectious agent, enlarging the spectrum of disease caused by viruses.

Persistent infection of tissue culture cells by RNA viruses

In this paper, the characteristics of cultured cells persistently infected with RNA viruses, other than leuko viruses are described. The roles that the host cell, interferon, virus mutants and defective interfering particles may play in the establishment and maintenance of persistent infection are discussed. It is proposed that the interaction of viruses with certain types of host cells can lead to persistent infection. The differences in virus-host interactions may be attributable to differences in membrane properties of various cells. Defective interfering particles may play a role in the establishment of persistent infections in cells which normally undergo lytic virus development. Mutant types of virus appear to be prominent in the virus released from persistently infected cells, but the role that various mutants play in the maintenance of persistent infections remains unclear.

Specific inhibitory factors of cellular immunity in children with subacute sclerosing panencephalitis

Employing a 51Cr release cytotoxicity microassay, and using both measles-and SSPE-infected target cells, four patients with documented SSPE were evaluated for specific cellular and humoral immunity. Mononuclear leukocytes from SSPE patients and control subjects exhibited comparable cytotoxicity. Serum and CSF from these SSPE patients inhibited the cellular response to SSPE-infected cells but not to measles-infected cells. Moreover, fresh whole serum alone from control donors produced significant 51Cr release from both cell lines, whereas SSPE whole serum was effective only against measles-infected cells. CSF from an additional ten patients with SSPE was examined for inhibitory activity: seven of these completely blocked and one partially blocked cell-mediated cytotoxicity to SSPE-infected cells. Preliminary characterization of the serum inhibitory factor suggested that it is IgM or antigen-antibody complexes. These data also suggest antigenic differences between the SSPE and measles viruses.

SSPE-like inclusion body disorder in treated childhood leukemia

Clinico-pathological report on a boy with cytostatically treated leukemia, dying with cerebral symptoms after passing clinical measles 10 weeks before death. At autopsy, numerous nuclear inclusion bodies in glial and nerve cells were found. By electron microscopy, nuclear inclusions appeared as loosely arranged smooth tubules, corresponding to paramyxovirus nucleocapsids. Frequently, cytoplasmic changes appeared too, consisting of incomplete tubular structures and an abundant dense "fuzzy" material. No regular tubuli of the coated granular type were present, as in common measles virus infection, nor any mature viral structures or differentiation of the surface membrane. The lack of maturation in cytoplasm together with a predominance of nuclear changes suggested a slow type of measles virus infection, while the particular cytoplasmic changes suggested a defect in synthesis of granular nucleocapsids, possibly a basic factor for the slow type of the viral infection. Possible pathogenetic factors are discussed.