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

Biosynthesis of measles virus hemagglutinin in persistently infected cells

The synthesis of the hemagglutinin (HA) glycoprotein of measles virus was investigated in a persistently infected cell line using a monoclonal anti-HA. The synthesis of the HA protein was shown to be associated with the rough endoplasmic reticulum. The unglycosylated (HA0) apoprotein is synthesized as a 65,000 dalton peptide and is inserted into the rough endoplasmic reticulum as a transmembrane protein with approximately 2 to 3000 daltons of the peptide exposed to the cytoplasmic membrane surface. Primary glycosylation of the HA protein was found to occur through the lipid-linked carrier, dolichol-phosphate, as determined by inhibition of glycosylation by tunicamycin. Glycosylation, however, was not a prerequisite for membrane insertion. Endo-beta-N-acetylglucosaminidase H digestion of the fully glycosylated HA protein indicated that both simple and complex oligosaccharides are present on the surface glycoprotein.

Cell mediated immunity and effects of "thymic humoral factor" in 15 patients with SSPE

Cell mediated immunity (CMI) in 15 patients with subacute sclerosing panencephalitis (SSPE) was assessed by E-rosette formation, leucocyte migration inhibition factor (LIF) production, and proliferative responses to mitogens. In eleven patients, one or more of these parameters were impaired. These defects varied among the different patients and no consistent or uniform pattern of immune deficiency could be demonstrated. Although no single patient had a generalized reduction of all the T-cell functions, a diminished percentage of E-rosetting cells was the most frequent abnormal parameter (7 out of 15 patients). There was no correlation between the clinical state of the patients and the immune defects. Thymic humoral factor (THF), a thymic hormone, reconstituted at least one CMI impaired function especially the reduced levels of E-rosette forming cells in 7 out of 9 patients. It seems unlikely that a generalized cell-mediated defect is the underlying cause of this disease, but immunomodulatory therapy should be considered in some selected cases.

Measles virus panniculitis subsequent to vaccine administration

A severe illness developed gradually in a healthy boy following administration of live measles vaccine at age 14 years. Killed measles vaccine had been given at age 2. Panniculitis began near the site of live vaccine injection, extended contiguously to involve the entire upper arm, and then began to appear in distant subcutaneous sites. He was febrile, leukopenic, anemic, and lost weight rapidly. Evidence of a cause-and-effect relationship between the lesions and the measles vaccine included biopsy findings of particles closely resembling measles nucleocapsids and complete virions by electron microscopy, positive fluorescence after staining with two anti-measles nucleocapsid sera, and immunologic aberrations. The lesions regressed after various treatments and completely remitted on two occasions, but recurred. He became severely malnourished and finally died 29 months after the measles vaccination. At autopsy, pannicultitis was found in the subcutis and mesentery, without evidence of involvement of the brain or other vital organs.

Cellular and humoral immunity in subacute sclerosing panencephalitis

Cellular and humoral immunity was studied in 26 patients with subacute sclerosing panencephalitis. Results were compared with those of 14 normal controls and 11 patients suffering from other neurological disorders. It was shown that cellular and humoral immune responses are adequate in subacute sclerosing panencephalitis. The persistently elevated levels of serum immunoglobulin G (IgG) and IgA indicated a persistent infection, and their progressive rise in later stages correlated with the progressive nature of the illness. IgG progressively increased with the clinical stage in the cerebrospinal fluid unaccompanied by a corresponding rise in the measles antibody titer. This suggests that antigenic determinants other than those tested play a role in the production of IgG in the cerebrospinal fluid. The progressive increase in the ratio of cerebrospinal fluid to serum IgG with the advance of the disease suggests synthesis of IgG locally in the central nervous system. Elevated measles antibody titer in serum and cerebrospinal fluid is a consistent aid in the diagnosis of subacute sclerosing panencephalitis. It is more specific in cerebrospinal fluid than in serum. Its level did not vary significantly with the clinical stages or duration of illness. Depressed serum complement activity has been detected in some subacute sclerosing panencephalitis patients in whom serum levels of the third and fourth components of the complement were normal.

Chronic canine distemper virus encephalitis in mature dogs

Five dogs 2 to 8 years old with old dog encephalitis were compared to five other dogs, 4 to 8 1/2 years old, with prolonged multifocal demyelinating distemper encephalitis. The dogs with old dog encephalitis had a diffuse panencephalitis involving most areas of the central nervous system with relative sparing of the cerebellum. The clinical signs were related to the cortical and subcortical lesions. The other dogs had severe focal necrotizing lesions mostly in the cerebellum and in the vicinity of the fourth ventricle; clinical signs were related to brainstem and spinal cord lesions. Viral isolation attempts were unsuccessful in the dogs with old dog encephalitis. In two dogs with multifocal encephalitis, canine distemper virus was isolated in tissue culture. The differences in lesions, clinical signs and observations in vitro indicate differences in pathogenesis between old dog encephalitis and multifocal demyelinating distemper encephalitis although both diseases may be caused by the same agent.

Complement-dependent cytotoxicity of sera obtained from subacute sclerosing panencephalitis patients

Human lymphoid cells (NC-37) persistently infected with either measles virus (Schwarz and TYCSA strains) or subacute sclerosing panencephalitis (SSPE) virus (Halle and Mantooth strains) were destroyed in the presence of complement by anti-measles sera as well as by sera from SSPE patients. The cytotoxic activity was demonstrated in both IgG and IgM fractions of measles convalescent sera, but only in IgG fraction of SSPE sera. Measles convalescent sera completely lost the cytotoxic activity to all the cell lines, when absorbed with any one of the cell lines, indicating that the viral surface antigens of these cell lines infected with measles or SSPE virus are identical. On the other hand, the cytotoxic activity of SSPE sera could not be readily absorbed with these cells. Thus, the affinity of SSPE sera for the viral surface antigens might be lower than that of measles convalescent sera.

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.

Defective bud formation in human cells chronically infected with subacute sclerosing panencephalitis virus

Human prostate cells chronically infected with the Mantooth strain of subacute sclerosing panencephalitis (SSPE) virus multiply normally, fuse only occasionally to form giant cells, and yet have twisted intracytoplasmic nucleocapsids. These cells are able to support replication of vesicular stomatitis virus, although they release only small amounts of SSPE virus. To determine why carrier cells do not produce virus, they were examined with techniques for surface replication, freeze-fracturing, and immunoperoxidase labeling with SSPE antibody. The surface of carrier cells, like that of productive cells, is characterized by ridges crowned with viral antigens and devoid of the intramembrane particles revealed by freeze-fracture techniques. Since surface ridges form where nucleocapsids attach to the membrane, the shape and length of ridges are indicative of the shape and length of the underlying nucleocapsid. Whereas ridges on productive cells are serpentine in shape, those on carrier cells are typically straight or hairpin shaped, and the hairpin ridges are twice as long as serpentine ridges on productive cells. Furthermore, the spacing between ridges on carrier cells is never as small as that in productive infections, so that continuous sheets of viral membrane are never formed. The majority of carrier cells lack the round viral buds observed in productive cells but have, instead, many elongated processes attached to the cell surface. Each of these processes contains one or two hairpin ridges overlying hairpin-shaped nucleocapsids. These "hairpin buds" are restricted to a single region of the carrier cell surface, whereas viral buds are distributed over the entire surface of productive cells. Thus, there are several structural defects in carrier cells that depend on the specific interaction of a certain viral strain with a certain cell type. These defects prevent the deployment of viral antigen in some regions of the cell surface, the formation of nucleocapsids of normal length, the coiling of attached nucleocapsids, and the consolidation of sheets of viral membrane into spherical buds with the nucleocapsids coiled inside. These defects may account for the failure of carrier cells to shed infectious virus.