Antibody reactivity to individual structural proteins of measles virus in the CSF of SSPE and MS patients.

BACKGROUND: Chronic progressive disorders of the central nervous system (CNS) impose diagnostic problems, particularly in younger patients. The demonstration of antibodies against measles virus (MV) in the cerebrospinal fluid (CSF) plays a major role in the laboratory diagnosis of subacute sclerosing panencephalitis (SSPE) as well as multiple sclerosis (MS). OBJECTIVES: Because intrathecally synthesized antibodies against MV can be found in both diseases, it is necessary to establish easy and reliable methods to improve the differential diagnosis. STUDY DESIGN: Seventy-one paired serum/CSF samples obtained from patients with the diagnosis of SSPE (n = 23), MS (n = 14), or acute postinfectious measles encephalitis (APME, n = 8) have been examined. The reactivity of intrathecally synthesized immunoglobulin to individual recombinant MV structural proteins was assessed using Western blot analysis, ELISA as well as isoelectric focusing (IEF). RESULTS: All CSF samples obtained from patients suffering from SSPE showed a strong antibody response to MV-nucleocapsid (N) and phosphoprotein (P). Sera from 15 of the 23 SSPE patients were reactive to MV-fusion protein (F). Faint reactivity was obtained against MV-matrix (M) or hemagglutinin protein (H) in the minority of samples (40 and 20%, respectively). CSF samples of MS patients only revealed a clear response to N, and in two cases to F. The other proteins were not recognized in the CSF samples of MS patients. In contrast to SSPE, the IEF of CSF from MS patients revealed only few MV-specific oligoclonal bands. In the CSF samples from APME patients, intrathecal MV antibodies were not detected. CONCLUSIONS: This study shows that discrimination between SSPE and MS can be achieved in doubtful cases by IEF using MV-N, P and F proteins.

Persistent and lytic infections with SSPE virus: a comparison of the synthesis of virus-specific polypeptides.

The synthesis of virus-specific polypeptides and messenger RNA in cell cultures persistently infected with an isolate of measles virus from a patient with subacute sclerosing panencephalitis (SSPE) has been compared to that found in a lytic infection with the homologous virus. The persistent infection described here was chosen as its biological characteristics reflect those of virus-infected brain cells from SSPE patients. The synthesis of H, N and possibly F protein was seen in both lytic and persistent infections, but the synthesis of M protein was only detected in the lytic infection. However, messenger RNA isolated from either the lytic or persistent infection directed the synthesis in a cell-free translation system of all structural polypeptides, including M, and also three non-structural polypeptides, with mol. wt. of 34 000, 30 000 and 18 000. Messenger RNAs coding for the virus-specific polypeptides were also shown to be polyadenylated. In addition, those polypeptides made in vitro which were antigenically related to the haemagglutinin, demonstrated structural changes after passage through a persistent infection.

Bone marrow cell scene segmentation by computer-aided color cytophotometry.

Computer scene segmentation of touching cell images in bone marrow, on the basis of color information, is achieved using digitized scans at three different wavelengths of light. With trivariate histograms and Euler's coordinate transformation, it is possible cytophotometrically to isolate, on the basis of chromatic differences, individual heterogeneous cells located in cell groups. The ability of the described computer methods to isolate correctly the touching cell images is determined by visual comparison of the cells as seen in the microscope and the computer-generated displays of the scanned and segmented scenes.

Antigenic variation among parainfluenza type 1 (Sendai) viruses: analysis of 6/94 virus.

6/94 virus, isolated originally from a multiple sclerosis (MS) patient, was compared antigenically with related parainfluenza type 1 strains. These included two Sendai strains of mouse and two Sendai strains of reported human origin as well as the HA2 strain. By standard hemagglutination inhibition (HI) or hemadsorption neutralization (HAD-N) tests or by the complement-fixation (CF) cross-block titration test for detecting surface antigens, 6/94 virus and the Sendai virus strains were indistinguishable from each other but distinct from the HA2 strain. By the kinetic HI test, however, 6/94 virus could be readily differentiated from the Sendai viruses isolated from mice and more closely resembled those recovered from man.

Antibody-mediated cytotoxicity after measles virus infection.

Antibody cytotoxicity in the presence of complement to measles virus-infected cells was determined in sera of individuals at various stages of measles virus infection. A measles virus carrier cell line, which possessed viral antigens on the cell membrane, was employed as target cells. The cytotoxic effect was measured by 51-Cr release from the measles virus-infected cells. A microtiter method was used to determine the titer of antibody cytotoxicity. Cytotoxic antibodies could be detected in serum specimens from individuals after natural measles virus infection and vaccination. Sera from subacute sclerosing panencephalitis (SSPE) patients had only slightly higher titers than were found in sera obtained from individuals 1 week to 3 months after measles virus infection. Sera from children inoculated with measles virus vaccine lost their ability to react in hemagglutination inhibition, neutralization (NT) and cytotoxicity (CT) tests after absorption with the hemagglutinin from measles virus. SSPE sera treated in a similar manner retained their activity in NT and CT tests. Cytotoxic antibody was, therefore, shown to be directed against the hemagglutinin and some other antigen of measles virus.