Silver staining of unconcentrated cerebrospinal fluid in agarose gel (Panagel) electrophoresis

We subjected cerebrospinal fluid (CSF) from 20 patients with multiple sclerosis and 20 patients with other neurological diseases to agarose gel ( Panagel ) electrophoresis followed by staining with silver. Ten microliters of unconcentrated CSF from multiple sclerosis patients containing 0.4 to 0.8 microgram of immunoglobulin G was found to be optimum for detection of oligoclonal IgG bands, so identified by immunofixation. The band patterns for unconcentrated CSF stained with silver were almost identical to those for the same CSF concentrated 40-fold and stained with Coomassie Brilliant Blue. Silver staining thus enables the clinical laboratory to electrophorese unconcentrated CSF on commercially prepared ( Panagel ) plates.

Silver staining of unconcentrated cerebrospinal fluid in agarose gel (Panagel) electrophoresis

We subjected cerebrospinal fluid (CSF) from 20 patients with multiple sclerosis and 20 patients with other neurological diseases to agarose gel ( Panagel ) electrophoresis followed by staining with silver. Ten microliters of unconcentrated CSF from multiple sclerosis patients containing 0.4 to 0.8 microgram of immunoglobulin G was found to be optimum for detection of oligoclonal IgG bands, so identified by immunofixation. The band patterns for unconcentrated CSF stained with silver were almost identical to those for the same CSF concentrated 40-fold and stained with Coomassie Brilliant Blue. Silver staining thus enables the clinical laboratory to electrophorese unconcentrated CSF on commercially prepared ( Panagel ) plates.

Absence of oligoclonal IgA in CSF and serum of multiple sclerosis patients

CSF and serum from patients with MS and other neurologic diseases were analyzed by isoelectric focusing (IEF) in polyacrylamide gel and immunofixation with specific anti human IgA sera. The IgA band patterns seen in pH 4.5-6.0 region were rather diffuse and lacked oligoclonal feature.

Detection of oligoclonal bands in unconcentrated CSF: isoelectric focusing and silver staining

We have developed a method to detect oligoclonal IgG bands in unconcentrated CSF from patients with MS or guinea pigs with chronic relapsing experimental allergic encephalomyelitis, by isoelectric focusing (IEF) in polyacrylamide gel and silver staining. Five to 10 microliters of CSF was sufficient. The bands were identified as IgG in immunofixation after IEF.

Presence of oligoclonal immunoglobulin G bands and lack of matrix protein antibodies in cerebrospinal fluids and sera of ferrets with measles virus encephalitis

Young adult ferrets were immunized with measles vaccine and 5 to 6 weeks later inoculated intracerebrally with Vero cells persistently infected with cell-associated strain D.R. of measles virus isolated from a patient with subacute sclerosing panencephalitis. Of nine ferrets which survived the infection for 3 weeks or longer, five showed neurological signs. At the time of death they had widespread inflammation in their brains, and cell-associated virus was isolated from three ferrets sacrificed from 5 weeks to 7 months after inoculation. Four ferrets did not develop clinical signs, but two of these had mild inflammation in the brain 7 months and 2 1/2 years after inoculation, respectively. Cerebrospinal fluids drawn by cisternal puncture from infected ferrets at the time of sacrifice had neutralizing titers against measles virus similar to the titers found in sera, but antibody against the measles virus matrix protein was not detectable. Cerebrospinal fluid showed increased immunoglobulin G (IgG) and had distinct measles virus-specific oligoclonal IgG bands. The intensity of the bands correlated with the neutralizing titers of the fluids. These results confirm and extend earlier findings and indicate that persistent measles virus infection in ferrets is similar to human subacute sclerosing panencephalitis and can be used to study certain aspects of persistent brain infections leading to subacute encephalitis.

Oligoclonal IgG bands with and without measles antibody activity in sera of patients with subacute sclerosing panencephalitis (SSPE)

Oligoclonal IgG bands from SSPE sera were isolated by combination of Protein A-Sepharose 4B column and preparative isoelectric focusing gel procedures. Each eluted fraction, when examined in analytic IEF, showed two or three individual bands with isoelectric points close to one another, compared to approximately fifteen IgG bands seen in whole serum. When the bands were tested for measles antibody activity in immunofixation with measles virus followed by peroxidase staining, the bands eluted in pH region 8.5 to 9.3 were found to be measles specific, whereas those in pH 7.0 to 8.4 lacked significant measles activity. When eluted fractions containing groups of bands were absorbed with measles virus, the bands in pH region 8.5 to 9.3 were removed, whereas those in pH 7.0 to 8.4 region remained unchanged; this indicated that a number of oligoclonal IgG bands without measles virus activities are present in SSPE. The bands lacking measles-specific activity may be synthesized against other infectious agents or they may represent nonspecific activation of B cell clones.

Oligoclonal IgG bands with and without measles antibody activity in sera of patients with subacute sclerosing panencephalitis (SSPE)

Oligoclonal IgG bands from SSPE sera were isolated by combination of Protein A-Sepharose 4B column and preparative isoelectric focusing gel procedures. Each eluted fraction, when examined in analytic IEF, showed two or three individual bands with isoelectric points close to one another, compared to approximately fifteen IgG bands seen in whole serum. When the bands were tested for measles antibody activity in immunofixation with measles virus followed by peroxidase staining, the bands eluted in pH region 8.5 to 9.3 were found to be measles specific, whereas those in pH 7.0 to 8.4 lacked significant measles activity. When eluted fractions containing groups of bands were absorbed with measles virus, the bands in pH region 8.5 to 9.3 were removed, whereas those in pH 7.0 to 8.4 region remained unchanged; this indicated that a number of oligoclonal IgG bands without measles virus activities are present in SSPE. The bands lacking measles-specific activity may be synthesized against other infectious agents or they may represent nonspecific activation of B cell clones.

Identification of virus-specific oligoclonal bands in subacute sclerosing panencephalitis by immunofixation after isoelectric focusing and peroxidase staining

We developed a sensitive peroxidase staining procedure to identify oligoclonal band specificity in subacute sclerosing panencephalitis by subjecting serum and cerebrospinal fluid to isoelectric focusing and immunofixation with measles virus. The gel was washed and stained with horseradish peroxidase-conjugated goat antihuman immunoglobulin G. The samples showed dark brown measles-specific oligoclonal bands in the alkaline pH region of the gel, whereas the controls showed no significant staining. This technique may be useful in identifying specific antibody activity against viral and other antigens in oligoclonal bands in cerebrospinal fluid and serum.

Precipitation of measles virus proteins by immunoglobulin G fractions containing groups of oligoclonal bands isolated from sera of patients with subacute sclerosing panencephalitis

Groups of oligoclonal immunoglobulin G (IgG) bands were isolated from sera of patients with subacute sclerosing panencephalitis by employing preparative isoelectric focusing. Six IgG fractions containing two to three oligoclonal bands with different isoelectric points were used to precipitate the proteins from Vero cells infected with measles virus. The results showed that all of the measles virus proteins except the M protein were precipitated by all of the IgG fractions and that the precipitation of viral proteins by the fractions containing groups of oligoclonal IgG showed slightly different patterns in some sera, whereas other sera showed no significant differences. The present study indicates that oligoclonal IgGs in subacute sclerosing panencephalitis sera are not specific to individual measles virus proteins.

Measles-specific IgG in CSF and serum from patients with subacute sclerosing panencephalitis

Sera and cerebrospinal fluid (CSF) from five subacute sclerosing panencephalitis (SSPE) patients were absorbed with a concentrated preparation of cell cultures infected with measles virus. The precipitates containing measles antigen-antibody complex were washed and measles-specific IgG was eluted at low pH. When the profiles of measles-specific IgG eluted from sera and the corresponding CSF were compared in immunofixation after isoelectric focusing they showed almost identical oligoclonal band patterns with respect to number, intensity, isoelectric point and light chain class. The results suggest that the same cell clones are responsible for the synthesis of measles-specific IgG in the central nervous system and serum of patients with SSPE.

Oligoclonal IgG bands in plaques from multiple sclerosis brains

We studied oligoclonal IgG band patterns of individual unbound plaque extracts from seven autopsy MS brains by immunofixation after isoelectric focusing (IEF). The specimens showed 10 to 15 distant oligoclonal bands in pH region 7.0 to 9.3. Band profiles of different sections from the same MS brain were similar, implying that there is a common immunologic response. When residues from these brain sections, after thorough washing, were eluted at low pH, only three of seven showed low levels of IgG by enzyme-linked immunosorbent assay. When the IEF profiles of unbound and bound IgG eluates from one brain were compared, two plaques showed similar profiles, whereas one had a different pattern. A plaque from two other brains showed band differences in the alkaline region of the gel. The data suggest that in some plaques there is a common immunologic response, but the response is different in others.

Identification of light chain type bands in CSF and serum oligoclonal IgG from patients with multiple sclerosis

The light (L) chain types (kappa and lambda) of oligoclonal IgG bands of matching CSF and serum from 10 MS patients were identified in immunofixation after isoelectric focusing in polyacrylamide gel. Each specimen showed 10-15 oligoclonal bands in pH region of 7.5-9.3. In 7 MS CSF and 5 sera a greater number of oligoclonal IgG bands were of kappa (kappa)-type whereas in 3 CSF and 2 sera the majority was of lambda (lambda)-type. In 3 sera a clearcut correlation of bands with either type of L chain was not observed due to diffuse staining background. Only a small number of oligoclonal IgG bands in 7 of 10 CSF and serum pairs had identical isoelectric points and the same type of L chain. The results show that the individual MS patient had oligoclonal IgG bands in serum, differ with respect to number, isoelectric point and L chain type from the oligoclonal IgG profile seen in the patient's CSF.

Light-chain profiles in sera from patients with subacute sclerosing panencephalitis

Sera from 2 subacute sclerosing panencephalitis (SSPE) patients were absorbed with a concentrated preparation of measles virus. Measles-specific IgG was eluted from the precipitates containing measles antigen-antibody complex. These IgGs, when subjected to immunofixation after isoelectric focusing showed a number of oligoclonal bands with one type of light-(L) chain. In urea polyacrylamide gel electrophoresis, the reduced and alkylated measles-specific IgG showed 1-3 homogeneous L-chain bands, whereas IgG isolated from unabsorbed sera and IgG isolated from supernatants of SSPE sera after absorption with measles virus showed a diffuse L-chain band. It can be concluded that in SSPE, measles virus is responsible for the synthesis of L-chain with restricted heterogeneity.

Isoelectric focusing and immunofixation of cerebrospinal fluid and serum in multiple sclerosis

CSF from 40 MS patients and 30 individuals with other neurologic diseases were analyzed using isoelectric focusing (IEF) in polyacrylamide gel method. The IgG bands were identified by immunofixation using specific goat anti-human IgG serum. CSF from 28 of 40 MS patients (95%) showed 10-15 distinct oligoclonal bands with different isoelectric points and varying intensities. In contrast, CSF from patients with other neurologic diseases showed a number of diffuse IgG bands in IEF after immunofixation. CSF from 30 of 40 MS patients (75%) showed 1-4 oligoclonal IgG bands in agarose gel electrophoresis (PANAGEL), however, the resolution of bands was generally poor. When 34 coded CSF specimens were analyzed in the IEF and immunofixation procedures, 15 of 17 MS patients (88%) showed distinct oligoclonal IgG bands. Thus, IEF in combination with immunofixation is a superior method for detecting oligoclonal bands in CSF and provides a more valuable tool for the diagnosis of MS. The results also showed that a number of distinct individual oligoclonal IgG bands of MS CSF were of either kappa-type or lambda-type, suggesting that these bands are monoclonal. IgG isolated from 12 of 17 MS sera (70%) showed oligoclonal bands in IEF partly similar to those seen in CSF in the pH region 8.5-9.3; whereas, those from other neurologic diseases showed diffuse bands.

Immunologic studies of chronic relapsing EAE in guinea pigs: similarities to multiple sclerosis

IgG/albumin ratios and presence of oligoclonal bands were studied in neutral pH brain extracts and sera of guinea pigs with chronic relapsing experimental allergic encephalomyelitis (R-EAE). The ratios were found to be significantly increased in central nervous system extracts of animals sacrificed during the first relapse and late stages of the disease relative to those of controls and of animals with acute EAE. These results are consistent with an intracerebral synthesis of IgG found in patients with multiple sclerosis (MS). When the immunofixation (after isoelectric-focusing) patterns of brain extracts and CSF from R-EAE animals were compared with those of controls, R-EAE animals showed distinct oligoclonal IgG bands in the pH region of 7.0 to 9.3, in contrast to diffuse patterns seen in controls. The finding of oligoclonal IgG in brain extracts of these animals further supports the usefulness of R-EAE as an experimental model for MS.

Immunologic studies of chronic relapsing EAE in guinea pigs: similarities to multiple sclerosis

IgG/albumin ratios and presence of oligoclonal bands were studied in neutral pH brain extracts and sera of guinea pigs with chronic relapsing experimental allergic encephalomyelitis (R-EAE). The ratios were found to be significantly increased in central nervous system extracts of animals sacrificed during the first relapse and late stages of the disease relative to those of controls and of animals with acute EAE. These results are consistent with an intracerebral synthesis of IgG found in patients with multiple sclerosis (MS). When the immunofixation (after isoelectric-focusing) patterns of brain extracts and CSF from R-EAE animals were compared with those of controls, R-EAE animals showed distinct oligoclonal IgG bands in the pH region of 7.0 to 9.3, in contrast to diffuse patterns seen in controls. The finding of oligoclonal IgG in brain extracts of these animals further supports the usefulness of R-EAE as an experimental model for MS.

Bound antibody in multiple sclerosis brains

Autopsy tissues of white and grey matter from brains of MS patients and controls were homogenized in PBS and centrifuged at 100,000 x g for 1 h. The residues were thoroughly washed with PBS and further extracted at acidic and alkaline pH. The eluates contained a low but significant amount of IgG, indicating that bound IgG was present in MS brains. A greater yield of IgG was obtained with alkaline pH buffer than with acidic pH buffer. In contrast, sections from 2 of 3 neurologic controls and 3 of 4 non-neurologic control failed to show detectable level of bound IgG extractable at acidic pH. These results might suggest the presence of antigen-antibody complexes in MS brains. Isoelectric focusing analysis demonstrated oligoclonal IgG bands in low pH eluates from MS brains and these bands were partly similar to those seen in neutral (unbound) pH brain extracts.

Quantitation of measles-specific IgG. Its presence in CSF and brain extracts of patients with multiple sclerosis

Twenty of 41 patients with multiple sclerosis (MS) and five of 30 patients with other neurological diseases had measles antibody titers in their CSF when examined in hemagglutination inhibition and neutralization tests. Quantitation of measles-specific IgG in CSF of patients with MS with significant measles antibody titers showed that less than 5% of the total IgG was measles virus specific. In contrast, using the identical quantitation procedures, 30% to 60% of the total IgG in CSF of patients with subacute sclerosing panencephalitis was found to be measles specific. Thus, only a very minor portion of the total IgG in CSF of patients with MS is synthesized against measles virus. When measles hemagglutination inhibition, complement fixation, and neutralizing antibody titers were measured in individual oligoclonal IgG bands isolated from neutral pH brain extracts of two patients with MS, low titers were present in all the oligoclonal bands rather than being restricted to any single band.

Immunological studies of subacute measles encephalitis in ferrets: similarities to human subacute sclerosing panencephalitis

Ferrets inoculated with subacute sclerosing panencephalitis virus strains D.R. and Biken developed a subacute encephalitis. Brain extracts, at neutral pH, from these ferrets showed high measles antibody titers, increased concentrations of immunoglobulin G (IgG), and higher IgG/albumin ratios than those of controls. Although the brain extracts of subacute encephalitic animals showed significant synthesis of measles-specific IgG (20 to 60% of the total IgG) within the central nervous system, the electrophoretic patterns of these extracts did not show oligoclonal bands in the gamma-globulin region. Brain residues from most ferrets with subacute encephalitis, when eluted at low pH, demonstrated the presence of bound measles-specific antibodies. Excluding the electrophoresis data, other results are identical to those seen in human subacute sclerosing panencephalitis, indicating that the subacute encephalitis in ferrets may serve as a model for human subacute sclerosing panencephalitis.

Comparison of wild-type and subacute sclerosing panencephalitis strains of measles virus. Neurovirulence in ferrets and biological properties in cell cultures

The neurovirulence of two wild type (wt) and seven Subacute Sclerosing Panencephalitis (SSPE) measles virus strains was tested in young adult ferrets by intracerebral (IC) inoculation of infected Vero cell suspensions. Wt strains Edmonston and Woodfolk and SSPE strains Mantooth, Halle, and LEC-S did not produce a detectable encephalitis in the ferrets, but caused a significant formation of serum antibodies against measles virus. SSPE strains LEC, IP-3, Biken, and D.R., on the other hand, were all neurovirulent in ferrets, particularly strain D.R. which caused an acute encephalitis in all inoculated animals. Strain Biken was of particular interest since it caused a subacute encephalitis in four of seven ferrets. The subacute encephalitis was characterized by a long incubation time, persistence of virus in the brain for at least 8 mo, widespread inflammatory lesions, and production of measles virus specific IgG in the brain. A study of the biological properties of the various measles virus strains showed that wt strains Edmonston and Woodfolk and SSPE strains Mantooth, Halle, and LEC-S produced free virus particles in significant titers both in Vero and ferret brain (FB) cultures. Cytopathic effect (CPE) with cell-fusion was marked in Vero cultures, whereas only minimal CPE and no cell-fusion were observed in the FB cultures. SSPE strains LEC, IP-3, Biken, and D.R., on the other hand, were mostly cell-associated in Vero and FB cultures, although atypical cell-free particles were produced by strains Biken and IP-3. All four strains showed cell-fusing activity in FB cultures, particularly strain D.R., which was the only strain that spread more actively by fusion in FB than in Vero cultures. The results are discussed in relation to the neurovirulence of the various measles virus strains in adult ferrets. Pronounced cell-fusing activity in FB cells and cell-association with minimal or no production of cell-free virus seem to be essential to establish a brain infection in the animals.

Further characterization of bound measles-specific IgG eluted from SSPE brains

Tissue residues from 3 SSPE brains extracted at neutral pH were thoroughly washed with phosphate-buffered saline and further extracted at acidic pH. The low-pH extracts had significant measles antibody titers, and their measles-specific IgG content ranged from 40 to 60% of total IgG. Agarose-gel electrophoretic analysis of the extracts showed oligoclonal IgG bands, most of which disappeared after suitable absorption with measles virus, demonstrating the presence of restricted measles antibody population. Ouchterlony analysis showed a reaction of identity between bound IgG and IgG extracted at neutral pH. Thus IgG extracted at low and neutral pHs is remarkably similar.

Encephalitis in ferrets caused by a nonproductive strain of measles virus (D.R.) isolated from patient with subacute sclerosing panencephalitis

A nonproductive, syncytiogenic strain (D.R.) of measles virus, isolated from a patient with subacute sclerosing panencephalitis (SSPE), was inoculated intracerebrally into ferrets in an attempt to induce subacute encephalitis. Inoculation of freeze-thawed syncytia before immunization was the least effective procedure, and inoculation of live syncytia after immunization with measles virus vaccine was the most effective procedure, for induction of subacute or persistent subclinical encephalitis in the animals. After the latter procedure three of five ferrets developed subacute or subclinical encephalitis, whereas ferrets inoculated with live syncytia without prior immunization consistently contracted acute fatal encephalitis in one to two weeks. The subacute encephalitis in ferrets was characterized by high titers of antibody to measles virus in serum. At the time of sacrifice 1.25, 4.5, or 8.0 months after inoculation, brains of the ferrets showed histologic lesions similar to those characteristic of SSPE, and nonproductive syncytiogenic measles virus was recovered from the brains of two of the animals. All three ferrets had greatly increased concentrations of gamma-globulin in their brains and high levels of neutralizing and hemagglutination-inhibiting antibodies to measles virus. Only one of these animals developed clinical signs 1.25 months after inoculation.

Quantitation of Measles Virus-Specific Immunoglobulins in Serum, CSF, and Brain Extract from Patients with Subacute Sclerosing Panencephalitis

The amount of measles-specific IgG in sera, CSF, and brain extracts from patients with SSPE was determined by radial immunodiffusion method with the use of a number of rabbit antisera specific for human γ-chain, after each sample was abosrbed suitably with a lyophilized preparation of measles-precipitating antigen (MPA) made in Vero cells infected with Edmonston strain of measles virus. The measles-specific IgG contents of the sera ranged from approximately 10 to 20% and those of CSF and brain extracts from 25 to 75% of the total IgG, indicating a synthesis of measlesspecific IgG within the CNS. By employing the same method, a significant amount of measles-specific IgM was demonstrated in sera of three out of six SSPE patients. Sera, CSF, and brain extracts from controls when absorbed with MPA and quantitated by the same method did not show significant amounts of measles-specific IgG. When the agarose gel electrophoretic patterns of unabsorbed and MPA-absorbed SSPE brain extracts were compared, the absorbed extracts were found to lack homogeneous bands in a γ-globulin region in contrast to the presence of two to three homogeneous IgG bands seen in the unabsorbed brain extracts. On the other hand, the patterns of unabsorbed and absorbed SSPE sera did not show such a significant difference in γ-globulin region. These data strongly support the concept that measles virus is responsible for the formation of homogeneous bands within the CNS in SSPE.

Relationship between homogeneous IgG fractions and measles virus antibody activities in subacute sclerosing panencephalitis brain

Cellulose acetate and agarose gel electrophoresis of pH 7.4 brain extracts from three patients with subacute sclerosing panencephalitis (SSPE) revealed two to three homogeneous bands in the gamma-globulin region. The IgG concentration in the brain extracts ranged from 6 to 8.5% of the total protein. The IgG was isolated by passing each brain extract twice through gel filtration on Sephadex G-200 column. The Sephadex-isolated IgG preparations, at a concentration of 1 mg/ml, had hemagglutination inhibition (HI) titers ranging from 512 to 800, complement fixation (CF) titers of 64 to 100, and neutralizing titers of 400 to 1024 when tested against envelope, nucleocapsids, and while measles virus, respectively. These IgG preparations were further separated into several fractions by isoelectric focusing (IEF) technique and the reactivities of these eluted fractions were examined against differnt specific measles virus components and against whole virus. The results showed that both slow and fast moving homogeneous IgG had high HI and neutralizing titers. However, CF antibodies were present only in specific IEF-eluted fractions and their profiles differed somewhat from one brain to another. The IgG fractions reacted with both kappa-and gamma-chain antisera, but the reactivity varied from one brain to another. When the polyacrylamide gel electrophoretic (PAGE) patterns of heavy (H) and light (L) chains of SSPE IgG were compared to those of IgG from controls, the H chain patterns of both groups were identical whereas the SSPE brain IgG demonstrated two distinct bands in L chain as compared to a single diffuse band observed in controls. These latter results, in addition to homogeneous bands and selective CF antibody activity in IEF eluted IgG fractions from SSPE brain, fulfill some of the criteria of monoclonality.