Immunoglobulin G subclass antibodies to measles virus in patients with subacute sclerosing panencephalitis or multiple sclerosis

An appraisal of antigen identification and IgG effector functions driving host immune responses in multiple sclerosis

Increased immunoglobulin G (IgG) antibodies and oligoclonal bands (OCB) are the most characteristic features of multiple sclerosis (MS), a neuroinflammatory demyelinating disease with neurodegeneration at chronic stages. OCB are shown to be associated with disease activity and brain atrophy. Despite intensive research over the last several decades, the antigen specificities of the IgG in MS have remained elusive. We present evidence which supports that intrathecal IgG is not driven by antigen-stimulation, therefore provide reasoning for failed MS antigen identification. Further, the presence of co-deposition of IgG and activated complement products in MS lesions suggest that the IgG effector functions may play a critical role in disease pathogenesis.

Measles virus fusion protein- and hemagglutinin-transfected cell lines are a sensitive tool for the detection of specific antibodies by a FACS-measured immunofluorescence assay

A FACS-measured immunofluorescence assay was developed for the detection of antibodies directed against the hemagglutinin (H) and fusion (F) glycoproteins of measles virus (MV). Human melanoma cell lines transfected with either the MV H or F genes, which showed a high surface expression of the respective proteins in their native conformation, were used as target cells. The cells were incubated with diluted plasma samples, and stained subsequently with FITC-conjugated secondary antibodies. The FACS-measured fluorescence signals correlated directly with the amount of specific immunoglobulins over a wide concentration range. The use of different conjugates enabled the separate detection of MV-specific IgG, IgM, IgA and IgG subclasses, with relatively low backgrounds. Hemagglutinin-specific IgG, IgM and IgA fluorescence signals were shown to correlate well with MV-specific IgG ELISA titers and MV-specific IgM or IgA capture ELISA OD450-values, respectively. The polyclonal conjugates with specificity for human immunoglobulins offered sufficient cross-reactivity to detect MV-specific IgG, IgM and IgA in plasma samples of cynomolgus macaques, making this technique a useful tool for studying serological responses in vaccination and challenge experiments in non-human primate models.

Measles virus-specific immunoglobulin G subclass response in serum and cerebrospinal fluid

BACKGROUND

While many previous studies have focused on the impairment in the cellular immunity during measles virus infection, to date, a limited amount of data is available concerning the virus-specific IgG subclass response during measles virus infection.

OBJECTIVE

The purpose of this study is to analyze the measles virus infection on the basis of virus-specific IgG subclass (G 1 and G 3).

STUDY DESIGN

Frozen-stored, serum and/or cerebospinal fluid samples from three groups of patients were tested retrospectively; Group 1 comprised 14 patients with measles primary infection, group 2, ten patients with reinfection/vaccine failure, and group 3, seven patients with subacute sclerosing panencephalitis. The method used was a modified ELISA method utilizing the Enzygnost IgG detection kit with mouse-monoclonal antibodies (clone HP6091 for IgG 1 and clone HP6050 for IgG 3). Avidity testing for each subclass IgG was also performed for selected samples by means of an 8 M urea-denaturation method.

RESULTS

In group 1, the IgG 3 could be detected in serum within 7 days from the onset of rash more frequently than IgG 1. In the cases of group 2, both subclasses were detected in very acute phase serum samples. In these cases, the IgG 1-specific avidity was always higher than that of IgG 3. In group 3, the subclass IgGs detected in the cerebrospinal fluid had a lower avidity than those in the serum.

CONCLUSIONS

Our results suggested that in measles virus infection, like other viral infections, the IgG 3 response normally occurs before the IgG 1 response, and plays a major role in the acute phase immunity during the primary infection, while the IgG 1 plays a major role in the maintenance of immunity. Continuously produced IgG 1 and IgG 3 in the central nervous system in cases of subacute sclerosing panencephalitis may be derived from cell populations different from those in the blood.

Herpes simplex virus-specific IgM, IgA and IgG subclass antibody responses in primary and nonprimary genital herpes patients

To clarify the humoral immunity in herpes simplex virus (HSV) infection, HSV-specific IgM, IgA and IgG subclass antibody responses were studied in patients with genital herpes: 17 primary, 13 recurrent and 6 nonprimary first episode. A total of 181 serum samples serially collected from the patients, 5 per patient until 213 days after the onset of disease (on average), were analyzed by an enzyme-linked immunosorbent assay. IgG1, IgG3 and IgA were detected in all patients with primary and nonprimary infections, whereas IgG4 was detected in 74% of only those with nonprimary infections and IgG2 was detected in none. IgM was detected in 100% of the patients with primary infections, but also in 68% of those with nonprimary infections. IgA showed a peak similar to that of IgM in patients with primary infections. No significant difference was observed in the detection rate or pattern of antibody responses between the recurrent and nonprimary first episode infections, nor between the HSV-1 and HSV-2 infections. These findings may be useful to improve the diagnostic potential of HSV serology.

Central nervous system virion detection in acute measles: histopathological, ultrastructural and pathogenetic aspects

Histopathological and ultrastructural studies of 23 patients who died with clinical diagnosis of measles were carried out. In 12 cases viral nucleocapsids were searched by electron microscopy and detected in 100% of the cases in the lungs and in 50% of the cases in the central nervous system. They were mostly intranuclear. Histopathological changes associated to neurological alterations and the detection of virion are discussed in relation to acute and delayed clinical manifestations.

Quantitation of intrathecal measles virus IgG antibody synthesis rate: subacute sclerosing panencephalitis and multiple sclerosis

A method for quantitating specific anti-viral antibodies in serum and cerebrospinal fluid (CSF) is established using enzyme-linked immunosorbent assay (ELISA). Quantitated antibody levels are used to determine intrathecal specific IgG synthesis rate for the particular antibody. Measles virus was used as a model for validating this quantitative technique: a mutated form of measles virus is a cause of subacute sclerosing panencephalitis (SSPE) and there is a possibility that measles virus is related to the cause of multiple sclerosis (MS). Matched serum and CSF samples were assayed. Concentration of anti-measles IgG was determined and intrathecal measles-specific IgG synthesis rate was calculated. For the SSPE samples, measles-specific IgG synthesis rate was elevated and comprised > 20% of the total intrathecal IgG synthesis rate; these results are consistent with the literature. The ELISA method can be performed routinely, providing a quick, simple, reproducible means of quantitating specific antibody concentrations, with sensitivity greater than 1 nanogram per milliliter. With this method, quantitation of IgG antibodies to any other viral antigen can be reliably and precisely determined.

Synthesis of antibodies against measles virus and myelin by in vitro stimulated B-cells derived from patients with subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis (SSPE) patients carry persistent measles virus infection in the brain. Furthermore, the blood lymphocytes contain viral RNA. Lymphocytes derived from 6 SSPE patients were stimulated with Epstein-Barr virus (EBV). Production of antibodies against measles virus of the IgG isotype was detected in the supernatants of cell cultures of all patients, regardless of the disease's activity, duration or interferon therapy. In contrast, only some of these cell cultures also produced antibodies against myelin.

The diagnostic significance of antibody specificity indices in multiple sclerosis and herpes virus induced diseases of the nervous system

The antibody specificity index (ASI) indicates the cerebrospinal fluid (CSF)/serum difference of antibody amounts per weight unit IgG (normal less than 1.5). It has proven to be the most sensitive inflammation parameter in CSF analysis so far, more sensitive than the Western blot, the "oligoclonal" response, and the empirical differentiation of CSF immunoglobulins. By this diagnostic criterion, several benign viral meningitis cases were found to be caused by the varicella/zoster virus. The diagnostic relevance of local zoster antibody synthesis was greatest in ganglionitis cases, e.g., in zoster oticus sine herpete (facial paresis) and acute radicular syndromes of the elderly. The diagnostic significance of the local immune response against measles, rubella, and zoster antigens (MRZ response) was ascertained further. Together with oligoclonal gamma-globulin fractionation, there is now only 1 out of 100 multiple sclerosis (MS) patients left who has been found to have a normal CSF.

Identification of IgG subclasses' oligoclonal bands in multiple sclerosis CSF

IgG subclasses' oligoclonal bands in unconcentrated CSF from MS patients were detected by isoelectric focusing in agarose gel with subsequent immunoblotting using mouse monoclonal antibodies to human IgG subclasses and double-antibody avidin-biotin-alkaline phosphatase system. All MS CSF showed presence of oligoclonal bands specific to the IgG1 subclass; in addition, several of these samples also had oligoclonal bands specific to IgG3, IgG2, or IgG4, in order of decreasing frequency. Since the CSF of a greater number of MS patients showed oligoclonal bands specific to the IgG1 and IgG3 subclasses, the findings are consistent with those reported in patients with chronic viral infections and autoimmune diseases.

Aberrant IgG subclass distribution to measles in healthy seropositive individuals, in patients with SSPE and in immunoglobulin-deficient patients

Sera from healthy seropositive donors, patients with acute measles, subacute sclerosing panencephalitis, common variable immunodeficiency, and CH gene deletions were analysed for anti-measles IgG1-4. Compared with other anti-viral immune responses of IgG1 and IgG3, an unusual predominance of specific IgG1 prevailed; only four out of a total of 68 patients showed anti-measles IgG3. Of the 17 healthy, measles seropositive serum donors, all showed specific IgG1, none showed IgG3 and six had IgG4. Eight out of 10 patients with SSPE showed an anti-measles IgG1 and IgG4 response while IgG3 was not seen. The IgG1 and IgG4 subclass patterns had some exceptions. Anti-measles IgG3 was found in five out of five patients with deletion of the gamma-1 encoding gene segments and in four out of 15 patients with recent measles antigen stimulation. The subclass pattern was suggested to reflect the immunological compromise associated with measles infections.