Intrathecal synthesis of virus-specific oligoclonal antibodies in patients with enterovirus infection of the central nervous system

Signature biochemical properties of broadly cross-reactive HIV-1 neutralizing antibodies in human plasma

The common properties of broadly cross-reactive HIV-1 neutralization antibodies found in certain HIV-1-infected individuals holds significant value for understanding natural and vaccine-mediated anti-HIV immunity. Recent efforts have addressed this question by deriving neutralizing monoclonal anti-envelope antibodies from memory B cell pools of selected subjects. However, it has been more difficult to identify whether broadly neutralizing antibodies circulating in plasma possess shared characteristics among individuals. To address this question, we used affinity chromatography and isoelectric focusing to fractionate plasma immunoglobulin from 10 HIV-1-infected subjects (5 subjects with broad HIV-1 neutralizing activity and 5 controls). We find that plasma neutralizing activity typically partitions into at least two subsets of antibodies. Antibodies with restricted neutralization breadth have relatively neutral isoelectric points and preferentially bind to envelope monomers and trimers versus core antigens from which variable loops and other domains have been deleted. In comparison, broadly neutralizing antibodies account for a minor fraction of the total anti-envelope response. They are consistently distinguished by more basic isoelectric points and specificity for epitopes shared by monomeric gp120, gp120 core, or CD4-induced structures. Such biochemical properties might be exploited to reliably predict or produce broad anti-HIV immunity.

Devastating epileptic encephalopathy in school-aged children (DESC): A pseudo encephalitis

PURPOSE

To describe the characteristics of a previously overlooked devastating epileptic encephalopathy that presents as intractable bilateral perisylvian epilepsy starting with prolonged status epilepticus (SE) in normally developing school-aged children.

METHODS

Retrospective study over 7 years of all normally developing children admitted in our institution for a prolonged SE following non-specific febrile illness with at least one seizure recorded on EEG.

RESULTS

Fourteen children were included at a median age of 7.5 years (4-11) (median follow-up of 4 years (1-7)). Intractable SE lasted 4-60 days (median 30). CSF cell count was normal in five cases and moderately increased in the others. During SE, seizures were recorded in 11 patients and involved temporal lobes in 7; the other 4 patients exhibited perisylvian clinical features with secondary generalization. Intractable epilepsy followed SE in all cases without any latent period. Persisting seizures were recorded in 10 patients and involved temporo-perisylvian regions in 8, frontal regions in 2; 3 others had perisylvian ictal semiology. Spiking was bilateral in 10 cases. MRI showed bilateral hippocampal hypersignal and/or atrophy in 10 cases (extended to the neocortex in 3). All children had major cognitive sequelae. When feasible (six patients), detailed neuropsychology suggested fronto-temporal impairment.

CONCLUSIONS

Among so called grey matter encephalitis patients, we identified a recognizable pattern we propose to call Devastating Epileptic encephalopathy in School-age Children (DESC) that begins with prolonged SE triggered by fever of unknown cause, and persists as intractable perisylvian epilepsy with severe cognitive deterioration.

Screening and optimisation of an ELISA method for the quantitative detection of enterovirus specific RT-PCR products by means of a two-level experimental design

In a previous paper, optimal reaction conditions were determined for the RT-PCR part of a quantitative enterovirus specific RT-PCR ELISA method (J. Pharm. Biomed. Anal., 25 (2001) 131-142). In order to obtain a detection limit as low as possible, the ELISA part of the procedure was optimised as well. This was done by investigating the influence of seven factors at three levels in a multivariate approach. A reflected two-level screening design, derived from a Plackett-Burman design, was used. Optimal reaction conditions were established by calculation and by evaluation of the effects of the factors on the measured absorbance of the ELISA detection. Under these conditions, the linear range and detection limit of the test were determined and compared with the ELISA conditions before optimisation. The optimised RT-PCR ELISA will be used to study a possible longitudinal relationship between enteroviruses and the development of multiple sclerosis and juvenile diabetes.

Epstein-Barr virus nuclear antigen-1 (EBNA-1) associated oligoclonal bands in patients with multiple sclerosis

Oligoclonal bands (OCBs) are frequently observed in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS), but the target antigens of these antibodies remain unknown. We used antigen specific immunoblotting to determine whether Epstein Barr virus nuclear antigen-1 (EBNA-1) was a target of the OCBs in the CSF of patients with MS. Antibody indices (AIs) were measured by ELISA and calculated by the formula of Reiber and Lange which includes correction factors for both breakdown of the blood brain barrier and intrathecal polyclonal IgG synthesis. A distinctive oligoclonal antigen specific banding pattern for EBNA-1 was observed in 5/15 MS patients, but 0/12 controls (P=0.037, Fisher's Exact Probability). AIs in this EBNA-l positive subgroup were extremely high, comparable with levels observed in viral CNS infections. In one patient with EBNA-1 specific OCBs, EBNA-1 and a peptide 'equivalent', p62, were able to absorb a component of the total IgG. Our results suggest that in a subset of MS patients, EBNA-1 may be a major target of selected OCBs.

Molecular approach to find target(s) for oligoclonal bands in multiple sclerosis

OBJECTIVES

Oligoclonal bands are a characteristic finding in the CSF of patients with multiple sclerosis, yet their target antigen(s) remain unknown. The objective was to determine whether a filamentous phage peptide library could be employed to allow the oligoclonal bands to select their own target epitopes.

METHODS

CSF IgG antibody from 14 patients with multiple sclerosis and 14 controls was used to select individual phage clones from a bacteriophage library containing approximately 4 x 10(7) different hexamers expressed on its surface pIII protein. The amino acid sequence selected was deduced by sequencing the DNA of the genetically engineered insert.

RESULTS

In general, after three rounds of selection, CSF from both patients with multiple sclerosis and controls selected one to two consistent peptide motifs. Five out of 14 patients with multiple sclerosis, and one control, selected the amino acid sequence motif, RRPFF. Given 20 possible amino acids per position, the likelihood of five patients selecting the same linear five amino acid sequence is at most 1.6 x 10(-3), corrected for the number of clones sequenced. A GenBank computer search showed that this sequence is found in the Epstein-Barr Virus nuclear antigen (EBNA-1), and a heat shock protein alphaB crystallin. Human serum antibodies to a synthetic peptide containing RRPFF were virtually exclusively found in patients with prior infection by Epstein-Barr virus. Other studies have suggested a relation between Epstein-Barr virus infection and multiple sclerosis, including nearly 100% Epstein-Barr virus seropositivity among patients with multiple sclerosis and increased concentrations of antibody to EBNA in CSF of patients with multiple sclerosis. By antigen specific immunoblotting, antibodies to the RRPFF motif in the CSF were shown to correspond to a subset of oligoclonal bands in the CSF from the same patient.

CONCLUSION

This study shows that phage epitope display libraries may be used to select amino acid motifs which are potentially relevant to the pathogenesis of multiple sclerosis.

The diagnostic significance of the polymerase chain reaction and isoelectric focusing in herpes simplex virus encephalitis

In this study, serum and CSF samples of 55 neurological patients have been examined to confirm the diagnosis of herpes simplex virus encephalitis (HSVE). Different methods were applied, including serological titer evaluations, determination of intrathecally-produced HSV-specific antibodies by isoelectric focusing with affinity immunoblotting (IEF), as well as HSV-specific ELISA and HSV-specific polymerase chain reaction (PCR). The results of IEF and PCR have been compared and contrasted to develop general directions for virological diagnosis of HSVE. Of 14 patients suffering from clinically diagnosed HSVE, HSVE was confirmed in 12 cases by the demonstration of PCR or IEF positivity. A HSV-specific CNS infection could be excluded in 2 of these 14 patients. In 17 patients suffering from non-HSVE, PCR and IEF results were negative. Twenty-four patients, suffering from other neurological diseases, serving as a control group, were PCR- and HSV-IEF-negative. The study indicated that there are two possibilities for unequivocal demonstration of HSV-specific CNS involvement: first, performance of PCR especially in the acute phase of disease and in suspicious relapses, and second, performance of HSV-specific IEF for determination of intrathecally synthesized HSV-specific antibodies. It is suggested that these two methods should be introduced in routine diagnosis of viral encephalitis.

Intrathecal immune response in patients with the post-polio syndrome

BACKGROUND

The syndrome of progressive muscular atrophy decades after acute paralytic poliomyelitis (post-polio syndrome) is not well understood. The theory that physiologic changes and aging cause the new weakness does not explain the immunologic abnormalities reported in some patients. An alternative explanation is persistent or recurrent poliovirus infection.

METHODS

We assessed the intrathecal antibody response to poliovirus and intrathecal production of interleukin-2 and soluble interleukin-2 receptors in 36 patients with the post-polio syndrome and 67 controls (including 13 who had had poliomyelitis but had no new symptoms and 18 with amyotrophic lateral sclerosis). Intrathecal antibody responses to measles, mumps, herpes simplex, and varicella zoster viruses were also determined.

RESULTS

Oligoclonal IgM bands specific to poliovirus were detected in the cerebrospinal fluid of 21 of the 36 patients with the post-polio syndrome (58 percent) but in none of the control group (P less than 0.0001). In quantitative studies there was evidence of increased intrathecal synthesis of IgM antibodies to poliovirus only among the patients with the post-polio syndrome; there was no increased synthesis of IgM to measles, mumps, herpes simplex, or varicella zoster viruses. The patients with post-polio syndrome had significantly higher mean (+/- SD) (cerebrospinal fluid levels of interleukin-2 and soluble interleukin-2 receptors than the controls (8.1 +/- 5.3 vs. 1.4 +/- 0.8 U per milliliter and 159.6 +/- 102.9 vs. 10.7 +/- 6.2 U per milliliter, respectively). The intrathecal synthesis of IgM antibodies to poliovirus correlated with the cerebrospinal fluid concentrations of interleukin-2 (P less than 0.0005) and soluble interleukin-2 receptors (P less than 0.001).

CONCLUSIONS

An intrathecal immune response against poliovirus is present in many patients with the post-polio syndrome. In some of these patients the recrudescence of muscle weakness may be caused by persistent or recurrent infection of neural cells with the poliovirus.