Search

Context DNA β-amyloid 1-42 (Aβ42) trimer immunization was developed to produce specific T helper 2 cell (T H 2)–type antibodies to provide an effective and safe therapy for Alzheimer disease (AD) by reducing elevated levels of Aβ42 peptide that occur in the brain of patients with AD. Objective To compare the immune response in wild-type mice after immunization with DNA Aβ42 trimer and Aβ42 peptide. Design and Intervention Wild-type mice received either 4 μg of DNA Aβ42 trimer immunization administered with gene gun (n = 8) or intraperitoneal injection of 100 μg of human Aβ42 peptide with the adjuvant Quil A (n = 8). Titers, epitope mapping, and isotypes of the Aβ42-specific antibodies were analyzed. Main Outcome Measures Antibody titers, mapping of binding sites (epitopes), isotype profiles of the Aβ42-specific antibodies, and T-cell activation. Results DNA Aβ42 trimer immunization resulted in antibody titers with a mean of 15 μg per milliliter of plasma. The isotype profile of the antibodies differed markedly. A predominant IgG1 antibody response was found in the DNA-immunized mice, indicating a T H 2 type of immune response (IgG1/IgG2a ratio of 10). The peptide-immunized mice showed a mixed T H 1/T H 2 immune response (IgG1/IgG2a ratio of 1) (P Conclusion In this preliminary study in a wild-type mouse model, DNA Aβ42 trimer immunization protocol produced a T H 2 immune response and appeared to have low potential to cause an inflammatory T-cell response.

Clemens Warnke1, Gerd Meyer zu Hörste1, Hans-Peter Hartung1, Olaf Stüve2,3,4, Bernd C Kieseier11Department of Neurology, Heinrich-Heine-University Düsseldorf, Germany; 2Neurology Section, VA North Texas Health Care System, Medical Service, Dallas, TX, USA; 3Department of Neurology; 4Department of immunology, University of Texas Southwestern Medical Center at Dallas, TX, USAAbstract: In the light of new cases of progressive multifocal leukoencephalopathy and induced autoimmunity in multiple sclerosis (MS) patients who received treatment with upcoming disease-modifying immunosuppressant drugs with a highly specific mode of action such as natalizumab, rituximab, or alemtuzumab, alternative oral treatment options for a subgroup of less severely affected MS patients are a major focus of drug development. These agents are currently investigated in phase III clinical trials and some of them are characterized by a favorable safety profile. With an emphasis on teriflunomide, the active metabolite of an immunosuppressant approved for the treatment of rheumatoid arthritis since 1998, a number of oral treatment options for patients with MS are discussed.Keywords: teriflunomide, multiple sclerosis, immunosuppressant, oral drugs

ON FEBRUARY 12, 2009, WE CELEBRATE THE 200TH anniversary of the birth of Charles Darwin. He has earned the scientific reputation as being the most influential naturalist-biologist of his generation and perhaps of all time. Achievement of his esteemed status resulted initially from studying the geographical distribution of wildlife and fossils collected on his 5-year voyage on the Beagle and concluding that the “transmutation of species” was due to natural selection. In 1858, he was in the process of documenting his research when he received an essay from Alfred Russel Wallace putting forth the same concept of natural selection as the mechanism for generation of new species, resulting in a joint publication that same year. On the Origin of Species was published by Darwin in 1859, making it now the 150th anniversary of its publication. This book proposed evolution as the scientific basis of diversity and species generation produced through the effects of natural selection. Evolution has been proven to be the mechanism for species generation and the engine for change is natural selection, providing the evolved species, beginning from a common organism, adaptation and fitness to maximize reproduction and survival. Dobzhansky put it succinctly by saying that “nothing in biology makes sense except in the light of evolution.” Darwin expressed it eloquently in 1859: There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved. Two hundred years after Darwin’s birth, molecular genomic analyses of the human genome have been implemented, seeking the genetic basis for natural selection providing biological fitness and also risk of developing disease. Genome-wide association studies (GWASs) seeking gene variations, or single-nucleotide polymorphisms (SNPs), causal of several human diseases have been conducted in recent years. These diseases include autism, schizophrenia, obesity, diabetes, and heart disease. Several GWASs for risk association with neurological diseases,orneuromicstudies,havebeenreported. Increasedrisks foramyotrophic lateral sclerosis,Alzheimerdisease(AD), restless legssyndrome,andmultiplesclerosishavebeenassociated with polymorphisms in specific genes. It was hoped that these observationswouldadvanceanunderstandingof thecausation of inherited, complexpolygenetic,multifactorialneurological diseases. They have been made possible by the publication of thehumangenomeandhaplotypestudies (HapMapanalyses). Awhole-genomeanalysisofsporadicamyotrophiclateralsclerosis was published by Dunckley et al. They identified 10 genetic loci that were associated with sporadic amyotrophic lateral sclerosis in 3 independent series of patients and control subjects.Themostsignificantassociationwithdiseasewasfound foraSNPnearanuncharacterizedgeneknownasFLJ10986on chromosome1.Thus, theydescribedspecificSNPs that areassociated with onset of sporadic amyotrophic lateral sclerosis. Reiman et al conducted a genome-wide survey of 502 627 SNPs to characterize and confirm late-onset AD susceptibility genes. They found that late-onset AD was associated with 6 SNPs from the GRB-associated binding protein 2 (GAB2) gene and a common haplotype encompassing the entire GAB2 gene. The GAB2 gene was overexpressed in pathologically vulnerable neurons, and interference with GAB2 gene expression increased tau phosphorylation. They concluded that GAB2 modifies late-onset AD risk in apolipoprotein E (APOE) e4 allele carriers. Coon et al found a single SNP in linkage disequilibrium to the APOE e4 allele in a neurome-wide association study. Grupe et al described 3 additional SNPs on chromosome 19 in linkage disequilibrium to the APOE e4 locus also in a neurome-wide association study. Liu et al described significant linkage to 3q23 markers associated with AD in a genetically isolated Dutch population. In 2008, Li et al described SNPs associated with risk and ageatonsetofADinaGWASof469 438SNPs.They identified theAPOE linkagedisequilibriumregionasthestrongestgenetic risk factor for AD. They concluded that this event could be a consequence of the coevolution of more than 1 susceptibility allele, includingAPOC1, inthesameregion.Additionalpotential at-riskgenes forADwereof interestandrequire furtherstudies.

Objective To extend our studies on the prolonged and differential effect of natalizumab on T lymphocyte numbers in the cerebrospinal fluid, we investigated the number and phenotypes of leukocytes and the expression of major histocompatibility complex (MHC) classes I and II in cerebral perivascular spaces (CPVS). We hypothesized that natalizumab reduces the number of antigen presenting cells in CPVS. Design A case-control study in which inflammatory cell numbers in the CPVS of cerebral tissue were assessed by immunohistochemical staining. Subjects A patient with multiple sclerosis (MS) who developed progressive multifocal leukoencephalopathy (PML) during natalizumab therapy. Controls included location-matched cerebral autopsy material of patients without disease of the central nervous system, patients with MS not treated with natalizumab, and patients with PML not associated with natalizumab therapy. Results The absolute number of CPVS in the patient with MS treated with natalizumab was significantly lower than in the control groups owing to extensive destruction of the tissue architecture. The expression of MHC class II molecules and the number of CD209 + dendritic cells were significantly decreased in the CPVS of the patient with MS treated with natalizumab. No CD4 + T cells were detectable. Conclusions Our observations may explain the differential and prolonged effects of natalizumab therapy on leukocyte numbers in the cerebrospinal fluid. Published online October 13, 2008 (doi:10.1001/archneur.65.12.noc80051).

Sir, On the basis of persisting demyelination and axonal degeneration in brains of patients with progressive multiple sclerosis (MS), Metz et al. (2007) concluded that ‘autologous hematopoietic stem cell transplantation fails to stop demyelination and neurodegeneration’. This was based on routine and immunohistochemical stains of brains from five patients who died at a median of 2 (range 0.5–18) months after high-dose immunosuppressive therapy (HDIT) and autologous hematopoietic stem cell transplantation (HSCT). Although this small series of autopsy cases contributed significant and interesting insights, the conclusion in the title would appear to be an overstatement of what is actually in evidence. In a ‘Scientific Commentary’ in response to Metz et al. , Martin (2007) also noted limitations in the study, including the small size of the series and that four of the five patients died early after the intervention. A general concern regarding the examination of biopsy or autopsy materials from patients to evaluate the effectiveness of therapeutic interventions has been that it provides only a single time point for each patient assessment. …

Treatment with natalizumab, a monoclonal antibody against the adhesion molecule very late activation antigen 4, an alpha4beta(1) integrin, was recently associated with the development of progressive multifocal leukoencephalopathy, a demyelinating disorder of the central nervous system caused by JC virus infection.To test the effect of natalizumab treatment on the CD4(+)/CD8(+) T-cell ratios in cerebrospinal fluid (CSF) and peripheral blood.Prospective longitudinal study.Academic and private multiple sclerosis centers.Patients with multiple sclerosis (MS) treated with natalizumab, untreated patients with MS, patients with other neurologic diseases, and human immunodeficiency virus-infected patients.CD4(+) and CD8(+) T cells were enumerated in CSF and peripheral blood. The mean fluorescence intensity of unbound alpha4 integrin on peripheral blood CD4(+) and CD8(+) T cells was analyzed before and after natalizumab therapy.Natalizumab therapy decreased the CSF CD4(+)/CD8(+) ratio of patients with MS to levels similar to those of human immunodeficiency virus-infected patients. CD4(+)/CD8(+) ratios in peripheral blood in patients with MS progressively decreased with the number of natalizumab doses, but they remained within normal limits. Six months after the cessation of natalizumab therapy, CSF CD4(+)/CD8(+) ratios normalized. The expression of unbound alpha4 integrin on peripheral blood T cells decreases with natalizumab therapy and was significantly lower on CD4(+) vs CD8(+) T cells.Natalizumab treatment alters the CSF CD4(+)/CD8(+) ratio. Lower expression of unbound alpha4 integrin on CD4(+) T cells is one possible mechanism. These results may have implications for the observation that some natalizumab-treated patients with MS developed progressive multifocal leukoencephalopathy.

Background A brief exposure to systemic hypoxia (i.e., hypoxic preconditioning; HPC) prior to transient middle cerebral artery occlusion (tMCAo) reduces infarct volume, blood-brain barrier disruption, and leukocyte migration. CCL2 (MCP-1), typically regarded as a leukocyte-derived pro-inflammatory chemokine, can also be directly upregulated by hypoxia-induced transcription. We hypothesized that such a hypoxia-induced upregulation of CCL2 is required for HPC-induced ischemic tolerance. Methods Adult male SW/ND4, CCL2-null, and wild-type mice were used in these studies. Cortical CCL2/CCR2 message, protein, and cell-type specific immunoreactivity were determined following HPC (4 h, 8% O2) or room air control (21% O2) from 6 h through 2 weeks following HPC. Circulating leukocyte subsets were determined by multi-parameter flow cytometry in naïve mice and 12 h after HPC. CCL2-null and wild-type mice were exposed to HPC 2 days prior to tMCAo, with immunoneutralization of CCL2 during HPC achieved by a monoclonal CCL2 antibody. Results Cortical CCL2 mRNA and protein expression peaked at 12 h after HPC (both p < 0.01), predominantly in cortical neurons, and returned to baseline by 2 days. A delayed cerebral endothelial CCL2 message expression (p < 0.05) occurred 2 days after HPC. The levels of circulating monocytes (p < 0.0001), T lymphocytes (p < 0.0001), and granulocytes were decreased 12 h after HPC, and those of B lymphocytes were increased (p < 0.0001), but the magnitude of these respective changes did not differ between wild-type and CCL2-null mice. HPC did decrease the number of circulating CCR2+ monocytes (p < 0.0001) in a CCL2-dependent manner, but immunohistochemical analyses at this 12 h timepoint indicated that this leukocyte subpopulation did not move into the CNS. While HPC reduced infarct volumes by 27% (p < 0.01) in wild-type mice, CCL2-null mice subjected to tMCAo were not protected by HPC. Moreover, administration of a CCL2 immunoneutralizing antibody prior to HPC completely blocked (p < 0.0001 vs. HPC-treated mice) the development of ischemic tolerance. Conclusions The early expression of CCL2 in neurons, the delayed expression of CCL2 in cerebral endothelial cells, and CCL2-mediated actions on circulating CCR2+ monocytes, appear to be required to establish ischemic tolerance to focal stroke in response to HPC, and thus represent a novel role for this chemokine in endogenous neurovascular protection.