CSF and serum levels of soluble interleukin-6 receptors (sIL-6R and sgp130), but not of interleukin-6 are altered in multiple sclerosis.

Interleukin-6 (IL-6) has recently been implicated in multiple sclerosis (MS), since IL-6 deficient mice were resistant to a demyelinating form of experimental autoimmune encephalomyelitis and IL-6 expression was upregulated in MS. The cytokine IL-6 and its action mediating soluble receptors (sIL-6R and sgp130) were measured in cerebrospinal fluid (CSF) and serum of 61 MS patients and 39 controls. In the presence of unchanged IL-6 concentrations, sIL-6R and sgp130 serum levels were significantly increased in MS and correlated with disease severity. Furthermore, sgp130 CSF levels were decreased in MS, suggesting a possibly altered IL-6 regulation in the CSF.

Oligoclonal bands and blood--cerebrospinal-fluid barrier dysfunction in a subset of patients with Alzheimer disease: comparison with vascular dementia, major depression, and multiple sclerosis.

As known from inflammatory diseases, oligoclonal bands in the cerebrospinal fluid (CSF-OCB) may indicate a humoral immune response within the central nervous system. Previous studies on the CSF IgG content in Alzheimer disease (AD)have been controversial about the relationship of OCB and elevated IgG indices. To explore this problem, we combined qualitative (isoelectric focusing) and quantitative methods (IgG index) to detect intrathecal IgG production and related these findings to the presence of blood--cerebrospinal-fluid barrier (BCB) dysfunction. Fifty-one AD patients were compared with patients with vascular dementia (VD), major depression (MD), multiple sclerosis (MS), and age-matched control subjects. CSF-OCB could be traced in 20% of AD patients. An elevated IgG index was found in 6% and a BCB dysfunction in 16% of all AD patients. Either intrathecal IgG synthesis or BCB dysfunction were detected in a subgroup of 36% of all AD cases and in 40% of patients with late-onset AD. Intrathecal IgG synthesis and BCB dysfunction may suggest underlying immunological or inflammatory changes in an as-yet undefined subgroup of AD patients and support the notion of a heterogeneous nature of AD.

Melanoma-associated adhesion molecule MUC18/MCAM (CD146) and transcriptional regulator mader in normal human CNS.

The proteins MUC18 and Mader have been identified as markers of tumor progression in melanoma cells. MUC18, also known as MCAM (melanoma cell adhesion molecule) and as CD146 (endothelial antigen), is a cell adhesion molecule belonging to the immunoglobulin superfamily. Mader is a transcriptional regulator shown to negatively regulate EGR-1. As it is known that neoplastic cells of neuroectodermal origin frequently express neuron-specific molecules, we studied whether these melanoma-associated antigens are found in normal CNS tissue. We investigated the expression of MUC18/MCAM and Mader in adult human post mortem CNS tissue by immunohistochemistry, immunoblot and two-dimensional gel electrophoresis. Our results show that Mader is preferentially expressed on neurons and glial cells and that the adhesion protein MUC18/MCAM is mainly expressed on vasculature within the CNS. These observations may have important implications for further studies investigating their possible roles in cell adhesion and proliferation control within the CNS.

Detection of the novel cell adhesion molecule MUC18 in human brain tissue.

The implication of cell adhesion molecules (CAMs) in the mediation of the immune response to inflammatory stimuli has been shown in different neurological syndromes. The neural cell adhesion molecule (NCAM) and the myelin associated glycoprotein (MAG) are functionally important CNS-cell adhesion molecules (CAMs) and members of the immunoglobulin gene superfamily (IgSF). Both CAMs are expressed from the time of neuronal induction and myelin formation and are likely to contribute to the generally adhesive properties of neurons and oligodendrocytes. The present study describes, by means of SDS-PAGE and immunoblotting, a novel CNS antigen which is a glycoprotein detected in post mortem frontal lobe tissue of ten subjects at an M(r) 65 and 113 kD which showed the greatest sequence homology to neuronal IgSF members like NCAM. This expected membrane CAM, with probable functions in CNS cell-cell interactions, had been detected first in primary human melanoma cells, with increasing expression as tumors progress and is expected to be a developmentally regulated CAM in neuroectodermal tissues.

Fibrin degradation products in post mortem brain tissue of schizophrenics: a possible marker for underlying inflammatory processes.

Alterations in protein composition are often present in diseases of the central nervous system (CNS). Inflammatory processes causing these alterations have been suggested by many authors to underlie the cerebral disturbance in some cases of schizophrenia. In a previous study, two disease-associated additional polypeptides P1 and P2 could be detected in the cerebrospinal fluid (CSF) of 60 out of 123 (49%) schizophrenic patients. These polypeptides were identified as cleavage products of the beta-chain of fibrin(ogen), an acute-phase protein which is increased in inflammatory processes. Because investigations of brain tissue might better reflect the disease process than cerebrospinal fluid, we examined 6 post mortem brains (3 schizophrenics, 3 normal controls) for the presence of fibrin(ogen) and its cleavage products by two dimensional gel electrophoresis followed by immunoblotting. We detected fibrin(ogen) and its degradation products P1 and P2 in all schizophrenic brain tissue samples, but not in that from controls. These results are consistent with previous CSF observations and suggest that a CNS inflammatory process may be occurring in a subgroup of schizophrenic patients.

Analysis of cerebrospinal fluid from patients with psychiatric and neurological disorders by two-dimensional electrophoresis: identification of disease-associated polypeptides as fibrin fragments.

Two-dimensional electrophoresis (2-DE) of cerebrospinal fluid (CSF) samples--from 347 patients with various psychiatric and neurological disorders--and subsequent silver staining revealed two additional polypeptides (Mr 40,000) in 49% of 111 schizophrenics, 46% of 43 schizoaffective patients, 36% of 41 patients with affective disorders, 43% of 28 patients with multiple sclerosis, but not in 25 patients without neurological symptomatology, nor in 9 patients with Lues, and in only 2 of 25 patients with AIDS. The two polypeptides, as detected by 2-DE, eluted after size exclusion chromatography in fractions containing proteins with Mr greater than 200,000. After 2-DE of CSF samples, enriched by gel chromatography, the polypeptides were immobilized by blotting onto glass-fiber membranes and subjected to N-terminal sequencing. Polypeptide A was identified as beta-chain remnant (beta 2), derived from plasmin cleavage of fibrin(ogen). After size exclusion chromatography, 2-DE, and Western blotting, polypeptide A and B, as well as several other spots, reacted with fibrinogen antibodies, suggesting that the polypeptides are subunits of a fibrin degradation complex.

Allosteric oxygen-binding properties of reassembled tarantula (Eurypelma californicum) hemocyanin with incorporated apo- or met-subunits.

4x6-meric hemocyanin of the tarantula Eurypelma californicum was dissociated into subunits; one type of subunit was removed by immunoaffinity chromatography and replaced by its apo- or met-form. The mixture was reassembled and the reconstituted 4x6-mers were isolated. This was performed for subunits a, bc, d, e, f and g, respectively. It was verified by crossed immunoelectrophoresis that each type of subunit including the modified one, was incorporated in the reassembled 4x6-mers. Oxygen binding curves of the purified reconstituted 4x6-mers were recorded at different pH values (pH 7.0-9.0; 20 degrees C). Half-saturation pressures (P50) and the cooperativities were calculated using unmodified, reassembled 4x6-mers as reference. In all cases, incorporation of a met-subunit increased oxygen affinity. In contrast, incorporation of an apo-subunit either slightly decreased oxygen affinity (bc, f and d) or had no detected influence (others). The Bohr effect remained more or less unchanged in every case. Cooperativity was generally decreased. The met-modification of subunit d had the strongest effect. No significant differences could be observed between the respective met- and apomodification, except for experiments with subunit d. Generally, the value of hmax exceeded h50 by a factor of 1.3 to 1.5. pH-sensitivity of cooperativity was distinctly influenced depending on the modified subunit. The strongest effect was observed for subunit bc. Our results demonstrate, for the first time, that each subunit of tarantula hemocyanin is involved in the allosteric processes. Apparently, they uniformly contribute to oxygen affinity and Bohr effect, but distinctly to cooperativity and pH sensitivity of the latter.