Helge Löfberg

Quantitation of γ-trace in human biological fluids: Indications for production in the central nervous system

Gamma-Trace was purified in large amounts from urine and used for the production of a specific rabbit antiserum. An enzyme immunoassay for quantitation of gamma-trace was developed using the pure protein as a primary standard. Its sensitivity was approximately 30 microgram/l. An enzyme amplified single radial immunodiffusion was developed as well. Its sensitivity was approximately 0.3 mg/l. These assays allowed quantitation of gamma-trace in normal human biological fluids. The following results were obtained (mean +/- SD): cerebrospinal fluid: 5.8 +/- 2.2 mg/l, plasma: 1.1 +/- 0.42 mg/l, saliva: 1.8 +/- 0.88 mg/l and urine: 0.095 +/- 0.057 mg/l. Plasma samples from patients with advanced renal failure revealed gamma-trace values up to 13 times the normal mean plasma value. The results indicate a production of gamma-trace in the central nervous system and that the protein is primarily catabolized by the kidney.

Abnormal Metabolism of γ-Trace Alkaline Microprotein : The Basic Defect in Hereditary Cerebral Hemorrhage with Amyloidosis

ALTHOUGH the total incidence of cerebral hemorrhage is high, comparatively few reports concerning the familial occurrence of this disease have been published.1 , 2 In 1935 Arnason described 10 fami...

Hereditary cystatin C (γ-trace) amyloid angiopathy of the CNS causing cerebral hemorrhage

Abstract Hereditary CNS amyloid angiopathy occurring in Icelanders is the first human disorder known to be caused by deposition of cystatin C amyloid fibrils in the walls of the brain arteries leading to single or or multiple strokes with fatal outcome. One or more affected members have been verified by histological examination in 8 families containing 127 affected. These originated from the same geographic area. Abnormally low value of cystatin C found in the cerebrospinal fluid of those affected can be used to support or make diagnosis of this disease, also in asymptomatic relatives. By amino acid sequence analysis the amyloid fibrils in the patients are found to be a variant of cystatin C (γ‐trace), a major cysteine proteinase inhibitor. The variant protein has an amino acid substitution (glutamine for leucine) at position 58 in the amyloid molecule. It is postulated that a point mutation has occurred leading to production of amyloidogenic protein causing the disorder.

Production, characterization and use of monoclonal antibodies against the major extracellular human cysteine proteinase inhibitors cystatin C and kininogen

Murine monoclonal antibodies against the major cysteine proteinase inhibitors of human biological fluids, cystatin C and kininogen, were produced. The cystatin C antibody, HCC3, with a Ka of 2 x 10(7) l/mol, increased the inhibition of papain by cystatin C and was suitable for use in immunoblotting, immunohistochemistry and in the construction of a sensitive sandwich enzyme immunoassay for quantification of cystatin C. It recognized not only free cystatin C but also cystatin C in complexes with cysteine proteinases. The kininogen antibody, HK4, was directed against the third, cysteine proteinase inhibitory domain of the heavy chain of kininogen (Ka = 1 X 10(7) l/mol), but did not influence the papain inhibitory activity of kininogen. It reacted with free kininogen as well as kininogen in complex with cysteine proteinases. Both antibodies could be used for the production of specific immunosorbents.

Immunohistochemical Demonstration of Age-related Deposition of Vitronectin (S-protein of Complement) and Terminal Complement Complex on Dermal Elastic Fibers

Immunoreactivity of vitronectin was investigated in 100 skin specimens from different body regions in 87 individuals of different ages using monoclonal and polyclonal anti-vitronectin antibodies in an avidin-biotin-peroxidase complex technique. Vitronectin immunoreactivity was found in conjunction with dermal elastic fibers in all subjects older than 13 years. No vitronectin immunostaining was detected in subjects younger than six years, suggesting deposition of vitronectin during late childhood or early adolescence. Using an immunogold staining procedure, vitronectin immunoreactivity was ultrastructurally localized to the periphery of elastic fibers. The blood level of vitronectin in 20 healthy newborns was 67% of the adult level, suggesting active biosynthesis already in the fetus. To investigate whether vitronectin is deposited as part of the SC5b-9 complex or as uncomplexed protein, the immunoreactivity of vitronectin was compared with that of C9, using monoclonal and polyclonal antibodies against the C9 neoantigen. Distinct C9 neoantigen immunoreactivity was demonstrated in association with dermal elastic fibers in human skin in adults but only in subjects older than 30 years. The intensity of C9 neoantigen immunoreactivity appeared to increase with age and was found to be stronger in sun-exposed skin than in sun-protected skin. These findings indicate that uncomplexed vitronectin is deposited during childhood or early adolescence and that terminal complement complexes (C5b-9 and/or SC5b-9) are deposited on elastic fibers later on in life. Hypothetically, the tissue form of vitronectin may be involved in the prevention of tissue damage in proximity to local complement activation. In addition, it may be physiologically important as substratum for cells, stimulating cell migration and anchorage.

Fixed drug eruption: an immunohistochemical investigation of the acute and healing phase

Five patients were each challenged orally with a drug which had previously induced a fixed drug eruption. A positive reaction occurred in all the patients. Punch biopsies were taken 6–12 h, 24h and 3 weeks after challenge. The specimens were tested with different mouse anti‐human monoclonal antibodies to identify T lymphocytes and phenotypic subsets, natural killer cells, B lymphocytes, OKT‐6 and HLA‐DR‐positive cells. T suppressor/cytotoxic cells seemed to play a major role in initiating the flare‐up reaction and preserving the cutaneous memory function of the fixed drug eruption.

The disulphide bridges of human cystatin C (γ-trace) and chicken cystatin

Human cystatin C, a powerful physiological protein inhibitor of cathepsins B, H and L, contains two disulphide bridges, at least one of which is essential to its inhibitory activity. The positions of these bridges in the single polypeptide chain of the protein have been determined by diagonal paper electrophoresis. The cysteine residues at positions 73 and 83 form one bridge, and those at positions 97 and 117 form the other. In the homologous cystatin of chicken egg‐white, the disulphides are Cys 71–Cys 81, and Cys 95–Cys 115.

Immunohistochemical demonstration of vitronectin in association with elastin and amyloid deposits in human kidney.

SummaryThe multifunctional glycoprotein vitronectin, also called serum spreading factor and S-protein of complement, is a potent inducer of cell adhesion and spreading in vitro, and also has a regulatory function in the complement and coagulation pathways. It is present both in plasma and tissue. Recently, vitronectin immunoreactivity was demonstrated in the elastic fibres of normal human skin. Normal and amyloid kidney tissue was investigated for vitronectin immunoreactivity using polyclonal and monoclonal antibodies in an avidin-biotin-peroxidase complex technique and in an alkaline phosphatase anti-alkaline phosphatase complex technique. Vitronectin was found in the elastic layers of normal vessel walls, and in glomerular selerotic lesions in cases of benign nephrosclerosis, but not in normal glomeruli. Strong specific vitronectin immunoreactivity was found in the amyloid deposits in kidneys from cases with amyloid A type amyloidosis, and in cases with amyloid light chain type amyloidosis. Structures immunostainable with anti-amyloid A antiserum were invariably immunostainable with anti-vitronectin. An antiserum against serum amyloid P component stained the same structures as did the anti-vitronectin antibodies, and in addition stained normal glomerular basement membranes. In conclusion, vitronectin immunoreactivity was demonstrated in clastic tissue, in amyloid deposits and in sclerotic lesions in human kidney.

Vitronectin colocalizes with Ig deposits and C9 neoantigen in discoid lupus erythematosus and dermatitis herpetiformis, but not in bullous pemphigoid

C9 neoantigen immunoreactivity has been found to colocalize with C3 immunoreactivity at the dermal‐epidermal junction zone (DEZ) in skin specimens from patients with bullous pemphigoid, lupus erythematosus and dermatitis herpetiformis. The present study was designed to elucidate whether the C9 neoantigen immunoreactivity represents deposition of membrane attack complexes or non‐lytic SC5b‐9 complexes. Skin specimens from 11 patients with pemphigoid, five patients with discoid lupus erythematosus and from nine patients with dermatitis herpetiformis were studied with immunofluorescence using both monoclonal and polyclonal antibodies against C9 neoantigen and against vitronectin (S‐protein), an inhibitor to the membrane attack complex of complement. Specimens from the pemphigoid patients demonstrated C9 neoantigen reactivity along the DEZ without detectable colocalized vitronectin. This suggests deposition of membrane attack complexes in the pemphigoid lesions. Immunoreactivity of both C9 neoantigen and vitronectin was detected in the DEZ in specimens of discoid lupus erythematosus and in the tips of dermal papillae in specimens of dermatitis herpetiformis. The combined presence of C9 neoantigen‐ and vitronectin immunoreactivity may indicate deposition of C9 as part of the non‐lytic SC5b‐9 complex. The finding reported here of differential deposition of vitronectin and C9 in different diseases indicates that the presence of C9 neoantigen immunoreactivity in tissue per se does not represent the deposition of membrane attack complexes, but that it may also be C9 deposited as part of the nonlytic SC5b‐9 complex.

Production of an amino acid sequence-specific antiserum against human amyloid A (AA) and serum amyloid A (SAA) protein

The hydrophilic nonapeptide Ser-Asp-Ala-Arg-Glu-Asn-Ile-Gln-Arg, identical with residues 59-67 of human amyloid protein A (AA) and serum amyloid protein A (SAA), was covalently bound via its carboxyl-terminal end to the carrier-protein keyhole limpet haemocyanin. The complex was injected subcutaneously into ten rabbits. All rabbits produced antisera which, unabsorbed, were specific for AA and SAA. The antisera and their isolated peptide specific antibodies were performance-tested and found to be excellent for demonstration of AA and SAA in immunoblotting and immunohistochemical techniques but unsuitable for immunoprecipitation. Since it is difficult to produce AA- and SAA-specific antisera by procedures earlier described and commercial supplies of good such reagents are unavailable, the easy production of sequence-specific such antisera will facilitate more extended studies of the corresponding antigens for diagnostic and scientific purposes.