Alkali-degradation of amyloid: an ancient method useful for making monoclonal antibodies against amyloid fibril proteins.

The systemic amyloidoses constitute a group of life-threatening disorders at which one out of about 15 different proteins have polymerized into fibrils. Prognosis and treatment varies widely and depends on the biochemical type. Determination of this has usually to be performed by immunohistochemistry which is a challenge because of lack of monospecific antibodies that can be used on formaldehyde-fixed tissue sections. We have here used an old method to create immunogenic fragments of AL-amyloid fibrils by partial degradation and solubilization with sodium hydroxide. The mouse monoclonal antibody pwlam raised against this material, labelled AL-amyloid deposits of lambda origin strongly and specifically in sections of formaldehyde-fixed and paraffin-embedded tissues.

Long-term juxtafoveal retinal telangiectasia.

PURPOSE: To determine the long-term natural history of idiopathic juxtafoveal telangiectasia (IJRT). METHODS: Record review in 2 university-based and 2 private vitreoretinal practices sought patients with IJRT documented by color photographs and fluorescein angiograms (FAs) during the period January 1, 1980, to December 31, 1993. Patients then had repeated examinations and FAs. RESULTS: Twenty patients with IJRT in 32 eyes had follow-up examinations. Fifteen patients had color photographs and FAs, and one had color photographs alone. Follow-up varied from 10 years to 21 years (average, 15 years). Six eyes were treated by laser photocoagulation at onset. Twenty-four of the 26 untreated eyes lost vision as measured by Snellen testing. Visual loss and morphologic progression depended on IJRT type. Six of 8 untreated eyes with type IA IJRT lost vision by >/ or = 3 lines (Snellen), 4 to 20/70 or worse. Vision loss was caused by progressive telangiectatic changes and intraretinal edema. Fifteen of 20 initially untreated eyes with type IIA IJRT developed either central retinal pigment epithelium membranes or subretinal neovascularization with loss of vision to 20/80 or less. CONCLUSION: IJRT prognosis depends on type and clinical features. Long-term prognosis for central vision is poor.

Biclonal systemic AL-amyloidosis with one glycosylated and one nonglycosylated AL-protein.

The amyloid fibril protein AL was isolated from the spleen of a patient with systemic amyloidosis. Size-exclusion chromatography of the solubilized amyloid fibrils revealed a distinct, retarded asymmetric peak. The symmetrical part of the peak showed on SDS-PAGE two positive periodic acid Schiff-staining bands at 14 and 16 kDa. Staining with Coomassie Brilliant Blue revealed in addition two proteins with masses of 13 and 20 kDa. The 14 and 16 kDa bands were the strongest ones. N-Terminal analyses of the four blotted bands showed that the N-termini were the same in all cases. Elucidation of the amino acid sequence established an AL-chain of 157 residues as well as a fragment covering positions 188-207 of the constant region. Two tryptic peptides derived from the same region, positions 25-46, showed an identical sequence, except for position 34 where both alanine and threonine residues occurred. Monosaccharide compositional analysis of the threonine-containing peptide revealed an oligosaccharide in the N-glycosylation site, position 32-34. Mass analysis of the glycopeptide verified the oligosaccharide. The AL-chains belong to the kappa 3a germline gene and verifies that the glycosylated chain is a mutated form. The AL-chains differ from that of the germline in 14 positions. The J-segment is of JkappaIII and is mutated in position 106.

Proteolysis of AA amyloid fibril proteins by matrix metalloproteinases-1, -2, and -3.

We recently demonstrated the presence of matrix metalloproteinases (MMPs)-1, -2, and -3 in AA amyloid deposits, which lead us to speculate that MMPs may participate in amyloidogenesis by either processing the precursor protein, or by degrading the amyloid deposits. Here we investigated this theory by determining the ability of MMP-1, -2, and -3 to degrade human acute-phase serum amyloid A (SAA) and human AA amyloid fibril proteins (AFPs). The following in vitro degradation experiments were performed: using either recombinant MMP-1, -2, or -3 and SAA as a substrate; using either recombinant MMP-1, -2, or -3 and AFP as a substrate; and using THP-1 cells as the protease source and AFP as the substrate. All three MMPs were able to cleave SAA and AFP within the region spanning residues 51 to 57. The following cleavage sites were identified: at 57 to 58 for MMP-1; at 7 to 8 and 51 to 52 for MMP-2; at 7 to 8, 16 to 17, 23 to 24, 51 to 52, 55 to 56, 56 to 57, and 57 to 58 for MMP-3. Cell culture experiments showed that THP-1 cells were able to degrade AFPs. Degradation was significantly delayed after addition of a general metalloproteinase inhibitor (o-phenanthroline) to dextran sulfate-stimulated cells. This is the first study to show that human SAAs and AFPs are susceptible to proteolytic cleavage by MMPs. Immunocytochemistry and electron microscopy showed that degradation takes place in the pericellular or extracellular compartment.

Chemical typing of amyloid protein contained in formalin-fixed paraffin-embedded biopsy specimens.

The human amyloidoses represent a heterogeneous group of disorders characterized by the deposition of fibrillar protein in vital organs. Given the fact that at least 20 different molecules can form fibrils, the unambiguous identification of the type of amyloid deposited is critical to the correct diagnosis and treatment of patients with these disorders. Heretofore, this information has been inferred from particular clinical features of the disease, ancillary laboratory tests, and results of immunohistochemical analyses. However, to establish unequivocally the kind of protein that is deposited as amyloid, it is necessary to determine its chemical composition through amino acid sequencing or mass spectroscopy of material extracted from fibrillar deposits. We have developed a micromethod whereby such studies can be performed readily using sections of formalin-fixed, paraffin-embedded biopsy specimens. The ability to identify precisely the nature of the tissue deposits has diagnostic, therapeutic, and prognostic implications for patients with amyloid-associated disorders.

Apolipoprotein A-1-derived amyloid in atherosclerotic plaques of the human aorta.

Previous studies have shown that the amyloid localized to the aortic intima may be a biochemical entity different from other forms of localized amyloid. The amyloid fibril protein in one patient studied consisted of an N-terminal fragment of apolipoprotein A-1 (apo A-1). Since this patient was later shown to carry a missense mutation in the apo A-1 gene, leading to a deletion at position 107 of the mature protein, the question remained whether wild-type apo A-1 is amyloidogenic. In autopsy specimens from the thoracic aorta from 69 individuals, intimal atherosclerotic plaque-related amyloid was present in 11 cases (16%) and amyloid outside plaques in 37 cases (54%). The immunoreactivity of amyloid localized to the aortic intima was evaluated with the aid of antisera against N-terminal segments of apo A-1. The amyloid in association with atherosclerotic plaques was positively labelled by immunohistochemistry. The amyloid fibril protein from one patient, previously shown not to carry any mutation in the apo A-1 gene, was purified and shown by amino acid sequence analysis to be of apo A-1 nature. The result shows that wild-type apo A-1 is amyloidogenic and gives rise to a common localized form of amyloid associated with atherosclerosis.

Glycosylation of immunoglobulin light chains associated with amyloidosis.

AL amyloidosis is a fatal disease caused by deposition of immunoglobulin light chains in a fibrillarforin (AL) in various organs. By searching the Kabat database of immunoglobulin sequences using the KabatMan software, we have shown that there is a preponderance of the consensus glycosylation sequon (AsnXxxSer/Thr) in the framework regions of amyloid light chains. We have characterised by computer graphics simulations, NMR spectroscopy and carbohydrate biochemistry the structure and conformation of the oligosaccharide from amyloid protein AL MS (lamba1) and from the amyloid associated Bence Jones protein of patient MH (kappa1). These proteins have glycosylation in the hypervariable complementarity-determining region versus framework region, respectively. Both contained a 2-6 sialylated core fucosylated biantennary chain mostly with bisecting GIcNAc. Together our results suggest that light chain glycosylation may be one of several modifications which may render the protein more prone to amyloid formation.

Streptococcus pneumoniae heat shock protein 70 does not induce human antibody responses during infection.

Mouse monoclonal antibodies (mAbs) were developed against Streptococcus pneumoniae in search for potential common pneumococcal proteins as vaccine antigens. mAb 230,B-9 (IgG1) reacted by immunoblotting with a 70-kDa protein which was isolated by immunoaffinity chromatography and subsequent preparative electrophoresis. N-terminal amino acid sequencing showed homology to that of heat shock protein 70 (hsp70). The hsp70 epitope reactive with mAb 230,B-9 was found in all the pneumococci examined as well as in other streptococci and enterococci. The epitope was not expressed in several other examined Gram-positive or -negative bacteria. Pneumococcal hsp70 has by other investigators been proposed to be a vaccine candidate. Binding experiments using flow cytometry showed that the epitope was not surface-exposed on live exponential phase grown S. pneumoniae. Human patient sera did not react with affinity-purified pneumococcal hsp70. Therefore the pneumococcal hsp70 does not seem to be of special interest in a vaccine formulation. The human sera contained antibodies to high molecular proteins co-purified with hsp70. Some of these proteins could be the pneumococcal surface protein A.

The amino acid sequence of a monoclonal gamma 3-heavy chain from a patient with articular gamma-heavy chain deposition disease.

Abnormal deposition of proteins, including monoclonal immunoglobulin gamma-heavy chains, may cause tissue damage and organ dysfunction. We here report the amino acid sequence of the free gamma-heavy chains present in serum and urine of the first reported case (patient G. L.) of synovial heavy chain deposition disease. The protein was heavily deleted and consisted of the hinge, in addition to the CH2 and CH3 domains, in a dimeric form, thus lacking its variable domain as well as the CH1 domain. The sequence was consistent with the gamma 3 subclass (gamma 3GL). Gm typing revealed the gamma 3 allotypes G3m(b0) and G3m(b1) in accordance with the residues Pro123, Phe128, Thr171 and Phe268 in gamma 3GL. Furthermore, the gamma 3GL molecule was glycosylated at Asn in position 129. Finally, the gamma 3GL protein was shown to contain a typical binding site for the first complement component, C1q, namely the residues Glu150, Lys152 and Lys154, with the potential of binding and activating complement, causing tissue damage following deposition.

Liver transplantation as rescue treatment in a patient with primary AL kappa amyloidosis.

Although involvement of the liver is common in systemic amyloidosis, clinical manifestations of hepatic dysfunction and liver biochemical abnormalities are often absent or only mild. Here we report on a patient with primary amyloidosis and rapid development of liver failure, who was successfully treated by liver transplantation. The patient is a 61-year-old Swedish man who was admitted to the local hospital for spontaneous rupture of the spleen. Before admission, he had suffered from diffuse upper abdominal discomfort, diminished appetite, and had lost 15 kg in 6 months. Shortly after splenectomy, he developed cholestatic liver failure with moderate hepatomegaly, jaundice, ascites and hyponatremia. Over a period of 3 weeks his liver failure progressed, renal function deteriorated rapidly, and he developed encephalopathy. Liver transplantation was performed on the 35th day after splenic rupture. Histological examination revealed extensive deposits of amyloid in the spleen and liver. N-terminal amino acid sequence analysis of the amyloid protein, purified from the patient's native liver, revealed an AL protein of kappa I-type origin. The postoperative course was uncomplicated, apart from one episode of sepsis and one course of treatment for acute rejection. He was discharged from hospital with normal liver function and good kidney function. One year after surgery, he was in good condition, with normal liver function. However, a liver biopsy taken at the same time showed de novo amyloid deposits in the grafted liver. We conclude that liver transplantation may be indicated as a life-saving procedure in rapidly progressing hepatic amyloidosis with cholestatic jaundice, although the underlying disease has not changed.

Oldenlandia affinis (R&S) DC. A plant containing uteroactive peptides used in African traditional medicine.

A review of the geographical distribution, clinical use, biological activity and phytochemistry of Oldenlandia affinis (R&S) DC. is presented. During an inventory of medicinal plants in northern Congo/Brazzaville and south-western Central African Republic in 1962, 196 different species were registered, one of which was O. affinis used for the facilitation of childbirth. A medical team working in Luluabourg (Kananga) in Congo during the troubled period in 1960, discovered also the traditional use of the same plant as an oxitocic agent during labour. The plant was collected and the uterotonic substances isolated. Cyclic peptides (called Kalata-peptides) were described, and the main peptide, B1, was subjected to pharmacological and chemical investigations. Later the three-dimensional structure of the peptide was determined. Similar cyclic peptides have been isolated also from other plants in the Rubiaceae family like Chassalia pasvifoloia and Psychotria longipes, and from Viola species: Viola tricolor L. and Viola arvensis Murray. Some of these peptides, included Kalata-peptide B1, have been shown to hold antimicrobial activity. They have recently been synthesized, and they may represent a starting point for the design of new peptide antibiotics.

An in vivo model of femtosecond laser intrastromal refractive surgery.

BACKGROUND AND OBJECTIVE: To develop an animal model for evaluation of femtosecond laser intrastromal refractive surgery. METHODS: Intrastromal photodisruption was performed in New Zealand Albino rabbits using a femtosecond laser system. This surgical pattern consisted of a 100 microm-tick pyramid of laser pulses starting 180 microm below the corneal surface. Animals underwent serial slit lamp examinations and corneal thickness measurements at 1,3,7,14, and 28 days, then monthly up to 1 year. RESULTS: Approximately 70 microm of central corneal thinning were seen at 1 week, remaining stable up to 7 months. CONCLUSIONS: Intrastromal photodisruption with femtosecond lasers produced consistent changes in corneal thickness without loss of corneal transparency. These changes were more stable than those produced with excimer laser procedures in a similar animal model.

What is the role of giant cells in AL-amyloidosis?

AL-amyloidosis is one of the most common amyloidoses and can be found in a localized and a systemic form. The precursor protein is an immunoglobulin light chain which as AL-protein in both localized and systemic AL-amyloidosis shows the same pattern of fragmentation and changes of primary structure. In this work it is shown that that there is a difference between localized and systemic amyloidosis in respect to accompanying giant cells which constantly are found associated with amyloid deposits in localized AL-amyloidosis. In addition, giant cells were found together with amyloid deposits in lymph nodes of some cases of systemic AL-amyloidosis. Based on these findings and electron microscopic studies, it is discussed whether the giant cells actively participate in amyloid fibril formation by uptake and modification of the precursor protein or the giant cells are part of a foreign body reaction. Included in this work are two new cases of localized lung (lambda I) and ureteric (kappa I) AL-amyloidosis.

Medin: an integral fragment of aortic smooth muscle cell-produced lactadherin forms the most common human amyloid.

Aortic medial amyloid is a form of localized amyloid that occurs in virtually all individuals older than 60 years. The importance and impact of the amyloid deposits are unknown. In this study we have purified a 5.5-kDa aortic medial amyloid component, by size-exclusion chromatography and RP-HPLC, from three individuals, and we have shown by amino acid sequence analysis that the amyloid is derived from an integral proteolytic fragment of lactadherin. Lactadherin is a 364-aa glycoprotein, previously known to be expressed by mammary epithelial cells as a cell surface protein and secreted as part of the milk fat globule membrane. The multidomain protein has a C-terminal domain showing homology to blood coagulation factors V and VIII. We found that the main constituent of aortic medial amyloid is a 50-aa-long peptide, here called medin, that is positioned within the coagulation factor-like domain of lactadherin. Our result is supported by the specific labeling of aortic medial amyloid in light and electron microscopy with two rabbit antisera raised against two synthetic peptides corresponding to different parts of medin. By using in situ hybridization we have shown that lactadherin is expressed by aortic medial smooth muscle cells. Furthermore, one of the synthetic peptides forms amyloid-like fibrils in vitro. Lactadherin was not previously known to be an amyloid precursor protein or to be expressed in aortic tissue. The structure of lactadherin may implicate an important regulatory function in the aorta.

Purification and partial amino acid sequence of plantaricin 1.25 alpha and 1.25 beta, two bacteriocins produced by Lactobacillus plantarum TMW1.25.

Two bacteriocins produced by Lactobacillus plantarum TMW1.25 have been purified by a four-step purification procedure, including ammonium sulphate precipitation and cation-exchange chromatography followed by hydrophobic-interaction chromatography on octyl sepharose. The final purification was performed by repeated reversed-phase chromatography steps which yielded two bacteriocin fractions designated plantaricin 1.25 alpha and plantaricin 1.25 beta. The molecular masses of the peptides in these fractions were 5979 and 5203 Da, respectively. Combination of the fractions did not have any synergistic effects on bacteriocin activity, indicating that they each contain a one-peptide bacteriocin. The major peptide in the alpha fraction was blocked at its N-terminus, and a partial sequence (25 residues) could only be obtained after cleavage with CNBr. This sequence did not show clear homologies with known bacteriocins. The beta peptide has been sequenced almost completely and consists, presumably, of 53 residues. This peptide displayed strong homology to the known N-terminal part of brevicin 27 produced by Lactobacillus brevis SB27. The results showed that the beta peptide contains as many as six consecutive lysine residues at the N-terminus.

Characterization, production, and purification of leucocin H, a two-peptide bacteriocin from Leuconostoc MF215B.

Leuconostoc MF215B was found to produce a two-peptide bacteriocin referred to as leucocin H. The two peptides were termed leucocin Halpha and leucocin Hbeta. When acting together, they inhibit, among others, Listeria monocytogenes, Bacillus cereus, and Clostridium perfringens. Production of leucocin H in growth medium takes place at temperatures down to 6 degrees C and at pH below 7. The highest activity of leucocin H in growth medium was demonstrated in the late exponential growth phase. The bacteriocin was purified by precipitation with ammonium sulfate, ion-exchange (SP Sepharose) and reverse phase chromatography. Upon purification, specific activity increased 10(5)-fold, and the final specific activity was 2 x 10(7) BU/OD280. Amino acid composition analyses of leucocin Halpha and leucocin Hbeta indicated that both peptides consisted of around 40 amino acid residues. Their N-termini were blocked for Edman degradation, and the methionin residues of leucocin Hbeta did not respond to Cyanogen Bromide (CNBr) cleavage. Absorbance at 280 nm indicated the presence of tryptophan residues and tryptophan-fracturing opened for partial sequencing by Edman degradation. From leucocin Halpha, the sequence of 20 amino acids was obtained; from leucocin Hbeta the sequence of 28 amino acid residues was obtained. No sequence homology to other known bacteriocins could be demonstrated. It also appeared that the two peptides themselves shared little or no sequence homology. The presence of soy oil did not affect the activity of leucocin H in agar.