Characterization of amyloid fibril proteins from medullary carcinoma of the thyroid.

Amyloid fibrils were studied from two different tissues of medullary carcinoma of the thyroid (MCT). The fibrils mainly consisted of a low molecular weight protein, AMCT, which was immunologically distinct and did not react with various antisera against known amyloid fibril proteins. A specific antiserum raised against the MCT amyloid proteins gave a reaction of identity with the degraded MCT amyloid fibrils from two patients, as well as with the isolated AMCT protein, but showed no reaction with other known amyloid proteins. The AMCT protein had a blocked N terminus, but the sequence analysis of a cyanogen bromide fragment revealed identity with human calcitonin in the 11 positions studied. Although the amino acid composition was similar, there were also distinct differences, and the mol wt of 5,700 daltons was considerably larger than that of calcitonin. For these reasons the AMCT protein may represent a prohormone of calcitonin.

New, third class of amyloid fibril protein.

An unusual protein AR was isolated from the amyloid fibril preparation derived from a patient with primary amyloidosis. Protein AR was unique in its antigenicity, and revealed no structural identity with any known amyloid proteins or with immunoglobulin chains or fragments. Thus a new third class of amyloid fibril proteins besides the immunoglobulin light-chain variable region fragments and the nonimmunoglobulin protein AS, has been characterized. A component antigenically related to protein AR was found in the serum of the patient.

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.

Amyloid A in systemic amyloidosis associated with cancer.

Amyloid fibrils from two cases of cancer-associated, systemic amyloidosis with renal cell carcinoma and mesothelioma as the respective underlying disorders were studied. The immunochemical studies suggested strongly that amyloid A comprised a principal fibril component in both cases of cancer-associated amyloidosis. This was definitively proven by amino acid sequence analyses, which revealed structural homology between a purified subcomponent of the amyloid fibrils from both of the two cases of cancer-associated amyloidosis and previously sequenced amyloid A proteins. The chemical composition of the amyloid fibrils from systemic amyloidosis associated with cancer thus corresponded to that seen in amyloidosis reactive to inflammatory diseases and Hodgkin's disease. Amyloid proteins of immunoglobulin light chain type, which are found associated with myelomatosis, macroglobulinemia, and idiopathic (primary) amyloidosis, were not found in the two amyloid preparations. Renal cell carcinoma appears to be an effective stimulator of amyloid formation, while only one case of amyloidosis associated with mesothelioma has been reported previously.

Purification and properties of a mitogenic lectin from Lathyrus sativus seeds.

A mitogenic lectin has been isolated from saline extract of Lathyrus sativus by (NH4)2SO4 precipitation, chromatography on DEAE-Sepharose and subsequent affinity chromatography on Sephadex G-100. The lectin has a molecular weight of 49,000, as determined by ultracentrifugation, and consists of heavy (Mr 19,000) and light subunits (Mr about 4,400). The amino acid composition and N-terminal sequence of both subunits are given. The lectin agglutinated human erythrocytes of different ABO groups equally well, and the agglutination is inhibited best by D-mannose and D-glucose and their alpha-methyl-glucosides. High concentrations of the lectin were needed for optimal stimulation of human lymphocytes.

Localized laryngeal amyloidosis: partial characterization of an amyloid fibril protein AL.

Amyloid fibrils were extracted from a patient Wr with more than 10 yr history of localized laryngeal amyloidosis. Degraded amyloid fibrils reacted in immunodiffusion with an antiserum against an amyloid protein of immunoglobulin kappa light chain origin, showing a line of identity with a kappa I amyloid protein. The protein Wr had a blocked aminoterminal, previously only reported in lambda chains. Amino acid sequence analysis of a fragment of the protein showed it to be an immunoglobulin light chain protein of V kappa I or V kappa III subgroup. The protein had a few unusual amino acid residues as compared to other kappa light chains. The findings support the view that the fibrils in localized, tumour-like amyloidosis are composed by homogeneous immunoglobulin light chain proteins in the same way as is seen in primary and myeloma associated systemic amyloidosis. It is possible that unusual light chains are over-represented in amyloid fibrils.

Cloning and sequencing of the gene encoding the phosphatidylcholine-preferring phospholipase C of Bacillus cereus.

A synthetic oligodeoxynucleotide probe was used to clone the gene encoding the phosphatidylcholine-preferring phospholipase C of Bacillus cereus. The sequence of a 2050-bp restriction fragment containing the gene was determined. Analysis of the gene-derived amino acid (aa) sequence showed that this exoenzyme is probably synthesized as a 283-aa precursor with a 24-aa signal peptide and a 14-aa propeptide. The mature, secreted enzyme comprises 245 aa residues. Sonicates of Escherichia coli HB101 carrying the gene on a multicopy plasmid showed phospholipase C activity. This activity was inhibited by Tris, a known inhibitor of the B. cereus enzyme and also by antiserum raised against pure B. cereus phospholipase C. We conclude therefore that the gene is expressed in E. coli. The cloning and sequencing described here complete the first step toward using in vitro mutagenesis for investigations of the structure-function relationships of B. cereus phospholipase C.

Efficient secretion of human parathyroid hormone by Saccharomyces cerevisiae.

A cDNA encoding mature human parathyroid hormone (hPTH) was expressed in Saccharomyces cerevisiae, after fusion to the prepro region of yeast mating factor alpha (MF alpha). Radioimmunoassay showed high levels of hPTH immunoreactive material in the growth medium (up to 10 micrograms/ml). More than 95% of the immunoreactive material was found extracellularly as multiple forms of hormone peptides. Three internal cleavage sites were identified in the hPTH molecule. The major cleavage site, after a pair of basic amino acids (aa) (Arg25Lys26 decreases Lys27), resembles that recognized by the KEX2 gene product on which the MF alpha expression-secretion system depends. The use of a protease-deficient yeast strain and the addition of high concentrations of aa to the growth medium, however, not only changed the peptide pattern, but also resulted in a significant increase in the yield of intact hPTH (1-84) (more than 20% of the total amount of immunoreactive material). The secreted hPTH (1-84) migrates like a hPTH standard in two different gel-electrophoretic systems, co-elutes with standard hPTH on reverse-phase high-performance liquid chromatography, reacts with two hPTH antibodies raised against different parts of the peptide, has a correct N-terminal aa sequence, and has full biological activity in a hormone-sensitive osteoblast adenylate cyclase assay.

p23, a novel mammalian nucleic acid-binding protein with homology to the yeast ribosomal protein YL43.

When separating perchloric acid-soluble proteins from cell cultures and tissues by chromatography on single stranded DNA agarose columns, a novel mammalian protein with extreme affinity for DNA was isolated. Cellular localization, amino acid composition and the N-terminal sequence suggest that the protein is a ribosomal protein with extensive sequence homology to the ribosomal protein, YL43, from Saccharomyces cerevisiae.

The transthyretin cDNA sequence is normal in transthyretin-derived senile systemic amyloidosis.

A variety of mutations leading to amino acid substitutions have been described in the transthyretin gene in association with different familial amyloidoses and have been implicated to be involved in the pathogenesis of amyloid deposits. However, there has been disagreement whether or not a transthyretin mutation is present in the most common form of transthyretin-derived amyloid, namely senile systemic amyloidosis. Therefore, the cDNA sequence of liver transthyretin was determined in a 91-year-old patient with typical senile systemic amyloidosis. This sequence was completely normal and lacked any variation. We conclude that in senile systemic amyloidosis factors other than the presence of a sequentially variant transthyretin must determine the amyloid fibril formation.

Protein purification and gene isolation of chlamysin, a cold-active lysozyme-like enzyme with antibacterial activity.

An antibacterial approximately 11 kDa protein designated chlamysin was isolated from viscera of the marine bivalve Chlamys islandica. Chlamysin inhibited the growth of all Gram-positive and Gram-negative bacteria tested. The isolated protein was highly efficient in hydrolyzing Micrococcus luteus cells only at low pH (4.5-6.2) and at low temperature (4-35 degrees C). No significant loss of enzyme activity was observed after 30 days storage at room temperature or after heating to 70 degrees C for 15 min, suggesting relatively high protein structure stability. Sequence-analyzed fragments of the protein revealed data which guided the isolation of the cDNA gene, encoding a 137 amino acid chlamysin precursor in scallops. The deduced protein contains a high portion of cysteine, serine and histidine residues and has a predicted isoelectric point below 7. The chlamysin protein was found to have sequence homology to an isopeptidase and to a recently published bivalve lysozyme.

Immunohistochemical localization of rat submandibular gland esterase B (homologous to the RSKG-7 kallikrein gene) in relation to other serine proteases of the kallikrein family.

The rat submandibular gland contains several members of the kallikrein family. In the present study we purified and raised an antiserum against one of these enzymes, i.e., esterase B, which was first described by Khullar et al. in 1986. N-terminal amino acid analysis revealed complete homology between esterase B and the kallikrein family gene RSKG-7. For characterization of the antiserum, flat-bed isoelectrofocusing with immunoblotting was superior to immunoelectrophoresis and double immunodiffusion in detecting and identifying crossreacting proteins. This was due to the fact that kallikrein-like enzymes were readily separated by isoelectrofocusing, and immunoreactivity was easily detected by the sensitive peroxidase-anti-peroxidase staining after blotting onto nitrocellulose membrane. Immunohistochemical controls were carried out accordingly, including homologous as well as crossreacting antigens. In the submandibular gland, esterase B was detected exclusively in all granular convoluted tubular cells, co-localized with tissue kallikrein and tonin. Some staining was also observed in striated duct cells; however, this staining reaction was induced by cross-reactivity with kallikrein, since staining was abolished by addition of kallikrein as well as esterase B to the primary antiserum. It was therefore concluded that like tonin and antigen gamma, but unlike kallikrein, esterase B was not detected in the striated ducts of the submandibular, parotid, or sublingual glands. This separation in anatomic distribution between esterase B and kallikrein may indicate that prokallikrein activation is not the only biological function of esterase B.

Aggregated, conformationally changed fibrinogen exposes the stimulating sites for t-PA-catalysed plasminogen activation.

The present paper shows that conformationally changed fibrinogen can expose the sites A alpha-(148-160) and gamma-(312-324) involved in stimulation of the tissue-type plasminogen activator (t-PA)-catalysed plasminogen activation. The exposure of the stimulating sites was determined by ELISA using mABs directed to these sites, and was shown to coincide with stimulation of t-PA-catalysed plasminogen activation as assessed in an assay using a chromogenic substrate for plasmin. Gel permeation chromatography of fibrinogen conformationally changed by heat (46.5 degrees C for 25 min) demonstrated the presence of both aggregated and monomeric fibrinogen. The aggregated fibrinogen, but not the monomeric fibrinogen, has exposed the epitopes A alpha-(148-160) and gamma-(312-324) involved in t-PA-stimulation. Fibrinogen subjected to heat in the presence of 3 mM of the tetrapeptide GPRP neither aggregates nor exposes the rate-enhancing sites. Thus, aggregation and exposure of t-PA-stimulating sites in fibrinogen seem to be related phenomena, and it is tempting to believe that the exposure of stimulating sites is a consequence of the conformational changes that occur during aggregation, or self-association. Fibrin monomers kept in a monomeric state by a final GPRP concentration of 3 mM do not expose the epitopes A alpha-(148-160) and gamma-(312-324) involved in t-PA-stimulation, whereas dilution of GPRP to a concentration that is not longer anti-polymerizing, results in exposure of these sites. Consequently, the exposure of t-PA-stimulating sites in fibrin as well is due to the conformational changes that occur during self-association.

The use of subcutaneous fat tissue for amyloid typing by enzyme-linked immunosorbent assay.

The amyloidoses are biochemically heterogeneous diseases with pathophysiologic deposits of various proteins. The clinical course, prognosis, and therapy are different for each type of amyloidosis and, therefore, a type-specific diagnosis is demanded as early as possible. We describe a method for typing the most common systemic amyloidoses of AL, AA, and transthyretin types by enzyme-linked immunosorbent assay (ELISA), using abdominal wall subcutaneous fat biopsy specimens. The method was tested on 21 abdominal fat biopsy specimens that were sent to the laboratory. Of these, 15 contained amyloid that was successfully characterized in 14 cases. One specimen contained amyloid that did not react with any antisera used. The 6 specimens without amyloid gave no reaction in ELISA. The described ELISA method is reliable and easy to perform, and the tissue sample needed is obtained by minor surgery.

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.

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.

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.

Use of subcutaneous abdominal fat biopsy specimen for detailed typing of amyloid fibril protein-AL by amino acid sequence analysis.

A simple technique for the purification of amyloid fibril proteins from patients with systemic amyloidosis was used on a 45 year old woman. The method is based on the use of a surgical subcutaneous fat tissue biopsy specimen which was used for the characterisation of the amyloid as a kappa I AL-protein by amino acid sequence analysis. The method permits the exact typing of amyloid in many patients with systemic amyloidosis, which, until now has been almost exclusively confined to necropsy tissue.

Prealbumin: its association with amyloid.

In recent years prealbumin has been shown to be a major component of two forms of systemic amyloid, senile systemic amyloid (SSA), and familial amyloidotic polyneuropathy (FAP). Despite the fact that the amyloid fibril proteins associated with these two forms of amyloid, designated ASc1 and AF, respectively, share many similarities the clinical features of the two diseases are remarkably different. To understand better this paradox the clinical, histochemical, immunological and biochemical features of SSA and FAP were reviewed.

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.