Faculty Bibliography

To ascertain if lambda VI light chains have unique structural features that account for the preferential association of these proteins with primary or multiple myeloma-related amyloidosis (amyloidosis AL) we have determined the complete amino acid sequence of the variable (V) region of the lambda VI Bence Jones protein SUT. This protein, obtained from a patient with amyloidosis AL, represents a complete light chain consisting of 216 residues and it has structural and serologic properties characteristic for lambda VI light chains. The sequence of the joining segment (J) (positions 100 to 111) of protein SUT is identical to that of the J lambda I segment of the mouse IG lambda light chain gene. V region SUT is closely homologous in sequence to that of another lambda VI amyloid fibrillar protein, AR, differing by 21 residues. The V regions of proteins SUT and AR contain a two-residue insertion at positions 68 and 69 that has also been found in two other lambda VI human light chains but not in the lambda-chains of other V region subgroups.

The complete amino acid sequence of the NH2-terminal domain obtained after trypsin digestion of human plasma fibronectin has been determined. It contains residues 1-259 and has a Mr of 29,000. The 29-kDa fragment was isolated from the other major tryptic cleavage products of 200, 180, and 31 kDa by affinity chromatography on gelatin- and heparin-Sepharose columns. The two high Mr fragments bound to gelatin and were easily removed; the 31-kDa fragment failed to bind to heparin while the 29-kDa fragment did and was eluted with 0.15 M NaCl. The 29-kDa domain has a blocked NH2-terminal (pyrrolidone carboxylic acid) which was removed by digestion with pyroglutamate aminopeptidase, and the amino acid sequence of the first 36 residues was obtained. The sequence showed a glutamine residue at position 3 which is probably the acceptor site for transglutaminase as reported for bovine fibronectin. Extensive trypsin digestion of the completely reduced and alkylated 29-kDa fragment yielded twenty-four peptides which were separated and purified by high performance liquid chromatography; their amino acid composition and amino acid sequence has been determined and the arrangement of peptides was achieved by comparison with the sequence recently reported for bovine fibronectin. The sequences in human and bovine fibronectin were nearly identical with only nine amino acid differences which can all be explained by single base substitutions. Apparently this domain is highly conserved in the two species studied thus far.

The predominance of the relatively uncommon V region subgroup isotype kappa III among the light chains of human monoclonal (IgM kappa) anti-IgG antibodies, (i.e., rheumatoid factors), was further documented through sequence analyses of ten such autoantibodies isolated from IgM-anti-IgG cold-insoluble immune complexes (mixed cryoglobulins). The amino-terminal sequence of all ten kappa-chains was characteristic for kappa III proteins and virtually identical to that of a prototype kappa III light chain. Similar sequence identity was found for kappa-chains isolated from three IgM kappa autoantibodies that formed cold-insoluble immune complexes with low-density lipoprotein (LDL). The thirteen light chains were found to be virtually identical in sequence for the first framework region (FR); ten of these proteins sequenced through the first complementarity-determining region (CDR) and into the second FR were markedly similar. The second CDR of five proteins was almost identical in sequence to that of the prototype kappa III-chain. Concordance was also demonstrated between the structural classification of the light chains as kappa III and their immunochemical classification as members of this V region subgroup. Serologic analyses of light chains isolated from seven IgM kappa autoantibodies (six anti-IgG, one anti-LDL) and of one intact IgM kappa anti-LDL antibody showed that each had antigenic determinants common to kappa II proteins. These light chains also expressed the antigenic determinant(s) of a V-region sub-subgroup of kappa III proteins designated kappa IIIb. Our studies confirm the preferential association of kappa III (and kappa IIIb) light chains with IgM kappa anti-IgG antibodies and demonstrate a similar association for IgM kappa anti-LDL antibodies. The finding that these and other types of IgM kappa autoantibodies, e.g., cold agglutinins, have remarkably similar light chains suggests an inherent restriction in the immune response to self-antigens.

Amyloid fibrils were isolated from the leptomeningeal blood vessels obtained at autopsy from three Icelandic patients dying of Hereditary Cerebral Hemorrhage with Amyloidosis (HCHWA) and verified by Congo red staining and electron microscopy. Gel filtration on Sephadex and Ultrogel columns yielded predominantly one component (molecular weight 11,500 daltons) and also another minor component (molecular weight 15,800 daltons). Automated amino terminal sequencing showed these proteins to be similar (36 residues) to a recently described human protein, gamma trace, beginning at its eleventh amino terminal residue. The amyloid deposits in all three patients stained with rabbit anti-gamma trace antiserum. Although the function of gamma trace is not known, it appears to have structural homology with several hormones and has been localized to the brain, pancreas and pituitary. The amyloid fibril subunits seem to have polymerized after cleavage of the amino terminal decapeptide from gamma trace-related proteins. Therefore, HCHWA appears to be the first genetically determined disease related to the gastroenteropancreatic neuroendocrine system.

Reports of renal amyloidosis occurring among narcotic addicts have been limited, for the most part, to case reports. In a prospective survey of 150 addicts examined at autopsy in the Office of the Chief Medical Examiner of the City of New York, 7 cases of renal amyloidosis were found. Immunohistologic examination demonstrated that in all of the 7 cases, the amyloid was AA protein-related. The amyloid extracted from the kidneys of two addicts and analyzed biochemically did not differ from the AA amyloid secondary to chronic infectious and inflammatory diseases. The combined data of previous reports and the present survey demonstrate that addicts who are subcutaneous users with skin infections most frequently develop amyloidosis. Our data demonstrating renal amyloidosis in 26% of addicts with chronic suppurative skin infections suggest that such addicts are at high risk for the development of amyloidosis.

We have determined the amino acid sequence of the Fv [variable heavy (VH) and variable light (VL)] region of a human monoclonal IgM-kappa with antibody activity against 3,4-pyruvylated galactose, isolated from the plasma of patient WEA with Waldenstrom macroglobulinemia. The VH region has 114 residues, belongs to subgroup III, and has a very short third complementarity-determining region (CDR3), probably due to a small D segment/or an unusual D-J rearrangement (D, diversity; J, joining). The VL region has 108 residues and belongs to subgroup V kappa I. Compared to other members of the human VHIII and V kappa I families, WEA Fv does not appear to have significant differences within the framework residues but has unique CDRs that might be responsible for the particular antibody activity. Another IgM-kappa (GAL), which has an as-yet-undetermined antibody activity, shares a striking homology in V kappa with WEA, including an identical CDR1.

Amyloid fibrils were isolated from a spleen obtained at surgery from a 58-year-old white man with primary amyloidosis presenting with factor X deficiency and responding dramatically to splenectomy. Gel filtration on Ultragel ACA 54 in 5 M guanidine 1 M acetic acid yielded components with molecular weights between 17,000 and 13,000. Two of them (17K and 15K) were studied in detail. Antigenic and amino acid sequence analysis showed that these proteins were related to lambda VI immunoglobulin light chain. The predominant protein subunits of the amyloid fibril of the deposits (17K) was processed at the carboxy terminus in the same section of the constant region as the only other lambda VI amyloid protein previously reported. Amino terminal sequence of the 15K protein revealed not only degradation at the C terminal, but also minor degradation at the amino terminal (three residues difference from the 17K species). P component was also isolated from the spleen and characterized. This represents the first antigenic and sequence analysis of tissue amyloid proteins and P component from a patient presenting with factor X deficiency and another example of amyloid proteins derived from the newly discovered amyloidogenic lambda VI light chain subgroup.

The complete amino acid sequence of three related amyloid proteins (Mr 14,000, 10,000, and 5,000) derived from tissues of a Jewish patient who suffered from a variant of familial polyneuropathic amyloidosis was determined. The protein, which contains 127 residues, is identical to a human serum prealbumin subunit. Only one amino acid substitution, glycine for threonine, was detected at position 49, where enzymatic cleavage occurred, yielding Mr 5,000 and 10,000 fragments which represent the amino terminus (residues 1-48) and carboxyl terminus (residues 49-127) of the molecule, respectively. Thus, a prealbumin variant and its fragments constitute the amyloid fibrils in a heredofamilial amyloidosis syndrome of dominant inheritance.