Natural catalytic antibodies: peptide-hydrolyzing activities of Bence Jones proteins and VL fragment

Monoclonal human light chains, i.e. Bence Jones proteins, and their recombinant variable fragments (VL) were screened for proteolytic activity using peptide-methylcoumarinamide (peptide-MCA) conjugates and vasoactive intestinal polypeptide (VIP) as substrates. Sixteen of 21 Bence Jones proteins and one of three VL fragments were capable of detectable cleavage of one or more substrates. The magnitude and kinetic characteristics of the activity varied with different substrates. Among the peptide-MCA substrates, the presence of tripeptide or tetrapeptide moieties with a basic residue at the scissile bond generally favored expression of the activity. The influence of N-terminal flanking residue recognition was evident from differing values of Km and kcat (turnover number) observed using different Arg-containing peptide-MCA substrates. Different light chains displayed different kinetic parameters for the same substrate, suggesting unique catalytic sites. Hydrolysis of VIP was characterized by nanomolar Michaelis-Menten constants (Km), suggesting comparatively high affinity recognition of this peptide. The 25-kDa monomer and the 50-kDa dimer forms of one light chain preparation were resolved by gel filtration in 6 M guanidine hydrochloride. Following renaturation, the monomer displayed 51-fold greater peptide-MCA-hydrolyzing activity than the dimer. A renatured VL domain prepared by gel filtration in 6 M guanidine hydrochloride displayed VIP-hydrolyzing activity in the 12.5-kDa peak fractions. These results provide evidence for the proteolytic activity of certain human light chains and imply that this phenomenon may have a pathophysiological significance.

Distinctive serologic, chemical, and molecular properties of human lambda IV light chains

Through extensive serologic, chemical, and molecular studies involving monoclonal Ig proteins and B cell-related populations, we provide definitive evidence that the V lambda IV subgroup of human light (L) chains is separate and distinct from V lambda III and all other known V lambda gene families. lambda IV and lambda III L chains were differentiated immunochemically using well-characterized polyclonal and monoclonal anti-V lambda subgroup-specific Abs. Prototypic L chains, originally classified as lambda IV on the basis of distinctive framework region 1 residues, were distinguished serologically from lambda IIIa, lambda IIIb, and lambda IIIc proteins and also from lambda I, lambda II, lambda VI, and lambda VIII L chains. Furthermore, by using anti-lambda IV reagents, we identified eight additional monoclonal V lambda IV-related populations, including three IgM rheumatoid factor-producing cell lines. The percentage of homology among the lambda IV proteins ranged from 83 to 100, vs 53 to 72 when compared with lambda III components. Moreover, lambda IV proteins shared particular subgroup-associated FR and complementarity-determining region residues. At the molecular level, the nucleotide sequences encoding two of the IgM lambda IV rheumatoid factors were identical to that found for the genomic counterpart, as well as to the previously reported IGLV3S1 and Humlv418 germ-line genes. Two other lambda IV cDNAs contained additional non-germ-line-encoded nucleotides at the V-J joint. The single or pauci-gene nature of the V lambda IV family was evidenced from Southern blotting and from the extensive sequence homology among lambda IV components. Our studies have provided further evidence for the prevalence of lambda IV L chains among Ig lambda autoantibodies, thus implying a functional significance for the V lambda IV subgroup.

Neural arch tuberculosis: a morbid disease. Radiographic and computed tomographic findings

We have reviewed the clinical features, together with the radiographs and computerised tomography, in 9 patients with tuberculosis of the vertebral body and neural arch. All presented with paraparesis or paraplegia. The morbidity associated with this disease is so serious that it is essential to have an accurate means of evaluating the lesion as early as possible. Routine radiographs can only indicate the level of the disease and the loss of disc space, but cannot define the full extent of the lesion. Computed tomography shows details of the tuberculous involvement of the neural arch, as well as the vertebral body and spinal canal; the site and extent of the soft tissue lesions can also be seen. This is essential for evaluation of the neural arch involvement which will enable the clinician to select the appropriate treatment, and so prevent neurological complications.

Distinctive serologic, chemical, and molecular properties of human lambda IV light chains

Through extensive serologic, chemical, and molecular studies involving monoclonal Ig proteins and B cell-related populations, we provide definitive evidence that the V lambda IV subgroup of human light (L) chains is separate and distinct from V lambda III and all other known V lambda gene families. lambda IV and lambda III L chains were differentiated immunochemically using well-characterized polyclonal and monoclonal anti-V lambda subgroup-specific Abs. Prototypic L chains, originally classified as lambda IV on the basis of distinctive framework region 1 residues, were distinguished serologically from lambda IIIa, lambda IIIb, and lambda IIIc proteins and also from lambda I, lambda II, lambda VI, and lambda VIII L chains. Furthermore, by using anti-lambda IV reagents, we identified eight additional monoclonal V lambda IV-related populations, including three IgM rheumatoid factor-producing cell lines. The percentage of homology among the lambda IV proteins ranged from 83 to 100, vs 53 to 72 when compared with lambda III components. Moreover, lambda IV proteins shared particular subgroup-associated FR and complementarity-determining region residues. At the molecular level, the nucleotide sequences encoding two of the IgM lambda IV rheumatoid factors were identical to that found for the genomic counterpart, as well as to the previously reported IGLV3S1 and Humlv418 germ-line genes. Two other lambda IV cDNAs contained additional non-germ-line-encoded nucleotides at the V-J joint. The single or pauci-gene nature of the V lambda IV family was evidenced from Southern blotting and from the extensive sequence homology among lambda IV components. Our studies have provided further evidence for the prevalence of lambda IV L chains among Ig lambda autoantibodies, thus implying a functional significance for the V lambda IV subgroup.

Recombinant immunoglobulin variable domains generated from synthetic genes provide a system for in vitro characterization of light-chain amyloid proteins

The primary structural features that render human monoclonal light chains amyloidogenic are presently unknown. To gain further insight into the physical and biochemical factors that result in the pathologic deposition of these proteins as amyloid fibrils, we have selected for detailed study three closely homologous protein products of the light-chain variable-region single-gene family VkIV. Two of these proteins, REC and SMA, formed amyloid fibrils in vivo. The third protein, LEN, was excreted by the patient at levels of 50 g/day with no indication of amyloid deposits. Sequences of amyloidogenic proteins REC and SMA differed from the sequence of the nonpathogenic protein LEN at 14 and 8 amino acid positions, respectively, and these amino acid differences have been analyzed in terms of the three-dimensional structure of the LEN dimer. To provide a replenishable source of these human proteins, we constructed synthetic genes coding for the REC, SMA, and LEN variable domains and expressed these genes in Escherichia coli. Immunochemical and biophysical comparisons demonstrated that the recombinant VkIV products have tertiary structural features comparable to those of the patient-derived proteins. This well-defined set of three clinically characterized human kIV light chains, together with the capability to produce these kIV proteins recombinantly, provide a system for biophysical and structural comparisons of two different amyloidogenic light-chain proteins and a nonamyloidogenic protein of the same subgroup. This work lays the foundation for future investigations of the structural basis of light-chain amyloidogenicity.

Molecular characterization of a human V lambda VIII germline gene

Human lambda light chains of the recently recognized variable region (VL) subgroup V lambda VIII can be distinguished from proteins of other V lambda gene families on the basis of distinctive chemical and serologic properties and by their preferential association with certain types of autoantibodies, i.e. rheumatoid factors (RFs). We now report that we have cloned from a human placental library a V lambda VIII-encoding germline gene, designated IGLV8A1, using as a molecular probe a partial V lambda VIII fragment generated by polymerase chain reaction (PCR) from genomic DNA. IGLV8A1 contained all the requisite elements of a potentially functional gene, including a V lambda exon with an open reading frame encoding 103 residues. Its expressed products were identified through analyses of cDNA cloned from two different monoclonal lambda VIII B-cell populations. The primary structure of lambda VIII light chains differed from that of lambda I, lambda II, lambda III, lambda IV and lambda VI proteins by the presence of distinctive residues within the first framework region (FR1) and an 11- rather than 7-residue second complementarity-determining region (CDR2). Remarkably, the IGLV8A1 gene was more homologous to the two functional rabbit V lambda germline genes, RV lambda 2 and RV lambda 3 (including the presence of one extra codon within the leader sequence), and to the murine V lambda x gene. Light chains encoded by the human, rabbit and mouse lambda VIII-related genes shared certain unique primary structural features, notably the four additional CDR2 residues. The evolutionary conserved nature of the human V lambda gene and, in particular, the apparently novel tertiary structural effects induced by an elongated CDR2 provide evidence for the biological and functional importance of the V lambda VIII subgroup.

Diseases with ocular and dental abnormalities

This report gives an overall view on the aspect of numerous diseases and symptom complexes affecting both eyes and teeth. The knowledge of these disorders enables the ophthalmologist to suspect and recognize certain types of dental malformation and enables the dentist to discover certain eye defects. Moreover, it is important that clinicians be aware that simultaneous eye and tooth defects may be the indication of possible disturbances in other, apparently unrelated, organs or systems. Because such disorders are frequently hereditary conditions, their early detection will aid in the diagnosis and treatment of other affected family members. This may also help the parents to cope with the disease and be of benefit to the infants because a cure may be forthcoming.

Use of the giant-pulse Nd:YAG laser for ab-externo sclerostomy in rabbits and humans

The giant-pulse Neodymium:YAG laser, a recently developed laser source, delivers up to 200 W of peak power at pulse widths of 20 or 40 msec. The instrument can create a sclerostomy with minimal surrounding damage and, consequently, relatively little postsurgical inflammation and scarring. We tested its efficacy in performing ab-externo sclerostomy in 10 adult pigmented rabbits and in five patients with end-stage glaucoma. All of the animal eyes were hypotonus immediately after the procedure. However, the intraocular pressure increased gradually, and by the third day, returned to presurgical levels in all of the eyes. All five of the glaucoma patients treated had patent sclerostomies following the procedure. They all had early hypotony, but after 3 months, four of the five sclerostomies apparently failed. The giant-pulse Nd:YAG laser appears useful for performing sclerostomy, but modifications are needed to solve the problems of early hypotony and late closure of the fistulula.

Comparison of crystal structures of two homologous proteins: structural origin of altered domain interactions in immunoglobulin light-chain dimers

The sequence and structure of a second human kappa 1 immunoglobulin light-chain variable domain, Wat, has been determined. The R-factor is 15.7% for 1.9-A data. One hundred and ninety-five water molecules were identified; 30 water molecules were located in identical positions in each of the monomers. Some of the water molecules are integral parts of the domains. This light chain is encoded by the same variable domain gene that encoded the previously characterized kappa I variable domain, Rei. Due to limited somatic mutation, the two highly homologous proteins differ in only 20 of the 108 residues. Wat crystallized in space group P6(4) while Rei crystallized in space group P6(1); in both crystals, the asymmetric unit was the noncovalent dimer. Although the basic domain structure is the same for both proteins, the relative positions of the domains within the two dimers differ. This difference is most likely accounted for by the replacement of Tyr36 in Rei by Phe in the Wat protein. Residue Tyr36 is part of the hydrogen-bonding network in the interface between the domains in Rei. Losing the hydrogen-bonding capability of residue 36 by replacement of Tyr by Phe alters the network of hydrogen bonds between the domains, resulting in a different domain-domain contact. The details of lattice contacts in the two crystals were compared. One type of contact that extends the beta-sheet of the individual domains was conserved, but because it involved different symmetry elements within the crystal, different crystal packing resulted. In the Wat crystal, one of the contacts shows an example of how a symmetrical binding site can "bind" an asymmetrical object. Further, the examination of the Wat crystal also illustrates how the different crystalline environments of the domains of the dimer results in different distributions of temperature factors for the residues within the domains.

Characterization of a novel interleukin-6 autocrine-dependent human plasma cell line

A new human monoclonal plasma cell line, designated UTMC-2, was established from the pleural effusion of a patient with immunoglobulin (Ig)A kappa-related multiple myeloma. The cultured cells were Epstein-Barr virus-negative and exhibited the morphological and ultrastructural features characteristic of plasma cells. Immunohistochemical analyses revealed the presence of cytoplasmic IgA kappa as well as the plasma cell-associated surface antigens CD38 and CD56. Other B-cell markers, including CD10, CD19, CD20, and HLA-DR, were absent. The UTMC-2 cells were interleukin (IL)-6 responsive: Co-culture with IL-6 increased IgA kappa synthesis and cell proliferation in a dose-dependent manner. In contrast, an IL-6 antisense oligonucleotide had an opposite effect. Although the UTMC-2 cells expressed IL-6 mRNA (as demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR)) and contained IL-6, the concentration of this cytokine in cell culture supernatants was less than that detectable by the enzyme-linked immunosorbent assay (ELISA) employed (i.e. <3 pg/ml). Further, cell growth was not inhibited by polyclonal or monoclonal anti-IL-6 antibodies. Flow cytometric analysis revealed that IL-6 receptors present on the surface of the UTMC-2 cells were not saturated with endogenous IL-6. Taken together, these results indicate that, in this human plasma cell line, IL-6 functions uniquely in an intracellular autocrine fashion to enhance Ig synthesis and cell growth. In this respect, the UTMC-2 cells represent a novel resource for further study of the role of IL-6 in the pathogenesis of multiple myeloma.

A novel membrane antigen selectively expressed on terminally differentiated human B cells

A monoclonal antibody (MoAb) that defines a novel terminal B-cell-restricted antigen, termed HM1.24, was developed against a human plasma cell line. The MoAb, designated anti-HM1.24, reacted with five different human myeloma cell lines, as well as with monoclonal neoplastic plasma cells obtained from the bone marrow or peripheral blood of patients with multiple myeloma or Waldenström's macroglobulinemia. The HM1.24 antigen was also expressed by mature Ig-secreting B cells (plasma cells and lymphoplasmacytoid cells) but not by other cells contained in the peripheral blood, bone marrow, liver, spleen, kidney, or heart of normal individuals or patients with non-plasma-cell-related malignancies. The anti-HM1.24 MoAb bound to human myeloma RPMI 8226 cells with an affinity constant of 9.2 x 10(8) M-1, indicating approximately 84,000 sites/cell. By immunoprecipitation assay under reducing conditions, this MoAb identified a membrane glycoprotein that had a molecular weight of 29 to 33 kD. Our studies indicate that the HM1.24-related protein represents a specific marker of late-stage B-cell maturation and potentially serves as a target antigen for the immunotherapy of multiple myeloma and related plasma cell dyscrasias.

Chemical and serologic characterization of human lambda VIII light chains

The primary structural features and serologic properties of a newly recognized human lambda light (L) chain V region subgroup (V lambda VIII) were elucidated through study of two monoclonal L chains, Bence Jones proteins HAG and BIV. The V region amino acid sequences of these components were highly homologous to each other and to that deduced from the prototypic V lambda VIII cDNA, Humla8f10, which encodes the L chains of the IgM lambda rheumatoid factor HAF10. Proteins HAG and BIV could be classified as members of the V lambda VIII subgroup and distinguished from L chains of the V lambda I, V lambda II, V lambda III, V lambda IV, and V lambda VI subgroups on the basis of amino acid sequence. In addition to distinctive residues found within the V lambda gene-encoded portion of the molecules, L chains HAG, BIV, and HAF10 contained remarkably different second complementarity-determining regions (CDR2) that consisted of 11 residues, rather than the seven typically found among members of the other five V lambda subgroups. This elongated structure would presumably impart to the ligand-binding site of lambda VIII molecules a markedly different canonical structure compared with those of lambda I, lambda II, lambda III, lambda IV, and lambda VI L chains. By using Bence Jones protein HAG as an immunogen, we obtained polyclonal and monoclonal anti-V lambda VIII subgroup-specific Abs that were used to identify and quantify lambda VIII-related molecules in normal and pathologic states. Among the Ig lambda components present in the serum of normal individuals, approximately 3% had lambda VIII L chains, a frequency comparable to that found among monoclonal Ig lambda proteins or surface(s) Ig lambda+ cells obtained from patients with malignant plasma cell- or B cell-related disorders, respectively. In contrast, lambda VIII L chains were detected on approximately 19% of monoclonal IgM lambda rheumatoid factors produced by B cell lines established from PBLs or synovial cells from patients with rheumatoid arthritis. The results of our studies provide new information on the structural and immunochemical features of lambda VIII L chains and the possible functional importance of the human V lambda VIII subgroup.

Chemical and serologic characterization of human lambda VIII light chains

The primary structural features and serologic properties of a newly recognized human lambda light (L) chain V region subgroup (V lambda VIII) were elucidated through study of two monoclonal L chains, Bence Jones proteins HAG and BIV. The V region amino acid sequences of these components were highly homologous to each other and to that deduced from the prototypic V lambda VIII cDNA, Humla8f10, which encodes the L chains of the IgM lambda rheumatoid factor HAF10. Proteins HAG and BIV could be classified as members of the V lambda VIII subgroup and distinguished from L chains of the V lambda I, V lambda II, V lambda III, V lambda IV, and V lambda VI subgroups on the basis of amino acid sequence. In addition to distinctive residues found within the V lambda gene-encoded portion of the molecules, L chains HAG, BIV, and HAF10 contained remarkably different second complementarity-determining regions (CDR2) that consisted of 11 residues, rather than the seven typically found among members of the other five V lambda subgroups. This elongated structure would presumably impart to the ligand-binding site of lambda VIII molecules a markedly different canonical structure compared with those of lambda I, lambda II, lambda III, lambda IV, and lambda VI L chains. By using Bence Jones protein HAG as an immunogen, we obtained polyclonal and monoclonal anti-V lambda VIII subgroup-specific Abs that were used to identify and quantify lambda VIII-related molecules in normal and pathologic states. Among the Ig lambda components present in the serum of normal individuals, approximately 3% had lambda VIII L chains, a frequency comparable to that found among monoclonal Ig lambda proteins or surface(s) Ig lambda+ cells obtained from patients with malignant plasma cell- or B cell-related disorders, respectively. In contrast, lambda VIII L chains were detected on approximately 19% of monoclonal IgM lambda rheumatoid factors produced by B cell lines established from PBLs or synovial cells from patients with rheumatoid arthritis. The results of our studies provide new information on the structural and immunochemical features of lambda VIII L chains and the possible functional importance of the human V lambda VIII subgroup.

Recovery of visual response of injured adult rat optic nerves treated with transglutaminase

Failure of axons of the central nervous system in adult mammals to regenerate spontaneously after injury is attributed in part to inhibitory molecules associated with oligodendrocytes. Regeneration of central nervous system axons in fish is correlated with the presence of a transglutaminase. This enzyme dimerizes interleukin-2, and the product is cytotoxic to oligodendrocytes in vitro. Application of this nerve-derived transglutaminase to rat optic nerves, in which the injury had caused the loss of visual evoked potential response to light, promoted the recovery of that response within 6 weeks after injury. Transmission electron microscopy analysis revealed the concomitant appearance of axons in the distal stump of the optic nerve.

Evaluation of asymptomatic subjects with low forced expiratory ratios (FEV1/VC)

BACKGROUND

Heightened bronchial hyperreactivity is frequently associated with airflow limitation, atopy, or cigarette smoking. The purpose of this study was to evaluate healthy subjects with significantly low values of forced expiratory volume in one second/vital capacity % (FEV1/VC%) by measuring their airway response to exercise and methacholine challenge, compared with a control group with normal spirometric values.

METHODS

Eighty four healthy subjects with significantly low flow rates (group A, FEV1/VC% < 2 SD% predicted) were evaluated and compared with 37 subjects with normal flow rates (group B). Static lung volumes, spirometric tests, exercise, and methacholine challenges were performed.

RESULTS

Lung volumes were normal for both groups. Mean FEV1/VC% was 69% for group A and 82% for the control group. Salbutamol improved baseline FEV1 in eight subjects in group A (mean 15%), while methacholine induced a drop in FEV1 in 12 subjects. The dose-response curve to methacholine reached a plateau in all the responders. None of the subjects in the control group improved their baseline FEV1/VC% to salbutamol, but three showed bronchial hyperreactivity similar to those in group A.

CONCLUSIONS

Bronchial hyperreactivity does not occur more often in asymptomatic subjects with mildly low FEV1/VC% so these subjects do not require special investigations for airway disease.

Preferential utilization of a novel V lambda 3 gene in monoclonal rheumatoid factors derived from the synovial cells of rheumatoid arthritis patients

OBJECTIVE

To further our understanding about the molecular genetics of rheumatoid factor (RF) in rheumatoid arthritis (RA).

METHODS

The heavy and light chain variable region (V) genes of 5 new human monoclonal IgM RFs were cloned and sequenced using the polymerase chain reaction and the dideoxynucleotide termination method.

RESULTS

The results reveal the recurrent usage in two RA patients of a novel V lambda 3 germline gene, designated Humlv3c93. Specifically, in 2 of 3 RFs (C93 and D53) from one patient, the light chains in the V lambda gene-encoded region were identical to each other and to the light chain of an RF (H4) from another patient. Serologically, the light chains of these 3 RFs were classified as members of the V lambda 3b sub-subgroup. Each of the RFs was encoded by a different VH gene. Both C93 and D53 bound specifically with human and rabbit IgG, whereas H4 was monospecific for rabbit IgG.

CONCLUSION

Since the lv3c93 gene is not homologous to any reported V lambda sequence from natural autoantibodies, it is possible that lv3c93 may represent a disease-specific RF-related V lambda gene. Moreover, the amino acid sequence CSGGSCY in the third complementarity-determining regions of 2 of the RF heavy chains is encoded by the DLR2 gene segment and has been found previously in 2 other RA-derived RFs, and thus may play a significant role in antigen binding.

Preferential expression of human lambda-light-chain variable-region subgroups in multiple myeloma, AL amyloidosis, and Waldenström's macroglobulinemia

We have compared the distribution of lambda-light-chain variable-region (V lambda) subgroups among Ig lambda molecules found in the serum of normal individuals with that of monoclonal Ig lambda components obtained from patients with plasma cell and related immunoproliferative disorders. A panel of monoclonal antibodies specific for each of the major human V lambda subgroups--V lambda I, V lambda II, V lambda III, V lambda IV, V lambda VI, and V lambda VIII--was used in a highly sensitive enzyme-linked immunosorbent assay (ELISA) to quantitate each of these populations. The mean distribution of Ig lambda I, Ig lambda II, Ig lambda III, Ig lambda IV, Ig lambda VI, and Ig lambda VIII molecules in serum specimens collected from 20 normal adults was approximately 40, 3, 43, 5, 5, and 3% of the total Ig lambda population, respectively. In contrast, that of monoclonal IgG, IgA, and IgD proteins and Bence Jones proteins obtained from patients with multiple myeloma and related gammopathies (n = 196) was approximately 27, 28, 39, 5, 0, and 1%, respectively. The percentage of monoclonal Ig lambda II components found in individuals with AL lambda amyloidosis (n = 41) was comparably increased to that seen in multiple myeloma and was even higher in patients with Waldenström's macroglobulinemia (n = 16), in whom 63% of the IgM lambda proteins were of the V lambda II subgroup. Also evidenced were differences in the distribution of other V lambda subgroups in the disease states: Most striking was the predominance (41%) of the V lambda VI subgroup among monoclonal lambda chains obtained from patients with AL amyloidosis and that this subgroup was found exclusively on amyloidosis-associated proteins. No Ig lambda VI-type myeloma- or macroglobulinemia-related proteins were identified. The observed alterations in V lambda subgroup distribution among "pathologic" monoclonal Igs were attributed to the particular disease and not related to the heavy-chain class. Our finding that certain V lambda subgroups are nonstochastically expressed in lambda-type multiple myeloma, AL amyloidosis, and Waldenström's macroglobulinemia provides evidence for abnormal VL gene usage in these disorders and, thus, furnishes new insight into their pathogenesis.

Human rheumatoid factors with restrictive specificity for rabbit immunoglobulin G: auto- and multi-reactivity, diverse VH gene segment usage and preferential usage of V lambda IIIb

To determine the molecular and functional properties of human rheumatoid factors (RF), we established stable hybridomas and Epstein-Barr virus-transformed B cell lines from the synovial fluid or peripheral blood of three patients with rheumatoid arthritis and one patient with systemic lupus erythematosus. 17 cell lines were obtained that produced high-titer immunoglobulin M (IgM) RF that reacted exclusively with rabbit but not human IgG or IgG of other mammalian species. Certain anti-rabbit IgG RF also had specificity for other mammalian antigens (Ag), including cytoskeletal proteins and intracellular proteins found in HeLa cells, as well as for Ag present in an extract prepared from the cell wall of group A streptococci. 13 of the 17 RF contained lambda-type light (L) chains, of which 12 were classified serologically as members of the lambda-L chain variable region (V lambda) subgroup, designated V lambda III. The heavy chain V region (VH) and V lambda sequences of nine of these IgM lambda RF were determined at the cDNA level. Five VH genes in three VH families were used by these antibodies (Ab), including VH1 (dp21/1-4b and dp10 [51p1]/hv1051), VH3 (dp38/3-15 and dp77/13-21), and VH4 (dp70/4-4b). The deduced V gene-encoded amino acid sequences of the lambda chains of these IgM lambda RF confirmed their serological classification as lambda III, and they were further classified as members of the relatively uncommon V lambda III subgroup, designated V lambda IIIb. Based on cDNA analyses, nine were the product of three different V lambda III b germline genes. Two such genes, designated hsiggll150 and hsiggll295, were cloned and sequenced from genomic DNA. Unique combinations of these VH and V lambda III b genes could be related to distinctive patterns of reactivity among the IgM lambda RF. Although the VH and V lambda regions of these Abs were expressed primarily as germline-encoded sequences, four of nine multireactive Abs had extensive V region mutation, indicative of an Ag-driven process. The finding that lambda IIIb L chains are preferentially found among anti-rabbit IgG RF, and that some of these Ab have specificity for other protein, cellular, and bacterial Ag, provides new insight into the pathogenesis of RA and related diseases.

Identification and characterization of a functional human Ig V lambda VI germline gene

We have isolated from a human genomic library a potentially functional and distinctive germline gene, designated IGLV6S1, that encodes for light chains of the V lambda VI subgroup. An identical germline gene was cloned from fibroblasts obtained from a patient with light-chain-associated amyloidosis (AL amyloidosis) whose serum and urine contained, respectively, a monoclonal IgG lambda VI protein and a lambda VI Bence Jones protein. Isolation and characterization of cDNA cloned from the patient's bone marrow-derived monoclonal plasma cells revealed that the nucleotide and predicted protein sequences of the rearranged gene were approximately 95% and approximately 90% homologous to those of the germline gene, respectively. The finding that the transcriptional start site for lambda VI RNA synthesis was located upstream of the putative TATA-box promoter, rather than downstream as found for the V lambda II subgroup, implies that a different transcriptional machinery controls the expression of the human V lambda VI-gene family.

Pathogenic potential of human monoclonal immunoglobulin light chains: relationship of in vitro aggregation to in vivo organ deposition

The deposition of certain Bence Jones proteins as tubular casts, basement membrane precipitates, or amyloid fibrils results in the human light-chain-associated renal and systemic diseases--myeloma (cast) nephropathy, light-chain deposition disease, and immunocyte-derived (primary or AL) amyloidosis. To determine if light-chain nephrotoxicity or amyloidogenicity is related to the propensity of these components to form high molecular weight aggregates under physiological conditions, we used a size-exclusion chromatographic system to study 40 different Bence Jones proteins. Each samples was tested over a wide range of protein concentration in three different buffers varying in pH, osmolality, and the presence or absence of low concentrations of urea. Thirty-three of the 35 proteins found clinically and/or experimentally to form in vivo pathologic light-chain deposits were shown to undergo high-order self-association and form high molecular weight aggregates. In contrast, of five nonpathologic proteins, one showed polymerization under the chromatographic conditions used. The correlation between the in vivo results achieved by size-exclusion chromatography and that found in vivo provides (i) a rapid diagnostic method to identify potential nephrotoxic or amyloidogenic Bence Jones proteins and (ii) an experimental means to gain new insight into the physicochemical basis of light-chain aggregation and the treatment of those invariably fatal disorders associated with pathologic light-chain deposition.

Cytokines modulate the inflammatory response and change permissiveness to neuronal adhesion in injured mammalian central nervous system

Axonal injury of peripheral nerves has been shown to be followed by rapid and massive invasion of the nerves by macrophages, which appear to play an important role in the subsequent ability of these nerves to regenerate. In contrast, macrophage invasion of injured nerves of the central nervous system is limited, and the relationship between the post-traumatic inflammatory response of central nervous system nerves and their poor ability to regenerate is not fully understood. We used the proinflammatory cytokine tumor necrosis factor-alpha and the macrophage growth factor, colony stimulating factor-1, to examine whether the inflammatory response can be augmented in the optic nerve following injury, and whether such augmentation is accompanied by regeneration-associated changes. It appeared that the two cytokines caused a significant increase in the number of macrophages invading the optic nerve immediately after injury. Interestingly, however, in the nerve treated with tumor necrosis factor-alpha (but not in the nerve treated with colony stimulating factor-1) this increase was accompanied by an increased permissiveness of the nerve to neuronal adhesion, which we examined in vitro using longitudinal sections of the nerve on which PC12 cells were seeded. The results are discussed with respect to the ability of tumor necrosis factor-alpha to modify the nonpermissive nature of central nervous system white matter.