Induction of lupus-associated autoantibodies by immunization with native and recombinant Ig polypeptides expressing a cross-reactive idiotype 4B4

A human mAb designated 4B4 with anti-Sm activity was derived from a patient with systemic lupus erythematosus. This antibody expressed a lupus-associated cross-reactive Id, partially related to the monoclonal murine anti-Sm (Y2) from MRL/lpr mice. Studies were performed to investigate the ability of 4B4 to induce lupus in nonautoimmune-prone mice. BALB/c mice immunized with 4B4 produced antibodies to dsDNA, ssDNA, Sm ribonucleoprotein, and mouse Fc fragment. There was no antibody activity against SSA/Ro, SSB/La, and hen egg lysozyme. Ag inhibition studies show that the autoantibodies were not polyreactive. Mice were also immunized with r4B4 polypeptides representing the H/L heterodimer, H chain and L chain. Autoantibodies were induced in mice immunized against the H/L and H polypeptides. No autoantibodies were induced in mice immunized with recombinant L chain. Furthermore, from 20 to 68% of antibody activity to Sm or dsDNA could be inhibited with anti-Id antiserum (either anti-4B4 or Y2). The autoantibody was initially IgM and then underwent an isotype switch to IgG. These results show that lupus-associated autoantibodies can be induced by immunization with 4B4 and that the 4B4 VH region is important in this induction process. The finding of murine IgG autoantibody expressing a cross-reactive Id similar to the immunizing 4B4 suggests a role for anti-idiotypic Th cells in this autoimmune response.

Induction of lupus-associated autoantibodies by immunization with native and recombinant Ig polypeptides expressing a cross-reactive idiotype 4B4

A human mAb designated 4B4 with anti-Sm activity was derived from a patient with systemic lupus erythematosus. This antibody expressed a lupus-associated cross-reactive Id, partially related to the monoclonal murine anti-Sm (Y2) from MRL/lpr mice. Studies were performed to investigate the ability of 4B4 to induce lupus in nonautoimmune-prone mice. BALB/c mice immunized with 4B4 produced antibodies to dsDNA, ssDNA, Sm ribonucleoprotein, and mouse Fc fragment. There was no antibody activity against SSA/Ro, SSB/La, and hen egg lysozyme. Ag inhibition studies show that the autoantibodies were not polyreactive. Mice were also immunized with r4B4 polypeptides representing the H/L heterodimer, H chain and L chain. Autoantibodies were induced in mice immunized against the H/L and H polypeptides. No autoantibodies were induced in mice immunized with recombinant L chain. Furthermore, from 20 to 68% of antibody activity to Sm or dsDNA could be inhibited with anti-Id antiserum (either anti-4B4 or Y2). The autoantibody was initially IgM and then underwent an isotype switch to IgG. These results show that lupus-associated autoantibodies can be induced by immunization with 4B4 and that the 4B4 VH region is important in this induction process. The finding of murine IgG autoantibody expressing a cross-reactive Id similar to the immunizing 4B4 suggests a role for anti-idiotypic Th cells in this autoimmune response.

Characterization of a cross-reactive idiotype on two human autoantibodies associated with systemic autoimmune disease

A human-human hybridoma was derived from a patient with primary Sjogren's Syndrome. The monoclonal antibody from this hybridoma, P36, was found to be polyreactive. P36 shared idiotypic cross-reactivity with a lupus-associated monoclonal antibody called 4B4. There was a strong correlation between P36 and 4B4 idiotype levels in systemic lupus erythematosus sera. Western blot studies showed that this shared idiotype was found on the heavy chain of both antibodies. This study shows that the heavy chain is important in the expression of this idiotype and provides another immunologic link between these two rheumatic diseases.

Two inactive fragments derived from the yeast mitochondrial ribosomal protein MrpS28 function in trans to support ribosome assembly and respiratory growth

The mitochondrial ribosomal protein MrpS28 of Saccharomyces cerevisiae is one of several mitochondrial ribosomal proteins homologous to Escherichia coli ribosomal proteins within the context of a larger protein. Relative to a region of homology with E. coli ribosomal protein S15, the mature MrpS28 protein has unique sequence domains of 117 and 48 amino acids at its amino and carboxyl terminus, respectively. To better understand the role of the various sequence domains of the MrpS28 protein in vivo, truncated derivatives were expressed under conditions where they were the only potential source of functional MrpS28 protein. The results shown here demonstrate that the amino-terminal domain and the S15-like domain are both essential for respiratory growth. Interestingly an inactive amino-terminal fragment can be complemented in trans by a second inactive fragment comprising the S15-like domain and the carboxyl-terminal 48 amino acids. Consequently, the assembly of these fragments into ribosomal subunits can be examined when they are expressed individually or together. Results from these studies indicate that each of the MrpS28-derived fragments facilitates the incorporation of the other into 37 S ribosomal subunits.

[1-stage repair of congenital blepharostenosis]

Nine cases of congenital blepharostenosis have been corrected by operation. The procedure included shortening of the ligaments of the inner canthus, correcting epicanthus, incision of the external canthus, and rectifying drooping of the upper lid in one stage. After operation, incision scar is not noticeable.

Human kappa chain expression in a lambda phage vector: methods of isolating amplified cDNA affects cloning efficiency

Three common methods of isolating amplified DNA were evaluated for their effects on cloning efficiency in a phage vector designed to express human kappa chain. The "glass milk" technique gave higher cloning efficiency and protein expression than phenol-chloroform extraction or microfiltration. This shows that the quality of amplified cDNA should be considered when studying the human antibody repertoire using this vector system.

Cloning of a human IgM autoantibody bearing a cross-reactive idiotype in a lambda expression vector: a new approach to studying autoantibodies

The monoclonal antibody 4B4 is a human IgM,kappa which expresses a cross-reactive lupus-associated idiotype and has anti-Sm binding activity. We find that the VL nucleotide sequence of 4B4, like the 4B4 VH region, is encoded by unmutated germline genes. The 4B4 VH and VL were cloned into the ImmunoZap lambda expression vector to produce three recombinant immunoglobulin polypeptides. These recombinant polypeptides expressed, respectively, either the 4B4 VH or VL alone or a VH/VL heterodimer. ELISA showed that the VH/VL heterodimer retained anti-Sm antibody activity. The 4B4 idiotype was found predominantly on the VH. This report describes: (i) a method for producing recombinant immunoglobulin molecules from an IgM-secreting B cell line and (ii) the ability of recombinant antibody fragments expressed in Escherichia coli to retain the structural and antigenic properties of the native molecule.

Spatial frequency evoked visuograms in multiple sclerosis

We obtained steady-state visual evoked potentials (VEPs) to sinusoidal gratings alternating at 4 Hz with spatial frequencies varying from 0.5 to 8 cpd in 21 normal controls and 21 patients with multiple sclerosis (MS), and analyzed responses by fast Fourier transform. Amplitude- and phase-spatial frequency functions were obtained and referred to as amplitude and phase "visuograms." We observed two types of abnormalities in the phase visuograms of MS patients: (1) abnormal responses at all spatial frequencies tested (37%), and (2) abnormal responses only at selective spatial frequencies (52%). Some patients had phase lag limited to low, middle, or high spatial frequencies. Steady-state and transient VEPs to 2 and 4 cpd showed a similar percent of abnormalities. The use of more than one spatial frequency stimulus increased the diagnostic yield by 17%. Our data confirm that MS may selectively affect specific neuronal channels within the visual pathways.

Are endogenous retroviruses involved in human autoimmune disease?

A role for viruses in the etiopathogenesis of human autoimmune diseases has long been suspected but has not yet been proven. In Sjögren's syndrome (SS), there is continuing experimental support for the possible involvement of Epstein-Barr virus. Since the advent of AIDS, there is also great interest in retroviruses and autoimmune disease. We previously reported that 30% of SS patients and 36% of systemic lupus erythematosus (SLE) patients have serum antibodies to the p24 gag protein of HIV-1. We now report that two mechanisms classic for retroviruses (molecular mimicry and immunosuppression) may be operative in SS and SLE. The p24 gag protein shares a proline-rich epitope with the Sm nucleoprotein to which many SLE patients have antibodies. The impaired lymphocyte activation seen in peripheral blood T cells in SS patients is also seen in a human T cell line infected with an A-type retroviral particle linked to SS. Many studies suggest that endogenous retroviral sequences are important in immunoregulation. We now suggest that endogenous retroviral sequences may also be important in the etiology and pathogenesis of SS and SLE.

Cross-reactivity of the subunit of the Sm ribonucleoprotein autoantigen with proline-rich polypeptides

Using recombinant fusion proteins representing different regions of the human Sm B/B' polypeptide, the 4B4 monoclonal anti-Sm antibody was found to bind a C-terminus epitope that is proline-rich. 4B4 cross-reacted with the p24 gag protein of HIV-1 and with other polypeptides rich in proline residues, including collagen. BALB/c mice immunized with human collagen not only produced antibodies to the immunizing antigen but also antibodies to Sm. This immune mouse serum also recognized C-terminus B/B' fusion proteins. These data suggest that the Sm B/B' antigen contains a poly-Pro epitope that is shared by several autoantigens and retroviral proteins. These sites may be important in the induction of autoantibodies through molecular mimicry.

Salivary and serum IgA antibodies to the Epstein-Barr virus glycoprotein gp340: incidence and potential for virus neutralization

Human antibody responses to the Epstein-Barr virus (EBV) glycoprotein gp340 have been measured using purified preparations of the native molecule as the substrate in ELISAs. This glycoprotein is the dominant component of the EBV envelope and a major target for the virus-neutralizing antibody response. Healthy virus carriers (both Caucasian and Chinese) regularly show detectable anti-gp340 IgG in serum and, unexpectedly, 21-30% of these individuals are also serum anti-gp340 IgA positive. Chinese patients with the EBV-genome-positive malignancy nasopharyngeal carcinoma (NPC) show elevated serum IgA antibodies to gp340 but, given the background of responses amongst healthy virus carriers, anti-gp340 IgA titres are a poorer diagnostic indicator of NPC than serum IgA antibodies detectable by immunofluorescence against the multicomponent EBV early antigen (EA). Salivary IgA antibody responses to gp340 are potentially important as a means of neutralizing orally-transmitted virus. We detected salivary IgA (but not IgG) to gp340 in a minority (12-19%) of healthy virus carriers and in a higher proportion (49%) of NPC patients. Even saliva samples chosen for their relatively high anti-gp340 IgA titres showed only weak neutralizing activity against transforming EBV preparations whether from B95.8 cell culture supernatant or from the throat washing of an infectious mononucleosis patient. We conclude that in healthy virus carriers, salivary IgA responses to gp340 are unlikely to provide effective local immunity against re-infection with a second EBV strain.

Structural and functional analyses of a yeast mitochondrial ribosomal protein homologous to ribosomal protein S15 of Escherichia coli

We have purified a small subunit mitochondrial ribosomal protein, MRPS28p, from the yeast, Saccharomyces cerevisiae. Sequence from the amino terminus of MRPS28p was used to design a degenerate oligonucleotide that was complementary to the MRPS28 gene. The MRPS28 gene was isolated and its sequence determined. The MRPS28 sequence encodes a 28 kDa protein that has a region of homology with ribosomal protein S15 of E. coli. This region spans the entire length of the E. coli protein, but as MRPS28p is larger, includes only the portion of the MRPS28p sequence from amino acids 150 to 238. Based on this homology, we predict that MRPS28p, like E. coli S15, interacts directly with small subunit rRNA and functions as an early protein in ribosome assembly. Cells carrying a disrupted chromosomal copy of MRPS28 are unable to respire and spontaneously lose portions of their mitochondrial genomes at a high frequency. These phenotypes are consistent with an essential role for MRPS28p in the assembly and/or function of the mitochondrial ribosome.

Accelerated expression of anti-Sm and Y2 idiotype differ in dependence on T cell subsets in MRL/+ mice

We investigated the role of MRl T cells in the induction of anti-Sm antibodies and Y2 idiotype. Four injections of Sm antigen in Freund's complete adjuvant were required to induce peak amounts of specific anti-Sm antibody in young BALB/c and MRL/+ mice. The Y2 idiotype was expressed in MRL/+ mice but not in BALB/c mice. Expression of both anti-Sm, predominantly IgG2a heavy chain, and Y2 idiotype was augmented in MRL/+ mice after two injections of Sm if, prior to immunization, mice received splenic T cells from naive MRL/lpr or immunized, but not naive MRL/+ mice. These results suggest that the lpr gene contributes to the ability of autoimmune T cells to augment the anti-Sm antibody response. Treatment of primed MRL/+ donor T cells with anti-CD4, but not anti-CD8, antibodies and complement removed the ability to augment anti-Sm antibody production. In contrast, augmentation of Y2 idiotype production was abrogated by pretreatment of donor T cells with either anti-CD4 or anti-CD8. These results suggest that, while MRL/+ CD4+ T cells play an important role in anti-Sm antibody production, additional interaction between CD4+ and CD8+ T cells augments Y2 expression.

A conserved idiotype and antibodies to retroviral proteins in systemic lupus erythematosus

22 of 61 systemic lupus erythematosus (SLE) patients produced antibodies to the p24 gag protein of HIV-1 demonstrated by Western blotting. 20 of these 22 patients (91%) also express the 4B4 idiotype (Id 4B4) previously identified on a human anti-Sm monoclonal antibody called 4B4. This represents an enrichment for this Id (seen in only 52% of SLE patients generally). Eight of these 22 SLE patients also have anti-Sm antibody activity. Sm partially inhibits the antibody binding of p24 gag suggesting immunologic cross-reactivity between the retroviral antigen p24 gag and the autoantigen Sm. Anti-Id 4B4 also inhibits p24 gag antibody binding by as much as 40%. Finally the monoclonal antibody 4B4 showed cross-reactivity to Sm and p24 gag. The following points emerge from our studies: (a) SLE patients make antibodies to p24 gag of HIV-1, (b) there is a relationship between immunity to p24 gag and a conserved idiotype, and (c) anti-Sm antibodies can cross-react with p24 gag.

Detection of serum antibodies to retroviral proteins in patients with primary Sjögren's syndrome (autoimmune exocrinopathy)

Primary Sjögren's syndrome (SS) is considered a benign autoimmune disease; it is characterized by lymphoid infiltration of salivary and lacrimal glands, often accompanied by the presence of serum autoantibodies, particularly anti-Ro (SS-A) and anti-La (SS-B). There are important immunologic similarities between primary SS and acquired immunodeficiency syndrome. To investigate for a possible immune response to retroviral proteins in primary SS, we performed immunoblotting against human immunodeficiency virus-1 (HIV-1) proteins using sera from 47 patients with primary SS. Moderate-to-strong reactivity, suggesting the presence of serum antibodies, was found in 14 patients (30%). Of 120 normal subjects, only 1 showed moderate positivity. All 14 positive SS sera reacted against p24 (gag) but failed to react against gp41 or gp120 (env). This response did not reflect hypergammaglobulinemia since immunoglobulin concentrations among the 29 SS patients studied were the same in sera that contained and sera that did not contain anti-gag reactivity. Two sera also reacted against p17 gag. Four reacted against HIV-2 core proteins, but none reacted with core proteins of human T lymphotropic virus-I. Only 1 of the 14 sera reacted against Ro (SS-A), and 1 other reacted against La (SS-B). These results identify a subset of SS patients characterized by 1) the presence of serum antibodies to HIV-1 group-specific, but not type-specific, proteins, and 2) the relative absence of anti-Ro (SS-A) and anti-La (SS-B) autoantibodies. In this latter respect, these SS patients constitute a subpopulation that resembles patients with HIV-induced SS-like disease.

Discoordinate expression of the yeast mitochondrial ribosomal protein MRP1

We have examined expression of the protein coded within the MRP 1 locus of Saccharomyces cerevisiae. Direct evidence is provided for the assignment of the MRP1 gene product as a protein component of the small subunit of mitochondrial ribosomes. Further studies examined the extent to which the expression of the MRP1 protein is coordinated with the expression of other mitochondrial ribosomal components coded in the nuclear and mitochondrial genomes. Extra copies of the MRP1 gene were introduced into yeast cells to perturb expression from MRP1 relative to other mitochondrial ribosomal components to determine whether forms of regulation function to limit the accumulation of either MRP1 mRNA or protein under these conditions. Increases in MRP1 gene dosage were accompanied by substantial increases in both MRP1 mRNA and protein, indicating that their accumulation was not linked to the level of expression of other mitochondrial ribosomal components. This conclusion was confirmed by additional studies that showed that the accumulation of the MRP1 protein was unaffected in cells that did not express mitochondrially-encoded rRNAs. These results contrast with previous studies on the expression of two other mitochondrial ribosomal proteins indicating that regulatory properties of mitochondrial ribosomal proteins are quite diverse.

Anti-peptide antibodies detect a lupus-related interspecies idiotype that maps to H chain CDR2

Antibodies to the small nucleoprotein Sm occur spontaneously in human and murine systemic lupus erythematosus. Human and mouse monoclonal anti-Sm autoantibodies designated 4B4 and Y2 share an idiotype (Id) determinant located on the Ig H chain. To understand the molecular basis of this cross-reactivity, the VH regions of both antibodies were sequenced and analyzed for homology. The antibodies showed only 49.6% homology. The second complementary determining region (CDR2) was the most likely candidate for the Id site. To investigate this possibility, rabbit antiserum was made against a peptide corresponding to the CDR2 of 4B4. This antiserum was specific for the immunizing peptide and reacted weakly to a peptide corresponding to the CDR2 of Y2. Anti-CDR2 antibody bound to 4B4 and Y2 but not to other human and mouse mAb. Binding was directed at the H chain when analyzed by Western blots. Anti-CDR2 antibody blocked anti-Id antibody binding to 4B4 and Y2 by 58% and 24%, respectively. These studies suggest that this interspecies Id maps to the H chain CDR2 and that a conserved Id can occur within molecules that are otherwise radically different.

Anti-peptide antibodies detect a lupus-related interspecies idiotype that maps to H chain CDR2

Antibodies to the small nucleoprotein Sm occur spontaneously in human and murine systemic lupus erythematosus. Human and mouse monoclonal anti-Sm autoantibodies designated 4B4 and Y2 share an idiotype (Id) determinant located on the Ig H chain. To understand the molecular basis of this cross-reactivity, the VH regions of both antibodies were sequenced and analyzed for homology. The antibodies showed only 49.6% homology. The second complementary determining region (CDR2) was the most likely candidate for the Id site. To investigate this possibility, rabbit antiserum was made against a peptide corresponding to the CDR2 of 4B4. This antiserum was specific for the immunizing peptide and reacted weakly to a peptide corresponding to the CDR2 of Y2. Anti-CDR2 antibody bound to 4B4 and Y2 but not to other human and mouse mAb. Binding was directed at the H chain when analyzed by Western blots. Anti-CDR2 antibody blocked anti-Id antibody binding to 4B4 and Y2 by 58% and 24%, respectively. These studies suggest that this interspecies Id maps to the H chain CDR2 and that a conserved Id can occur within molecules that are otherwise radically different.

Characterization of the IL-2-receptor on rheumatoid arthritis synovial fluid T cells

We studied the hypoproliferative response of synovial fluid (SF) T cells in rheumatoid arthritis (RA) using a mitogenic monoclonal antibody (MoAb) specific for the T-cell antigen receptor-associated CD3 complex. RASF T cells are defective in their proliferative response and in the induction of the Tac (p55) component of the IL-2-receptor (IL-2-R) when stimulated with anti-CD3 monoclonal antibody (MoAb). However, fresh RASF T cells bear demonstrable IL-2-R in cross-linking experiments which are not seen in unstimulated peripheral blood (PB). These receptors are functional since RASF T cells proliferate in response to recombinant IL-2 (rIL-2) better than fresh PB T cells from either normal or RA patients. Scatchard analysis indicates increased (4-fold) numbers of high affinity IL-2-R on (phytohaemagglutinin) PHA-activated RASF T cells as compared with comparably activated RAPB T cells. Phorbol myristate acetate (PMA) induces Tac antigen expression in RASF but does not lead to proliferation. The hyporesponsiveness of RASF T cells does not appear to result from lack of IL-2-R, lack of IL-2-R inducibility, or proliferative potential.

Pupil-sparing oculomotor palsy caused by fusiform arteriosclerotic aneurysm of the basilar artery--a case report

Paresis of the oculomotor nerve is a very rare complication of an unruptured arteriosclerotic fusiform aneurysm of the basilar artery. A handful of cases are described in the world literature. A fifty-four-year-old man with a history of hypertension and diabetes mellitus presented with painless partial oculomotor palsy of sudden onset. A cerebral angiogram demonstrated a tortuous fusiform deformity of the basilar artery and the origin of the posterior cerebral arteries, indicative of an arteriosclerotic aneurysmal dilation. A sudden onset of a pupil-sparing ophthalmoplegia is the typical history of a microvascular infarct of the third nerve, whereas pupillary sparing in aneurysmal oculomotor paresis is a very rare event. Special emphasis has been placed on the pupillary size as a guide for the indication of arteriography. The many exceptions to this rule suggest that cerebral arteriography may be indicated more often than generally believed.