Phase I study of direct gene transfer of an allogeneic histocompatibility antigen, HLA-B7, in patients with metastatic melanoma.

PURPOSE: To determine the safety, toxicity, and efficacy of direct intratumoral injection of an allogeneic major histocompatibility complex (MHC) class I gene, HLA-B7, in a cationic lipid vector (Allovectin-7; Vical Inc, San Diego, CA) in patients with metastatic melanoma. PATIENTS AND METHODS: Seventeen HLA-B7-negative patients were treated with intralesional injection of Allovectin-7. Twelve patients received a single intralesional injection containing 10 micrograms (four patients), 50 micrograms (five patients), or 250 micrograms (three patients) of plasmid DNA. Five patients received two or three injections of 10 micrograms DNA to a single tumor site at 2-week intervals. Tumor biopsies pretherapy and 2 and 4 weeks after gene injection were obtained to determine expression of the plasmid by polymerase chain reaction (PCR), reverse transcriptase (RT)-PCR, flow cytometry, and immunohistochemistry. RESULTS: Toxicities were related to technical aspects of the injections or biopsies. These included pain, hemorrhage, pneumothorax, and hypotension. Two patients were hospitalized overnight for observation. Seven patients (50%) had tumor responses insofar as the injected nodule decreased > or = 25% by radiologic or physical examination. One patient with a single site of disease achieved a complete remission. Ninety-three percent of the patients' post-gene therapy biopsies contained HLA-B7 plasmid DNA, mRNA, or protein. CONCLUSION: Intratumoral injection of the allogeneic histocompatibility gene, HLA-B7, in a lipid vector can be performed safely at plasmid DNA doses < or = 250 micrograms. The safety profile and biologic activity of this therapy warrants further studies to define the mechanism of action, predictors of response, and antitumor efficacy of this approach.

Immunomodulation by immunopeptides and autoantibodies in aging, autoimmunity, and infection.

The operation of the immune system is a complex orchestration of specific self and non-self-recognition capacities mediated by cells of the innate system acting in coordination with T and B lymphocytes in a series of processes modulated by cytokines. We provide evidence for a natural immunomodulatory system involving autoantibodies directed against a controlling segment of T cell receptor Vbeta chains that downregulate production of stimulatory cytokines balanced by the peptides which in turn upregulate inflammatory activities mediated by TH1-type helper cells. TCR Vbeta-derived peptides effective in retrovirally induced immunosupression could also reverse the effects of immunosenescence in aged mice by restoring the balance of TH1- and TH2-type immunity and the resistance of the animals to cardiac pathology caused by infection with coxsackievirus. An unexpected finding was an adaptive role of the T cells from peptide-treated mice in remodeling damaged hearts by increasing net collagen synthesis by cardiac fibroblasts.

Binding of human IgG myeloma proteins to autologous T-cell receptor determinants.

IgG myeloma proteins (MPs) produced by monoclonal plasma cells derived from B2 lymphocytes have been reported to bind to various autoantigens but the binding generally has been of low affinity. Moreover, T cells from some multiple myeloma patients can respond specifically to idiotypes of their own paraproteins. We analyzed the capacity of more than 20 human IgG MP to bind, a recombinant single-chain molecule containing complete V beta 8.1 and V alpha 1 structures, sets of synthetic peptide epitopes corresponding to a complete TCR beta chain, and a set of CDR1 epitopes corresponding to 24 human V beta gene products, and intact monoclonal T cells. Two of 20 MPs bound strongly to the recombinant TCR. Five of the same set, including these, bound to a synthetic epitope corresponding to the CDR1 segment. On a mass basis, the binding was approximately 1000-fold greater than that of pooled polyclonal IgG. The binding activity was confined to the Fab fragment and was specifically inhibitable by appropriate peptide determinants. Spectrotypic analysis using a set of CDR1 epitopes indicated that individual proteins showed characteristic binding patterns ranging from highly specific to relatively promiscuous. Highly reactive MPs also bound to TCR on intact cells in immunocytofluorescence by flow cytometry. These results are consistent with the relatively frequent occurrence of autoantibodies to TCR determinants and indicate that MPs can be derived from this autoantibody subset.

Sequence analysis of homogeneous peptides of shark immunoglobulin light chains by tandem mass spectrometry: correlation with gene sequence and homologies among variable and constant region peptides of sharks and mammals.

Morphologically, sharks are living fossils that are remarkably similar to their Devonian ancestors of ca. 400 million years ago. If a parallel conservation in biochemical properties characterizes shark evolution, knowledge of the properties of shark immunoglobulins should provide information on the structure of primordial immunoglobulins and their genes. The problem of polyclonality of shark immunoglobulins has precluded detailed analysis of shark immunoglobulin light polypeptide chains. Here, we approach the problem of obtaining direct sequence information on polyclonal light chains of shark immunoglobulins by isolating homogeneous peptides from tryptic digests of shark light chains and sequencing these by tandem mass spectrometry. To confirm the location of the peptides, we isolated a complementary DNA (cDNA) clone from a sandbar shark cDNA library in the expression vector lambda gt11, identifying the clone by its ability to produce a peptide serologically detectable using rabbit antibody to purified shark light chain. The correspondence between peptide sequence and that derived from gene sequence provided direct proof that the gene studied was that of a major expressed serum light chain. Using this combined approach, we isolated homogeneous peptides from both constant and variable regions. The variable region peptides showed homology to corresponding sequences of mammalian V lambda and V kappa sequences. The constant region gene sequence we obtained was homologous to mammalian C lambda sequence. The four constant region tryptic peptides we sequenced corresponded exactly to stretches of the C lambda sequence derived from the DNA sequence. The combined approach described here shows that shark light chains exhibit heterogeneity at both the protein and gene level, but that the constant regions of these chains can be identified as homologs of mammalian lambda chains and that evolutionary conservation has occurred in V region sequences ranging from elasmobranchs to man.

Immunoglobulin epitopes defined by synthetic peptides corresponding to joining region sequence: conservation of determinants and dependence upon the presence of an arginyl or lysyl residue for cross-reaction between light chains and T-cell receptor chains.

Joining or J region sequences of rearranging immunoglobulins and T-cell receptors show considerable sequence homology, particularly in their C-terminal portion corresponding to the fourth framework region of immunoglobulin variable regions. In order to test the question of whether serological cross-reactions between immunoglobulin variable regions and T-cell receptors were due to antigenic similarities in their J regions, we synthesized synthetic peptides corresponding to immunoglobulin J regions and to J regions predicted from gene sequence of the T-cell receptor beta chain. We found that antibodies produced against a synthetic 16-mer J beta sequence reacted with T-cell receptor chains and also with immunoglobulin light chains. The cross-reactivity was dependent upon the J signature sequence FG()GT(R or K)L where the presence of a positively charged lysyl or arginyl residue was essential for cross-reactivity. We were able to classify J region determinants into two distinct antigenic sets; one corresponding to JH and the other corresponding to J kappa, J lambda, J beta and J alpha. Although considerable homology occurs between JH and JL (or J beta) sequences, little cross-reactivity was observed between these two J subsets. Antibodies raised against polyclonal murine IgG immunoglobulins contained antibody subpopulations specifically reactive with either JH or J beta peptides. The serological data derived here using antipeptide antibodies are consistent with computer modeling studies that indicate that the conformations of T-cell receptor variable regions resemble those of classical immunoglobulins. Our data comparing cross-reactivities restricted to the J region indicate that the expression of the J region by intact T-cell receptor beta chains is probably more similar to that of light chains than it is to the corresponding region of heavy chains.

Lack of preferential V beta usage in synovial T cells of rheumatoid arthritis patients.

The T-cell receptor V beta subfamily repertoires of synovial and peripheral T cells of 8 rheumatoid arthritis (RA) patients were determined using the polymerase chain reaction. Three normal controls were included. Some of the rheumatoid synovial samples did not express the complete range of V beta families and lacked as many as 6 gene families. However, these patients showed considerable individual variation in expression. Overall, the data do not support preferential T-cell receptor V beta usage in synovial T cells of RA patients either in comparison to their autochthonous peripheral T cells or to peripheral T cells of normal subjects.

Antibodies to synthetic peptides corresponding to variable-region first-framework segments of T cell receptor. Detection of T cell products and cross-reactions with classical immunoglobulins.

Recent studies at the gene level have shown that T cells express rearranged genes for four types of T cell receptors that are strongly homologous to classical immunoglobulins in the joining region and in the framework 1 (Fr1) and 3 segments of the variable region. Based upon the homologies in gene sequence, it follows that the gene products would show similarities in amino acid sequence and in the folding of the proteins so that cross-reactivities in antigenic determinants would be expected between variable regions of the T cell receptors and classical immunoglobulins. We have synthesized peptides corresponding to predicted protein sequences of the Fr1 residues of T cell receptor alpha, beta- and gamma-chains and have produced antibodies in rabbits against these synthetic peptides. Use of antisera and affinity-purified antipeptide antibodies indicated that high-titer antibodies could be raised that were specific for individual Fr1 peptides. Cross-reactions among Fr1 peptides of T cell receptors and immunoglobulin light chains were observed. In addition, some rabbit antisera raised against classical polyclonal immunoglobulins or affinity-purified immunoglobulin-like T cell receptors were found to exhibit binding activity against Fr1 peptides of T cell receptor beta- and gamma-chains. The sequence homology, although real among the Fr1 of T cell receptors and immunoglobulin light chains, is moderate and the antigenic cross-reaction must reflect the configuration and types of amino acids present. The development of antipeptide antibodies holds promise for the characterization of T cell receptors of various T cell sources and also offers a new means for the identification of molecules related to rearranging immunoglobulins.

Expression of an antisense transforming growth factor-beta1 transgene reduces tumorigenicity of EMT6 mammary tumor cells.

Transforming growth factor-beta (TGF-beta) is a potent immunosuppressive cytokine produced by many tumor cells. Secretion of TGF-beta by malignant cells may therefore be a mechanism by which tumor cells escape destruction by tumor-specific T lymphocytes. In order to evaluate the role of tumor-derived TGF-beta on tumor progression, we have inhibited the production of this cytokine by introducing a gene encoding antisense TGF-beta1 into the EMT6 murine mammary tumor cell line using a retroviral vector (Las-TGF-beta1SN). EMT6 cells transduced with this vector (EMT6as-TGF-beta1) stably expressed the antisense gene and secreted 52% less TGF-beta than did tumor cells transduced with the backbone vector alone. Supernatant fluid recovered from tumor cells expressing the antisense TGF-beta1 gene also exhibited a decreased capacity to inhibit alloantigen-specific cytotoxic T-cell responses in vitro. Furthermore, tumor growth in mice injected with EMT6as-TGF-beta1 tumor cells was inhibited compared to mice injected with control tumor cells. These results demonstrate that expression of antisense TGF-beta1 by transduced EMT6 cells decreases their tumorigenicity and suggest that this approach of eliminating immune suppression is a potentially useful strategy to enhance antitumor responses.

The interaction of lactose-specific lectins with acid-treated and lactose-substituted sepharose.

The binding of two lectins, one a galactosyl/lactosyl and the other a lactosyl binding protein, to various Sepharose 4B derivatives has been investigated. The adsorbents, lactose-substituted Sepharose, acid-treated Sepharose and acid-treated, lactose-substituted Sepharose, were each tested with regard to their overall binding capacity and for the ability to separate the lectins by differential elution with solutions of galactose and lactose. The binding capacity for both lectins decreased in the order Lac-acid-Sepharose greater than Acid-Sepharose greater than Lac-Sepharose much greater than Untreated Sepharose. The ability of the gels to bind both lectins with a sufficient affinity to allow the proteins to be purified by differential elution decreased in a similar order. Acid-treated, lactose-substituted Sepharose proved the most useful gel and was utilised to isolate each lectin in a pure form.

Immunoproteins in evolution.

All vertebrates respond to antigenic challenge by specific cellular reactions and by producing circulating antibodies, and they also contain recognition molecules that are evolutionary relics of primitive non-immune recognition. One such ancient recognition molecule is C-reactive protein (CRP), a member of the pentraxin family, that has homologs occurring in species as diverse as vertebrates, tunicates and the horseshoe crab (an ancient arachnoid). This molecule has lectin-like properties, can act as an opsonin and interact with complement and cells in a manner paralleling immunoglobulins (Igs). The horseshoe crab lectin and CRP, although unrelated to Igs, share functional idiotopes with classical antibodies. This finding reflects either an evolutionary convergence or a mechanism of "mini gene insertion" that allows molecules of distinct evolutionary histories to react to the same ligands. Serum antibodies of all vertebrates are polydisperse in charge and are composed of polypeptide chains comparable in mass to those of mammalian light and heavy chains. Molecular genetic studies of placoderm derived vertebrates are incomplete but are sufficient to allow the conclusion that Igs of these species are specified by variable (V), joining (J) and constant (C) gene segments and that rearrangement are an essential feature for the generation of antibody diversity. Here we present new evidence following from the use of antibodies directed against synthetic joining region peptides as probes in the study of rearranging Igs in evolution, the use of recombinant DNA technology to study T cell receptor V beta genes in a goldfish genomic library and the isolation and characterization of a gene fragment specifying sandbar shark light chain C region. We reached the following conclusions: (1) J region segments are the most conserved in evolution, and this most probably reflects the essential requirements for these gene segments in the formation of intact Ig genes by rearrangement; (2) the framework segments of V regions are highly conserved in vertebrate evolution for both T cell receptors and classical Igs; and (3) although C region segments of light chains of lower vertebrates are homologous to their mammalian counterparts, the degree of conservation of C region structure in phylogeny is apparently less than that for V regions. Essentially, phylogenetic trees can be built using C regions but not V regions. We have identified a molecule of approximate mass of 26 kDa in the hemolymph of the tunicate, Boltenia ovipera, that is serologically cross-reactive with shark heavy chain and with J region peptides.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibody production in sharks and humans: a role for natural antibodies.

Although gene segments specifying Igs of all vertebrates show clear homology, their arrangements differ markedly, thereby suggesting that the mechanisms for the generation of diversity and for the regulation of gene expression may be quite distinct. In the sandbar shark, light chain gene segments are distributed as apparently independent clusters consisting of V, J, and C elements that require rearrangement for expression. The usual distance between V and C in the clusters is 3 kb but larger clusters occur. The V, J, and C elements are clearly homologous to those of human lambda chains. Shark Igs resemble mammalian IgM in structure and gene similarity. IgM may comprise as much as 50% of serum proteins in the shark. By contrast, IgM in humans comprises less than 5%. Human autoantibodies usually are IgM. These show little dependence on thymic function for expression and tend to increase with age. We have carried out a study of the capacity of Igs of unimmunized sharks and people (normals and patients suffering from autoimmune diseases) to react against a panel of antigens, including those usually considered autoantibodies, such as thyroglobulin and single-stranded DNA. Sharks and humans possess IgM antibodies that react with thyroglobulin and ssDNA. Affinity-purified natural shark antibodies to thyroglobulin or ssDNA constitute small fractions of total IgM. They illustrate extensive cross-reactivity comparable to that shown by polyspecific IgM autoantibodies produced by human B cells (CD5+) that appear early in ontogeny.

Partial characterization of immunoglobulin light chains of carcharhine sharks: evidence for phylogenetic conservation of variable region and divergence of constant region structure.

Isolated light chains of IgM-type immunoglobulins of carcharhine sharks were analyzed by serological and biochemical means. When analyzed by isoelectric focusing analysis, light chains of the tiger shark (Galecerdo cuvieri), the galapagos shark (Carcharhinus galapagensis) and the sandbar shark (Carcharhinus plumbeus) showed a broad, but patterned, spectrum of bands ranging from pI 5.0 to 7.7 in which discrete families were observed. Serologically, light chains of the galapagos shark cross-reacted with rabbit antibodies against mouse immunoglobulin and a synthetic peptide corresponding to the J segment of T cell receptor beta chain. The latter cross-reaction is shared among light chains and T cell receptors. Although there was considerable heterogeneity in isoelectric focusing analysis, the light chains were homogeneous on the basis of apparent mass (23 kDa) and those of tiger shark and galapagos shark had relatively homogeneous dominant N-terminal sequences representing the first framework. The N-terminal sequences of these two shark light chains, were strongly homologous to one another and showed 75% identity to certain V kappa sequences of man and dog. Homology was also shown to V lambda sequences, but the degree of identity was approximately 50%. Following cleavage of the tiger shark light chain with o-iodosobenzoic acid which cleaves at tryptophanyl residues, a constant region peptide was isolated by gel filtration. It was possible to identify the homolog of this peptide within the constant regions of mammalian kappa and lambda chain, but the relationship to C kappa chain was stronger. The degree of identity among the corresponding C region peptides of mammalian, avian and elasmobranch species was much less than that observed for the framework 1 sequence of the light chain variable region. These data support the concept that variable and J region sequence have been conserved in the evolution of placoderm-derived vertebrates, but that constant regions show much greater phylogenetic variation.

Identification of the HA-2 agglutinin in the haemolymph of the ascidian Botrylloides leachii as the factor promoting adhesion of sheep erythrocytes to mouse macrophages.

The HA-2 agglutinin purified from B. leachii haemolymph is shown to mediate the binding of sheep erythrocytes to mouse macrophages. This agglutinin appears to be wholly responsible for the adhesive activity of haemolymph, since upon chromatography of the latter through Sephadex G-200, the adhesive activity for both sheep and guinea pig erythrocytes was confined to those fractions containing the HA-2 agglutinin. The HA-1 agglutinin recovered in earlier fractions was unable to promote the adhesion of guinea pig erythrocytes to macrophages. Adsorption experiments indicated that this was due to a lack of ligand sites on the macrophage surface. These data support earlier conclusions that the HA-1 and HA-2 agglutinins have distinct binding specificities.

Development of an immune system.

Minimally, an immune response is an induced cellular and/or humoral defense mechanism specific for the challenging agent. The system is a cognitive one inasmuch as a second stimulus with the same antigen can specifically induce either an enhanced response (memory) or diminished response (tolerance). The cells responsible for the initial antigen-specific recognition in higher vertebrates are clonally restricted T and B lymphocytes. Accessory cells are necessary for the processing and presentation of antigen, and physiologic mediators (cytokines) are essential for proliferation, interaction, and regulation of the system. Although it now appears that the recombination mechanisms essential for the anticipatory immune response occurred late in the deuterostome stream leading to vertebrates, molecules required for cell adhesion and regulation are widely spread in phylogeny. Their emergence must have preceded the divergence between ancestral protostomes and deuterostomes. Genetic mechanisms underlying the generation of diversity in the light and heavy chains of antibodies of mammals may be quite distinct in primitive vertebrates, particularly elasmobranchs, the ancestors of which diverged from those of mammals more than 400 million years ago. Despite this, clonal selection of antigen receptors of lymphocytes is most probably universal within the vertebrates. There is no need to force induced recognition in protostomes (e.g. insects) or lower deuterostomes (e.g. echinoderms) into mammalian models of immunity.

Recognition molecules and immunoglobulin domains in invertebrates.

We have used specific antibody probes to conserved antigenic motifs to identify and characterize immunoglobulin-related molecules in tunicates and a C-type lectin found in lamprey that is related to molecules found in tunicates and mammals. The tunicate immunoglobulin cross-reactive molecule (mu CRM) reacts with antibodies raised to shark IgM heavy chains. Intact tunicate mu CRM is a monomer of Ig light-chain-sized subunits and is oligoclonal by IEF. That this molecule is related to Ig is indicated both by immunochemical data and by peptide sequence homologies. The lamprey lectin is a large polymer (> 500,000 kDa) of 35-kDa and 60-kDa subunits. It appears to be related to C-type lectins as shown by peptide sequence homology and the requirement of Ca2+ for activity. Related molecules appear to be present in tunicates and mammals as shown by cross-reactivity of antibodies in Western blots with single bands from hemolymph and T-cell extracts.

Cell surface recognition and the immunoglobulin superfamily.

Immunoglobulins serve as humoral recognition and effector molecules and as antigen-specific cell surface receptors on B and T cells. These molecules are constructed according to a characteristic domain pattern. Variable and constant domains diverged from one another early in vertebrate evolution, and they are joined by a "switch peptide" specified by the joining gene segments. Peptides specified by J-gene segments are strongly conserved in evolution in comparison among Ig light chains and T-cell receptors. Molecules less strongly related to Ig domains have been assembled into an Ig "superfamily" where the identities to classical IgC or V domains are < or = 20%. Among these are cell surface adhesion molecules, receptors for cytokines, and Fc receptors. Moreover, MHC antigens have an Ig-like membrane-proximal domain significantly related to IgC regions. We will analyze putative evolutionary relationships among canonical Igs and members of the Ig superfamily using highly conserved sequences from light and heavy chains of primitive vertebrates (e.g., the sandbar shark) as prototypes to ascertain similarities between Ig-related molecules of vertebrates and invertebrates.

Conservation among the immunoglobulins of carcharhine sharks and phylogenetic conservation of variable region determinants.

To study primitive vertebrate recognition molecules we have purified the immunoglobulins of three species of carcharhine sharks. The tiger (Galeocerdo cuvieri), the sandbar (Carcharhinus plumbeus) and the galapagos sharks (Carcharhinus galapagensis) possess 18S high molecular weight and 7S low molecular weight immunoglobulin forms. Both within and between species these forms closely resemble each other in polypeptide chain composition, heavy chain mass, carbohydrate content, amino acid composition, antigenic character and amino terminal sequence. These carcharhine species are separated by at least 30 million years of evolutionary time and it is remarkable that so little diversification of immunoglobulin structure has occurred during their evolution. By several criteria carcharhine immunoglobulins most closely resemble mammalian IgM. Studies of serological cross-reactions indicate that some immunoglobulin determinants have been conserved over a broad phylogenetic range of vertebrate classes; most notably JH and VHa-related markers are shared between forms as diverse as sharks and mammals.

Naturally occurring human autoantibodies to defined T-cell receptor and light chain peptides.

We used synthetic peptides duplicating the structures of a human lambda light chain (Mcg), and a human T-cell receptor (Tcr) alpha and a Tcr beta chain predicted from gene sequence to determine the presence and loci of activity of natural human autoantibodies directed against these antigen recognition molecules. We report that normal individuals and patients suffering from autoimmune diseases have antibodies directed against regions of lambda light chains and Tcr beta chains corresponding to the first complementarity determining region and the third framework region of the variable domain and to constant region determinants. The levels of IgM natural antibodies particularly against the CDR1 peptides tend to be higher in RA patients than in normals or SLE patients. Although polyclonal IgG immunoglobulins from healthy individuals did not show detectable reactivity to Tcr alpha peptides, such reactivity was found in the IgM immunoglobulins of RA patients, thereby showing that Tcr alpha peptides can be autoantigenic in man. The levels of IgM autoantibodies to V beta CDR1 peptides tend to decrease with age. By contrast, there was a marked increase in IgG natural autoantibodies to certain CDR1 sequences with advancing age. We suggest that the natural antibodies to defined regions of immunoglobulins and T-cell receptors are part of a physiological network for the regulation of the immune response.

Cross-reactions of anti-immunoglobulin sera with synthetic T-cell receptor beta peptides: mapping on a 3-dimension model.

The derived amino acid sequences of human T-cell receptor beta chain shows significant homology to lambda light chains of immunoglobulins in its variable, joining, and constant regions. We assessed the cross-reactivity between Tcr beta chains and immunoglobulin light chains by determining the capacity of rabbit antisera to human or murine immunoglobulins to react to a synthesized set of nested, overlapping 16-mer peptides corresponding to the VDJC sequence of the Tcr beta chain YT35. The observed reactivities were consistent with homologies to lambda and kappa light chains, the strongest reactivity being with a peptide that corresponds to the "switch peptide" of light chains, as assessed by ELISA binding and competitive inhibitions assays. Other regions reactive with anti-light chain sera corresponded to CDR1 and Fr3 segments of the variable domain and a segment of the constant region predicted to loop out of the tight globular structure. The peptide immunochemical results, together with the identification of specific regions of sequence correspondence between Tcr beta and the characterized lambda light chain Mcg, allowed us to develop a 3-dimensional model of the beta chain consistent with its role in antigen recognition.

Characterization of autoantibodies directed against T cell receptors.

Recently it has been observed that administration of intravenous immunoglobulin (IVIG) can have profound effects on a wide variety of diseases related to the dysregulation of the immune system. The mechanisms which explain these activities are poorly understood. Human IVIG and various Cohn plasma fractions contain autoantibodies directed against T cell receptors (Tcr). Previous studies have shown that IVIG contains autoantibodies against T cell receptor peptides. In order to further our understanding of autoantibody specificities, a single chain Tcr (scTcr) was constructed by recombinant DNA techniques from the variable alpha and variable beta chains of the Jurkat cell line. Anti-Tcr autoantibodies were isolated from IVIG and Cohn fractions I + III using a scTcr affinity column. This scTcr affinity purified material reacted with the surfaces of T cells at 10 micrograms/ml whereas non-purified IVIG did not. Sera from patients with rheumatoid arthritis (RA) as well as serum from patients with systemic lupus erythematosus (SLE) reacted with the scTcr at levels above that of normals.