Idiotype-specific intravenous immunoglobulin (IVIG) for therapy of autoimmune diseases

Intravenous immunoglobulin (IVIG) is used successfully for therapy of inflammatory and autoimmune diseases, especially in cases of conventional therapy resistance. Within the broad spectrum of immunomodulatory activities of IVIG in vitro and in vivo, the anti-idiotypic activity, neutralizing the autoimmune disease related idiotypes, is one of the main mechanism. We and others have proven that from the IVIG composition, diverse fractions of autoimmune disease specific IVIG can be affinity purified (sIVIG). This sIVIG was shown to be more efficient than the whole compound of IVIG in experimental animal models of autoimmune diseases.The affinity purification of disease sIVIG encompasses three stages. The first stage is to construct an autoantigen column for affinity purification of the autoantibodies. In the second stage the purified autoantibodies are used to construct a new column composed of the autoantibodies. The later is utilized for affinity purification of anti-autoantibodies (anti- idiotypes) IVIG defined as autoimmune disease specific IVIG- sIVIG.

Use of phage display to isolate specific human monoclonal antibody fragments against a potential target for multiple myeloma

INTRODUCTION

Multiple myeloma (MM), a malignancy of plasma cells, accounts for 10% of all haematological malignancies and is currently incurable. Although it can be treated, the disease tends to relapse after several years and becomes increasingly resistant to conventional therapy. Investigations into using humoral therapy for MM are now underway with a view that novel therapeutic agents may provide a more targeted therapy for MM.

MATERIALS AND METHODS

Here, phage display, a faster and more efficient method compared to classical hybridoma fusion technology, was used as a proof-of-concept to isolate several single-chain Fragment variables (scFv) against Ku86.

RESULTS

Anti-Ku86 polyclonal scFvs biopanning was successful where third round scFvs (A(450)~1.1) showed a 1/3 increase in binding as compared to the fi rst round scFvs (A(450)~0.4) with 100 microg/mL of antigen (purified human Ku86). Subsequent selection and verification of monoclonal antibodies using third round biopanning revealed 4 good affinity binding clones ranging from A(450)~0.1 to A450~0.15 on 12.5 microg/mL of antigen as compared to low binders (A(450)~0.07) and these antibodies bind to Ku86 in a specific and dose-dependent manner. Comparative studies were also performed with commercially available murine antibodies and results suggest that 2 of the clones may bind close to the following epitopes aa506-541 and aa1-374.

CONCLUSIONS

These studies using phage display provide an alternative and viable method to screen for antibodies quickly and results show that good affinity antibodies against Ku86 have been successfully isolated and they can be used for further studies on MM and form the basis for further development as anti-cancer therapeutic agents.

Cloning of idiotype immunoglobulin genes in B cell lymphomas by anchored PCR and production of individual recombinant idiotype vaccines in Escherichia coli

OBJECTIVES

Individual immunoglobulins expressed by B-cell lymphomas represent tumor-specific antigens ('idiotypes'). Immunization with idiotype in follicular lymphoma patients may induce specific immune responses, sustained progression-free survival, and disappearance of minimal residual disease. Manufacturing of idiotype vaccines has mostly relied on heterohybridomas established from viable lymphoma cells. This paper describes the feasibility of production of GMP-grade idiotype vaccines as recombinant Fab fragments in Escherichia coli.

METHODS

IgH and IgL transcripts were analyzed by anchored PCR from 106 lymphoma and nine control biopsies. Lymphoma-derived V segments were inserted into prokaryotic expression plasmids. Recombinant idiotype Fab fragments were expressed in E. coli in a fermentation system.

RESULTS

Idiotype IgH and IgL transcripts were identified in 95% of 106 lymphoma biopsies according to stringent clonality criteria. Large-scale idiotype expression was successful in 69 of 78 cases (89%) and yielded a median of 17 mg (range: 1.2-250 mg) recombinant Fab protein. After affinity chromatography, median vaccine purity was 99% heterodimeric Fab protein (range: 72-100%). Bacterial protein contamination was detectable in one vaccine only. Fab proteins with IgL lambda chains had a tendency for inferior yield and lesser purity than kappa-type Fabs. Among other structural idiotype features (isotype, V family usage, somatic hypermutation pattern, novel glycosylation sites, CDR III net charge), no consistent influences on Fab yield or purity were detected.

CONCLUSIONS

Anchored PCR cloning and subsequent protein expression in E. coli provides a reliable technological basis for clinical idiotype vaccination trials.

Production of myeloid dendritic cells (DC) pulsed with tumor-specific idiotype protein for vaccination of patients with multiple myeloma

BACKGROUND

Immunotherapy of cancer with DC vaccines has produced encouraging results in clinical trials. Antigen (Ag)-pulsed DC have elicited CD4+ and CD8+ T-cell immunity and tumor regression in humans. However, there is no standard method of DC production. The DC phenotype, number and Ag-loading process used in these studies have varied, making comparisons between trials difficult.

METHODS

In the present report a reproducible method was developed for the production of a DC-based vaccine. Monocytes were enriched by adhesion from healthy donor apheresis products and cultured with growth factors for maturation into DC. The cells were loaded with the tumor Ag idiotype proteins from patients with multiple myeloma. DC culture and Ag loading were performed in an automated and closed system. The DC product was characterized for phenotype by flow cytometry and for function in Ag uptake and Ag presentation.

RESULTS

These monocyte-derived DC expressed high levels of costimulatory molecules (CD80/86). Ag-pulsed DC functioned to induce allogeneic proliferative lymphocyte responses and Ag-specific cytotoxic T lymphocyte (CTL) responses. The DC viability, phenotype and function were well preserved following prolonged frozen storage. Aliquots from the product of a single DC preparation could be used for sequential vaccinations without batch to batch variability.

DISCUSSION

Ag-pulsed DC can be reproducibly generated for clinical use. These standardized methods are now being employed for a clinical trial to evaluate idiotype-pulsed DC vaccine therapy following non-myeloablative transplant for the treatment of multiple myeloma.

Combined vaccination with idiotype-pulsed allogeneic dendritic cells and soluble protein idiotype for multiple myeloma patients relapsing after reduced-intensity conditioning allogeneic stem cell transplantation

BACKGROUND AND OBJECTIVE

To combine the use of idiotype-pulsed allogeneic dendritic cells (alloDC) and soluble protein Id conjugated with KLH (Id-KLH) in a vaccine strategy for multiple myeloma (MM).

DESIGN AND METHODS

Four MM patients received the combined vaccine after having experienced disease relapse/progression following reduced intensity conditioning (RIC) allogeneic stem cell transplantation (alloSCT) and failure to rescue therapy with donor lymphocyte infusion or chemotherapy (CHT).

RESULTS

Vaccination was well tolerated and induced an anti-KLH antibody response in all 4 patients as well as substantial cell proliferation. In contrast, no case showed similar effects against either tumor-specific Id or irrelevant isotype control immunoglobulins (Ig). In turn, vaccination was associated with modulation of biological responses linked to both inflammatory and T-cell activation, with secretion of effector Th1 cytokines. In particular, an important increase in the spontaneous ex vivo secretion of TNFalpha, IL-6 and IFNgamma as well as IL-2 and IL-10 was frequently observed prior to the fourth vaccination. Moreover, in vitro stimulation with Id-KLH and Id-KLH plus alloDC, but not with alloDC alone was associated with an enhanced number of TNF-alpha+ T-cells and an increased secretion of IFNgamma and IL-2 before the third and fourth vaccination. From a clinical standpoint, 2 patients had a transient response and 1 has stable disease after stopping vaccination, while 3 of them ultimately progressed.

INTERPRETATION AND CONCLUSIONS

The results show for the first time that the use of Id-pulsed alloDC following RIC alloSCT is safe and feasible. However, crucial strategy improvements are warranted to possibly achieve clinical benefit.

Molecular identification of pathogenetic IdLNF+1 autoantibody idiotypes derived from the NZBxSWR F1 model for systemic lupus erythematosus

The acceleration of nephritis in SNF(1) mice by CD4(+) T-cell clones reactive with a nephritogenic idiotype, Id(LN)F(1) [1], as well as the ability of anti-Id(LN)F(1) antisera to down-regulate the production of Id(LN)F(+)(1) immunoglobulin (Ig) in vivo and delay nephritis [2], suggests that dysregulation of this idiotype may contribute to the development of SNF(1) nephritis. Herein, we show that a monoclonal Id(LN)F(1)-expressing antibody, 540, significantly (P< or = 0.01) stimulated Id(LN)F(1)-reactive T-cell clones B6 and D2 to proliferate, while other Id(LN)F+1 antibodies did not. Further, injection of 540-producing hybridoma cells into nonautoimmune (SWRxBalb/c)F(1) mice resulted in the deposition of Id(LN)F(+)(1) Ig in the kidneys, in a pattern indicative of early nephritis. To identify the pathogenetic Id(LN)F(1) epitope(s) at the molecular level, we compared the deduced amino acid sequences of the heavy and light chain variable regions of pathogenetic and non-pathogenetic Id(LN)F(1)-expressing Igs 540, 317, and 533. Two overlapping peptides derived from the V(H) sequence of 540 (aa 54-66 and 62-73), which both contain the triple basic amino acid motif K(X)K(X)K, stimulated SNF(1) T cells and T-cell clones B6 and D2. These results further support the involvement of a subset of Id(LN)F(1)-expressing Ig in SNF(1) nephritis.

Idiotype-specific cytotoxic T lymphocytes in multiple myeloma: evidence for their capacity to lyse autologous primary tumor cells

Multiple myeloma (MM) is a B-cell malignancy. The monoclonal immunoglobulin, secreted by myeloma plasma cells, carries unique antigenic determinants (idiotype [Id]) that can be regarded as a tumor-specific antigen. Id-based immunotherapy has been explored in myeloma patients for the purpose of enhancing or inducing Id-specific immune responses that might lead to tumor destruction. However, despite some evidence obtained from mouse plasmacytoma models, it is still unclear whether Id-specific immunity may play a role in the regulation of tumor cells in MM. In the current study, using dendritic cells (DCs) as antigen-presenting cells, autologous Id-specific cytotoxic T lymphocyte (CTL) lines containing both CD4+ and CD8+ T cells were generated from myeloma patients. The results show that Id-specific CTLs not only recognized and lysed autologous Id-pulsed DCs but also significantly killed the autologous primary myeloma cells. The cytotoxicity against the primary tumor cells was major histocompatibility complex (MHC) class I- and, to a lesser extent, class II-restricted, indicating that myeloma cells could process Id protein and present Id peptides in the context of their surface MHC molecules. Furthermore, the CTLs lysed the target cells mainly through the perforin-mediated pathway because Concanamycin A, but not Brefeldin A-the selective inhibitors for perforin- or Fas-mediated pathways-abrogated the cytolytic activity of the cells. These CTLs secreted predominantly interferon-gamma and tumor necrosis factor-alpha on antigen stimulation, indicating that they belong to the type-1 T-cell subsets. Taken together, these findings represent the first demonstration that Id-specific CTLs are able to lyse autologous tumor cells in MM and, thus, provide a rationale for Id-based immunotherapy in the disease.

Secondary V(D)J rearrangements and B cell receptor-mediated down-regulation of recombination activating gene-2 expression in a murine B cell line

It has recently become clear that recombination of Ig genes is not restricted to B cell precursors but that secondary rearrangements can also occur under certain conditions in phenotypically immature bone marrow and peripheral B cells. However, the nature of these cells and the regulation of secondary V(D)J recombination in response to B cell receptor (BCR) stimulation remain controversial. In the present study, we have analyzed secondary light chain gene rearrangements and recombination activating gene (RAG) expression in the surface IgM+, IgD- murine B cell line, 38C-13, which has previously been found to undergo kappa light chain replacement. We find that 38C-13 cells undergo spontaneous secondary Vkappa-Jkappa and RS rearrangements in culture, with recombination occurring on both productive and nonproductive alleles. Both 38C-13 cells and the Id-negative variants express the RAG genes, indicating that the presence of RAG does not depend on activation via the 38C-13 BCR. Moreover, BCR cross-linking in 38C-13 cells leads to a rapid and reversible down-regulation of RAG2 mRNA. Therefore, 38C-13 cells resemble peripheral IgM+, IgD- B cells undergoing light chain gene rearrangement and provide a possible in vitro model for studying peripheral V(D)J recombination.

Isolation of tumor-derived immunoglobulin-idiotype from peripheral blood mononuclear cells in a B-cell lymphoma patient with minimal disease

Active immunization with autologous idiotypic immunoglobulin, obtained by somatic fusion techniques, has been shown to be a useful alternative treatment in patients with B-cell lymphoma. Nevertheless, the requirement for biopsy specimens to obtain lymphoma cells could be a limitation to this therapeutic strategy. We address the question of whether peripheral blood samples containing small amounts of tumor cells can be used as appropriate fusion partners to rescue tumor-derived idiotypic proteins. In this report, we show that hybrid cells can be obtained from somatic fusions of K6H6/B5 heterohybridoma with lymphoma cells obtained from both lymph node (LN) and peripheral blood mononuclear cells (PBMC) containing only minor amounts of tumor cells. Some hybrid cells obtained from LN or PBMC fusions present an immunoglobulin (Ig) heavy-chain gene rearrangement identical with that of the original tumor and secrete identical Ig protein containing the expected H and L chains.

Shared idiotypes in mesangial deposits in IgA nephropathy are not disease-specific

The antigenic specificity of the mesangial IgA in IgA nephropathy (IgAN) remains unknown. Because shared antigenic specificities may be reflected in the usage of shared idiotypes, we prepared five monoclonal anti-idiotypic antibodies (MoAbs) specific for the mesangial IgA eluted from the kidney of an IgAN patient. All five MoAbs reacted with the same idiotype, which proved to be of a public nature. Although the idiotype could be identified in the mesangial deposits of the majority of IgAN patients studied, it was not specific for the disease because it was also found in the glomerular deposits of other types of glomerulonephritis. The idiotype was also expressed in polyethylene glycol precipitates of sera and in pokeweed mitogen-induced plasma cells from both IgAN patients and healthy controls. The conclusion that no disease-specific idiotypes are present in the renal eluate was further supported by the failure to produce polyclonal anti-idiotypic antibodies by immunizing a rabbit with the eluted mesangial IgA. Our results support the concept that mesangial IgA deposits in IgAN are of a polyclonal nature.

Comparison of two different HPLC hydroxylapatite matrices for resolution of IgG idiotypes

High-performance liquid chromatography hydroxylapatite (HPHT) is a well-known matrix utilized to separate macromolecules by differential surface binding to phosphate or calcium sites on the matrix. HPHT columns are commercially available packed with a crystalline structure formed of angular particles conferring a relatively poor elastic resistance to the matrix. In the present paper, we compare a conventional HPHT column to a new ceramic-type hydroxylapatite, which consists of globular particles providing a more mechanically stable matrix. The two hydroxylapatite matrices were compared in the purification of monoclonal antibodies produced by a hybridoma secreting three different types of antibodies. The two HPHT columns were able to separate the three antibodies molecules with equivalent peak resolution, and immunoreactivity analysis identified the active idiotype. HPLC columns packed with the ceramic hydroxylapatite resin exhibited a higher mechanical resistance than the crystalline material allowing significantly higher flow rates.

Brain nicotinic receptors isolated by a monospecific antibody against a synthetic alpha-3 subunit receptor peptide compared to a monoclonal anti-idiotypic (to nicotine) antibody

Nicotinic cholinergic receptor proteins purified from rat brain by immunoaffinity chromatography were characterized using the anti-S3 polyclonal antibody vs. the anti-idiotypic monoclonal antibody 422F11 (generated against an antibody to nicotine). Anti-S3 IgG was purified to homogeneity; anti-S3-Sepharose 4B and 422F11-Sepharose 4B each depleted 3H-nicotine binding sites from brain. Nicotinic receptors isolated from both immunoaffinity columns showed major bands (silver-stained) at 55K and 70K. Using anti-S3 serum as probe, Western blots of nicotinic receptors isolated by the two immunoaffinity gels also showed major bands at 55 and 70K. However, Western blots of fresh brain extracts revealed a major band at 80K and minor bands at 55K and 70K. These results show similar nicotinic cholinergic receptor proteins isolated by the anti-S3 and 422F11 anti-idiotypic antibodies; 80K was dominant only when fresh brain extract was subjected to Western blotting without prior immunoaffinity purification.

Detection of in ovo derived idiotypic antibodies. I. A model for maternal-neonatal idiotype network studies

Idiotypic vaccines appear to have many advantages over conventional vaccines. Maternal Id or anti-Id that are passively transferred to the fetus or neonate could provide another avenue for vaccination. Based on this premise we have investigated the transmission of idiotypic antibodies from dam to embryo by inoculating laying hens and analyzing their egg yolks for the presence of Id, anti-Id, and anti-anti-Id. The Ag chosen for these studies was BSA. After isolation and concentration BSA Id titers were approximately 256,000. The presence of anti-Id antibody in yolk samples is characterized by the ability of anti-Id to inhibit BSA binding to Id. The anti-Id extracted from yolks inhibited BSA binding to Id by 7 to 53%. Not all of the anti-Id present in samples was binding to a paratope-associated Id because 11 to 16% of the fluoresceinated anti-Id bound to Id-coated beads in the presence of excess BSA. Because a portion of the anti-Id antibodies were internal images of the BSA Id, they should be able to mimic Ag. This idea was confirmed when anti-Id inoculated in hens caused the synthesis of antibodies that would bind BSA and could be detected in an ELISA. Binding of anti-anti-Id to BSA-coated wells could be inhibited by preincubation of anti-anti-Id with BSA in solution. The chicken model provides a novel system to investigate maternal-fetal and maternal-neonatal interactions in the idiotypic network and the cellular mechanisms involved in the ontogeny of the Id network in neonates.

Molecular characterization of a major autoantibody-associated cross-reactive idiotype in Sjogren's syndrome

Primary Sjogren's syndrome is an autoimmune disorder characterized by lymphocytic infiltration of the salivary and lacrimal glands, producing associated dry eyes (keratoconjunctivitis sicca), dry mouth, and intermittently swollen salivary glands. A high proportion of the infiltrating B lymphocytes express surface and cytoplasmic Ig bearing a kappa-L chain-associated CRI defined by reactivity with the murine mAb, 17.109. To determine the structural basis for CRI expression in this disease, we generated CRI+ lymphoblastoid cell lines and a cDNA library from lymphocytes extracted from Sjogren's syndrome patients' salivary gland biopsy specimens. Nucleic acid sequence analyses of the mRNA of one such 17.109-CRI+ lymphoblastoid cell line (NOV) reveals the expressed kappa light chain variable region gene (V kappa gene) to be homologous to Humkv325, a conserved V kappa gene used at relatively high frequency in certain B cell malignancies. In addition, synthetic oligonucleotides, corresponding to the first and third frameworks and the second complementarity determining region of the Humkv325 gene, were used to identify and isolate clones from a cDNA library generated from SS salivary gland lymphocytes. Clones annealing specifically with one or more of these oligonucleotide probes contained kappa light chain cDNA. The sequences corresponding to the variable region of two clones (Taykv320 and Taykv306) were homologous to Humkv325. The V kappa genes of four other cDNA clones (Taykv322, Taykv310, Taykv308, and Taykv312) most likely were generated somatically from the rearranged Humkv325 gene through a limited number of nucleic acid base substitutions. Our results suggest that the high frequency of 17.109-CRI expression in Sjogren's syndrome patients results from a multiclonal expansion of B cells using Humkv325, and that the expressed Humkv325 may undergo somatic diversification in an apparent Ag-driven response.

Quantitative analyses of immune network components

Polyclonal immune network antibodies were quantitated and characterized in a syngeneic BALB/c murine system. Immunizations of BALB/c antifluorescein mAb 9-40 conjugated to keyhole limpet hemocyanin, produced anti-Id (anti-9-40, 39 to 190 micrograms/ml) as well as anti-fluorescein (anti-Fl, 12 to 109 micrograms/ml). Separately, immunizations of polyclonal anti-9-40, developed significant anti-Fl serum levels in the secondary (2 degrees) response (50 to 270 micrograms/ml), which decreased in the 3 degrees response (50 to 180 micrograms/ml) and thereafter, although levels of 9-40 idiotypically related antibodies increased. Polyclonal 2 degrees anti-anti-9-40 exhibited variant anti-Fl active sites, was antigenically more cross-reactive than polyclonal 2 degrees anti-Fl, but did not exhibit affinity maturation for fluorescein relative to 1 degrees anti-anti-9-40. In addition, the 9-40 idiotype constituted a small (less than 1.0%) percent of the 2 degrees and 3 degrees anti-Fl (ab1) immune response. When viewed within the context of an antigenic system that possesses widely diverse idiotypy, continued introduction of polyclonal anti-Id appears eventually to: 1) induce polyclonal ab3 with quantitative expression of idiotypically related antibodies in preference to ab3 of ancestral (9-40) antigenic specificity, 2) relative to ab1, induce a 100-fold increase in the level of ab3 antibodies that have both ancestral idiotype and ancestral antigen reactivity, and 3) induce polyclonal ab3 antibodies with a measurably wider range of antigenic reactivities than those of polyclonal ab1. These quantitative data may reflect the natural state of an immune network in a diverse antigenic response.

Expression of a cross-reactive idiotope on naturally occurring murine antibodies against 3-fucosyllactosamine, levan, and dextran

We recently identified a cross-reactive Id (6C4) that is expressed on the H chain of many BALB/c mAb against the 3-fucosyllactosamine (3-FL) determinant, Gal(beta 1-4) (Fuc(alpha 1-3] GlcNAc-R. The VH segments of seven mAb that we recently sequenced are encoded by VH441, which also encodes VH segments of antibodies against galactan, levan, and dextran. To analyze the expression of the 6C4 Id on naturally occurring anti-carbohydrate antibodies, we isolated 6C4+ antibodies by affinity chromatography from pools of normal BALB/c serum. Approximately 20 to 30% of antibodies against 3-FL and levan, and all antibodies against dextran, were removed from the sera by passage over a column containing mAb 6C4. Absorption of the eluate with 3-FL beads removed anti-3-FL antibodies but not anti-dextran or anti-levan. The expression of a cross-reactive Id on naturally occurring antibodies against several carbohydrate Ag suggests that these antibodies may participate in an Id network. We also reported previously that BALB/c mice have naturally occurring anti-3-FL antibodies and respond well to immunization against this determinant, whereas C57BL/6 mice do neither. To examine the role of the Igh-C allotype in the regulation of the anti-3-FL response, we studied congenic strains of BALB/c and C57BL/6 mice. Both congenic strains produced anti-3-FL antibodies in response to immunization, but only C.B-20 mice exhibited naturally occurring antibodies. These data suggest that the naturally occurring and elicited antibody responses against 3-FL are differentially regulated.

Amino acid substitutions in VH CDR2 change the idiotype but not the antigen-binding of monoclonal antibodies to alpha(1----6)dextrans

An idiotype defined by mAb and polyclonal antibodies to 10.16.1, an anti-alpha(1----6) dextran was previously reported to be expressed on most BALB/c anti-alpha(1----6)dextrans with groove-type sites and to involved CDR3 and probably CDR2. By comparing amino acid sequences of VH and VL derived from cDNA of idiotype+ and idiotype- anti-alpha(1----6)dextran hybridoma proteins, an idiotope was assigned to VH CDR2. Substitution of phenylalanine for leucine at residue 52 in CDR2 coupled with amino acid changes at either residue 58 or residues 57 and 60 abolished expression of this idiotype without affecting Ag binding.

Production and characterization of monoclonal idiotypes and anti-idiotypes for small ligands

The procedures described in this chapter have enabled us to identify and characterize monoclonal antibodies and their respective anti-idiotypes. We have developed several different types of immunoassays which afford greater flexibility to the investigator, depending on the type of antibodies desired and the availability of labeled antigens. Use of the intrasplenic injection technique for the final booster immunization prior to the fusion protocol has enabled us to achieve more consistent results than the usual intravenous or intraperitoneal injection routes. Isoelectric focusing of tissue culture supernatant from monoclonal antibody-secreting clones can easily identify possible duplicate clones, and thereby reduces the amount of labor required for extensive characterization of a large number of clones. We have found that these techniques have enabled us to identify "sister clones" or redundancies in our collection of antiligand and anti-idiotype antibodies rapidly and accurately. These various techniques have allowed us to save much time, labor, and money in the search for specific antibodies with desired characteristics.

Analysis of T hybridomas prepared from a T cell clone with three specificities. Recognition of self + X and allo-H-2 determinants segregates from recognition of Mlsa determinants

To see k information on T cell recognition of Mlsa determinants, hybridomas were prepared from a well-characterized F23.2+ (V beta 8.2+) T cell clone specific for three different ligands, i.e., 1) Mlsa determinants, 2) fowl gamma-globulin (F gamma G) plus self-H-2 (H-2d), and 3) allo-H-2, e.g., H-2p, determinants. Fusion of the clone to the BW5147 thymoma line produced a triple-reactive T hybridoma which generated two types of spontaneous variants. One type of variant (type I) lost Mlsa reactivity but retained reactivity to both F gamma G/H-2d and allo-H-2p. These variants, which were generated at high frequency, stained strongly with a mAb, A1.57, with idiotypic specificity for the TCR molecules of the parental clone. The second type of variant (type II) reacted to Mlsa determinants but showed no reactivity to F gamma G/H-2d or to allo-H-2p. These variants failed to express the A1.57 idiotypic determinants of the parent clone, but were F23.2+ (V beta 8.2+); nonequilibrium pH gradient electrophoresis analysis suggested that these hybrids expressed a mixed TCR heterodimer composed of the parental clone beta-chain and the BW5147 alpha-chain. Three aspects of the data are very difficult to accommodate with the view that Mlsa, F gamma G, and allo-H-2 determinants are all recognized via a common TCR molecule: 1) the independent (and frequent) segregation of Mlsa reactivity from F gamma G/H-2d and allo-H-2p reactivity, 2) the retention of Mlsa reactivity by the type II variants despite loss of the parental clone alpha-chain, and 3) the loss of Mlsa reactivity by the type I variants despite high expression of the A1.57+ TcR molecules derived from the parental clone. The data support a model in which Mlsa determinants are recognized by a separate T cell structure, which we envisage as a monomorphic accessory molecule unrelated to the TCR. Since the type II hybridoma variants invariably retained quantitatively normal TcR expression, the triggering phase of anti-Mlsa responses appears to be TCR dependent. The model we favor is that anti-Mlsa/Mlsa interaction increases TCR binding with Ia epitopes to above the threshold required for cell triggering. A key feature of this model is that Mlsa and Ia determinants are recognized as separate structures rather than as a complex.

A human monoclonal anti-DNA antibody derived from a patient with polymyositis having the common lupus 16/6 idiotype

A human IgM monoclonal antibody (Pol-1, SA-1) was generated by the human hybridoma technique from the peripheral blood lymphocytes (PBL) of a patient with active polymyositis. The antibody was found to bind to ssDNA, dsDNA, poly(I) and poly(G) and to carry the common lupus anti-DNA antibody idiotype (16/6 Id). Another human IgM monoclonal antibody (Pol-2, SA-2) produced by similar methods from the PBL of the same patient while in remission lacked the ligand-binding capacities of Pol-1 SA-1 and did not have the 16/6 Id. Analyses of 19 sera samples from patients with polymyositis showed no antinuclear antibodies, excluding a 40% prevalence of the 16/6 Id. The serum of the patient whose lymphocytes were employed to generate the hybridoma was negative for anti-DNA activity as well as for the 16/6 Id. This study suggests that the hybridoma technique may enable expression of dormant idiotypic affinities which do not normally appear in sera.

Idiotypic and subgroup analysis of human monoclonal rheumatoid factors. Implications for structural and genetic basis of autoantibodies in humans

Rheumatoid factors (RFs) in humans have been studied intensively because of their association with autoimmune and lymphoproliferative diseases. Many human IgM-RFs express cross-reactive idiotypes (CRIs) and have homologous light chains, some of which are encoded by a single V kappa gene, termed V kappa 325. However, although antibody activity generally requires the interaction between heavy and light chain variable regions, much less is known about structural relationships among RF heavy chains. To delineate further the structural and genetic basis of RF autoantibody synthesis, we generated "sequence-dependent" reagents specific for the human heavy and kappa light chain subgroups, and used them to analyze a panel of 27 monoclonal RFs. In addition, these proteins were tested for the expression of a heavy chain-associated CRI (G6), and a light chain-associated CRI (17.109). The results showed that most 17.109-reactive RFs contain heavy chains of the VHI subgroup, which bear the G6 idiotypic marker. However, among the 14 17.109-reactive RFs, two have heavy chains of the VHII subgroup, and another two contain heavy chains of the VHIII subgroup. Previously, we have shown that 17.109 is a phenotypic marker of the human V kappa 325 gene. Accordingly, these results demonstrate that the same human V kappa gene can combine with several VH genes from different VH gene subgroups to generate RF activity.

Incidence of three cross-reactive idiotypes on human rheumatoid factor paraproteins

The basis for rheumatoid factor (RF) production in autoimmune or lymphoproliferative diseases cannot be understood without defining the molecular factors that dictate RF structure and specificity. Recently three different mAb (6B6.6, 17.109, and G6) have been developed that define cross-reactive idiotypes (CRI) on intact L or H chains of human monoclonal RF cryoglobulins. However, the true incidence of these CRI among RF and their relationship to each other have not been delineated. In the present experiments, a panel of 163 randomly selected IgM paraproteins was evaluated for the expression of the two kappa L chain CRI, 6B6.6 and 17.109, and the H chain CRI, G6. Among the paraproteins with kappa L chains, 14% expressed the 17.109 CRI, and 9% expressed the 6B6.6 CRI. Both ELISA and Western immunoblotting experiments showed that the two L chain CRI were mutually exclusive. Anti-IgG activity was documented in 22 of the IgM-kappa paraproteins, among which mAb 6B6.6 reacted with 7 (32%) and mAb 17.109 with 6 (27%). Both CRI were expressed exclusively by L chains within the kappaIII variable gene subgroup. Although 17.109 CRI+ paraproteins had kappaIIIb L chains, none of the 6B6.6 CRI+ paraproteins possessed L chains with this kappa sub-subgroup specific Ag. The G6 CRI was found predominantly among RF paraproteins and was frequently yet not exclusively associated with the 17.109 CRI+ L chains. Additional experiments were performed on a panel of normal adult human sera and documented the presence of 6B6.6 and 17.109 CRI on a small percentage (0.1 to 2.0%) of IgM from most individuals. These data indicate that 1) the mAb 6B6.6 and 17.109 identify two major and distinct CRI among IgM-RF paraproteins, 2) both CRI are associated exclusively with kappaIII L chains, 3) kappaIIIb and kappaIII non-b L chains are equally prevalent among IgM-RF, 4) the G6 H chain CRI is frequently associated with 17.109 CRI+ L chains, but not with 6B6.6 CRI+ L chains, and 5) although the ability to make 6B6.6 and 17.109 CRI+ kappa L chains is common in humans, these CRI are present in low concentrations in normal IgM.

[An immunoenzyme test system for detecting adenovirus antibodies based on anti-idiotypic antibodies]

Anti-idiotypic antibodies simulating the cross-reacting antigenic determinants of adenoviral hexon has been obtained. On their basis the enzyme immunoassay system for the detection of specific antibodies to adenoviruses has been developed.

Isolation of anti-idiotypic antibodies to T cells using an anti-framework determinant antibody

A panel of anti-idiotypic antibodies to the T cell line HPB-ALL was produced by screening with a novel enzyme-linked immunoadsorption assay (ELISA). Using the beta framework I (beta F1) monoclonal antibody directed at a common determinant on the human T cell receptor beta subunit, we were able to specifically capture the receptor molecule from a cell lysate preparation and use this as the basis of an ELISA assay. Hybridoma supernatants were tested for their ability to bind to the receptor thus captured. A total of four antibodies were isolated by this method, and they were shown to immunoprecipitate a disulfide-linked heterodimer composed of alpha (49 kDa) and beta (40 kDa) subunits from HPB-ALL cells, similar to the subunits recognized by the beta F1 antibody. Furthermore, all four antibodies blocked the binding of T40/25, an anti-idiotype to HPB-ALL. Three of these antibodies blocked the binding of anti-Leu 4 to a similar degree as did T40/25, while one did not. This suggests that these new anti-idiotypic antibodies recognize distinct but associated idiotypic determinants. The isolation of such antibodies for any particular T cell line or tumor promises to be useful for biological studies of T cell malignancy in humans.

Studies on immunity in hybridoma-bearing mice. A. Immune response to antigens. II. inhibition of production of anti-dinitrophenyl antibodies in mice which have rejected the B 53 anti-dinitrophenyl-producing IgE hybridoma

When BALB/c mice, which had rejected the anti-dinitrophenyl (DNP) IgE-producing hybridoma B 53, were immunized with DNP proteins, they produced much less anti-DNP antibodies than control (normal) mice. The anti-DNP plaque-forming cell (PFC) number was much less when spleen cells from mice immunized with DNP proteins were treated with sera of mice which had rejected the hybridoma B 53 than the PFC number from the same spleen cells not treated by the sera. The sera of mice which had rejected the hybridoma B 53 contained an inhibitor which was adsorbed and eluted from an anti-mouse immunoglobulin column and also a mouse anti-DNP IgG2a column. The inhibition of PFC was hapten-reversible. In Western blotting the eluates from the anti-DNP IgG2a column reacted as well with the blotted anti-DNP IgE B 53 as an anti-idiotypic antibody to anti-DNP IgE B 53. These criteria establish that the inhibitor in the sera of the mice which had rejected the B 53 tumor was an anti-idiotypic antibody of the type which mimics the epitope (DNP) of the immunizing antigen.

Linkage of low and high affinity anti-fluorescein idiotype families

Data presented in this study describes the isolation and characterization of two anti-fluorescein (F1) hybridoma proteins 3-24 and 12-40, both IgG1, kappa with a Ka = 2.8 and 3.4 X 10(6) M-1, respectively, at 37 degrees C. These clones inhibited (6.8 +/- 2.8 -20.8 +/- 0.6% at 1 microgram/well) the idiotype-anti-idiotype interactions (IAII) of anti-F1 clones 3-13 and 3-17, which define a previously described low affinity idiotype family. Antibodies 3-24 and 12-40 also inhibited (45.0 +/- 3.0 and 61.3 +/- 5.6%, respectively, at 1 microgram/well) an IAII defined by a high affinity (Ka = 5.2 +/- 1.5 X 10(9) M-1 at 37 degrees C) anti-F1 clone, 4-4. Hybridoma proteins 3-13 and 3-17 possess similar affinities for F1 (Ka = 3.8 +/- 5.1 and 5.9 +/- 4.0 X 10(4) M-1) and are known to be idiotypically unrelated to clone 4-4. While 3-24 and 12-40 appeared very similar, non-identity of their active sites was established by heterologous idiotypic inhibitions, fine specificity of binding and spectral measurements (Qmax and lambda max) of bound F1. All IAII (3-13, 3-17, 9-40 and 4-4) were inhibited greater than 80% by the presence of 10(-4) M F1 or F1-BSA. In addition, four intermediate affinity (6.0 X 10(6) less than or equal to Ka less than or equal to 5.3 X 10(8) M-1) anti-F1 clones, comprising a second previously described idiotype family (designated the 9-40 family) were further analyzed. Inhibition of the 9-40 IAII by all heterologous proteins in the 9-40 family (except clone 5-27), and clones 3-24, 12-40 and 4-4 ranged from 87.7 +/- 1.3 to 95.4 +/- 1.0% at 1 microgram/well. Titration of the 9-40 IAII inhibition by antibodies 9-40, 3-24, 12-40 or 4-4 generated essentially superimposable profiles. In reciprocal inhibition experiments, using the 4-4 IAII, clones 3-24, 12-40, 9-40 and 4-4 gave distinct idiotypic titration patterns. Thus, members of the 9-40 family, 3-24 and 12-40 were more closely related to intermediate affinity clone 9-40 than high affinity clone 4-4.(ABSTRACT TRUNCATED AT 400 WORDS)

Expression of three cross-reactive idiotypes on rheumatoid factor autoantibodies from patients with autoimmune diseases and seropositive adults

Approximately one-half of human monoclonal IgM anti-IgG autoantibodies (rheumatoid factors (RF] from unrelated individuals with cryoglobulinemia coordinately express three cross-reactive idiotypic antigens (CRI). The CRI are detected with: 1) monoclonal antibody 17.109, which recognizes a conformation-dependent CRI on K-light chains; and 2) two rabbit anti-peptide antibodies that react with primary sequence-dependent CRI (PSL2 and PSL3) corresponding to the conserved second and third K-chain complementarity-determining regions, respectively. In the present experiments, the structural features of polyclonal RF autoantibodies from diverse patients with rheumatoid arthritis and from those with primary Sjögren's syndrome, and from seropositive elderly subjects without overt autoimmune diseases, were investigated with these three defined anti-CRI reagents. The pattern of expression of the CRI differed among patient groups. Only the RF autoantibodies from Sjögren's syndrome patients frequently displayed all three CRI. However, the RF from nearly every subject tested, including patients with rheumatoid arthritis, were enriched in the primary sequence-dependent PSL2-CRI as compared to RF-depleted Ig from the same subjects. Amino acid sequence analysis of monoclonal IgM-RF indicates that PSL2-CRI-positive light chains probably represent the products of a single Vk gene. Therefore, a proportion of the polyclonal RF from different autoimmune states may represent somatic variants of this germ-line RF Vk gene which retain the PSL2 sequence as a common element.

Influence of avidity and idiotope recognition on the modulation of surface immunoglobulin on malignant human B cells by rat monoclonal anti-idiotype antibodies

Immunoglobulin (Ig) was obtained from the tumor cells of patients with B cell malignancies by somatic cell hybridization to mouse-human heteromyeloma cells. The human Ig secreted by one of these hybridomas was used as an immunogen for the production of rat monoclonal antibodies (mAb). A panel of mAb specific for the idiotype (Id) was produced and characterized. Competitive binding studies that made use of [Se]-labeled anti-Id mAb (MAID) demonstrated several distinct yet topographically related Id on the Id-bearing Ig. These antibodies were shown to have avidities ranging from 0.38 to 45.3 X 10(8) l/mol. Additional studies demonstrated varying degrees of antigenic modulation of surface Id in vitro by MAID. The degree of modulation correlates with antibody avidity.

Rational design and application of idiotope vaccines

Current emphasis on risk factors associated with established vaccines and pressing needs for vaccines against certain viral transmitted diseases have stimulated the search for new conceptual and practical approaches to vaccine production. Among these developments, the idiotope vaccine method has produced promising results. In this review the basic and conceptual principles for idiotype vaccine design are discussed. A novel approach for identifying idiotopic structures in the three dimensional structure of internal idiotope antigens is developed. The method is based on the relationship of the immune response with the evolutionary variation and diversity of the immunoglobulin family. Idiotopic structures are found in specialized topographic regions on the surface of the immunoglobulin molecule. The knowledge of these idiotope domains will facilitate the synthesis of idiotope expressing peptides and the computer modeling of the three dimensional structure of internal idiotope antigens. Finally, the existing evidence for successful application of the idiotope vaccine method is summarized and new disease groups are identified which could benefit from the development of idiotope vaccines.

An idiotope expressed on a monoclonal antibody specific for human haemoglobin beta chain and naturally occurring immunoglobulin(s)

HId-1A (gamma 1:kappa), HId-2a (mu:kappa) and HId-4a (gamma 1:kappa) monoclonal anti-idiotopes of BALB/c origin were induced by the human haemoglobin-reactive, B10.D2-derived monoclonal antibody Hb-2d. HId-1a and HId-4a seem to react with the same idiotope and may, in fact, be encoded by the same V, D and J genes. HId-2a, on the other hand, seems to react with an idiotope different from that recognized by the other two anti-Id's and present in the sera of non-immune B10-H-2 congenic mice. HId-2a, but not HId-1a or HId-4a, may react with an idiotope in or near the antigen binding site of Hb-2d. Naturally occurring immunoglobulin carrying the HId-2a idiotope was affinity-purified from the pooled sera of B10-H-2 congenic mice and partially characterized. It possesses primarily the gamma 2b heavy chain, but small amounts of gamma 1, gamma 2a and mu heavy chains are also detectable. The kappa and lambda 1 light chains are both present in significant amounts. In addition, the affinity-purified immunoglobulin is unreactive with human haemoglobin, is not a rheumatoid factor and does not express in detectable amounts the idiotope recognized by HId-1a and HId-4a. It is possible that all or some part of this polyclonal reagent is specific for antigens normally present in the environment.

Idiotypic analysis of anti-I-Ak monoclonal antibodies. I. Production and characterization of syngeneic anti-idiotypic mAb against an anti-I-Ak mAb

To analyze the idiotype (Id) of anti-Ia antibodies elicited during alloimmune responses, we produced syngeneic mouse anti-Id monoclonal antibodies (mAb) reactive with the Id of the 11-5.2.1.9 (11-5) mouse anti-I-Ak (BALB/c anti-CKB) mAb. Two such anti-Id mAb, IA2 (IgG2a) and IIID1 (IgG1), detect structurally related idiotopes located within the binding site of 11-5 for I-Ak antigens. A third anti-Id mAb, VC6 (IgG1), detects an idiotope located either inside or outside of, but presumably proximal to, the 11-5 antigen-binding site, because its expression correlates with the antigenic specificity of 11-5. None of the idiotopes detectable by these three anti-Id mAb are accessible when the binding site of 11-5 is occupied by an I-Ak molecule. The association constants of these anti-Id mAb for their cognate Fab-linked Id range from 2 X 10(9) to 1 X 10(10) M-1. The three anti-Id-producing hybridomas were found with a frequency of 0.008% among growing hybrid colonies. Even though these anti-Id mAb detect public idiotopes (IdX) on 11-5, they do not detect the presence of such IdX markers in the sera of five syngeneic BALB/c mice hyperimmunized with C3H (I-Ak) spleen cells. This suggests that 11-5 represents a BALB/c idiotype infrequently expressed by serum immunoglobulins. The 11-5 idiotopes detectable by IA2, IIID1, and VC6 seem to be conformationally determined by the interaction of 11-5 H and L chains and are not confined to one or the other of these subunit polypeptides. Thus, the expression of the 11-5 Id may be regulated by both VH and VL genes.

Complete heavy and light chain variable region sequence of anti-arsonate monoclonal antibodies from BALB/c and A/J mice sharing the 36-60 idiotype are highly homologous

Structural and serologic studies on murine A/J monoclonal anti-arsonate antibodies resulted in the identification of a second idiotype family (Id36-60) in addition to the predominant idiotype family (IdCR). Id36-60, unlike IdCR, is a dominant idiotype in the BALB/c strain but is a "minor" idiotype in the A/J strain. The complete heavy and light chain variable region (VH and VL) amino acid sequences of a representative Id36-60 hybridoma protein from both the A/J and BALB/c strains have been determined. There are only four amino acid sequence differences between the VH of antibody 36-60 (A/J) and antibody 1210.7 (BALB/c). Two of these differences arise from single nucleotide changes in which the A/J and BALB/c Id36-60 VH germline gene sequences differ. The two other differences are the result of somatic mutation in hybridoma protein 36-60. In addition, Id36-60 heavy chains employ the same D and JH3 segments in both strains. The entire Vk2 VL of 36-60 and 1210.7 differ by only two amino acids, suggesting that like the heavy chains, they are derived from highly homologous VL genes. The same Jk segment is used in both antibodies. A comparison of the amino acid sequence data from Id36-60-bearing hybridomas suggests that a heavy chain amino acid difference accounts for the diminished arsonate binding by the 1210.7 hybridoma protein. Because the 1210.7 heavy chain is the unmutated product of the BALB/c VH gene, somatic mutation in VH may be required to enhance Ars affinity in this system.

Production of large quantities of human immunoglobulin in the ascites of athymic mice: implications for the development of anti-human idiotype monoclonal antibodies

Human-murine hybridomas, generated by fusion of human CLL cells with non-Ig-secreting murine myeloma NS-1, and secreting the IgM kappa expressed on the CLL cell surface, were grown in the peritoneal cavity of doubly pristane-primed nude mice to produce large quantities of highly concentrated human IgM kappa for the development of anti-idiotype monoclonal antibodies. Although the hybridomas secreted only 0.8 to 1.5 micrograms/ml/10(6) cells in tissue culture, they produced 8 to 12 ml of ascites from two mice containing 1.7 mg/ml of human IgM. Partial purification was then easily accomplished by euglobulin precipitation. Two weekly injections of 100 micrograms of this material into BALB/c mice resulted in the development of both anti-idiotypic and anti-human IgM antibodies. This system overcomes the major hurdle of generating sufficient quantities of the human idiotypic Ig to immunize and screen for specific murine antiidiotypes, and provides the material to produce these therapeutically promising reagents rapidly for clinical trials. This is, to our knowledge, the first report of a human Ig produced in mouse ascites.

Immunochemical characterization of factor VIII inhibitors

Factor VIII inhibitors are antibodies, predominantly of the IgG class, that inactivate factor VIII procoagulant activity. They do not fix complement and cannot be detected by standard immunoprecipitin assays. Their immunochemical properties are unusual, for the alloantibodies have consistent light chain restriction (kappa) and most allo- and auto- anti-VIII:C are predominantly or exclusively IgG4. This property may be responsible for the lack of complement fixation and immunoprecipitation. Human anti-VIII:C react with several different VIII:C antigenic determinants, and recent studies have begun to characterize the major epitopes. In addition, anti-VIII:C idiotypes have been identified using both rabbit anti-idiotype serum and monoclonal antibodies. These reagents provide a new way to obtain more precise immunochemical characterization.

A filtration double antibody radioimmunoassay that simplifies and semi-automates the isolation of immune precipitates

A semi-automation of fluid phase double antibody radioimmunoassay has been developed. The immune precipitate that was formed in 96-well microtitration plates was harvested and washed on microfibre filters using a Titertek cell harvester. A disc transfer system originally designed for use with the harvester was used as a quick and easy method of transferring the filter discs containing immune precipitate into vials for counting. The results of radioimmunoassay using the microtitration plate-filtration and conventional tube-centrifugation method are essentially identical. The microtitration plate-filtration radioimmunoassay has the following advantages over the conventional tube-centrifugation method: (1) there is no centrifugation required; (2) handling of microtitration plate is easier than the tubes in racks; and (3) it requires much less time to perform the assay.

Immunotypes of Chlamydia trachomatis isolates in Seattle, Washington

The immunotype distribution of 493 Chlamydia trachomatis isolates from 467 adults and 26 infants in the Seattle area from 1965 to 1982 is presented. All except one of the isolates from adults were from the genitourinary tract, rectum, or bubo. The proportions of each immunotype were ED, 46.5%; GF, 24.6%; H, I, J/CJ, and K, 5 to 7% each; B, 3.5%; and L2, 1%.

Isolation characterization and idiotype of Lewis rat antibodies against peptide 68-88 of guinea pig myelin basic protein

Antibodies against the 19 amino acid encephalitogenic peptide )residues 68-88) of guinea pig myelin basic protein (GPBP) were raised in Lewis (Le) rats. Anti-peptide antibodies were isolated from immune ascitic fluids by affinity chromatography using peptide 43-88-Sepharose 4B. The purified antibodies were characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and isoelectric focusing. Immunoglobulin class was determined by radioimmunoassay. Anti-idiotypic (anti-ID) antibodies were raised in a rabbit using purified anti-peptide antibodies from a single rat. The results of these experiments showed antibody heterogeneity both within an individual anti-peptide antiserum and between antisera from different rats. Antibody activity was found in IgG1, IgG2, and IgE immunoglobulin classes. Isoelectric focusing revealed multiple bands within a population of purified antibodies with significant pattern variation from one antiserum to another. Idiotypic characterization showed various levels of cross-reactive idiotypes present in some sera while these were absent in others.

[Discovery of a unique strain-specific idiotypic antigenic determinant of mouse T-lymphocyte antigen-recognizing receptors]

The cellular radioimmunoassay using rabbit anti-CBA-anti-C57BL/6 antiidiotypic serum was performed to detect a private strain-specific antigenic idiotypic determinant (s) on activated CBA-anti-C57BL/6 T cells. This private idiotype was not expressed on other activated T cells under study: CBA-anti-BALB/C; C3H-anti-C57BL/6; AKR-anti-C57BL/6; A/Sn-anti-C57BL/6; BALB/C-anti-C57BL/6; DBA/2-anti-C57BL/6. It is suggested that gene (s) coding the private strain-specific idiotypic antigenic determinant of the antigen-recognition receptor of T cells is not localized on the H-2 complex of mice.

Anti-idiotypes to monoclonal anti-H-2 antibodies. II. Expression of anti-H-2Kk idiotypes on antibodies induced by anti-idiotype or H-2Kk antigen

Anti-idiotypic antibodies were prepared against two monoclonal anti-H-2Kk antibodies, 11-4.1 and 3-83P. These reagents were used to examine idiotype (Id) expression on anti-H-2Kk antibodies induced by the in vivo administration of the anti-idiotypic antibodies and/or H-2Kk antigen. Treatment of BALB/c mice with anti-Id induced both antigen-binding and nonantigen-binding Id-positive molecules in the absence of antigen. The level of production of anti-Id-induced Id (Id') has been shown to be linked to VH genes using allotype congenic mice and backcross analyses. The idiotypes expressed on the Id' induced in anti-Id-treated mice were closely related or identical to those of the original monoclonal anti-H-2Kk antibody. However, the idiotopes were present on immunoglobulins of different subclasses and in some cases were not all expressed on the same molecules, as reflected by differences in their antigen specificities and isoelectric focusing patterns. In vivo administration of anti-Id had a marked influence on the subsequent humoral response to immunization with H-2 antigen.

Idiotype-anti-idiotype interactions and the control of the anti-beta (2 leads to 6) polyfructosan response in the mouse: specificity and idiotypy of anti-ABPC48 anti-idiotypic monoclonal antibodies

Seventeen hybridomas, secreting monoclonal anti-idiotypic antibodies (IDA) directed against the BALB/c ABPC48 idiotype, were isolated from one immunized BALB/c mouse. Several IDA also bind another Balb/c idiotype: UPC10. ABPC48 and UPC10 are both myeloma proteins with a beta (2 leads to 6)-polyfructosan (levan) specificity. The binding of every IDA to the ABPC48 idiotype can be completely inhibited by levan molecules, but at different concentrations. Mutual inhibition assays between the IDA made it possible to define six groups of IDA which bind at least three different idiotopes of ABPC48. Sixteen IDA have been studied by means of mouse anti-anti-idiotypic antibodies (Ab3) directed against two of them, IDA3 and IDA10. Anti-IDA3 Ab3 recognize idiotopes particular to IDA3 which are not found on other monoclonal anti-idiotypic antibodies (Ab2). Anti-IDA10 AB3 cross-reacts with several monoclonal Ab2, including Ab2 with different spectrotypes belonging or not to the same isotype and Ab2 with different specificities for the ABPC48 idiotype. Some IDA10 idiotopes are present in the polyclonal anti-ABPC48 antibody response of BALB/c, A/J and CBA mice showing that they are recurrent and that their expression is not linked to a particular Igh-C haplotype. In contrast, IDA3 idiotopes are not detected in the same anti-ABPC48 antisera.

Properties of a minor cross-reactive idiotype associated with anti-p-azophenylarsonate antibodies of A/J mice

Experiments are described that further characterize an A/J anti-phenylarsonate (anti-Ar) antibody population, which is idiotypically cross-reactive within the strain but differs from the family of antibodies expressing the major cross-reactive idiotype (CRI). This population has been designated as expressing a "minor" cross-reactive idiotype. Chain recombination studies with hybridoma products (HP) revealed that 2 of 3 HP expressing minor idiotypic determinants contain L chains that are idiotypically closely related to L chains in anti-Ar antibodies bearing the major CRI. The results indicate the expression of the same or very similar L chains in antibodies that differ in idiotype. The minor idiotypic population in serum was investigated by separating antibodies with minor and major idiotypic determinants by use of an immunoadsorbent containing anti-idiotype directed to an HP expressing the major CRI. Studies with the nonadherent, minor idiotypic population showed that such molecules constitute about 8 to 10% of the anti-Ar antibodies in a pool of serum but that individual sera vary markedly in their content of anti-Ar antibodies bearing minor idiotypes. Preinoculation of mice with conventional anti-idiotypic antiserum before immunization with KLH-Ar was found to suppress the appearance of the minor idiotypes as well as the major CRI upon subsequent immunization. The suppression of the minor idiotypic population is presumably mediated by the small fraction of rabbit anti-id antibodies directed against such molecules.

Suppression of the benzylpenicilloyl- (BPO) specific IgE formation with isologous anti-idiotypic antibodies in BALB/c mice

In vivo effects of actively produced or passively administered isologous anti-idiotypic antisera (aId) on the benzylpenicilloyl- (BPO) specific IgE and IgG formation in BALB/c mice have been studied. Isologous anti-BPO aId were raised in BALB/c mice by immunization with purified anti-BPO antibodies isolated from ascites induced with BPO-bovine gamma-globulin in the same mouse strain. Mice producing isologous anti-BPO aId exhibited long-term suppression of BPO-specific IgE and IgG antibody responses induced by BPO-ovalbumin (BPO-OVA) in aluminum hydroxide. Simultaneously, they produced increased amounts of anti-BPO aId after each challenge with the BPO-OVA antigens. Passive administration of isologous anti-BPO aId into syngeneic mice previously sensitized with BPO-OVA caused depression of BPO-specific IgE antibody levels for 2 to 3 weeks. When anti-BPO IgE had again reached its previous level, passively administered aId had decreased to the level of untreated mice. Passive administration of anti-BPO aId also depressed the primary anti-BPO IgE formation for 2 to 3 weeks. In all these experiments the IgE antibody formation against the carrier proteins used for BPO-antigens was not affected. These results show that IgE and IgG antibodies share major idiotypic determinants and that IgE production is accessible to regulation by aId.

Cross-idiotypic antigens among monoclonal immunoglobulin M from patients with Waldenström's macroglobulinemia and polyneuropathy

The monoclonal immunoglobulin (Ig)M from 5 to 16 patients with Waldenström's macroglobulinemia and a polyneuropathy shared cross-idiotypic antigenic determinants as demonstrated by hemagglutination and hemagglutination inhibition experiments as well as by precipitin reactions. This reactivity was located to the Fab (and not Fc) fragment of the protein. The IgM from 73 patients with macroglobulinemia but without neuropathy all gave negative reactions. In contrast, the monoclonal IgG from a patient with polyneuropathy also possessed similar idiotypic determinants. Since cross-idiotypic determinants are usually related to the combining site of a monoclonal Ig, this finding suggests that the monoclonal Ig of these patients may mediate the nerve injury via their antibody activity, which could be directed either to a nerve antigen or to some component involved in the pathogenesis of the neuropathy.

Idiotypic analysis of anti-GAT antibodies. I. Presence of common idiotypic specificities in both responder and nonresponder mice

The synthetic terpolymer of L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT) induced anti-GAT antibodies in D1.LP mice. Some of these antibodies shared common idiotypic specificities. The interaction between idiotypic antibody and anti-idiotypic antiserum was specifically inhibited by GAT and the closely related polymer of L-glutamic acid and L-tyrosine (GT) but not by the copolymer of L-glutamic acid and L-alanine (GA). The binding of labeled GAT by the anti-GAT antibodies was also specifically inhibited by the anti-idiotypic antiserum. These results indicated a close association of idiotypic determinants with the antibody-combining sites. Furthermore, such active site-related common idiotypic specificities were found in individual sera of both responder mice (D1.LP) and nonresponder mice (DBA/1) immunized with GAT and GAT-MBSA, respectively, indicating that both responder and nonresponder mice carry B cells with common clonotypes.