Anti-idiotypic mAb Research Articles

Overview of the clinical efficacy of investigational anticancer drugs.

The purpose of this overview was to make a broad inventory of investigational drugs for medicinal cancer treatment and, specifically, to indicate the evidence of clinical efficacy. Information was retrieved from electronic database searches in Medline and CANCERLIT and relevant published reviews. As the most recent findings are first reported as conference abstracts, an important basis for identification of new drugs and clinical results was a hand search of 13,392 abstracts from five major recent cancer conferences. A total of 209 investigational approaches or drugs were identified and classified into one of eight groups according to proposed mechanism of action. For 28 drugs/approaches survival data were available from randomized controlled trials. Statistically significant benefit was observed for only 12. In earlier phases no or modest anticancer activity was reported. It is speculated that the expanding knowledge in tumour biology might not easily translate into new substantially better anticancer drugs.

The production and characterisation of a chimaeric human IgE antibody, recognising the major mite allergen Der p 1, and its chimaeric human IgG1 anti-idiotype

Background: Two mouse monoclonal antibodies have been described, namely: mAb 2C7 (IgG2bκ), which is directed against the major house dust mite allergen Der p 1, and mAb 2G10 (IgG1κ), which...

Assessment of safety and the immune response to the CD4 "internal antigen" mouse anti-idiotypic Mab 16D7 in four patients with SLE.

We have analyzed the immune response elicited with the human CD4 internal antigen anti-idiotypic monoclonal antibody 16D7 in four patients with active systemic lupus erythematosus and assessed the safety of the treatment. Patients I and 2 received three 2-mg 16D7 subcutaneous (SC) injections at 3-week intervals and mainly developed IgGI, whereas IgG1, IgG3, and IgG4 were detected in the sera of the other two patients (3 and 4) who received the same amount of 16D7 on days 0, 28, and 70. 16D7-F(ab')2 isotypic determinant-specific antibodies levels, evaluated by sera reactivity with the 16D7-isotype matched anti-idiotypic monoclonal antibody 14D6-F(ab')2, were low or undetectable in patient 1 and became detectable following the first and second boosters in patient 3 and patients 2 and 4, respectively. The highest level was seen in patients 3 and 4. The focusing pattern (spectrotype) of 16D7 idiotypic-specific antibodies suggested that multiple V genes are involved or many somatic mutations occur. Once established, each patient's spectrotype remained stable. Although spectrotype were individually distinct, all four patients produced CD4-specific antibodies, indicating that this response crosses the genetic barrier. Disease relapsed after 11 (patient 2), 40 (patients 3 and 4), and 125 (patient 1) weeks. The lack of side effects and the prolonged periods of disease control (33 and 103 weeks after the last booster) warrants an extension of this study.

Immunogenetic analysis of variable regions encoding AB1 and gamma-type AB2 antibodies from the NeuGc-containing ganglioside family.

The variable regions from P3, a murine monoclonal antibody (MAb) against NeuGc-containing gangliosides, and two anti-idiotype MAbs directed to P3 MAb were cloned and sequenced. Comparisons with previously reported sequences showed that P3 is a germline antibody encoded by genes from the V(H)Q52 and V(kappa)19 families. Analysis of nucleotides at the heavy chain CDR3 (H-CDR3) showed the presence of an extensive 3' N region that contains almost 50% of the nucleotides of this CDR. In addition, amino acid sequence analysis of the H-CDRs of this MAb revealed the presence of three arginines, two of which are present in the H-CDR3, that could be involved in the interaction of P3 MAb with its electronegative epitope on gangliosides. Anti-idiotype 1E10, which seems to define a "regulatory" idiotope on P3 MAb (it induces Id+ Ab3), represents a germline Ab2 that belongs to the V(H)J558 and V(kappa)10 gene families. By contrary, the anti-idiotype 3B11 is an extensively mutated antibody that belongs to the V(H)3660 and V(kappa)4/5 gene families, defining a "private" idiotope on P3 MAb. Even when different V genes contribute to the variable regions of 1E10 and 3B11 MAbs, they share an acidic motif E/D-D-Y/D-Y-D in H-CDR3, suggesting that both Ab2s recognize paratope positive residues on the Ab1. Therefore, complementary electrostatic interactions involving H-CDR3 from both Ab1 and Ab2, might provide a clue to understand the molecular basis for the generation of gamma-type anti-idiotype antibodies to V regions recognizing glycolylated ganglioside antigens.

Prediction of the interacting surfaces in a trimolecular complex formed between the major dust mite allergen Der p 1, a mouse monoclonal anti-Der p 1 antibody, and its anti-idiotype

Background—Two mouse monoclonal antibodies (mAbs) have been described recently; namely, mAb 2C7 (IgG2bκ), which is directed against the major house dust mite allergen Der p 1, and mAb 2G10 (IgG1κ),...

Novel cross-reactive anti-idiotype antibodies with properties close to the human intravenous immunoglobulin (IVIg).

The most important link between the immune network theory and clinically useful therapies so far is the use of human intravenous immunoglobulin (IVIg) in the treatment of autoimmune diseases. Although still controversial, one of the main mechanisms that has been postulated for the in vivo effects of IVIg, is the selection of immune repertoires through idiotypic interactions. We describe here anti-idiotype IgG monoclonal antibodies (MAbs), which were obtained by immunization of syngeneic mice (Balb/c) with an anti-ganglioside antibody. These anti-idiotype MAbs show multiple idiotypic connections and share some of the properties of the IVIg pool. The antiidiotype (Ab2) MAbs B7 and 34B7 showed heterogeneous binding with the idiotypes of several anti-ganglioside antibodies, MAbs obtained from splenocytes of nonimmunized newborn mice, F(ab')2 fragments of IgG human myeloma proteins, and nonimmunoglobulin antigens. The recognition pattern of the B7 MAb to the idiotypes of human immunoglobulins was also studied using a phage display library obtained from the variable region genes of an asymptomatic AIDS patient and also F(ab')2 fragments obtained from an IVIg pool of healthy human donors. We also demonstrated that these MAbs produced some of the in vitro effects reported for the human IVIg pool, such as the inhibition of cell proliferation of human B and T cell lines and of normal human lymphocytes activated with different mitogens. Another striking property of the MAb B7 was its ability to induce a dose-dependent specific antibody T-cell response in vivo in syngeneic mice. Both anti-idiotype MAbs showed anti-metastatic effect in vivo when injected intravenously to mice inoculated with MB16-F10 melanoma cells. The antimetastatic effect of the antiidiotype MAbs was not observed in athymic mice inoculated with the same tumor. This kind of antibody can become an interesting tool for further exploration of the role of idiotypic network connections in the regulation of the immune system and to study the effects of interventions on network connectivity in experimental autoimmune disease, using a reagent better chemically defined than the IVIg pool.

CELL-MEDIATED DELIVERY OF PROGRAMMED CELL DEATH SIGNALS FOLLOWING GENE TRANSFER OF A MEMBRANE-ANCHORED SINGLE-CHAIN ANTIBODY SPECIFIC FOR CLASS I MHC

821 Introduction. Gene transfer of death signaling molecules has not been reliably successful in protecting allogenic cellular and tissue transplants from immune rejection. We describe the use of a membrane anchored, single-chain antibody (5H7Fv-GPI) that delivers human lymphoid programmed cell death (PCD) signals by ligation of class I MHC. 5H7Fv-GPI is derived from 5H7, a mAb specific for the α3 domain of class I MHC that induces veto-like PCD signals in human lymphoid cells. Derivation of a single-chain version of 5H7 provides a means for achieving cell surface expression of the 5H7 idiotype on cells that lack the machinery to properly assemble whole mAb. Methods. Chinese Hamster Ovary (CHO) cells were stably transfected with pC5H7Fv-GPI (5H7Fv coupled to CD58-derived glycosylphosphotidylinostitol (GPI)). Lymphoid PCD was assessed by co-culture of CHO-v5 (pC5H7Fv-GPI transfected) or CHO-neo (control vector pCDNA 3.1 transfected) cells with lymphoid targets. Competitive release of target cells from CHO cells was achieved by addition of A2.4, an anti-idiotypic mAb specific for the 5H7 idiotype. PCD morphology was determined by fluorescence microscopy following ethidium bromide/acridine orange staining and confirmed by Annexin V-FITC flow cytometric measurements. Results. CHO-v5 cells actively bound recombinant-derived soluble class I MHC, as determined flow cytometry. CHO-v5 cells induced PCD in Jurkat and BeVD lymphoid tumor cell lines, but not in control Daudi cells (class I MHC deficient). Jurkat cell PCD is not observed with use of whole 5H7 mAb, suggesting that 5H7Fv-GPI provides a modified or augmented PCD signal, when compared to parental mAb. Observations from several studies indicate that 5H7Fv-GPI delivers PCD signal with a potency comparable to that of the parental 5H7 mAb. Human PBMC were also susceptible to class I MHC-induced PCD following exposure to CHO-v5 cells. Preactivation of PBMC with immobilized anti-CD28 and anti-CD3 mAbs augmented PCD after co-culture with CHO-v5, a finding similar to that observed with the 5H7 mAb. The specificity of class I MHC signalling was addressed by the addition of excess A2.4 mAb, which reduced lymphoid PCD to background levels. Splenocytes derived from B6 mice transgenic for class I HLA-B27 also underwent PCD after coculture with CHO-v5, while splenocytes from transgene negative littermates did not show PCD. Thus, the inability of CHO-v5 to induce PCD in Daudi cells, B6 non-transgenic mice splenocytes, and the inhibition of PCD by A2.4 mAb confirm that CHO-v5 mediates PCD via class I MHC. Conclusions. 1) Cell surface expression of the 5H7Fv-GPI gene reconstitutes the 5H7 idiotype and retains ability to bind to class I MHC. 2) 5H7Fv-GPI PCD induces PCD in lymphoid cells that express class I MHC 3) Gene transfer of 5H7Fv-GPI provides a promising approach for modulating immune responses to human allografts.

Molecular Mimicry by Antiidiotypic Monoclonal Antibody to Gonadotropin Releasing Hormone

Antipeptide and antiidiotypic antibodies to several receptors are known to mimic their respective ligands in transducing signals on binding their receptors. In our attempts to study gonadotropin releasing hormone receptor, antipeptide and antiidiotypic monoclonal antibodies specific to the receptor were established earlier. The antipeptide mAb F1G4 was to a synthetic peptide corresponding to the extracellular domain of human GnRH receptor and the antiidiotypic mAb 4D10C1 was to the idiotype of a GnRH specific mAb. Here we report the physiological effects of the two mAbs on binding the receptor, as investigated using in vitro cultures of (a) human term placental villi and (b) rat pituitaries. The mAb 4D10C1 exerted a dose-dependent release of human chorionic gonadotropin in cultures of human term placental villi as well as luteinising and follicle stimulating hormones in cultures of rat pituitaries.

HLA (A*0201) Mimicry by Anti-Idiotypic Monoclonal Antibodies

Soluble MHC Ags and anti-Id (anti-anti-MHC) Abs have both been shown to inhibit MHC alloantigen-specific B cell responses in vivo. We hypothesized that some anti-idiotypic Abs function as divalent molecular mimics of soluble HLA alloantigen. To test this idea, we studied two well-defined anti-idiotypic mAbs, T10-505 and T10-938, elicited in syngeneic BALB/c mice by immunization with CRll-351, an HLA-A2,24,28-specific mAb. Each anti-Id induced "Ab-3" Abs in rabbits that cross-reacted with HLA-A2 but not with HLA-B Ags. Furthermore, each anti-Id could bind to and block Ag recognition by Ha5C2.A2, a human homologue of mAb CRll-351. Both anti-Id mAb displayed weak reactivity with the human mAb SN66E3, which recognized an overlapping but distinct determinant of HLA-A2 Ags; neither reacted with human mAb MBW1, which recognized a nonoverlapping HLA-A2 determinant. Amino acid sequence comparison of mAb CRII-351 heavy and light chain variable region complementarity-determining regions (CDRs) with those of mAb Ha5C2.A2 and SN66E3 revealed short regions of homology with both human mAb; a large insert in the light chain CDR1 of mAb SN66E3 distinguished it from both CRll-351 and Ha5C2.A2. The amino acid sequences of mAb T10-505 and T10-938, which differed markedly from each other, revealed no homology to the alpha2 domain sequence of HLA-A*0201 that contains the CRll-351 mAb-defined epitope. We conclude that structurally different anti-Id Abs can mimic a polymorphic conformational epitope of an HLA Ag. In the case of T10-505 and T10-938 mimicry was not based on exact replication of the epitope by the hypervariable loops of the anti-Id mAb.

Improved tumor targeting of rhenium-186-labeled anti-human high-m.w. melanoma-associated antigen monoclonal antibody 763.74 following purification with anti-idiotypic monoclonal antibody MK2-23.

Because of its high-energy beta emissions and imageable gamma emissions, 186Re represents an attractive isotope to radiolabel monoclonal antibodies (MAbs) recognizing human tumor-associated antigens (TAAs) for radioimmunoscintigraphy (RIS) and radioimmunotherapy (RIT) of patients with malignant diseases. Application of 186Re, however, is hindered by the frequent denaturation of MAbs following exposure to the strong reducing conditions employed in the labeling procedures. To overcome this problem, we have utilized a direct labeling procedure and combined it with affinity chromatography over columns of immobilized anti-idiotypic (anti-id) MAbs which recognize idiotopes in the antigen-combining site of the radiolabeled MAb. The validity of the procedure was demonstrated with the anti-high-m.w. melanoma-associated antigen (HMW-MAA) MAb 763.74 and its corresponding anti-id MAb MK2-23. Utilizing this approach, MAb 763.74 was labeled to specific activities of 2.8 +/- 0.6 mCi/mg with 186Re. Furthermore, its immunoreactivity, which was reduced to about 30% following labeling with 186Re, was improved to about 50% by affinity chromatography over columns of anti-id MAb MK2-23. The improvement in immunoreactivity of 186Re MAb 763.74 resulted in a significant (p < 0.05) increase in targeting to human melanoma tumors grown in nude mice and an increase in sensitivity of RIS. Our results suggest that direct labeling of anti-TAA MAb with 186Re coupled with purification over affinity columns of anti-id MAb may facilitate the application of 186Re to RIS and RIT.

Isolation of single chain antibody fragments with specificity for cell surface antigens by phage display utilizing internal image anti-idiotypic antibodies

Recombinant single chain antibody fragments (scFv) with specificity for membrane-bound antigens can be isolated by phage display techniques. The strategy involves selection of recombinant phage antibodies by binding to cells expressing the respective antigen. This results frequently in high nonspecific adherence of phages to cellular membranes. To resolve the problem we have made use of an internal image anti-idiotypic antibody mimicking the membrane-bound CD30 antigen and successfully isolated scFv fragments with specificity for CD30. The cDNA coding for the immunoglobulin heavy and light chain variable regions of the anti-CD30 monoclonal antibody (mAb) HRS3 was expressed by phage display techniques. Recombinant HRS3-scFv phages were efficiently enriched by one cycle of panning on the internal image anti-idiotypic mAb 9G10. The isolated HRS3-scFv clone retained the binding specificity of the parental mAb HRS3 to the internal image anti-idiotypic mAb 9G10 as well as to an anti-idiotypic mAb without the internal image. Furthermore HRS3-scFv reacted with recombinant and cell-bound CD30 antigen, respectively. Binding of scFv fragments to anti-idiotypic mAbs will provide a versatile strategy for the efficient isolation of recombinant antibody fragments.

Monoclonal anti-idiotypic antibodies mimicking the immunodominant epitope of influenza virus haemagglutinin elicit biologically significant immune responses.

The MAb IIB4 recognizes an immunodominant epitope on influenza virus haemagglutinin (HA) which is shared by different strains of the human subtype H3. This epitope includes amino acids 198, 199 and 201, as determined by selection of IIB4 escape mutants, and is involved in haemagglutination-inhibition (HI) and virus-neutralization (VN). We have developed anti-idiotypic MAbs (Ab2) that mimic the IIB4 epitope. Two Ab2, 78 and 464, completely inhibited binding of MAb IIB4 to the virus. Nucleotide sequences of VL- and VH-encoding regions were determined for IIB4 and both Ab2. VH of IIB4 and 78 belong to the same IgG family (VII) and show high nucleotide identity (89%). Conversely, VH and VL sequences of both internal image-bearing Ab2 revealed lower degrees of identity (61 and 50%, respectively). Ab2 were used for syngeneic immunization to elicit polyclonal Ab3 responses. Like Ab1, Ab3 immunoprecipitated viral HA and displayed HI and VN activity. The different VN activity of anti-78 and anti-464 in vitro correlated with the affinities of their corresponding Ab2 to IIB4. In vivo immunization with either Ab2 protected 15-37% of mice against lethal influenza infection or delayed dying. In contrast to VN activity of Ab3 in vitro, there was no significant difference between the protection of mice induced by Ab2 78 and 464. We demonstrate, for the influenza model, that active immunization with a single influenza virus HA epitope in the form of its internal image leads to partial protection in vivo.

Anti-idiotype monoclonal antibodies against anti-microcystin antibody and their use in enzyme immunoassay

Microcystins (MCs), a group of heptapeptide hepatotoxins produced by cyanobacteria, are suspected as tumor-promoter contaminants of environmental water. We have previously developed an enzyme-linked immunosorbent assay (ELISA) for MCs based on an anti-MC MAb (MAb-mc). We describe here the production of anti-idiotype MAbs (MAb-ids) which react with MAb-mc and their use in a new ELISA for MCs. For the production of MAb-id, hybridoma cells were generated from mice immunized with MAb-mc. Two MAbs were selected for their ability to inhibit the binding of MAb-mc to microcystin-LR (MCLR)-bovine serum albumin conjugate in ELISA. The one with the higher inhibitory activity, designated Id7 (IgG 1, κ), was further characterized. ELISA and immunoprecipitation analysis revealed that Id7 specifically bound to MAb-mc but not to control IgG 1, and the binding was inhibited by free MCLR. Therefore, Id7 is a MAb-id to MAb-mc and potentially possesses the structural image of MCLR. To establish MAb-id based ELISA, Id7 was tested for use in three types of competitive ELISA for MCs. The best format enabled reliable measurements of MCLR in the range of 100–1000 pg/ml with a coefficient of variation of less than 3%. In addition, microcystin-RR and microcystin-YR, principal MCs found in environmental water, were cross-reacted well (67–111% of MCLR) in the ELISA although 6(Z)-MCLR, a minor component, was less reactive (7% of MCLR). A comparative study of the MAb-id based ELISA with previously established MAb-mc based ELISA revealed good correlation ( n=14, r=0.97) between the two methods for measurements of MCs content in freshwater samples. Thus, developed MAb-id based ELISA is an useful alternative for environmental monitoring of MCs.

Effects of a Hybrid Recombinant Human Alpha Interferon (A/D) on in vitro Cytotoxicity and in vivo Localization of Monoclonal Antibody L6-Cytosine Deaminase Conjugate in a Colon Cancer Model

L6 is an IgG2a murine monoclonal antibody which we have demonstrated binds well to HT29 human colon carcinoma cells by flow cytometry, whole cell ELISA, and mixed hemadsorption. In vitro cytotoxicity studies revealed that the monoclonal antibody L6-cytosine deaminase (L6-CD) immunoconjugate plus the nontoxic prodrug, 5-fluorocytosine (5-FC), is equivalent to 5-fluorouracil (5-FU) in its ability to kill HT29 cells. Human alpha-interferon (A/D) was able to enhance this cytotoxic effect. The I.C.50's revealed that very small amounts of L6-CD are needed for this cytotoxic effect (approximately, 5 pg/ml resulted in 50% viability). The limiting factor was the amount of 5-FC employed with L6-CD (3 microM yielded 50% cell viability). alpha-Interferon (A/D) lowered the requirement of 5-FC to 1 microM to achieve 50% cell lethality. In vivo biodistribution experiments indicated that 1 microgram of L6-CD is nonspecifically taken up by the liver and spleen and cleared rapidly from the blood. Significant localization of L6-CD to HT29 tumors occurred only when 99 micrograms of unlabeled L6-CD was added to 1 microgram of 125I-labeled immunoconjugate injected intravenously. Further augmentation of tumor/blood ratios without reduction in percent injected dose per gram of tumor was possible with the intravenous injection of 100 micrograms of anti-idiotypic monoclonal antibody 13B, 24 hours after L6-CD, which bound unreacted L6-CD and cleared it from the blood. The addition of 100,000 U of alpha-interferon (A/D) given intraperitoneally every day increased the clearance of L6-CD by the liver and spleen, but impaired tumor localization (percent injected dose per gram). These studies demonstrated that in vivo localization of the L6-CD conjugate to HT29 tumors could be optimized by injecting excess L6-CD followed by an equal amount of L6 anti-idiotype mAb 13B, 24 hours after L6-CD.

分子生物学的手法による先端的治療の展望 遺伝子治療と抗イディオタイプ抗体療法

As recent advances in the treatment of malignant melanoma, we described the experimental study of gene therapy and the clinical trials of anti-idiotypic monoclonal antibody. Firstly, IFN-β gene encapsulated liposome was used for vector in our study. Cultured human melanoma cell could produce IFN-β by transfection with human IFN-β gene in vitro. Moreover, growth inhibition of subcutaneously transplanted human melanoma cells was clearly shown by transfection with human IFN-β gene. These results suggest IFN-β is a promising candidate for gene therapy of melanoma. Secondly, we described the background of idiotype network and characterization of anti-idiotypic monoclonal antibody to anti-HMW-MAA mAb. Then we reviewed the clinical trials of anti-idiotypic mAb in the States. Finally, we summarized the frequency and the mechanism of HLA Class I down regulation in melanoma cells, since these results will give negative impact on the T-cell based immunotherapy.

Distinct Classes of Chaperoned IL-6 in Human Blood: Differential Immunological and Biological Availability

Transport of IL-6 in blood is fundamental to the biology of this cytokine. In the present study, IL-6 transport, immunological reactivity, and biological availability were investigated in blood from melanoma patients subjected to different active specific immunization regimens (an anti-idiotypic mAb immunization protocol (mAb-keyhole limpet hemocyanin (KLH)-Calmette-Guerin bacillus (BCG), an autologous anti-cancer vaccine protocol (AAAP), or both). Sera were subjected to Sephadex G-200 gel filtration chromatography, and the structure and biological activity of IL-6 complexes in the eluate fractions were probed using five IL-6 ELISAs and two bioassays. Sera from patients administered mAb-KLH+BCG followed by AAAP contained three distinct classes of IL-6 eluting at 30, 200, and 450 kDa, each with its characteristic ELISA reactivity and bioactivity: the 30- and 450-kDa complexes were bioactive in the B9 and Hep3B assays, but the 200-kDa complex was not. The 30- and 450-kDa IL-6 complexes were preferentially reactive in the 7IL6/5IL6 ELISA, the 200-kDa IL-6 complexes were preferentially reactive in the 4IL6/5IL6 ELISA, while the three commercial ELISAs (R&D, Endogen, and Genzyme) detected essentially only the 30-kDa IL-6. In contrast, 1) sera from AAAP patients contained biologically active 30- and 450-kDa IL-6 complexes, while 2) sera from mAb-KLH+BCG patients contained 200-kDa IL-6 complexes inactive in ex vivo bioassays. Both the 450- and 200-kDa complexes included soluble IL-6R, with the 200-kDa complexes additionally containing ligand-occupied anti-IL-6 and anti-soluble IL-6R IgG. The data indicate the existence of specific mechanisms that regulate the transport and function of IL-6 in vivo.

527 - Immunotherapy of advanced ovarian cancer with the anti-idiotypic antibody MAb ACA 125 — Results of a clinical phase IB study

527 - Immunotherapy of advanced ovarian cancer with the anti-idiotypic antibody MAb ACA 125 — Results of a clinical phase IB study

Titration calorimetry study of an anti-idiotypic antibody cascade in a human melanoma-associated antigen system

The thermodynamic parameters of interactions between six variants of the anti-idiotypic monoclonal antibody (mAb) CGP 60686 produced by the hybridoma MK 2–23 with an idiotypic mAb and five different anti-anti-idiotypic mAb were studied with high sensitivity titration calorimetry. CGP 60686 recognizes an epitope in the antigen-combining region of the human high-molecular-weight-melanoma-associated antigen (HMW-MAA)-specific mouse mAb CGP 76873 produced by the hybridoma 763.74. The five HMW-MAA-specific anti-anti-idiotypic mAbs GH 464, GH 518. GH 149, GH 386 and GH 586 were generated from mice immunization with mAb CGP 60686. All interactions between the anti-idiotypic mAb and the idiotypic mAb or the anti-anti-idiotypic mAb showed large exothermic binding enthalpies between −15 and −23 kcal/mol and binding affinities larger than 6 × 10 9 M −1. Four of the five anti-anti-idiotypic mAbs tested exhibited significantly higher binding enthalpies for the interaction with the anti-idiotypic than the idiotypic mAbs. Replacement of either the heavy or the light chain variable region of the anti-idiotypic mAbs with an unrelated variable region abolished the idiotype to anti-idiotype interaction. Thus, both the heavy and the light chain variable region of the anti-idiotypic mAbs are required for binding to the idiotype. The values of the binding enthalpy showed only small variations when binding of the idiotypic mAb CGP 76873 to four variants of the anti-idiotypic mAb CGP 60686 with different immunoglobulin constant regions, but identical variable regions were compared. Furthermore. Fab fragments of the idiotypic mAbs showed almost the same binding enthalpy per binding site as the whole IgG molecules. Immunoglobulin constant regions thus had little influence on the idiotype to anti-idiotype interactions. Taken together, the observed thermodynamic parameters suggest that the idiotype to anti-idiotype interactions studied here are enthalpy-driven processes with only minor entropic contributions. High sensitivity titration calorimetry was used to monitor protein-protein interactions within an anti-idiotypic antibody cascade. It was found that the direct measurement of the interaction enthalpy allowed a quantitative characterization of the binding processes studied.

Active specific immunotherapy with mouse anti-idiotypic (anti-id) mAb MK2???23

Active specific immunotherapy with mouse anti-idiotypic (anti-id) mAb MK2???23

Immunological responses to CA125 induced by the anti-idiotypic antibody MAb ACA125 — Results of a clinical phase Ib study

Immunological responses to CA125 induced by the anti-idiotypic antibody MAb ACA125 — Results of a clinical phase Ib study