Anti-idiotypic Antibodies Research Articles

Autoantibodies to Neuropeptides in the Different States of Opium Addiction

During the last years the addiction rate remains stable high. While the neurochemical drug effect remains unclear. To analyze the changes of the idiotypic (аАТ1) and anti-idiotypic (аАТ2) autoantibodies to the neuroproteins S100, MBP, GFAP, NGF on the different stages of opium addiction and to indicate prognosis criteria of their effect. 70 patients (only men, aged 22−38) with diagnosis opium addiction underwent examination. According to the results of testing, we detected the intoxication in 24 patients, withdrawal ― in 24, and 22 patients were at remission stage of 21−28 days. The control group included only healthy people (n=18). The survey was focused on the rate detection of the idiotypic and anti-idiotypic IgG class antibodies in relation to the rate of neural proteins (S100, MBP, GFAP, NGF) in the serum with the IEA. In patients with opium intoxication, we revealed statistical assurance in the rate of autoantibodies amount and their counterweights to the neural proteins rate between control and experimental groups. Only the rate of the аАТ2 protein significantly decreased relatively to the MBP. In patients with abstinence, the rate of аАТ1 to the MBP, GFAP (р≤0,05) increased. The rate of аАТ2 in relation to the GFAP and MBP also increased (р≤0,05), at the same time it decreased in relation to the S100 and NGF (р≤0,05). The autoantibodies amount at the remission stage corresponded to the amount at the intoxication stage. The comparative analysis of the patient groups with the different stages of opium addiction detected the identity criteria both in the intoxication and remission. We revealed statistical assurance in the rates of аАТ1 to MBP and аАТ2 to NGF in patients with intoxication and abstinence, and in the rates of аАТ1 to GFAP, MBP, and аАТ2 to GFAP (decreased in the remission) and to S100, MBP (increased in the remission) in patients with abstinence and at remission. Levels of idiotypic and anti-idiotypic antibodies to the neural proteins S100, MBP, GFAP, NGF (especially аАТ2 to MPB) could be used as diagnostic factor and for accessing different states of opium addiction.

New mAb therapies in multiple myeloma: interference with blood transfusion compatibility testing.

Immunotherapeutic strategies are emerging as novel therapeutic approaches in multiple myeloma, with several mAbs being in advanced stages of clinical development. Of these, CD38 targeting antibodies appear very promising. In trials with anti-CD38 mAb daratumumab, all patients demonstrated panreactivity in red blood cell (RBC) panel testing, complicating the selection of compatible RBCs for transfusion. This review provides an overview of the interferences and solutions to safely transfuse these patients. CD38 is weakly expressed on human erythrocytes. Since the first reports on the interference, different solutions have been reported, including the neutralization of anti-CD38 mAbs in plasma by sCD38 or antiidiotype antibodies, CD38 depletion of RBCs using dithiothreitol or cord blood test cells, and transfusion of extensively typed RBCs. All methods have (dis)advantages, and it depends on the facilities of the immunohematology laboratory what strategy to choose. As the selection of suitable RBC units can be seriously delayed, hospitals should have protocols to communicate this interference with patients, laboratories, and physicians in a timely manner. As CD38 antibodies may also have a role in the treatment of diseases beyond hematological malignancies, chances are high that health professionals will encounter this issue in the nearby future.

Standardization of the homogeneous mobility shift assay protocol for evaluation of anti-infliximab antibodies. Application of the method to Crohn’s disease patients treated with infliximab

BackgroundThe availability of a quantitative method to measure anti-infliximab (IFX) antibodies (ATI) would facilitate the implementation of therapeutic drug monitoring in clinical decision-making. Our aim was to standardize the homogeneous mobility shift assay (HMSA) used in the measure of ATI levels. MethodsIn this prospective longitudinal multicenter study, 50 IFX-treated Crohn’s disease (CD) patients were followed up for 54weeks. During this period 360 human serum samples were analysed. Monomeric ATI levels were measured by a quantitative HMSA-method using an anti-IFX calibrator. IFX trough levels measured by ELISA were correlated with ATI levels. ResultsUsing HMSA and a pure anti-idiotypic monoclonal antibody specific for IFX (anti-IFX calibrator), we measured the levels of monomeric ATI generated in Crohn’s disease patients treated with IFX. Anti-IFX calibrator allowed to quantify monomeric antibodies against IFX with a low limit of quantification (3nM). The threshold level of ATI in order to classify the immunogenicity of the patients was 10nM. We observed that 24% (12/50) of IFX-treated patients developed ATI (>10nM) during the observation period (54weeks). Serum concentration of ATI higher than 10nM dramatically increased the probability (OR=51.1; 95% CI: 20.4–128.0; p<0.0001) of presenting low levels of IFX (⩽1.5nM) in serum, as observed in some CD patients treated with standard doses of the drug. ConclusionsThe HMSA-method described here allows an accurate quantification of ATI concentration in international units (IU) and therefore it could be useful in the study of the relationship between ATI concentration, infliximab level and the clinical response to the drug.

Phenotypic modulation of porcine CD14+ monocytes, natural killer/natural killer T cells and CD8αβ+ T cell subsets by an antibody-derived killer peptide (KP)

An engineered killer peptide (KP) based on a recombinant anti-idiotypic antibody representing the functional image of a yeast killer toxin (KT) was demonstrated to mediate antimicrobial effects against fungi and viruses. KP binds to murine dendritic cells and macrophages and up-regulate co-receptor expression, thus sustaining CD4+ lymphocyte activation. No immunological data are available in domestic animals thus KP-induced immunomodulation was evaluated in porcine monocyte and lymphocyte subsets. PBMC from healthy adult pigs were stimulated with KP or a scramble peptide (SP), or kept unstimulated for 24, 48 and 72h, and subsequently analyzed by flow cytometry.In monocytes, KP induced a strong dose-dependent shift from a major fraction of CD172α+CD14+low cells to a predominant fraction of CD172α+CD14+high cells, known to sustain leukocyte activation/differentiation and inflammatory responses. The CD16+ cell percentages, specifically the CD3+CD16+ natural killer T (NKT) cell fraction and CD16 expression showed an intense and stable dose-dependent increase while the CD3−CD16+ NK cell fraction decreased. CD4+ and CD8+ T cells increased and CD8α and CD8β expression were up-regulated. CD8β+ cytotoxic T cells and CD16+ cells comparably increased. A marked stimulation of activated CD16+CD25+ and CD8β+CD25+ cells was observed at 24h.The increase of CD8α+ cells and CD8α expression were due to increased CD4+CD8α+ (memory T helper) cells, also showing a CD8α+high phenotype. Concomitantly, the CD4+CD8α- T helper lymphocyte fraction significantly decreased.Overall, KP induced a wide modulation of innate immune and T cells that can exert regulatory and cytotoxic functions, which are fundamental for an efficient Th1 response.

An innovative and highly drug-tolerant approach for detecting neutralizing antibodies directed to therapeutic antibodies.

Immunogenicity testing of biotherapeutic drugs is a regulatory requirement. Herein, we describe a drug-tolerant assay for detecting neutralizing antibodies against a therapeutic antibody. Excess target of the therapeutic antibody was incorporated into the detection step of an affinity capture elution assay. Signal generated from binding of antidrug antibody (ADA) to the therapeutic antibody was compared with signal from binding of ADA to the therapeutic antibody preincubated with its target. The results demonstrated that the target blocked binding of the therapeutic antibody to neutralizing monkey ADA and to two anti-idiotypic antibodies. This highly drug-tolerant novel approach enables the detection of neutralizing antibodies and allows for one basic assay format to achieve complete characterization of ADA responses.

Development of an ELISA using anti-idiotypic antibody for diagnosis of opisthorchiasis

Monoclonal antibody specific for an epitope of cretory-secretory antigen protein of Opisthorchis felineus (Rivolta, 1884) (Trematoda: Opisthorchiidae) with a molecular weight of 28 kDa was used in a sandwich enzyme-linked immunosorbent assay (ELISA) for immobilisation of liver fluke specific antigen to the solid phase. Examination of human sera by this ELISA compared with commercial assays demonstrated that the monoclonal antibody epitope is located within this significant parasite protein. Anti-idiotypic antibody specific for the paratope of this monoclonal antibody was obtained by a hybridoma technique. Mimicking an epitope of excretory-secretory antigen of O. felineus, it had the capacity to bind specific antibody and elicit an antibody response. The value of anti-idiotypic antibody as a substitute for the liver fluke antigen was tested by ELISA using serum samples of infected dogs. Anti-idiotypic antibody proved to be of value in both an indirect-ELISA and a competitive-ELISA for diagnosis of opisthorchiasis. Mature trematodes were isolated from all infected animals. The faecal egg counts were negative in dogs with a relatively small number of parasites, despite finding antibodies in serum by ELISA. Substitution of parasite antigen with anti-idiotype avoids the use of experimental animals and also reduces time-consuming steps of antigen preparation.

Optimized purification strategies for the elimination of non-specific products in the isolation of GAD65-specific monoclonal autoantibodies

Autoantibodies against antigens expressed by insulin-producing β cells are circulating in both healthy individuals and patients at risk of developing Type 1 diabetes. Recent studies suggest that another set of antibodies (anti-idiotypic antibodies) exists in this antibody/antigen interacting network to regulate auto-reactive responses. Anti-idiotypic antibodies may block the antigen-binding site of autoantibodies or inhibit autoantibody expression and secretion. The equilibrium between autoantibodies and anti-idiotypic antibodies plays a critical role in mediating or preventing autoimmunity. In order to investigate the molecular mechanisms underlying such a network in autoimmunity and potentially develop neutralizing reagents to prevent or treat Type 1 diabetes, we need to produce autoantibodies and autoantigens with high quality and purity. Herein, using GAD65/anti-GAD65 autoantibodies as a model system, we aimed to establish reliable approaches for the preparation of highly pure autoantibodies suitable for downstream investigation.

Optimized purification strategies for the elimination of non-specific products in the isolation of GAD65-specific monoclonal autoantibodies

Autoantibodies against antigens expressed by insulin-producing β cells are circulating in both healthy individuals and patients at risk of developing Type 1 diabetes. Recent studies suggest that another set of antibodies (anti-idiotypic antibodies) exists in this antibody/antigen interacting network to regulate auto-reactive responses. Anti-idiotypic antibodies may block the antigen-binding site of autoantibodies or inhibit autoantibody expression and secretion. The equilibrium between autoantibodies and anti-idiotypic antibodies plays a critical role in mediating or preventing autoimmunity. In order to investigate the molecular mechanisms underlying such a network in autoimmunity and potentially develop neutralizing reagents to prevent or treat Type 1 diabetes, we need to produce autoantibodies and autoantigens with high quality and purity. Herein, using GAD65/anti-GAD65 autoantibodies as a model system, we aimed to establish reliable approaches for the preparation of highly pure autoantibodies suitable for downstream investigation.

Anti-bevacizumab idiotype antibody vaccination is effective in inducing vascular endothelial growth factor-binding response, impairing tumor outgrowth.

Tumors require blood supply and, to overcome this restriction, induce angiogenesis. Vascular endothelial growth factor (VEGF) plays an important role in this process, which explains the great number of antiangiogenic therapies targeting VEGF. The research and development of targeted therapy has led to the approval of bevacizumab, a humanized anti‐VEGF monoclonal antibody (mAb), in clinical settings. However, side effects have been reported, usually as a consequence of bolus‐dose administration of the antibody. This limitation could be circumvented through the use of anti‐idiotype (Id) antibodies. In the present study, we evaluated the efficacy of an active VEGF‐binding immune response generated by an anti‐bevacizumab idiotype mAb, 10.D7. The 10.D7 anti‐Id mAb vaccination led to detectable levels of VEGF‐binding anti‐anti‐Id antibodies. In order to examine whether this humoral immune response could have implications for tumor development, 10.D7‐immunized mice were challenged with B16‐F10 tumor cells. Mice immunized with 10.D7 anti‐Id mAb revealed reduced tumor growth when compared to control groups. Histological analyses of tumor sections from 10.D7‐immunized mice showed increased necrotic areas, decreased CD31‐positive vascular density and reduced CD68‐positive cell infiltration. Our results encourage further therapeutic studies, particularly if one considers that the anti‐Id therapeutic vaccination maintains stable levels of VEGF‐binding antibodies, which might be useful in the control of tumor relapse.

MYH9 is an Essential Factor for Porcine Reproductive and Respiratory Syndrome Virus Infection.

Porcine reproductive and respiratory syndrome (PRRS) caused by the PRRS virus (PRRSV) is an important swine disease worldwide. PRRSV has a limited tropism for certain cells, which may at least in part be attributed to the expression of the necessary cellular molecules serving as the virus receptors or factors on host cells for virus binding or entry. However, these molecules conferring PRRSV infection have not been fully characterized. Here we show the identification of non-muscle myosin heavy chain 9 (MYH9) as an essential factor for PRRSV infection using the anti-idiotypic antibody specific to the PRRSV glycoprotein GP5. MYH9 physically interacts with the PRRSV GP5 protein via its C-terminal domain and confers susceptibility of cells to PRRSV infection. These findings indicate that MYH9 is an essential factor for PRRSV infection and provide new insights into PRRSV-host interactions and viral entry, potentially facilitating development of control strategies for this important swine disease.

Generation and Characterization of a Human/Mouse Chimeric GD2-Mimicking Anti-Idiotype Antibody Ganglidiximab for Active Immunotherapy against Neuroblastoma.

Vaccination with proteins mimicking GD2 that is highly expressed on neuroblastoma (NB) cells is a promising strategy in treatment of NB, a pediatric malignancy with poor prognosis. We previously showed efficacy of ganglidiomab in vivo, a murine anti-idiotype (anti-Id) IgG1. In order to tailor immune responses to variable regions, we generated a new human/mouse chimeric anti-Id antibody (Ab) ganglidiximab by replacing murine constant fragments with corresponding human IgG1 regions. DNA sequences encoding for variable regions of heavy (VH) and light chains (VL) were synthesized by RT-PCR from total RNA of ganglidiomab-producing hybridoma cells and further ligated into mammalian expression plasmids with coding sequences for constant regions of human IgG1 heavy and light chains, respectively. We established a stable production cell line using Chinese hamster ovarian (CHO) cells co-transfected with two expression plasmids driving the expression of either ganglidiximab heavy or light chain. After purification from supernatants, anti-idiotypic characteristics of ganglidiximab were demonstrated. Binding of ganglidiximab to anti-GD2 Abs of the 14.18 family as well as to NK-92tr cells expressing a GD2-specific chimeric antigen receptor (scFv(ch14.18)-zeta) was shown using standard ELISA and flow cytometry analysis, respectively. Ganglidiximab binding affinities to anti-GD2 Abs were further determined by surface plasmon resonance technique. Moreover, binding of anti-GD2 Abs to the nominal antigen GD2 as well as GD2-specific Ab-mediated cytotoxicity (ADCC, CDC) was competitively inhibited by ganglidiximab. Finally, ganglidiximab was successfully used as a protein vaccine in vivo to induce a GD2-specific humoral immune response. In summary, we report generation and characterization of a new human/mouse chimeric anti-Id Ab ganglidiximab for active immunotherapy against NB. This Ab may be useful to tailor immune responses to the paratope regions mimicking GD2 overexpressed in NB.

Development of a Novel, Anti-idiotypic Monoclonal Anti-prolactin Antibody That Mimics the Physiological Functions of Prolactin.

In this work, we prepared a panel of monoclonal anti-idiotypic antibodies to ovine prolactin (oPRL) by the hybridoma technique. Among these antibodies, one anti-idotypic antibody (designated B7) was chosen for further characterization by a series of experiments. We first demonstrated that B7 behaved as a typical Ab2β based on a series of enzyme-linked immunosorbent assays. Subsequently, the results of a competitive receptor-binding assay confirmed that B7 could specifically bind to the prolactin receptor (PRLR) expressed on target cells. Finally, we examined its biological activities in CHO-PRLR and Nb2 cells and observed that B7 could activate Janus kinase 2-signal transducer and activator of transcription signalling in CHO-PRLR and Nb2 cells and induce BaF3 proliferation. The present study suggests that i) B7 can serve as a PRLR agonist or PRL mimic and has potential applications in regulating mammary gland development, milk production and maintenance of lactation in domestic animals and ii) B7 may be a biological reagent that can be used to explore the mechanism of PRLR-mediated intracellular signalling.

Autologous Immunoglobulin Therapy in Patients With Severe Recalcitrant Atopic Dermatitis: Long-Term Changes of Clinical Severity and Laboratory Parameters.

This report evaluated long-term changes in clinical severity and laboratory parameters in 3 adult patients with severe recalcitrant atopic dermatitis (AD) who were treated with intramuscular injections of 50 mg of autologous immunoglobulin G (IgG) twice a week for 4 weeks (autologous immunoglobulin therapy, AIGT) and followed up for more than 2 years after the treatment. We observed the following 4 major findings in these 3 patients during the long-term follow-up after AIGT. (1) Two of the 3 patients showed a long-term clinical improvement for more than 36 weeks after AIGT with a maximum decrease in clinical severity score greater than 80% from baseline. (2) These 2 patients also showed long-term decreases in serum total IgE concentrations and peripheral blood eosinophil count for more than 36 weeks after AIGT with a maximum decrease in the two laboratory parameters of allergic inflammatory greater than 70% from baseline. (3) No significant side effect was observed during the 2 years of follow-up period after the AIGT in all 3 patients. (4) Serum levels of IgG anti-idiotype antibodies to the F(ab')2 fragment of autologous IgG administered for the treatment were not significantly changed after AIGT in all 3 patients. These findings suggest that AIGT has long-term favorable effects on both clinical severity and laboratory parameters in selected patients with severe recalcitrant AD. Further studies are required to evaluate the clinical usefulness and therapeutic mechanism of AIGT for AD.

Neutralisation of factor VIII inhibitors by anti-idiotypes isolated from phage-displayed libraries.

Following replacement therapy with coagulation factor VIII (FVIII), up to 30 % of haemophilia A patients develop FVIII-specific inhibitory antibodies (FVIII inhibitors). Immune tolerance induction (ITI) is not always successful, resulting in a need for alternative treatments for FVIII inhibitor-positive patients. As tolerance induction in the course of ITI appears to involve the formation of anti-idiotypes specific for anti-FVIII antibodies, such anti-idiotypes might be used to restore haemostasis in haemophilia A patients with FVIII inhibitors. We isolated anti-idiotypic antibody fragments (scFvs) binding to murine FVIII inhibitors 2-76 and 2-77 from phage-displayed libraries. FVIII inhibitor/anti-idiotype interactions were very specific as no cross-reactivity with other FVIII inhibitors or isotype controls was observed. ScFvs blocked binding of FVIII inhibitors to FVIII and neutralised their cognate inhibitors in vitro and a monoclonal mouse model. In addition, scFv JkH5 specific for FVIII inhibitor 2-76 stained 2-76-producing hybridoma cells. JkH5 residues R52 and Y226, located in complementary determining regions, were identified as crucial for the JkH5/2-76 interaction using JkH5 alanine mutants. SPR spectroscopy revealed that JkH5 interacts with FVIII inhibitor 2-76 with nanomolar affinity. Thus, FVIII inhibitor-specific, high-affinity anti-idiotypes can be isolated from phage-displayed libraries and neutralise their respective inhibitors. Furthermore, we show that anti-idiotypic scFvs might be utilised to specifically target inhibitor-specific B cells. Hence, a pool of anti-idiotypes could enable the reestablishment of haemostasis in the presence of FVIII inhibitors in patients or even allow the depletion of inhibitors by targeting inhibitor-specific B cell populations.

Anti-Idiotype Antibody against Pre-Membrane-Specific Antibody as an Adjunct to Current Dengue Vaccination Strategy

Anti-Idiotype Antibody against Pre-Membrane-Specific Antibody as an Adjunct to Current Dengue Vaccination Strategy

The Molecular Engineering of an Anti-Idiotypic Antibody for Pharmacokinetic Analysis of a Fully Human Anti-Infective.

Anti-idiotype monoclonal antibodies represent a class of reagents that are potentially optimal for analyzing the pharmacokinetics of fully human, anti-infective antibodies that have been developed as therapeutic candidates. This is particularly important where direct pathogen binding assays are complicated by requirements for biosafety level III or IV for pathogen handling. In this study, we describe the development of a recombinant, anti-idiotype monoclonal antibody termed E1 for the detection of a fully human, serotype-specific, therapeutic antibody candidate for the BSLIII pathogen Dengue virus termed 14c10 hG1. E1 was generated by naïve human Fab phage library panning technology and subsequently engineered as a monoclonal antibody. We show that E1 is highly specific for the fully-folded form of 14c10 hG1 and can be employed for the detection of this antibody in healthy human subjects’ serum by enzyme linked immunosorbent assay. In addition, we show that E1 is capable of blocking the binding of 14c10 hG1 to dengue virus serotype 1. Finally, we show that E1 can detect 14c10 hG1 in mouse serum after the administration of the therapeutic antibody in vivo. E1 represents an important new form of ancillary reagent that can be utilized in the clinical development of a therapeutic human antibody candidate.

Case-Control Pilot Study of the Immune Modulating Effect of FEIBA® on Patients with Haemophilia a and Inhibitors

Background: Immune tolerance therapy (ITT) is the only available therapy for eliminating the inhibitor in patients with haemophilia and high-responding inhibitors. However, it is a very expensive treatment with an efficacy of up to 60%-75%. Factors influencing the outcome of ITT are not completely understood. Some studies have suggested that plasma derived factor VIII (FVIII) concentrates might offer certain advantages in the elimination of the inhibitor when compared with recombinant derivatives. The presence of von Willebrand factor (Auerswald et al,Haematologica 2003;88:EREP05; Kreuz et al,Haematologica 2001;86:16-20) and some molecules with immunomodulatory effect like anti-idiotype antibodies, transforming growth factor-β, HLA type I molecules and soluble FAS ligand in plasma derived concentrates may be involved in such effect (Berntorp et al,Haemophilia 2001;7:109-13; Hodge et al,Br J Haematol 2001;115:376-81; Hodge et al, Haemophilia 2006;12:133-9; Ghio et al, Thromb Haemost 2003;89:365-73). The activated prothrombin complex concentrate (FEIBA®) is a plasma derived product used for bleeding control in patients with haemophilia A and high-responding inhibitors. We hypothesize that FEIBA® may have an immunomodulatory activity due to its plasmatic origin. This effect might be observed in patients with intense treatment with FEIBA® (e.g. prophylaxis treatment) by the reduction in levels of antibodies against FVIII compared with patients on demand treatment with this product.Objective: The aim of this study was to compare levels of inhibitors in patients with severe haemophilia A and inhibitors on demand or under prophylactic treatment with FEIBA®.Methods and results: This was a prospective, observational and multicenter study. A total of 12 adult patients with severe haemophilia A and high-responding inhibitors (6 patients on demand and 6 patients under prophylaxis treatment with FEIBA®) were included. All patients had normal levels of serum creatinine, serum alanine aminotransferase and CD4+ lymphocyte counts at inclusion. Levels of inhibitors were determined by Bethesda assay. Levels of inhibitors in patients on prophylaxis with FEIBA® were lower than those observed in patients on demand treatment but differences were not statistical significant. In most of the patients on prophylaxis, levels of inhibitors went down along the prophylaxis regimen.TableMedical history of patients.Patient NºAgeType of treatmentUsual dose (IU/kg)FrecuencyTiter (BU)Time frame with start of prophylaxis (months)**48010153Prophylaxis60Three times a week64*4.4804.1961.3250-1.348010258Prophylaxis55Three times a week5*3.3122.17-3.812-6.1150101UNKProphylaxis60Three times a week4*3.05-6.06-8.028010128Prophylaxis56Every other day109*7.3774.1101-8.3101-9.728010257On Demand56 x 8 dosesN/A174*N/A37N/A83N/A21N/A25N/A184N/A28010357On Demand55 x 6 dosesN/A8000*N/A64N/A5N/A21N/A28010458On Demand68 x 6 dosesN/A152*N/A28010523On Demand68 x 3 doses 40 x 6 dosesN/A30*N/A08010128On Demand50 x 5 dosesN/A5.2*N/A7.07.24.07.846010137Prophylaxis66every 48hNegative21,046010257On demand702 doses/ bleeding usually66.5*More than 20 years30000150Prophylaxis85Three times a week8*3*Titer at inclusion. **Positive values represent number of months after starting prophylaxis and negative values are referred to number of months before starting prophylaxis. For example, the patient number 480101 had 250 BU at 1.3 months before starting prophylaxis (in the table= -1.3 months) and 64 UB at month 4.4 after initiation of prophylaxis (in the table= 4.4 months). N/A: not applicable.Conclusion: Prophylaxis with FEIBA® might decrease levels of inhibitors in patients with severe haemophilia A and high-responding inhibitors. However, a broader study is needed to confirm this result. DisclosuresIruin:Baxalta: Research Funding. Bonanad:Baxalta: Research Funding. López Fernández:Baxalta: Research Funding. Altisent:Baxalta: Research Funding. García Candel:Baxalta: Research Funding. Rivas Pollmar:Baxalta: Research Funding. Canales:Baxalta: Research Funding.

A144: New laboratory marker of metastatic thyroid cancer

Existing methods for the preoperative detection of metastases in thyroid cancer have low efficiency and highly invasive. Therefore, the searches for laboratory markers that will indicate the presence of metastases including hidden with high reliability in cancer of the thyroid gland are relevant. Immune system is one of the key mechanisms for regulation of tissue proliferation. Autoreactive lymphocytes restrict the growth and proliferation of tissues. In turn autoreactive lymphocytes are controlled by idiotypic lymphocytes. Abnormalities in the regulation system can be the cause of tumor growth, such as excess activity of anti-idiotypic lymphocytes. Previously we conducted a comparative analysis of the level of autoantibodies to various antigens (thyroglobulin, thyroid stimulating hormone receptor, native DNA, anionic proteins vascular endothelium), as well as anti-idiotypic antibodies to thyroglobulin in thyroid cancer patients with metastases and without metastases. Significant differences between investigated groups were found in the level of anti-idiotypic antibodies against antibodies to thyroglobulin. Therefore, the aim of this study was to analyze the feasibility of using anti-idiotypic antibodies against antibodies to thyroglobulin as a marker of metastatic thyroid cancer. All studied patients with thyroid cancer were hospitalized at Primushko Regional Clinical Oncology Center of the Ministry of Health of the Udmurt Republic, Izhevsk. Blood was taken from patients before surgery. The level of anti-idiotype antibodies (AIAT) against autoantibodies to thyroglobulin (Tg) and the level of autoantibodies (AUAT) to thyroglobulin were determined in the blood plasma using the test system manufacturing MRC ”Immunkulus”. To determine the AIAT against AUAT to Tg, we used the principle of competitive inhibition of the binding reaction with antibodies to thyroglobulin in the presence of analyzed serum. As a source of antibodies to thyroglobulin, we used serum from patients with autoimmune thyroiditis in effective dilutions for competition. Analyzed samples were previously depleted by antibodies to thyroglobulin. The level of the test antibodies was expressed in conventional unit (CU) - optical density of the reaction of antibody binding to the antigen. We found that AIAT against AUAT to Tg were not defined in 43% of thyroid cancer patients with metastases (group I), 57% revealed a relatively high level of AIAT against AUAT to Tg – 0.343 ± 0.027 CU (Group II). In patients with thyroid cancer without metastases, the level of AIAT against AUAT to Tg (0.185 ± 0.083 CU) was lower than that of cancer patients with metastases. Metastatic cancer cannot be differentiated from cancer without metastases in 23% of studied cases. The level of AUAT to Tg in patients with thyroid cancer in the group I was 0.997 ± 0.084 CU and in the group II was 1.087 ± 0.174 CU. The level of AUAT to TG in cancer patients without metastasis was 0.794 ± 0.038 CU. It was found that when the level of AIAT against AUAT to Tg does not allow to distinguish metastatic thyroid cancer from cancer without metastases, it is possible to differentiate status data of thyroid cancer by using the level of autoantibodies to Tg. Moreover, the high level of AIAT against AUAT to Tg in patients with cancer without detectable metastases may be a marker of poor prognosis. So in one of the studied patients diagnosed with papillary cancer without metastasis, the level of AIAT against AUAT to Tg was equal to 0.37 CU, thus indicating the presence of metastases. Indeed, metastases were found in this patient 4 months later. Thus, the level of anti-idiotypic antibodies against autoantibodies to thyroglobulin may be used as a marker for metastases in the differential diagnosis of thyroid cancer.

Clonidine inhibits anti-non-Gal IgM xenoantibody elicited in multiple pig-to-primate models.

Survival of vascularized xenografts is dependent on pre-emptive inhibition of the xenoantibody response against galactosyltransferase knockout (GTKO) porcine organs. Our analysis in multiple GTKO pig-to-primate models of xenotransplantation has demonstrated that the anti-non-gal-α-1,3-gal (anti-non-Gal) xenoantibody response displays limited structural diversity. This allowed our group to identify an experimental compound which selectively inhibited induced anti-non-Gal IgM xenoantibodies. However, because this compound had an unknown safety profile, we extended this line of research to include screening small molecules with known safety profiles allowing rapid advancement to large animal models. The NIH clinical collections of small molecules were screened by ELISA for their ability to inhibit xenoantibody binding to GTKO pig endothelial cells. Serum collected from non-immunosuppressed rhesus monkeys at day 14 post-injection with GTKO pig endothelial cells was utilized as a source of elicited xenoantibody for initial screening. Virtual small molecule screening based on xenoantibody structure was used to assess the likelihood that the identified small molecules bound xenoantibody directly. As a proxy for selectivity, ELISAs against tetanus toxoid and the natural antigens laminin, thyroglobulin, and single-stranded DNA (ssDNA) were utilized to assess the ability of the identified reagents to inhibit additional antibody responses. The identified inhibitory small molecules were further tested for their ability to inhibit xenoantibody elicited in multiple settings, including rhesus monkeys pre-treated with an anti-non-Gal selective anti-idiotypic antibody, non-immunosuppressed rhesus monkeys immunized with wild-type fetal pig isletlike cell clusters, and non-immunosuppressed baboons transplanted with GTKO multiple transgenic pig kidneys. Four clinically relevant small molecules inhibited anti-non-Gal IgM binding to GTKO pig endothelial cells in vitro. Three of these drugs displayed a limited region of structural similarity suggesting they may inhibit xenoantibody by a similar mechanism. One of these, the anti-hypertensive agent clonidine, displayed only minimal inhibition of antibodies elicited by vaccination against tetanus toxoid or pre-existing natural antibodies against laminin, thyroglobulin, or ssDNA. Furthermore, clonidine inhibited elicited anti-non-Gal IgM from all animals that demonstrated a xenoantibody response in each experimental setting. Clinically relevant small molecule drugs with known safety profiles can inhibit xenoantibody elicited against non-Gal antigens in diverse experimental xenotransplantation settings. These molecules are ready to be tested in large animal models. However, it will first be necessary to optimize the timing and dosing required to inhibit xenoantibodies in vivo.

Anti-idiotypic VHH phage display-mediated immuno-PCR for ultrasensitive determination of mycotoxin zearalenone in cereals

Immunoassay is frequently used to analyze mycotoxin contamination. However, the introduction of mycotoxins or their conjugates in conventional immunoassay threatens the safety of individuals and the environment. The variable domain of heavy-chain antibodies (VHHs) can be used as alternative compounds to produce anti-idiotypic antibodies, which work as non-toxic surrogate reagents in immunoassay. In this work, anti-zearalenone (ZEN) monoclonal antibody (mAb) was used as the target for biopanning anti-idiotypic VHH from a naïve alpaca VHH phage display library. After four panning cycles, one anti-idiotypic VHH phage clone (Z1) was isolated and the Z1 based phage ELISA for ZEN showed a half inhibitory concentration (IC50) of 0.25±0.02ng/mL, a linear range of 0.11–0.55ng/mL, and a limit of detection (LOD) of 0.08ng/mL. Furthermore, the phage particles of Z1 were also applied to immuno-polymerase chain reaction (PD-IPCR), which supplied both the detection antigens and deoxyribonucleic acid (DNA) templates. Compared with that of phage ELISA, the LOD of Z1 based PD-IPCR was 12-fold improved, with a detection limit of 6.5pg/mL and a linear range of 0.01–100ng/mL. The proposed method was then validated with liquid chromatography–tandem mass spectrometry (LC–MS/MS). Results showed the reliability of PD-IPCR for the determination of ZEN in cereal samples. The use of anti-idiotypic VHH phage as non-toxic surrogate and signal-amplification function of PCR make it a promising method for actual ZEN analysis in cereals.