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Dear Editor,A 62-year-old woman was admitted to our hospital because of edema of both lower limbs for more than 3 months and oliguria for 1 week. The patient’s laboratory test results were listed i...

We report the case of a French woman with acquired von Willebrand syndrome who presents recurrent subarachnoid and intra-cerebral hemorrhage since 2012. She had no family or personal bleeding history. In the biologic explorations, APTT was abnormally high with no anticoagulant drugs (it was normal, historically). Two monoclonal IgG and IgM kappa proteins were detected without any lymphoproliferative disorder. Intravenous infusion of immunoglobulin is very effective in AVWS with immunoglobulin G monoclonal gammapathie of undetermined significance. We had a satisfactory correction of coagulation factors for about 30 days. The exploration of APTT is surely essential for the diagnosis and treatment.

The aim of this study was to investigate neonatal Fc receptor (FcRn) concentration developmental pharmacology in adult and pediatric subjects using minimal physiologically-based pharmacokinetic (mPBPK) modelling. Three types of pharmacokinetic (PK) data for three agents (endogenous/exogenous native IgG, bevacizumab and palivizumab) were used. The adult group contained six subjects with weights from 50 to 100 kg. For pediatric subjects, seven age groups were assumed, with five subjects each having the weight of 95%, 75%, 50%, 25% and 5% percentile of the population. A first evidence-based rating system to evaluate the quality of the source data used to derive pediatric-specific mPBPK model parameter was proposed. A stepwise approach was used to examine the best combination of age/weight effect on the parameters of the mPBPK model in adult and pediatric subjects. IgG synthesis rate (K(syn)), extravasation rate (ER) and FcRn were fitted simultaneously to the PK of bevacizumab and native-IgG in both adult and pediatric. All fitting showed good fits based on the graphs and the coefficient of variation of the fitted parameters (

Capillary electrophoresis sodium dodecyl sulfate (CE-SDS) is widely used for purity analysis of monoclonal antibody therapeutics for release and stability to demonstrate product consistency and shelf life during the manufacturing and life cycle of the product. CE-SDS method development is focused on exploring the method capability to provide the information about the product purity and product related degradants (fragmentation, aggregation etc.). In order to establish the functionality of the instrumentation, software, and sample preparation; system suitability criteria need to be defined for analytical methods using a well characterized reference standard run under the same protocol and analysis as the test articles. Typically the reference standard is produced using a manufacturing process representative of the clinical material. The qualification, control, and maintenance of in-house reference standards are established through rigorous quality and regulatory guidelines. The U.S. Pharmacopeia (USP) has developed a monoclonal IgG System Suitability Reference Standard to be utilized for assessment of system suitability in CE-SDS methods. In this communication, we evaluate the system suitability acceptance criteria performance of the USP IgG standard using two methods, the recommended USP protocol provided in monograph129and a molecule specific Bristol-Myers Squibb (BMS) CE-SDS method. The results from USP IgG standard were compared with two in-house monoclonal antibody reference standards. The data suggest that the USP CE-SDS method may not be suitable for CE-SDS analysis for release and stability of monoclonal antibody therapeutics due to the high level of method induced partial reduction observed for all molecules tested. This high level of fragmentation observed utilizing the USP method will result in reporting lower purity levels, which will impact the overall quality assessment of the molecule. The system suitability criteria recommended by the USP method can be achieved by using the USP reference standard during the development and pre-validation stages. Furthermore, the USP reference standard does not offer significant advantages to existing SST criteria in the BMS method during release and stability testing, and therefore we propose use of the USP standard only during the optimization and pre-validation stages of method development.

Glomerulopathy due to dysproteinemia can have a wide spectrum of pathologic and clinical features based on specific characteristics of the abnormal protein and the response induced within the parenchymal tissue. Monoclonal immunoglobulin G (IgG) deposition can manifest as a different glomerular disease. Proliferative glomerulonephritis (GN) with monoclonal IgG deposits (PGNMID) is a unique entity mimicking immune complex GN that does not conform to any of those subtypes. IgG monoclonal granular deposition in the glomeruli with a pattern similar to immune complex disease suggested by C3 and C1q deposition should prompt consideration of PGNMID. Literature is scarce in terms of recurrence of disease in renal allografts. In this article we present the clinical-pathologic features of three cases of PGNMID in the renal allograft showing the variable course and manifestation of the disease.

Proliferative glomerulonephritis with monoclonal immunoglobulin G deposits (PGNMID) is a newly identified and rare form of glomerulonephritis which is characterized by endocapillary proliferative or membranoproliferative with monoclonal deposit stain for IgG and a single light chain. We describe the case of a 63-year-old woman with type 2 diabetes who was considered to have PGNMID.

Background Measurement of serum prostate specific antigen (PSA) concentrations remains one of the leading methods for diagnosing prostate cancer. We developed and evaluated an immunoglobulin Y (IgY)-based ELISA to measure total PSA (tPSA) concentrations in human serum that could be used as an alternative to commercially available in vitro diagnostic assays that rely on mouse monoclonal IgG. Methods A sandwich ELISA based on an anti-PSA IgY antibody was developed. We evaluated the ability of the anti-PSA IgY antibody to detect free and complexed PSA at the same molar ratio. The assay was optimized, and its analytical performance was verified by calculating limit of background (LoB), limit of detection (LoD), and limit of quantification (LoQ). We performed correlation and regression analyses between tPSA concentrations measured by our ELISA and those from commercial assays: Cobas 6000 (Roche Diagnostics, Warszawa, Poland) and PSA total ELISA (IBL International, Hamburg, Germany). Results LoB, LoD, and LoQ, were 0.061, 0.083, and 0.100 ng/mL, respectively, and linearity range was 0.100-3.375 ng/mL. tPSA concentrations from our IgY-based ELISA strongly correlated with those from the commercial assays. Conclusions Our IgY-based ELISA is an efficient equivalent to the above commercial assays. The use of IgY as the detecting agent could reduce the risk of false positive results, as well as decrease the overall cost of analysis.

Proliferative glomerulonephritis occurring as a consequence of monoclonal glomerular deposits of IgG is uncommon. It is a form of renal involvement in monoclonal gammopathy that mimics immune complex glomerulonephritis. Here, we report the first series of proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) from the Indian subcontinent highlighting use of light chain immunofluorescence (IF) in routine renal biopsy interpretation. We retrieved 6 patients diagnosed as proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) out of 160 biopsies (3.7%) with membranoproliferative patterns over 5 1/2 years (2009–2014), one of whom had recurrence 6 months post-renal transplant. Four (67%) patients presented with rapidly progressive renal failure and two (33%) with nephrotic syndrome. None of these patients had overt multiple myeloma. The predominant histologic pattern was membranoproliferative with all the biopsies showing IgG3 Kappa deposits on IF. The deposits were primarily subendothelial on electron microscopy.

International audience; Le STUDIUM conference was held November 24-25, 2016 in Tours, France as a satellite workshop of the 5(th) meeting of the French GDR 3545 on "G Protein-Coupled Receptors (GPCRs) - From Physiology to Drugs", which was held in Tours during November 22-24, 2016. The conference gathered speakers from academia and industry considered to be world leaders in the molecular pharmacology and signaling of GPCRs, with a particular interest in the development of therapeutic GPCR antibodies (Abs). The main topics were new advances and challenges in the development of antibodies targeting GPCRs and their potential applications to the study of the structure and function of GPCRs, as well as their implication in physiology and pathophysiology. The conference included two sessions, with the first dedicated to the recent advances in methodological strategies used for GPCR immunization using thermo-stabilized and purified GPCRs, and the development of various formats of Abs such as monoclonal IgG, single-chain variable fragments and nanobodies (Nbs) by in vitro and in silico approaches. The second session focused on GPCR Nbs as a "hot" field of research on GPCRs. This session started with discussion of the pioneering Nbs developed against GPCRs and their application to structural studies, then transitioned to talks on original ex vivo and in vivo studies on GPCR-selective Nbs showing promising therapeutic applications of Nbs in important physiological systems, such as the central nervous and the immune systems, as well as in cancer. The conference ended with the consensus that Abs and especially Nbs are opening a new era of research on GPCR structure, pharmacology and pathophysiology.

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) is a recently described entity. It is featured by glomerular nonorganized monoclonal immunoglobulin G deposits. Monoclonal IgG deposits are associated with glomerular proliferative lesions, mimicking different types of immune-complex glomerulonephritis. We report two classic cases of PGNMID which fulfilled all criteria of this disease. We conclude that recognition of proliferative glomerulonephritis with monoclonal IgG deposits requires routine immunostaining for light chain and IgG isotype.

A male patient is presented with long-lasting paraproteinemia of monoclonal IgG λ, who suffered from recurrent, and until the last one, mostly reversible episodes of dermatoneuro syndrome, described exclusively in scleromyxedema. The skin biopsy revealed λ-light chain amyloid deposition instead of changes typical for scleromyxedema. Systemic AL amyloidosis was diagnosed post mortem since the patient had no clinical signs of any other organ impairment except skin and brain. Neuropathology is described and possible etiopathogenesis of brain involvement is considered.

Contains fulltext : 167798.pdf (Publisher’s version ) (Closed access) Optimal glycosylation of immunoglobulins is essential in the generation of therapeutic biologicals with respect to efficacy, pharmacokinetics and immunogenic properties. This challenge in the field of biopharmaceuticals requires technologies for fast, robust and quantitative analysis of glycosylation. Current analyses of monoclonal antibody glycosylation are proteolysis-based mass spectrometry methods, which provide detailed structural information, but suffer a number of drawbacks such as lengthy sample preparation with the possibility to introduce artifacts. Here, we describe a fast, robust and high-resolution nanoLC-chip-QTOF method for quantitative analysis of intact monoclonal IgG glycosylation profiling. The method is able to detect hypoglycosylation, i.e. the lack of whole glycans, which is an important advantage over the well-established methods for free N-glycan or glycopeptide analysis. Moreover, the method is highly amenable to automation and because no digestion steps are involved, it provides direct relative quantitative information of both glycans on each IgG attachment site. We demonstrate that the ease and robustness make this technique ideally suited for quality control of the production process of mAb biopharmaceuticals, and provides new opportunities to study the clinical impact of mAb-glycosylation in patients with monoclonal gammopathies.

In the diagnosis of atherosclerosis, detailed evaluation of biomarkers related to its lesion formation is desired for estimation of its progression rate. In our previous proteomic studies of atherosclerosis mice, the protein level of thrombospondin-4 (TSP4) in the aorta, but not in plasma, elevated relatively with atherosclerotic plaque formation. Therefore, we supposed that TSP4 would be a potential biomarker for diagnostic imaging of atherosclerotic progression. Immunoglobulin G (IgG) has been widely used as a basic molecule of imaging probes providing images specific to their target biomolecules, owing to the antigen-antibody reaction. Therefore, we first developed anti-TSP4 monoclonal IgG radiolabeled with 99mTc (99mTc-TSP4-mAb). 99mTc-TSP4-mAb showed higher accumulation in atherosclerotic aortas of apoE−/− mice (atherosclerotic model mice); however, we found that the non-targeted monoclonal IgG radiolabeled with 99mTc also showed similar distribution in atherosclerotic aortas of apoE−/− mice. IgG has also known to accumulate nonspecifically in the immunological disease such as inflammatory arthritis. However, the accumulation mechanism of IgG has still been unclear in detail. In this chapter, we would like to introduce recent topics on atherosclerotic imaging, focused on our work exploring the accumulation mechanisms of IgG in atherosclerotic lesions, and elucidating the usefulness of radiolabeled IgG images in the diagnosis of atherosclerosis.

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) is a rare and recently identified disease with a poor prognosis irrespective of the treatment. Recently, the possibility of recurrent or de novo PGNMID after kidney transplantation has been reported, which is associated with a better prognosis compared to PGNMID on native kidneys. Nevertheless, at present, due to the very few cases of recurrent PGNMID diagnosed, there is no proven effective treatment. Here, we report a case of recurrent PGNMID successfully treated with plasmapheresis, steroids and mycophenolate mofetil. Our report suggests that plasmapheresis might be a valid therapeutic option to treat recurrent PGNMID.

SummaryHuman cytomegalovirus (CMV) is a common but difficult to treat infection of immunocompromised patients. MSL-109 is a human monoclonal IgG isolated from a CMV seropositive individual that recognizes the viral glycoprotein H (gH) surface antigen complexes that mediate entry. Although MSL-109 blocks CMV infection in vitro, it lacked sufficient efficacy in human trials, and CMV isolated from treated patients suggested the evolution of MSL-109 resistance. To understand how CMV escapes MSL-109, we characterized a MSL-109-resistant CMV strain. Our results elucidate a nongenetic escape mechanism in which the antibody is selectively taken up by infected cells and incorporated into assembling virions in a dose-dependent manner. The resistant virus then utilizes the Fc domain of the incorporated antibody to infect naive nonimmune cells. This resistance mechanism may explain the clinical failure of MSL-109, illustrate a general mechanism of viral antibody escape, and inform antiviral vaccine and therapeutic development.

In this paper, we describe guided-mode resonance biochemical sensor technology. We briefly discuss sensor fabrication and show measured binding dynamics for example biomaterials in use in our laboratories. We then turn our attention to a particularly powerful attribute of this technology not possessed by competing methods. This attribute is the facile generation of multiple resonance peaks at an identical physical location on the sensor surface. These peaks respond uniquely to the biomolecular event, thereby enriching the data set available for event quantification. The peaks result from individual, polarization-dependent resonant leaky modes that are the foundation of this technology. Thus, by modeling the binding event and fitting to a rigorous electromagnetic formalism, we can determine individual attributes of the biolayer and its surroundings and avoid a separate reference site for background monitoring. Examples provide dual-polarization quantification of biotin binding to a silane-coated sensor as well as binding of the cancer biomarker protein calreticulin to its monoclonal IgG capture antibody. Finally, we present dual-polarization resonance response for poly (allylamine hydrochloride) binding to the sensor with corresponding results of backfitting to a simple model; this differentiates the contributions from biolayer adhesion and background changes.

Membranous-like glomerulopathy with masked IgG-κ deposits (MGMID) is a novel entity requiring antigen retrieval on formalin-fixed paraffin-embedded tissue to detect the immunoglobulin by immunofluorescence. MGMID is clinically distinct from other glomerulopathies with non-organized monoclonal IgG deposits, although the source of the kappa-restricted IgG is uncertain. Careful examination including ultrastructural analysis is essential for identifying diseases such as MGMID that may be misclassified by routine methods and ultimately require alternative techniques for accurate diagnosis.

At 150 kDa, antibodies of the IgG class are too large for their structure to be determined with current NMR methodologies. Because of hinge-region flexibility, it is difficult to obtain atomic-level structural information from the crystal, and questions regarding antibody structure and dynamics in solution remain unaddressed. Here we describe the construction of a model of a human IgG1 monoclonal antibody (trastuzumab) from the crystal structures of fragments. We use a combination of molecular-dynamics (MD) simulation, continuum hydrodynamics modeling, and experimental diffusion measurements to explore antibody behavior in aqueous solution. Hydrodynamic modeling provides a link between the atomic-level details of MD simulation and the size- and shape-dependent data provided by hydrodynamic measurements. Eight independent 40 ns MD trajectories were obtained with the AMBER program suite. The ensemble average of the computed transport properties over all of the MD trajectories agrees remarkably well with the value of the translational diffusion coefficient obtained with dynamic light scattering at 20 degrees C and 27 degrees C, and the intrinsic viscosity measured at 20 degrees C. Therefore, our MD results likely represent a realistic sampling of the conformational space that an antibody explores in aqueous solution.

A robust cation-exchange chromatofocusing method was developed for the routine analysis of a recombinant humanized monoclonal IgG antibody. We compare the chromatofocusing method to the conventional cation-exchange chromatography (CEX) employing a salt gradient and show clear advantages of chromatofocusing over CEX. We demonstrate the suitability of the present chromatofocusing method for its intended purpose by testing the validation characteristics. To our knowledge, this is the first chromatofocusing method developed for the routine analysis of monoclonal antibody charge species.

This paper describes a method for the purification of monoclonal antibodies (rat anti-2,4-dinitrophenyl IgG: IgG(DNP); and mouse antidigoxin IgG: IgG(Dgn)) from ascites fluid. This procedure (for IgG(DNP)) has three steps: (i) precipitation of proteins heavier than immunoglobulins with ammonium sulfate; (ii) formation of cyclic complexes of IgG(DNP) by causing it to bind to synthetic multivalent haptens containing multiple DNP groups; (iii) selective precipitation of these dimers, trimers, and higher oligomers of the target antibody, followed by regeneration of the free antibody. This procedure separates the targeted antibody from a mixture of antibodies, as well as from other proteins and globulins in a biological fluid. This method is applicable to antibodies with a wide range of monovalent binding constants (0.1 microM to 0.1 nM). The multivalent ligands we used (derivatives of DNP and digoxin) isolated IgG(DNP) and IgG(Dgn) from ascites fluid in yields of >80% and with >95% purity. This technique has two advantages over conventional chromatographic methods for purifying antibodies: (i) it is selective for antibodies with two active Fab binding sites (both sites are required to form the cyclic complexes) over antibodies with one or zero active Fab binding sites; (ii) it does not require chromatographic separation. It has the disadvantage that the structure of the hapten must be compatible with the synthesis of bi- and/or trivalent analogues.

We report a 5-month-old Amish girl with atypical recombinase-activating gene (RAG)-deficient severe combined immunodeficiency disease. There was a lys992glu RAG-1 substitution leading to impaired RAG activity. Immunological studies revealed mildly decreased CD3+ T cells, markedly decreased CD4+ T cells, and oligoclonal T-cell receptor-Vβ T cells. B cells were markedly decreased but serum immunoglobulin levels were normal with monoclonal IgG and IgM antibodies.

First description of a case of early myeloma with monoclonal IgG, type kappa, anomaly plus Bence-Jones proteinuria and Fanconi's syndrome in a 67-year-old woman. Characteristic crystalline inclusion bodies were found in plasma cells of bone marrow and renal tissue.

A panel of four natural human monoclonal IgG antibodies derived from B lymphocytes isolated from regional draining lymph nodes of cancer patients has been developed and characterized. The four human antibodies are termed, RM1, RM2, RM3, and RM4. The immunoreactivity of this panel of four human antibodies is restricted to tumor cells. Individually, these human MAbs show tumor targeting and are effective in inhibiting tumor growth in nude mouse xenograft models. When used in combination the antibodies show an additive effect in slowing down the progression of tumors in xenograft models suggesting that cocktails of antibodies may be useful in the clinic.

An IgG mouse monoclonal antibody (10F05) against polyethylene glycol has been generated. The antibody reacts with PEG regardless of the linker used for PEG attachment, and is able to recognize a PEGylated peptide in plasma at concentrations as low as 3 pg/mL. The antibody is readily purified in substantial quantities. The PEG IgG will find significant utility in the sensitive detection of PEG derivitives during the pharmacokinetic characterization of PEGylated compounds.

This research was conducted to evaluate the changes in allergenicity of shrimp by physical treatments using competitive indirect enzyme-linked immunosorbent assay (Ci-ELISA). Shrimp was subjected to physical treatments such as high hydrostatic pressure (HHP), sonication, autoclave and microwave. Heat-stable protein (HSP) purified from raw shrimp was used as a major allergen. The binding ability of monoclonal IgG and shrimp-allergic patients` IgE to HSP treated with HHP decreased, increasing the pressure up to 400 MPa. Especially, it became less than 50% at 400 MPa. The binding ability of mAb to HSP treated with sonication (10, 20, 30 and 60 min) decreased with the treated time. Especially, it became less than 60% with the treatment for 60 min. The allergenicity change of HSP treated with autoclave and microwave little decreased. The binding ability of mAb to HSP during the treatment for 20 min became more than 70%. The results suggest that allergenicity of HSP in raw shrimp be more easily lost by HHP or sonication treatment than by autoclave or microwave treatment.

Summary The features of GPs with Congo red-negative, non-cryoglobulinaemic deposits have been surveyed. Thesedisorders are rare and clinically heterogeneous andtheir pathogenesis is unclear. There is controversyconcerning the nomenclature of Congo-red negativeglomerular fibrilloses. A practical and reproducibleapproach is to classify these GPs on the basis of thesubstructure and arrangement of the deposits assessedat conventional electron microscopic magnifications.Accordingly, FGN and ITG can be identified. FGN ischaracterized by randomly arranged microfibrils (dia-meter: 12–30nm) composed of subclass-restrictedpolyclonal IgG and a low incidence of underlyingsystemic disease. In contrast, ITG is characterized byparallel bundles of microtubules (diameter: 10–90nm)composed mainly of monoclonal IgG and a highincidence of associated lymphoproliferative disease ormonoclonal gammopathy. The finding of Congo red-negative organized deposits on renal biopsy shouldprompt a careful search and follow-up for mono-clonal gammopathy, cryoglobulins and haemopoieticmalignancy.

Vibratory angio-oedema is a rare form of physical urticaria characterized by pruriginous weals and angio-oedema at the site of exposure to vibration. Severe treatment-resistant disease can occur, and is associated with significant disability. Therapy with omalizumab, a monoclonal IgG anti-IgE antibody, has been shown to be successful in several types of physical urticaria. We report a patient with vibratory angio-oedema for whom all standard treatments for urticaria, including omalizumab, failed to show a clinical benefit. Finally, ketotifen was tried, and unexpectedly reduced symptoms significantly. Ketotifen may thus represent a therapeutic option in patients with treatment-resistant vibratory angio-oedema.

Clostridium difficile infection has emerged as a growing worldwide health problem. The colitis of Clostridium difficile infection results from the synergistic action of C. difficile secreted toxins A and B upon the colon mucosa. A human monoclonal IgG anti-toxin has demonstrated the ability in combination therapy to reduce mortality in C. difficile challenged hamsters. This antibody is currently in a clinical trial for the treatment of human Clostridium difficile infection. More than one group of investigators has considered using polyclonal bovine colostral antibodies to toxins A and B as an oral passive immunization. A significant proportion of the healthy human population possesses polyclonal antibodies to the Clostridium difficile toxins. We have demonstrated that polyclonal IgA derived from the pooled plasma of healthy donors possesses specificity to toxins A and B and can neutralize these toxins in a cell-based assay. This suggests that secretory IgA prepared from such pooled plasma IgA may be able to be used as an oral treatment for Clostridium difficile infection.

A 69-year-old man presented with severe pain in hands and feet related to necrosis. Extensive explorations revealed type I cyroglobulinemia associated to monoclonal IgG kappa. Unfortunately he died a few months after.

A 78-year-old woman developed acute-onset nephrotic syndrome. A renal biopsy showed mild mesangial proliferative glomerulonephritis. Immunofluorescence studies revealed granular IgG3- λ deposits within the mesangial area and along the glomerular capillary walls. Electron microscopy showed mesangial and subendothelial granular electron-dense deposits. The pattern of deposition was predominantly mesangial. Serum or urine monoclonal proteins were not detected. Middle-dose steroid therapy induced a rapid remission of nephrotic syndrome. We consider that this is the first case of steroid-responsive nephrotic syndrome due to an extremely rare glomerular disease, proliferative glomerulonephritis with monoclonal IgG deposits associated with pure mesangial proliferative features.

We show that the natural autoantibody activity of amniotic IgG dramatically increases after purification, and that the IgG-depleted fraction can suppress the activity of IgG natural antibodies from amniotic fluid or from the maternal serum. This suppression is also observed towards serum IgG from unrelated adults but does not impair the tetanus antitoxin activity of serum-derived IgG. Absorption experiments and immunoglobulin separation by gel permeation demonstrate that this suppression is due to monomeric immunoglobulins of the IgA isotype. The inhibition is associated with an anti-F(ab')2 activity of the amniotic IgA, involving hypervariable regions of the IgG as demonstrated by different reactivities towards monoclonal IgG sharing the same family of VH and Vkappa domains. These results indicate that the inhibition of natural autoantibodies not only occurs with fetal and adult serum IgM, as reported by other groups, but also with amniotic IgA, suggesting a general and important phenomenon. In the case of the amniotic fluid, IgA could protect the fetus against maternal IgG autoantibodies without interfering with simultaneously translocated antigen-induced IgG antibodies to pathogens.

The relationship between the efficiency of the neutralization process and the affinity of five monoclonal IgG antibodies specific for the haemagglutinin of type A influenza virus has been investigated by determining their neutralization rate constants (Kneut.) and affinities (Kdissoc.). We addressed the hypothesis that if antibody affinity alone determined the efficiency of neutralization, then the Kneut.:Kdissoc. ratio would be the same for all antibodies. However, we found that the Kneut.:Kdissoc. ratio varied by up to 125-fold, suggesting that properties unique to the epitope are of major importance in determining the efficiency of neutralization. These data suggest that vaccines should preferentially stimulate antibodies to epitopes that mediate the most efficient neutralization, and that a high Kdissoc. should be an important but secondary consideration.

A residual IgG line is frequently observed inside the monoclonal IgG line on immunoelectrophoresis of IgG myeloma serum in reaction with anti-whole human serum. We found that the residual IgG line was observed exclusively in serum from IgG-λ type M-proteinemia when a goat antiserum to whole human serum was employed. However, with a horse antiserum to whole human serum, the residual IgG line was observed in sera from both the IgG-λ and κ type M-proteinemias. These phenomena led us to an idea that the appearance of the residual IgG line resulted from reaction with anti-κ or λ antibodies present in the anti-whole human serum antisera. Investigations of sera from a number of IgG M-proteinemia by anti-κ and λ antisera, and absorption tests with partially purified BJP of both types indicated that the occurrence of the residual IgG line is due to the reaction of polyclonal IgG with anti-κ or λ chain antibody present in the anti-whole human serum.