Not all therapeutic antibody isotypes are equal: the case of IgM versus IgG in Pertuzumab and Trastuzumab

Defining the Features of Complement-Active IgM

Immunoglobulin M (IgM) is a class of mammalian antibody that is critical for the early stages of adaptive immunity, and is the most potent Ig-activator of the classical complement cascade. While the relationship between IgM and complement has been appreciated for decades, the structural transitions within IgM upon antigen binding that promote the activation of complement component C1 remain unresolved. Here we examine in vitro complement activation, C1 binding kinetics, and conformational changes within IgM in different antigen-bound states. Binding studies using biolayer interferometry revealed that only in a multivalent complex with a surface-displayed antigen was IgM fully capable of initiating complement activation. Hydrogen/Deuterium exchange with mass spectrometry revealed the predominant structural changes within the Fc domains during transition to the active conformation. Collectively, this work establishes key structural and functional qualities that define the complement-active form of IgM.

Understanding IgM Structure and Biology to Engineer New Antibody Therapeutics

Immunoglobulin M (IgM) antibodies are an essential and conserved part of adaptive immunity. IgMs assemble into pentamers and hexamers that bind to antigens with high avidity. Pentamers incorporate a small protein called J-chain (JC) that is important for their transcytosis via the poly-immunoglobulin receptor (pIgR). IgM antibodies can efficiently activate complement and interact with different Fc receptors (FcμR, Fcα/μR, pIgR) that trigger distinct effector functions and biodistribution. Even if these features have made the clinical use of IgM attractive over the past decades, there are currently no approved therapeutic IgMs on the market. In this review, we summarize the recent advances in the knowledge of IgM biogenesis and structure and discuss the therapeutic opportunities of IgM over IgG arising from high avidity, target clustering, binding to distinct IgM receptors, complement activation, transcytosis, and protein engineering opportunities. In addition, we summarize possibilities and outstanding challenges in the production of therapeutic IgM, including available technologies for IgM purification. Finally, we review recent preclinical and clinical data showing that IgM outperforms IgG in various in vitro assays but still fails to pass through clinical trials successfully. Challenges remain for IgM development, such as the need for a better understanding of IgM biology to facilitate a smoother transition from the preclinic to successful clinical trials.

A non-classical view of antibody properties: Allosteric effect between variable and constant regions

Historically, antibodies have been divided into two functionally independent domains, the variable (V) region for antigen binding and the constant (C) region for mediating effector functions. However, this classical view of antibody function has been severely challenged by a large and growing number of studies, which reveal long-range conformational interactions and allosteric links between the V and C regions. This review comprehensively summarizes the existing studies on antibody allostery, including allosteric conformational changes induced by covalent modifications or noncovalent ligand binding. In addition, we discuss how intramolecular allosteric signals are transmitted from the V to C regions and vice versa. This review argues that there is sufficient evidence to revisit the structure-function relationship of antibodies. These advances in antibody allostery will provide a blueprint for regulating antibody functions in a simple and highly predictable manner. More focus on antibody allostery will definitely benefit antibody engineering and vaccine design in the field of biotechnology.

Comprehensive review of drug resistance in mammalian cancer stem cells: implications for cancer therapy

Cancer remains a significant global challenge, and despite the numerous strategies developed to advance cancer therapy, an effective cure for metastatic cancer remains elusive. A major hurdle in treatment success is the ability of cancer cells, particularly cancer stem cells (CSCs), to resist therapy. These CSCs possess unique abilities, including self-renewal, differentiation, and repair, which drive tumor progression and chemotherapy resistance. The resilience of CSCs is linked to certain signaling pathways. Tumors with pathway-dependent CSCs often develop genetic resistance, whereas those with pathway-independent CSCs undergo epigenetic changes that affect gene regulation. CSCs can evade cytotoxic drugs, radiation, and apoptosis by increasing drug efflux transporter activity and activating survival mechanisms. Future research should prioritize the identification of new biomarkers and signaling molecules to better understand drug resistance. The use of cutting-edge approaches, such as bioinformatics, genomics, proteomics, and nanotechnology, offers potential solutions to this challenge. Key strategies include developing targeted therapies, employing nanocarriers for precise drug delivery, and focusing on CSC-targeted pathways such as the Wnt, Notch, and Hedgehog pathways. Additionally, investigating multitarget inhibitors, immunotherapy, and nanodrug delivery systems is critical for overcoming drug resistance in cancer cells.

A novel complement-fixing IgM antibody targeting GPC1 as a useful immunotherapeutic strategy for the treatment of pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers with a very low survival rate at 5 years. The use of chemotherapeutic agents results in only modest prolongation of survival and is generally associated with the occurrence of toxicity effects. Antibody-based immunotherapy has been proposed for the treatment of PDAC, but its efficacy has so far proved limited. The proteoglycan glypican-1 (GPC1) may be a useful immunotherapeutic target because it is highly expressed on the surface of PDAC cells, whereas it is not expressed or is expressed at very low levels in benign neoplastic lesions, chronic pancreatitis, and normal adult tissues. Here, we developed and characterized a specific mouse IgM antibody (AT101) targeting GPC1.

METHODS

We developed a mouse monoclonal antibody of the IgM class directed against an epitope of GPC1 in close proximity to the cell membrane. For this purpose, a 46 amino acid long peptide of the C-terminal region was used to immunize mice by an in-vivo electroporation protocol followed by serum titer and hybridoma formation.

RESULTS

The ability of AT101 to bind the GPC1 protein was demonstrated by ELISA, and by flow cytometry and immunofluorescence analysis in the GPC1-expressing "PDAC-like" BXPC3 cell line. In-vivo experiments in the BXPC3 xenograft model showed that AT101 was able to bind GPC1 on the cell surface and accumulate in the BXPC3 tumor masses. Ex-vivo analyses of BXPC3 tumor masses showed that AT101 was able to recruit immunological effectors (complement system components, NK cells, macrophages) to the tumor site and damage PDAC tumor tissue. In-vivo treatment with AT101 reduced tumor growth and prolonged survival of mice with BXPC3 tumor (p < 0.0001).

CONCLUSIONS

These results indicate that AT101, an IgM specific for an epitope of GPC1 close to PDAC cell surface, is a promising immunotherapeutic agent for GPC1-expressing PDAC, being able to selectively activate the complement system and recruit effector cells in the tumor microenvironment, thus allowing to reduce tumor mass growth and improve survival in treated mice.

Binding Affinity of Trastuzumab and Pertuzumab Monoclonal Antibodies to Extracellular HER2 Domain

The binding affinity of trastuzumab and pertuzumab to HER2 has been studied using both experimental and in silico methods. The experiments were conducted using the antibodies in their complete IgG form, as used in clinical therapy, and the extracellular domain of the HER2 protein in solution. This approach provides a precise, reproducible, and reliable view of the interaction between them in physicochemical conditions similar to those found in the tumoral environment. Dynamic light scattering and size exclusion chromatography coupled with tetra detection were utilized to characterize the protein complexes, measure their concentrations, and calculate the equilibrium-free binding energy, ΔGbind. In addition, PRODIGY, a QSAR-like model with excellent predictive ability, was employed to obtain in silico ΔGbind estimations. The results obtained indicate that pertuzumab exhibits a slightly higher binding affinity to HER2 than trastuzumab. The difference in binding affinity was explained based on the contribution of the different interfacial contact (IC) descriptors to the ΔGbind value estimated by the PRODIGY model. Furthermore, experiments revealed that the pertuzumab IgG antibody binds preferentially to two HER2 proteins, one per Fab fragment, while trastuzumab mainly forms a monovalent complex. This finding was interpreted based on a geometrical model that identified steric crowding in the trastuzumab-HER2 complex as compared with the pertuzumab-HER2 complex.

Glyco engineered pentameric SARS-CoV-2 IgMs show superior activities compared to IgG1 orthologues

Immunoglobulin M (IgM) is the largest antibody isotype with unique features like extensive glycosylation and oligomerization. Major hurdles in characterizing its properties are difficulties in the production of well-defined multimers. Here we report the expression of two SARS-CoV-2 neutralizing monoclonal antibodies in glycoengineered plants. Isotype switch from IgG1 to IgM resulted in the production of IgMs, composed of 21 human protein subunits correctly assembled into pentamers. All four recombinant monoclonal antibodies carried a highly reproducible human-type N-glycosylation profile, with a single dominant N-glycan species at each glycosite. Both pentameric IgMs exhibited increased antigen binding and virus neutralization potency, up to 390-fold, compared to the parental IgG1. Collectively, the results may impact on the future design of vaccines, diagnostics and antibody-based therapies and emphasize the versatile use of plants for the expression of highly complex human proteins with targeted posttranslational modifications.

An IgM monoclonal antibody against domain 1 of CD147 induces non-canonical RIPK-independent necroptosis in a cell type specific manner in hepatocellular carcinoma cells

CD147/Basigin/EMMPRIN is overexpressed in several cancerous tissues and it has been shown to induce matrix metalloproteinases (MMPs) whose expression is associated with cancer metastasis. Thus, targeting CD147 with monoclonal antibodies (mAbs) potentially has therapeutic applications in cancer immunotherapy. Here, we report the use of anti-CD147 mAbs targeting domain 1 of CD147, namely M6-1D4 (IgM), M6-1F3 (IgM), M6-2F9 (IgM) and M6-1E9 (IgG2a), against several human cancer cell lines. Strikingly, IgM but not IgG mAbs against CD147, especially clone M6-1D4, induced acute cellular swelling, and this phenomenon appeared to be specifically found with hepatocellular carcinoma (HCC) cells. Furthermore, molecular investigation upon treating HepG2 cells with M6-1D4 showed unfolded protein response (UPR) activation, autophagosome accumulation, and cell cycle arrest, but without classic apoptosis related features. More interestingly, prolonged M6-1D4 treatment (24 h) resulted in irreversible oncosis leading to necroptosis. Furthermore, treatment with a mixed lineage kinase domain-like psuedokinase (MLKL) inhibitor and partial knockout of MLKL resulted in reduced sensitivity to necroptosis in M6-1D4-treated HepG2 cells. Surprisingly however, the observed necroptotic signaling axis appeared to be non-canonical as it was independent of receptor-interacting serine/threonine-protein kinase (RIPK) phosphorylation. In addition, no cytotoxic effect on human dermal fibroblast (HDF) was observed after incubation with M6-1D4. Taken together, this study provides clues to target CD147 in HCC using mAbs, as well as sheds new light on a novel strategy to kill cancerous cells by the induction of necroptosis.

IgM antibodies derived from memory B cells are potent cross-variant neutralizers of SARS-CoV-2

Humoral immunity to SARS-CoV-2 can be supplemented with polyclonal sera from convalescent donors or an engineered monoclonal antibody (mAb) product. While pentameric IgM antibodies are responsible for much of convalescent sera's neutralizing capacity, all available mAbs are based on the monomeric IgG antibody subtype. We now show that IgM mAbs derived from immune memory B cell receptors are potent neutralizers of SARS-CoV-2. IgM mAbs outperformed clonally identical IgG antibodies across a range of affinities and SARS-CoV-2 receptor-binding domain epitopes. Strikingly, efficacy against SARS-CoV-2 viral variants was retained for IgM but not for clonally identical IgG. To investigate the biological role for IgM memory in SARS-CoV-2, we also generated IgM mAbs from antigen-experienced IgM+ memory B cells in convalescent donors, identifying a potent neutralizing antibody. Our results highlight the therapeutic potential of IgM mAbs and inform our understanding of the role for IgM memory against a rapidly mutating pathogen.

The clinical relevance of humoral immune responses to Globo H-KLH vaccine adagloxad simolenin (OBI-822)/OBI-821 and expression of Globo H in metastatic breast cancer

An international randomized phase II trial of Globo H (GH) vaccine, adagloxad simolenin/OBI-821 in 349 patients with metastatic breast cancer showed longer progression-free survival (PFS) in vaccinated patients who developed anti-Globo H (anti-GH) IgG than those who did not and the placebo group. The impacts of anti-GH IgM and GH expression on peak anti-GH IgG and clinical outcome were further evaluated. The titers of anti-GH IgG and IgM were determined by ELISA. GH expression in tumor was examined by immunohistochemical staining. Immunophenotyping was conducted by flow cytometry. Adagloxad simolenin elicited anti-GH IgM which peaked at titers ≥1:80 between weeks 5 and 13. The mean anti-GH IgG titer peaked at week 41 and decreased thereafter on the completion of vaccination. One log increase in peak IgM was associated with 10.6% decrease in the HR of disease progression (HR: 0.894, 95% CI: 0.833 to 0.960, p=0.0019). Patients with anti-GH IgM ≥1:320 within first 4 weeks after vaccination had significantly higher maximum anti-GH IgM (p<0.0001) and IgG titers (p<0.0001) than those with <1:320. Moreover, the median PFS appears to be longer for patients with anti-GH IgM ≥1:320 within first 4 weeks than those with anti-GH IgM titer <1:320 (11.1 vs 7.3 months, p=0.164), but not statistically significant. Among patients with H score ≥80 for GH expression by immunohistochemistry, the vaccination group (n=42) seemed to have better PFS than the placebo group (n=23) (HR=0.59; 95% CI: 0.32 to 1.10, p=0.10), but the difference did not reach statistical significance. In addition, peak levels of anti-GH IgM were higher in patients who had lower percentage of activated regulatory T cells (Treg cells; CD4⁺CD45RA^-Foxp3^high) at baseline than those who had higher activated Treg cells (p=0.042). This study demonstrates that adagloxad simolenin induced both IgG and IgM antibodies against GH. Anti-GH IgM ≥1:320 within first 4 weeks or low activated Treg cells at baseline may help to select patients who are likely to produce a higher level of GH-specific IgM and IgG in the future.

Variable-heavy (VH) families influencing IgA1&2 engagement to the antigen, FcαRI and superantigen proteins G, A, and L

Interest in IgA as an alternative antibody format has increased over the years with much remaining to be investigated in relation to interactions with immune cells. Considering the recent whole antibody investigations showing significant distal effects between the variable (V) and constant (C)- regions that can be mitigated by the hinge regions of both human IgA subtypes A1 and A2, we performed an in-depth mechanistic investigation using a panel of 28 IgA1s and A2s of both Trastuzumab and Pertuzumab models. FcαRI binding were found to be mitigated by the differing glycosylation patterns in IgA1 and 2 with contributions from the CDRs. On their interactions with antigen-Her2 and superantigens PpL, SpG and SpA, PpL was found to sterically hinder Her2 antigen binding with unexpected findings of IgAs binding SpG at the CH2-3 region alongside SpA interacting with IgAs at the CH1. Although the VH3 framework (FWR) is commonly used in CDR grafting, we found the VH1 framework (FWR) to be a possible alternative when grafting IgA1 and 2 owing to its stronger binding to antigen Her2 and weaker interactions to superantigen Protein L and A. These findings lay the foundation to understanding the interactions between IgAs and microbial superantigens, and also guide the engineering of IgAs for future antibody applications and targeting of superantigen-producing microbes.

Allosteric perspective on the mutability and druggability of the SARS-CoV-2 Spike protein

Recent developments in the SARS-CoV-2 pandemic point to its inevitable transformation into an endemic disease, urging both refinement of diagnostics for emerging variants of concern (VOCs) and design of variant-specific drugs in addition to vaccine adjustments. Exploring the structure and dynamics of the SARS-CoV-2 Spike protein, we argue that the high-mutability characteristic of RNA viruses coupled with the remarkable flexibility and dynamics of viral proteins result in a substantial involvement of allosteric mechanisms. While allosteric effects of mutations should be considered in predictions and diagnostics of new VOCs, allosteric drugs advantageously avoid escape mutations via non-competitive inhibition originating from alternative distal locations. The exhaustive allosteric signaling and probing maps presented herein provide a comprehensive picture of allostery in the spike protein, making it possible to locate potential mutations that could work as new VOC "drivers" and to determine binding patches that may be targeted by newly developed allosteric drugs.

Sagacious epitope selection for vaccines, and both antibody-based therapeutics and diagnostics: tips from virology and oncology

The target of an antibody plays a significant role in the success of antibody-based therapeutics and diagnostics, and vaccine development. This importance is focused on the target binding site—epitope, where epitope selection as a part of design thinking beyond traditional antigen selection using whole cell or whole protein immunization can positively impact success. With purified recombinant protein production and peptide synthesis to display limited/selected epitopes, intrinsic factors that can affect the functioning of resulting antibodies can be more easily selected for. Many of these factors stem from the location of the epitope that can impact accessibility of the antibody to the epitope at a cellular or molecular level, direct inhibition of target antigen activity, conservation of function despite escape mutations, and even non-competitive inhibition sites. By incorporating novel computational methods for predicting antigen changes to model-informed drug discovery and development, superior vaccines and antibody-based therapeutics or diagnostics can be easily designed to mitigate failures. With detailed examples, this review highlights the new opportunities, factors and methods of predicting antigenic changes for consideration in sagacious epitope selection.

More Than Meets the Kappa for Antibody Superantigen Protein L (PpL)

Immunoglobulin superantigens play an important role in affinity purification of antibodies and the microbiota-immune axis at mucosal areas. Based on current understanding, Staphylococcal Protein A (SpA), Streptococcal Protein G (SpG) and Finegoldia Protein L (PpL) are thought to only bind specific regions of human antibodies, allowing for selective purification of antibody isotypes and chains. Clinically, these superantigens are often classified as toxins and increase the virulence of the producing pathogen through unspecific interactions with immune proteins. To perform an in-depth interaction study of these three superantigens with antibodies, bio-layer interferometry (BLI) measurements of their interactions with a permutation panel of 63 IgG1 variants of Pertuzumab and Trastuzumab CDRs grafted to the six human Vκ and seven human VH region families were tested. Through this holistic and systemic analysis of IgG1 variants with various antibody regions modified, comparisons revealed novel PpL-antibody interactions influenced by other non-canonical antibody known light-chain framework regions, whereas SpA and SpG showed relatively consistent interactions. These findings have implications on PpL-based affinity antibody purification and design that can guide the engineering and understanding of PpL-based microbiota-immune effects.

Lateral Flow Assay for the Detection of African Swine Fever Virus Antibodies Using Gold Nanoparticle-Labeled Acid-Treated p72

African swine fever is a widespread and highly contagious disease in the porcine population, which is caused by African swine fever virus (ASFV). The PCR and ELISA detection methods are the main conventional diagnostic methods for ASFV antigen/antibody detection in the field. However, these methods have limitations of expensive equipment, trained technicians, and time-consuming results. Thus, a rapid, inexpensive, accurate and on-site detection method is urgently needed. Here we describe a double-antigen-sandwich lateral-flow assay based on gold nanoparticle-conjugated ASFV major capsid protein p72, which can detect ASFV antibody in serum samples with high sensitivity and specificity in 10 min and the results can be determined by naked eyes. A lateral flow assay was established by using yeast-expressed and acid-treated ASFV p72 conjugated with gold nanoparticles, which are synthesized by seeding method. A high coincidence (97.8%) of the assay was determined using clinical serum compared to a commercial ELISA kit. In addition, our lateral flow strip can detect as far as 1:10,000 diluted clinically positive serum for demonstration of high sensitivity. In summary, the assay developed here was shown to be rapid, inexpensive, accurate and highly selective. It represents a reliable method for on-site ASFV antibody detection and may help to control the ASFV pandemic.

Communication pathways bridge local and global conformations in an IgG4 antibody

The affinity of an antibody for its antigen is primarily determined by the specific sequence and structural arrangement of the complementarity-determining regions (CDRs). Recent evidence, however, points toward a nontrivial relation between the CDR and distal sites: variations in the binding strengths have been observed upon mutating residues separated from the paratope by several nanometers, thus suggesting the existence of a communication network within antibodies, whose extension and relevance might be deeper than insofar expected. In this work, we test this hypothesis by means of molecular dynamics (MD) simulations of the IgG4 monoclonal antibody pembrolizumab, an approved drug that targets the programmed cell death protein 1 (PD-1). The molecule is simulated in both the apo and holo states, totalling 4 μs of MD trajectory. The analysis of these simulations shows that the bound antibody explores a restricted range of conformations with respect to the apo one, and that the global conformation of the molecule correlates with that of the CDR. These results support the hypothesis that pembrolizumab featues a multi-scale hierarchy of intertwined global and local conformational changes. The analysis pipeline developed in this work is general, and it can help shed further light on the mechanistic aspects of antibody function.

Importance and Considerations of Antibody Engineering in Antibody-Drug Conjugates Development from a Clinical Pharmacologist's Perspective

Antibody-drug conjugates (ADCs) appear to be in a developmental boom, with five FDA approvals in the last two years and a projected market value of over $4 billion by 2024. Major advancements in the engineering of these novel cytotoxic drug carriers have provided a few early success stories. Although the use of these immunoconjugate agents are still in their infancy, valuable lessons in the engineering of these agents have been learned from both preclinical and clinical failures. It is essential to appreciate how the various mechanisms used to engineer changes in ADCs can alter the complex pharmacology of these agents and allow the ADCs to navigate the modern-day therapeutic challenges within oncology. This review provides a global overview of ADC characteristics which can be engineered to alter the interaction with the immune system, pharmacokinetic and pharmacodynamic profiles, and therapeutic index of ADCs. In addition, this review will highlight some of the engineering approaches being explored in the creation of the next generation of ADCs.

A general Fc engineering platform for the next generation of antibody therapeutics

Rationale: Fc engineering has become the focus of antibody drug development. The current mutagenesis and in silico protein design methods are confined by the limited throughput and high cost, while the high-throughput phage display and yeast display technologies are not suitable for screening glycosylated Fc variants. Here we developed a mammalian cell display-based Fc engineering platform. Methods: By using mammalian cell display and next generation sequencing, we screened millions of Fc variants for optimized affinity and specificity for FcγRIIIa or FcγRIIb. The identified Fc variants with improved binding to FcγRIIIa were substituted into trastuzumab and rituximab and the effector function of antibodies were examined in the PBMC-based assay. On the other hand, the identified Fc variants with selectively enhanced FcγRIIb binding were applied to CD40 agonist antibody and the activities of the antibodies were measured on different cell assays. The immunostimulatory activity of CD40 antibodies was also evaluated by OVA-specific CD8+ T cell response model in FcγR/CD40-humanized mice. Results: Using this approach, we screened millions of Fc variant and successfully identified several novel Fc variants with enhanced FcγRIIIa or FcγRIIb binding. These identified Fc variants displayed a dramatic increase in antibody-dependent cellular cytotoxicity in PBMC-based assay. Novel variants with selectively enhanced FcγRIIb binding were also identified. CD40 agonist antibodies substituted with these Fc variants displayed activity more potent than the parental antibody in the in vitro and in vivo models.Conclusions: This approach increased the throughput of Fc variant screening from thousands to millions magnitude, enabled screening variants containing multiple mutations and could be integrated with glycoengineering technology, represents an ideal platform for Fc engineering. The initial efforts demonstrated the capability of the platform and the novel Fc variants could be substituted into nearly any antibody for the next generation of antibody therapeutics.

Augmented reality in scientific visualization and communications: a new dawn of looking at antibody interactions

The use of augmented reality (AR) in providing three-dimensional (3D) visual support and image depth have been applied in education, tourism, historical studies, and medical training. In research and development, there has been a slow but growing use of AR tools in chemical and drug discovery, but little has been implemented for whole 3D antibody structures (IgE, IgM, IgA, IgG, and IgD) and in communicating their interactions with the antigens or receptors in publications. Given that antibody interactions can vary significantly between different monoclonal antibodies, a convenient and easy to use 3D visualization can convey structural mechanisms clearer to readers, especially in how residues may interact with one another. While this was previously constrained to the use of stereo images on printed material or molecular visualization software on the computer, the revolution of smartphone and phablets now allows visualization of whole molecular structures on-the-go, allowing rotations, zooming in and out, and even animations without complex devices or the training of visual prowess. While not yet as versatile as molecular visualization software on the computer, such technology is an improvement from stereo-images and bridges the gap with molecular visualization tools. In this report, we discuss the use of AR and how they can be employed in the holistic view of antibodies and the future of the technology for better scientific communication.

Sagacity in antibody humanization for therapeutics, diagnostics and research purposes: considerations of antibody elements and their roles

The humanization of antibodies for therapeutics is a critical process that can determine the success of antibody drug development. However, the science underpinning this process remains elusive with different laboratories having very different methods. Well-funded laboratories can afford automated high-throughput screening methods to derive their best binder utilizing a very expensive initial set of equipment affordable only to a few. Often within these high-throughput processes, only standard key parameters, such as production, binding and aggregation are analyzed. Given the lack of suitable animal models, it is only at clinical trials that immunogenicity and allergy adverse effects are detected through anti-human antibodies as per FDA guidelines. While some occurrences that slip through can be mitigated by additional desensitization protocols, such adverse reactions to grafted humanized antibodies can be prevented at the humanization step. Considerations such as better antibody localization, avoidance of unspecific interactions to superantigens and the tailoring of antibody dependent triggering of immune responses, the antibody persistence on cells, can all be preemptively considered through a holistic sagacious approach, allowing for better outcomes in therapy and for research and diagnostic purposes.