Shark IgNAR: The Next Broad Application Antibody in Clinical Diagnoses and Tumor Therapies?

Nanoscale warriors against viral invaders: a comprehensive review of Nanobodies as potential antiviral therapeutics

Viral infections remain a significant global health threat, with emerging and reemerging viruses causing epidemics and pandemics. Despite advancements in antiviral therapies, the development of effective treatments is often hindered by challenges, such as viral resistance and the emergence of new strains. In this context, the development of novel therapeutic modalities is essential to combat notorious viruses. While traditional monoclonal antibodies are widely used for the treatment of several diseases, nanobodies derived from heavy chain-only antibodies have emerged as promising "nanoscale warriors" against viral infections. Nanobodies possess unique structural properties that enhance their ability to recognize diverse epitopes. Their small size also imparts properties, such as improved bioavailability, solubility, stability, and proteolytic resistance, making them an ideal class of therapeutics for viral infections. In this review, we discuss the role of nanobodies as antivirals against various viruses. Techniques used for developing nanobodies, delivery strategies are covered, and the challenges and opportunities associated with their use as antiviral therapies are discussed. We also offer insights into the future of nanobody-based antiviral research to support the development of new strategies for managing viral infections.

Shark immune system: A review about their immunoglobulin repertoire

In the past few decades, the literature about the immune system of vertebrates has increased thanks to the research about new therapies and new biomolecules able to treat or eradicate many human autoimmune diseases. Researchers found that immunoglobulins (Igs) are the most versatile biomolecules able to recognize almost every existing epitope with their binding domains. Phylogenetically, the most recent vertebrates exhibit the greatest sequence diversification in their Igs to extend their ability to distinguish different antigens. Among cartilaginous fishes, the most ancient vertebrates on phylogenetic history, sharks possess four types of Igs with similar pathways to extend sequence diversity and binding domains variability. Their Ig new antigen receptor (IgNAR) represents one of the most versatile and small Ig type upon all other species. The shark species are fundamental sources of new therapeutic receptors lending a further step to treatments against several human diseases. The aim of this review is to analyze sharks Igs, focusing on IgNARs for each species.

Screening and Interaction Analysis of Shark-Derived Nanobodies against Crayfish Major Allergen Pro c 2

Pro c 2 (arginine kinase) is a major allergen in crayfish (Procambarus clarkii). Shark-derived variable domains of new antigen receptors (VNARs) have advantages in developing allergen detection and immunotherapy. This study constructed a VNAR domain library from Chiloscyllium plagiosum immunized with Pro c 2. Three VNARs (VNAR-11, VNAR-20, and VNAR-29) against Pro c 2 obtained by screening the library were expressed in the HEK293F cells, fusing with the immunoglobulin (Ig) G1 Fc fragment (VNAR-Fc-11, VNAR-Fc-29, and VNAR-Fc-20). The VNAR-Fc fusions bound to Pro c 2 with an affinity KD ranging from 0.2131 ∼ 465.3 μM, with the ability to inhibit patients' IgE binding to Pro c 2. VNAR-20 and VNAR-29 displayed more stable binding with Pro c 2 during molecular dynamics simulation. The binding sites of the VNARs are distributed in the conserved IgE epitopes of arginine kinase. These achievements indicate the application potential of VNARs in allergen detection and allergy therapeutics.

Discovery of nanobodies: a comprehensive review of their applications and potential over the past five years

Nanobodies (Nbs) are antibody fragments derived from heavy-chain-only IgG antibodies found in the Camelidae family as well as cartilaginous fish. Their unique structural and functional properties, such as their small size, the ability to be engineered for high antigen-binding affinity, stability under extreme conditions, and ease of production, have made them promising tools for diagnostics and therapeutics. This potential was realized in 2018 with the approval of caplacizumab, the world's first Nb-based drug. Currently, Nbs are being investigated in clinical trials for a broad range of treatments, including targeted therapies against PDL1 and Epidermal Growth Factor Receptor (EGFR), cardiovascular diseases, inflammatory conditions, and neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. They are also being studied for their potential for detecting and imaging autoimmune conditions and infectious diseases such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A variety of methods are now available to generate target-specific Nbs quickly and efficiently at low costs, increasing their accessibility. This article examines these diverse applications of Nbs and their promising roles. Only the most recent articles published in the last five years have been used to summarize the most advanced developments in the field.

Screening and anti-angiogenesis activity of Chiloscyllium plagiosum anti-human VEGFR2 single-domain antibody

Recently, the incidence of malignant tumors is on the rise and searching for new treatments on it has become the research priority. Blocking the vascular endothelial growth factor (VEGF) and its receptor (VEGFR) is one of the treatment strategies that used in the development of specific anti-angiogenic drugs. The deficiencies in tissue penetration and affinity maturation become the weakness of these drugs in anti-tumors applications. The single heavy chain antibody found in Chiloscyllium plagiosum, which has a low molecular weight and superior tissue penetration of variable region (variable new antigen receptor, VNARs), was considered to have the high antigen-binding activity and stability. This type of antibody has a simple structure that can be prokaryoticaly expressed, which makes it easily to produce new antiangiogenic target drugs. Specific anti-IgNAR rabbit multiple antibodies have been used to assess the level of VNARs in sharks and have shown a significant enrichment of IgNAR after triple immunization. An anti-VEGFR2 phage library was used for the targeted VNARs screening, and five candidate VNARs sequences were subsequently obtained by phage screening, followed by combined screening with the transcriptome library, and analysis of conserved regions along with 3D modelling matched the VNAR profile. ELISA and cell-based assays showed that two of the VNARs, VNAR-A6, and VNAR-E3, had a superior antigen affinity and anti-angiogenic activity thereby being able to inhibit human Umbilical Vein Endothelial Cells proliferation and migration. The anti-VEGFR2 VNARs derived from the immunized C. plagiosum and screened by phage library, which provide the new research ideas and specific approaches for the development of new drugs. The anti-VEGFR2 VNARs are capable for blocking the VEGF-VEGFR pathway, which of these may contribute to expanding the use of anti-angiogenic drugs.

Exclusion of PD-1 from the immune synapse: A novel strategy to modulate T cell function

Targeting immune checkpoint receptors on T cells is a common cancer treatment strategy. Frequently, this is accomplished through antibodies targeting the ligand of inhibitory co-receptors. Blocking the immune checkpoint PD-1 binding to its ligands PD-L1 and PD-L2 prevents downstream signaling and enhances anti-tumor T cell responses. This approach improves cancer patients' outcomes. However, only one-third of the patients respond to these treatments. To better understand the mechanism of anti-PD-1 antibodies, we explored the location of PD-1 within the immune synapse. Surprisingly, we discovered that anti-PD-1 antibodies, besides blocking the interaction between PD-1 and its ligands, also removed PD-1 from the synapse. We demonstrated a correlation between removing PD-1 from the synapse by anti-PD-1 antibodies and the extent of T cell activation. Interestingly, a short version of the anti-PD-1 antibody, F(ab')2, failed to remove PD-1 from the synapse and activate T cells. Using the syngeneic tumor model, we showed a superior anti-tumor effect of the anti-PD-1 antibody over the shorter version of the same antibody. Our data indicate that anti-PD-1 antibodies activate T cells by removing PD-1 from the synapse, and changing the location of PD-1 or other immune receptors within the immune synapse could serve as an alternative, efficient approach to treat cancer.

vNARs as Neutralizing Intracellular Therapeutic Agents: Glioblastoma as a Target

Glioblastoma is the most prevalent and fatal form of primary brain tumors. New targeted therapeutic strategies for this type of tumor are imperative given the dire prognosis for glioblastoma patients and the poor results of current multimodal therapy. Previously reported drawbacks of antibody-based therapeutics include the inability to translocate across the blood-brain barrier and reach intracellular targets due to their molecular weight. These disadvantages translate into poor target neutralization and cancer maintenance. Unlike conventional antibodies, vNARs can permeate tissues and recognize conformational or cryptic epitopes due to their stability, CDR3 amino acid sequence, and smaller molecular weight. Thus, vNARs represent a potential antibody format to use as intrabodies or soluble immunocarriers. This review comprehensively summarizes key intracellular pathways in glioblastoma cells that induce proliferation, progression, and cancer survival to determine a new potential targeted glioblastoma therapy based on previously reported vNARs. The results seek to support the next application of vNARs as single-domain antibody drug-conjugated therapies, which could overcome the disadvantages of conventional monoclonal antibodies and provide an innovative approach for glioblastoma treatment.

Exclusion of PD-1 from the immune synapse: a novel strategy to modulate T cell function

Targeting immune checkpoint receptors on T cells is a common cancer treatment strategy. Frequently, this is accomplished through antibodies targeting the ligand of inhibitory co-receptors. Blocking the immune checkpoint PD-1 binding to its ligands PD-L1 and PD-L2 prevents downstream signaling and enhances anti-tumor T cell responses. This approach improved cancer patients' outcome. However, only one-third of the patients respond to these treatments. To better understand the mechanism of anti-PD-1 antibodies, we explored the location of PD-1 within the immune synapse. Surprisingly, we discovered that anti-PD-1 antibodies, besides blocking the interaction between PD-1 and its ligands, also removed PD-1 from the synapse. We demonstrated a correlation between removing PD-1 from the synapse by anti-PD-1 antibodies and the extent of T cell activation. Interestingly, a short version of the anti-PD-1 antibody, F(ab') 2 , failed to remove PD-1 from the synapse and activate T cells. Using syngeneic tumor model, we showed a superior anti-tumor effect to anti-PD-1 antibody over the shorter version of the antibody. Our data indicates that anti-PD-1 antibodies activate T cells by removing PD-1 away from the synapse and changing the location of PD-1 or other immune receptors within immune synapse could serve as an alternative, efficient approach to treat cancer.