Antibodies isotype families

InvivoGen provides a series of clinically relevant antibodies in their original format or with different immunoglobulin isotypes. Their engineered antibodies are designed to adjust their effector functions, including half-life, complementdependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cell phagocytosis (ADCP). The variety of the immunoglobulin constant regions helps you determine the most suitable isotype for your application.

Monoclonal antibodies (mAbs) have become a major tool in the treatment of cancer and auto-immune diseases. The efficacy of antibodies is governed by their bifunctional nature. On the one hand, the variable domain of the immunoglobulin, within the fragment of antigen binding (Fab), confers antigen specificity function. On the other hand, the fragment crystallizable region (Fc) in the constant domain of the immunoglobulin triggers antibody-mediated effector functions by engaging a variety of Fc receptors. Antibody isotype switching is a biological process enabling changes in the ability of the antibody to interact with different Fc receptors and thus, reduce or potentiate effector functions. InvivoGen’s antibody isotype families consist of clinically relevant mAbs comprising the same variable domain and the constant domain of various isotypes, therefore differing in their suitability for a given application.

Native and engineered isotypes

• Native isotype antibodies – Physiological native isotypes trigger various combinations of effector functions that are summarized in the table below.
• IgG1NQ isotype antibodies – This isotype contains a N-glycosylation mutation of the constant region where potential asparagine (N) glycosylation sites are substituted by glutamine (Q) residues. These mAbs are non-glycosylated and their effector mechanisms mediated through the Fc receptor (FcγRI, FcγRII and FcγRIII), and the C1q component of the complement, are severely compromised or ablated.
• IgG1fut isotype antibodies – The constant region of these mAbs is not fucosylated. This results in dramatic enhancement of ADCC without any change in CDC.
• IgG4 (S228P) isotype antibodies – IgG4 antibodies undergo a process known as Fab arm exchange that potentially reduces their therapeutic efficacy. IgG4 (S228P) mAbs contain an engineered hinge region mutation (S228P) designed to prevent exchange of IgG4 molecules.

Features of InvivoGen antibody isotype families

Antibody specificities

• Human CD20 – CD20 (also known as B1) is a cell-surface marker expressed in both malignant and normal B cells. CD20 plays a role in the differentiation process of B cells into plasma cells. The hCD20 antibody family features the variable region of rituximab, a chimeric human/mouse IgG1 mAb. Binding of rituximab to CD20 results in cell destruction through different mechanisms including direct signaling of apoptosis, complement activation and cell-mediated cytotoxicity.
• Human CTLA4 – CTLA-4 (also known as CD152) is transiently expressed by activated T cells and highly expressed by regulatory T cells and it transduces negative intracellular signals upon binding to CD80 and CD86. The hCTLA4 antibody family features the variable region of ipilimumab which is a fully human IgG1 mAb. Ipilimumab blocks the immunosuppressive action of CTLA-4 and enhances antitumor T-cell responses. In addition, ipilimumab induces ADCC and TNF-α production.
• Human EGFR – The epidermal growth factor receptor (EGFR) is over-expressed in cancer cells and plays a key role in their proliferation and survival. The anti-hEGFR family features the variable region of cetuximab. Cetuximab is a chimeric human/mouse IgG1 mAb that targets EGFR, a cell surface receptor over-expressed in many types of cancer. Binding of cetuximab to EGFR blocks ligand/receptor binding, and induces receptor internalization and subsequent degradation.
• HER2 receptor – The human epidermal receptor HER2 (or HER2/neu, or ERBB2) is expressed at the cell membrane of epithelial cells and plays an important role in normal cell growth and differentiation. However, in some cancers, particularly in breast and ovarian cancers, HER2 is over-expressed and causes uncontrollable cell proliferation. The HER2 antibody family features the variable region of trastuzumab. Trastuzumab is a humanized IgG1 mAb whose binding to HER2 results in cell death through ADCC and ADCP.
• Human PD-1 – The programmed cell death 1 (PD-1) receptor is expressed mostly by activated T cells, but also by activated B cells, dendritic cells, monocytes and natural killer cells. Upon its binding to PD-L1, PD-1 mediates a negative intracellular signaling. The anti-hPD1 family features the variable region of nivolumab or pembrolizumab. Nivolumab is a fully human IgG4 (S228P) and pembrolizumab is a humanized IgG4 (S228P). These two mAbs bind and block the activation of PD-1, thus relieving immuno-suppression.
• Human PD-L1 – The programmed cell death ligand 1 (PD-L1) is a transmembrane protein over-expressed on tumor cells and tumor infiltrating immune cells, such as macrophages. Binding of PDL1 to PD-1 on cytotoxic T cells inhibits the antitumor immune response. The anti-hPD-L1 isotype family features the variable region of atezolizumab, a fully humanized IgG1 mAb that contains an Asp to Ala change introduced at position 298 (N298A) to eliminate its ability to bind to human Fcγ receptors. Atezolizumab is a blocking mAb targeting both human and mouse PD-L1.
• Human TNF-α – The tumor necrosis factor alpha (TNF-α) is a pro-inflammatory cytokine mainly secreted by macrophages and is implicated in a number of diseases, notably autoimmune diseases and cancer. The TNF-α antibody family features the variable region of adalimumab, a fully human mAb which blocks the interaction of TNF-α with TNF receptors, thereby downregulating the inflammatory reactions associated with autoimmune diseases.
• Human VEGF – The vascular endothelial growth factor (VEGF) plays an essential role in angiogenesis and it is over-expressed in many tumors. The antihVEGF family features the variable region of bevacizumab, a humanized IgG1 mAb which blocks VEGF interaction with the VEGF receptor thus inhibiting downstream pathways that regulate cell growth and angiogenesis.

Antibodies