DCs also express receptors for match fragments such as C3a and C5a, and signaling through these receptors increase major histocompatibility complex (MHC) expression, antigen internalization, and antigen presentation. may contribute to the vaccine effect of mAbs. These different aspects of match are also briefly examined in the specific context of FDA-approved therapeutic anti-cancer IgG1 mAbs. Keywords: therapeutic monoclonal antibodies (mAbs), match, antibody dependent cellular cytotoxicity, phagocytosis, match receptors 1. Introduction Human IgG1 monoclonal antibodies (mAbs), after antigen binding, have the ability to activate the classical pathway of the match U 73122 cascade and mediate complement-dependent cytotoxicity (CDC) [1,2]. They can also cross-link Fc receptors expressed by immune cells, including natural killer (NK) cells, monocytes/macrophages, and neutrophils, and thereby activate cell-mediated innate immunity [2,3,4]. IgG1 mAbs therefore have the ability to activate both the humoral and cellular immune system U 73122 for the immunological control of tumor growth and metastasis. These two pathways may also interact with each other, with potential synergy [5]. This is why most therapeutic mAbs that target a tumor antigen have been designed to bear a functional or even enhanced human IgG1 Fc portion. The tumor-specific unconjugated mAbs approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA) are outlined in Table 1. The first part of the table lists mAbs approved for hematological malignancies, and the U 73122 second part lists mAbs approved to target solid tumors. The gold standard for these mAbs is the anti-CD20 rituximab, which was the first approved anti-cancer mAb (in 1997) and has shown considerable therapeutic activity in several B cell tumor subtypes, initially as monotherapy, and subsequently in combination with chemotherapy. Indeed multiple phase III clinical studies have exhibited the clinical efficacy of rituximab in combination with chemotherapy or as maintenance therapy in B-cell non-Hodgkins lymphoma (B-NHL) (in particular follicular lymphoma T and diffuse large B cell lymphoma) and, to a lesser extent, chronic lymphocytic leukemia (CLL), Burkitts lymphoma, and mantle cell lymphomas (examined in Recent, Present, and Future of Rituximab-The Worlds First Oncology Monoclonal Antibody Therapy [6]). Rituximab efficiently activates CDC, antibody-dependent cellular cytotoxicity (ADCC), and antibody-dependent cellular phagocytosis (ADCP) in vitro, and these different mechanisms must all contribute to its efficacy [4,7]. CD20 is usually well expressed in most mature B-cell leukemias and lymphomas and is nearly exclusively restricted to the B cell lineage, a factor likely contributing to the success of rituximab and other anti-CD20 antibodies. Table 1 Approved unconjugated IgG1 monoclonal antibodies (mAbs) targeting tumor antigen.
RituximabCD20Chimeric IgG1B-NHL1997CDC, ADCC, ADCPOfatumumabCD20Human IgG1CLL2009CDC, ADCC, ADCPObinutuzumabCD20Humaniz. IgG1, Glycoengin.CLL2013ADCC, ADCP, PCDDaratumumabCD38Human IgG1MM2015CDC, ADCC, ADCP, neutral.IsatuximabCD38Chimeric IgG1kMM2020Neutral. ADCC, ADCPAlemtuzumabCD52Humanized IgG1CLL2001CDC, ADCC, ADCPElotuzumabSLAMF7Humanized IgG1MM2015ADCC. NK agonist, ADCPMogamulizumabCCR4Humanized IgG1, low fucoseT leuk/lymph2012 Japan U 73122 2018 EUADCC, ADCP, Treg elimin.TrastuzumabHER2Humanized IgG1Breast cancer1998ADCC, neutral.PertuzumabHER2Humanized IgG1Breast cancer2012Neutral. (HER2/HER3 dimerization)CetuximabEGFRChimeric IgG1CRC2004Neutral., ADCC, CDCPanitumumabEGFRHuman IgG2CRC2006Neutral., PMN mediated ADCCNecitumumabEGFRHuman IgG1NSCLC2015ADCC, neutral.DinutuximabGD2Chimeric IgG1Neuroblastoma2015CDC, ADCC, ADCP Open in a separate window 1 Food and Drug Administration (FDA) and/or European Medicines Agency (EMA) approval. B-NHL: B- Non Hodgkins lymphoma; CLL: Chronic lymphocytic leukemia; MM: Multiple myeloma; CRC: Colorectal carcinoma; NSCLC: Non small cell lung carcinoma; CDC: Match dependent cytotoxicity; ADCC: Antibody dependent cellular cytotoxicity; ADCP: Antibody dependent cellular phagocytosis. U 73122 Beyond their activation of innate immune mechanisms mentioned above, mAbs targeting tumor antigens may also act by blocking (neutralizing) the antigen receptor or enzymatic function through their Fab portion,.
