Anti-CD64 Monoclonal Antibody Fab Fragment

One of the representative genes of the FCGR1 family, FCGR1A (CD64) is the most essential gene that produces the highly recombinant immunoglobulin G (IgG) Fc receptor, a crucial immunological regulator. This family includes the following members: FCGR1A, FCGR1B, and FCGR1C. They are all found in the 1q21–23 region of human chromosome 1.These genes' proteins are structurally and functionally very similar, but they are encoded on different expression platforms and different function. The most researched gene is FCGR1A and its CD64 protein is the principal Fc receptor on the surface of monocytes and macrophages. It has a unique high affinity, enabling it to tightly bind monomeric IgG, whereas the functions of FCGR1B and FCGR1C are relatively less studied. It is currently believed that these receptors may play a role in regulating FCGR1A.The role and medical importance of CD64 differ across diseases situations where it plays a part, in facilitating antibody dependent cellular cytotoxicity (ADCC) especially in cases of infectious diseases and cancer as well as inflammatory conditions. Cytokines, such as interferon gamma (IFN gamma) and granulocyte macrophage colony stimulating factor (GM CSF), affect the CD64 levels; they increase during infections and inflammation states. In bacterial sepsis, researchers found that CD64 is a sensitive marker for infection, and its high levels on neutrophils separate bacteria from viruses. CD64 plays a diagnostic role particularly relevant to pediatric sepsis, where measuring the neutrophil CD64 index can aid early diagnosis and management. Additionally, in chronic infections such as tuberculosis and brucellosis, sustained high expression of CD64 is thought to be closely related to persistent pathogen stimulation and the long-term activation of the immune system.

Figure 1. Protein-Protein Interaction Network of FCGR1A. (Source: Wu J, et al., 2022)

In inflammatory disorders, changes in CD64 expression indicate immune status. Studies show that CD64 activity on peripheral blood monocytes is highly increased in rheumatoid arthritis patients, and that this is related to disease severity. Furthermore, in systemic lupus erythematosus (SLE), CD64 expression patterns correlate with certain inflammatory markers (such as antinuclear antibodies and complement levels), suggesting its potential as an indicator of disease activity. In rare autoinflammatory diseases such as periodic fever syndromes, dynamic changes in CD64 offer references for disease monitoring and treatment efficacy assessment. CD64's function in cancer goes beyond immune regulation to the remodeling of the tumor microenvironment. Tumor-secreted ligands regulate CD64 expression in TAMs. Such TAMs typically display M2 polarization, which encourages tumor development and immune escape. For some solid tumors, including cervical cancer and cholangiocarcinoma, greater CD64 expression predicts better outcomes, perhaps by driving antigen release and T-cell activation and so triggering anti-tumor immune responses. But in other cancers (such as clear cell renal carcinoma), elevated levels of CD64 might be a sign of a hyper-repressive microenvironment, one that has poor prognosis. Furthermore, CD64 is strongly correlated with the effectiveness of some immunotherapies. In ADC therapies, for example, the high affinity binding property of CD64 leads to the uptake of drugs in effector cells, increasing treatment efficiency. CD64's involvement in allergic disorders has garnered much interest, too. Although its primary role is mediating IgG-related immune responses, some studies suggest that excessive activation of CD64 may contribute to the exacerbation of allergic inflammation. By inhibiting CD64 signaling, tissue damage and inflammation may be reduced, providing a potential target for anti-allergic drug development.

The genetic polymorphisms of CD64 represent another important area of research. A number of studies have reported that SNPs in CD64 could be related to the individual's vulnerability to infection, inflammation and cancer. Some SNPs, for instance, lead to an increased risk of bacterial infections in certain populations; others might affect CD64's affinity and function, thereby impacting the efficacy of antibody therapies. Such findings provide promising insights for individualized treatment plans. For lab and clinical purposes, CD64 can be detected by various means, such as flow cytometry, enzyme-linked immunosorbent assay (ELISA), and immunofluorescence staining. These diagnostic tools provide precise instruments for research and diagnosis. With advances in technology, novel diagnostic kits based on CD64 are continuously emerging, offering more efficient solutions for the rapid detection of infection- and inflammation-related diseases. Meanwhile, CD64's promise as a target for therapeutic action is being explored. Monoclonal antibodies against CD64, for instance, have been shown to be efficacious in preclinical studies, as inhibiting the IgG binding site prevents overactive FcR signaling and suppresses immune tissue damage. As a high-affinity Fc receptor, FCGR1A (CD64), in short, is a representative high-affinity receptor with diverse functions within the immune system and with significant diagnostic and therapeutic value in infectious disease, inflammation and cancer. We expect that future work on CD64, including how it is involved in disease-like processes and how its activity is controlled by polymorphisms, will lead to further avenues for personalized medicine and new immunotherapies. This multi-dimensional research will undoubtedly drive the widespread clinical application of CD64.

CD64 Monoclonal Antibody
Anti-CD64
CD64 Antibody