tag-53 Antibody

Overview of CD53 and IGHV3-53/3-66 Antibodies

CD53 is a tetraspan membrane protein (35–42 kDa) expressed on leukocytes, including neutrophils, monocytes, and T/B cells, but absent on platelets or erythrocytes . It plays roles in signal transduction and interacts with proteins like CD20, CD2, and integrins .

IGHV3-53/3-66 refers to immunoglobulin heavy-chain variable genes encoding public antibodies frequently observed in SARS-CoV-2 immune responses. These antibodies target the receptor-binding domain (RBD) of the spike protein and demonstrate potent neutralizing activity against viral variants .

CD53 Antibodies

• Clone QA19A07: A mouse IgG1 monoclonal antibody (TotalSeq™-A1274) used for flow cytometry and immunohistochemistry .

• Epitope: Recognizes CD53’s extracellular loops; critical for leukocyte activation and adhesion .

• Applications: Immune cell profiling, leukemias, and autoimmune disease studies .

Table 1: CD53 Antibody Characteristics

IGHV3-53/3-66 Antibodies

• Neutralization Breadth:

  • Target SARS-CoV-2 RBD with high affinity ($K_d$: 0.04–17 nM) .

  • Neutralize Omicron subvariants (e.g., BA.2.86, JN.1) and reduce viral loads in animal models .

• Structural Features:

  • Short CDR H3 loops (9–15 amino acids) with low somatic hypermutation (SHM) .

  • Bind RBD at overlapping ACE2-binding sites, blocking viral entry .

Table 2: Key IGHV3-53/3-66 Antibodies

Mechanistic Insights and Research Findings

• IGHV3-53/3-66 Antibodies:

  • Public Antibody Response: Identified in 53.8% of top SARS-CoV-2 neutralizers across patients, indicating a conserved immune mechanism .

  • Delta Breakthrough Maturation: Delta variant infection enhances SHM, broadening neutralization to Omicron subvariants .

  • Escape Mutations: K417N (B.1.351 variant) abolishes neutralization, highlighting vulnerability to antigenic drift .

• CD53 Antibodies:

  • Therapeutic Potential: Modulate B cell activation and leukocyte adhesion, with implications for immunotherapy .

Applications and Clinical Relevance

• IGHV3-53/3-66 Antibodies:

  • Vaccine Design: Basis for pan-coronavirus vaccines due to conserved epitope targeting .

  • Antiviral Therapeutics: K4-66 reduces lung viral loads in hamsters by >90% .

• CD53 Antibodies:

  • Diagnostics: Biomarker for hematopoietic cancers (e.g., leukemia) via flow cytometry .

  • Autoimmunity: Targeting CD53 disrupts pathogenic immune cell interactions .

Comparative Analysis of Antibody Classes

Table 3: Functional Comparison