Anti-SARS-CoV-2 Spike S2 ECD Rabbit Polyclonal Antibody for WB, DB, IF/ICC, IP, and ELISA - P0DTC2

Core Product Specifications and Parameters

Biological Background: Spike Glycoprotein (S) Function and Localization

• The spike (S) glycoprotein is a class I viral fusion protein that is cleaved into S1 and S2 subunits. S1 contains the receptor-binding domain, while S2 anchors the protein and executes membrane fusion.
• S1 attaches to the host receptor ACE2 to initiate infection. Alternative entry receptors include neuropilin-1 (NRP1), neuropilin-2 (NRP2), integrins, and asialoglycoprotein receptor 1 (ASGR1), which may contribute to SARS-CoV-2 tropism in cells with low ACE2 expression.
  Related references:
  PMID:32142651, PMID:32155444, PMID:33607086, PMID:33082294, PMID:33082293, PMID:35150743, PMID:34837059
• Proteolytic cleavage of S2 at the S2' site by host TMPRSS2 (cell surface) or cathepsin L (endosomal) triggers irreversible conformational changes that lead to fusion of the viral envelope with the host membrane, releasing the viral genome into the cytoplasm.
  Related references:
  PMID:32142651, PMID:32703818, PMID:34159616, PMID:34561887
• The S2 subunit contains heptad repeat regions (HR1 and HR2) that fold into a six-helix bundle, bringing the viral and cellular membranes into close apposition for fusion.
• Subcellularly, the spike protein localizes to the virion membrane, the host ER-Golgi intermediate compartment (ERGIC), and the host cell plasma membrane.
• Spike is heavily N-glycosylated and palmitoylated, contains disulfide bonds, and functions as a superantigen; it also suppresses host innate immune responses and counteracts tetherin.

Experimental Guidance and Technical Tips

• The immunogen spans the S2 extracellular domain (aa 686-1214), covering conserved functional elements including the fusion peptide and heptad repeats. This design enables detection of S2 even after S1 shedding.
• For Western blot, the full-length spike protein migrates at ~141 kDa under reducing conditions; a band of ~70-80 kDa may be observed for cleaved S2. Validate your lysis and sample preparation conditions.
• In immunofluorescence/ICC, include a permeabilization step to detect spike localized to intracellular compartments (ERGIC) in addition to the plasma membrane.
• For capture ELISA, consider pairing this pAb with a monoclonal antibody against the S1 subunit to specifically measure full-length spike, or use it as a detection reagent to quantitate S2 levels.
• Dot blot (DB) can be used for quick screening of antigen expression in cell lysates or recombinant proteins; optimize antigen concentration and buffer conditions.
• Immunoprecipitation (IP) may capture spike complexes; include appropriate negative controls to assess non-specific binding.

CamelBio: Your One-Stop Sourcing Bridge

CamelBio provides diagnostic manufacturers, labs, and research institutes with one-stop access to IVD raw materials, technical services, and consulting—covering every stage from concept to clinic. For SARS-CoV-2 spike protein research and serological assay development, our sourcing platform offers validated antibody pairs, optimized polyclonal and monoclonal antibodies, and bulk ancillary reagents. Whether you need rare-target raw materials or reliable supply for large-scale manufacturing, CamelBio bridges your IVD needs.