Hepatitis B Virus Pre-S2 Antigen ELISA Kit

Short Description:

Hepatitis B virus (HBV) pre-S2 antigen (Pre-S2) is a domain of the large surface protein (LHBs) present in the viral envelope, particularly enriched in infectious virions (Dane particles) and subviral particles. It is expressed during active viral replication and plays a role in hepatocyte attachment and viral entry. Pre-S2 antigen typically appears early in the course of HBV infection, often detectable in serum shortly after or concurrently with HBsAg, and serves as a sensitive marker of ongoing viral replication and high infectivity.

Detection of Pre-S2 antigen in serum indicates active HBV replication and is particularly useful in the early diagnosis of acute infection, assessment of viral activity in chronic carriers, and monitoring response to antiviral therapy. In acute hepatitis B, Pre-S2 usually disappears during resolution of infection, often preceding HBsAg clearance. Persistent positivity of Pre-S2 antigen beyond 6 months in the acute phase strongly suggests progression to chronic infection. Compared to other replication markers such as HBeAg or HBV DNA, Pre-S2 detection can provide complementary information, especially in HBeAg-negative cases where replication may persist due to precore or core promoter mutations.

Pre-S2 antigen testing enhances the comprehensive evaluation of HBV infection status when used alongside conventional serological markers (HBsAg, HBeAg, anti-HBc) and molecular assays (HBV DNA quantification), aiding in clinical decision-making for patient management and treatment initiation.

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Principle:

This kit employs the double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) principle for the qualitative detection of hepatitis B virus pre-S2 antigen (HBV Pre-S2 Ag) in human serum or plasma samples. The polystyrene microwell strips are pre-coated with monoclonal antibodies specific for HBV Pre-S2 antigen (capture antibodies). Upon addition of the serum or plasma specimen, any Pre-S2 antigen present in the sample binds specifically to the immobilized capture antibodies during incubation. Unbound components are subsequently removed by washing. In the next step, horseradish peroxidase (HRP)-conjugated detection antibodies (typically anti-HBs or anti-Pre-S2 specific antibodies) are added, which bind to different epitopes on the captured Pre-S2 antigen, forming a (capture Ab) - Pre-S2 Ag - (HRP-detection Ab) sandwich complex. Following a wash step to remove unbound HRP conjugates, a chromogenic substrate (TMB) is added to the wells. In the presence of the immunocomplex, the HRP enzyme catalyzes the substrate reaction, producing a blue color proportional to the amount of captured Pre-S2 antigen. The reaction is terminated by adding a stop solution (typically 50 μL per well), which changes the color to yellow. The absorbance (optical density) is then measured using a microplate reader at the appropriate wavelength (e.g., 450 nm, with a reference wavelength of 620-690 nm if required) to determine the presence or absence of HBV Pre-S2 antigen in the sample.

Product Features:

High sensitivity, specificity and stability

Product Specification:

Principle	Enzyme linked immunosorbent assay
Type	Double-antibody Sandwich
Certificate	NMPA
Specimen	Human serum / plasma
Specification	48T / 96T
Storage temperature	2-8℃
Shelf life	12 months