SERPINB8 Antibody

Definition and Basic Characteristics

SERPINB8 Antibody is an immunoglobulin specifically engineered to detect Serpin B8, a member of the serine proteinase inhibitor superfamily. These antibodies are available in both monoclonal and polyclonal forms, with varying specificities and applications depending on the manufacturer and preparation method. The monoclonal variant SERPINB8 Antibody (PI-8) is a mouse monoclonal IgG1 kappa light chain antibody that specifically detects human SerpinB8 protein through multiple experimental techniques . Other variants include rabbit-derived polyclonal antibodies targeting specific epitopes of the Serpin B8 protein .

These antibodies bind with high specificity to their target protein, making them valuable tools for detecting, quantifying, and characterizing Serpin B8 in various biological samples. The consistent detection capability of these antibodies enables reliable research outcomes when studying the expression patterns and functions of Serpin B8 across different tissues and experimental conditions.

Structure and Molecular Properties

Serpin B8, the target of SERPINB8 antibodies, is a 42-45 kDa protein belonging to the ovalbumin (clade B) subfamily within the larger Serpin superfamily of protease inhibitors. Human Serpin B8 is 374 amino acids in length . The protein contains critical functional regions, including the reactive center loop that connects beta sheets A and C, which is essential for its inhibitory function . This reactive site is located between Arg336 and Arg342 in the protein sequence .

The gene encoding Serpin B8 (SERPINB8) is situated on human chromosome 18, in a region containing a cluster of serpin genes, highlighting the evolutionary significance of this protein family . The protein is characterized by a high degree of homology to chicken ovalbumin, lack of N- and C-terminal extensions, absence of a signal peptide, and a serine residue at the penultimate position .

Biological Functions and Expression

Serpin B8 plays multiple crucial roles in human physiology:

• Regulation of platelet aggregation

• Modulation of pathophysiological responses related to hemostasis and inflammation

• Inhibition of proteases including furin and chymotrypsin

• Maintenance of epithelial desmosome-mediated cell-cell adhesion

Despite lacking a traditional signal sequence, Serpin B8 can be both cytoplasmic and secreted, particularly released by platelets . The protein is expressed at high levels in vital tissues including the lung, liver, heart, and skeletal muscle, underscoring its importance in multiple physiological processes .

Research Applications

SERPINB8 antibodies have been validated for multiple research applications, enabling comprehensive investigation of Serpin B8 biology:

Western Blotting (WB)

Western blotting represents one of the primary applications for SERPINB8 antibodies, allowing researchers to detect and quantify Serpin B8 protein in complex biological samples. The recommended dilution range for Western blotting varies by product, typically between 1:500-1:2000 . This technique enables assessment of protein expression levels across different tissues or experimental conditions.

Immunohistochemistry (IHC)

SERPINB8 antibodies have been validated for immunohistochemistry with paraffin-embedded tissue sections (IHC-P), permitting visualization of Serpin B8 expression patterns within tissue architecture. For example, Human Serpin B8 Monoclonal Antibody has been successfully used to detect Serpin B8 in human pancreas tissue sections at 15 μg/mL concentration following heat-induced epitope retrieval .

Immunofluorescence (IF)

Several SERPINB8 antibodies are suitable for immunofluorescence applications, particularly those conjugated with fluorescent tags. This technique allows for direct visualization of Serpin B8 localization within cells, providing insights into its subcellular distribution and potential interactions .

Enzyme-Linked Immunosorbent Assay (ELISA)

ELISA represents another major application, with most SERPINB8 antibodies being validated for this technique. For ELISA applications, a starting concentration of 1 μg/mL is typically recommended, with optimization based on specific assay requirements .

Immunoprecipitation (IP)

Select SERPINB8 antibodies, particularly those available in agarose-conjugated forms, are suitable for immunoprecipitation studies, enabling isolation of Serpin B8 and its interacting partners from complex protein mixtures .

HIV-1 Inhibition Mechanisms

One of the most significant research discoveries involving SERPINB8 antibodies relates to Serpin B8's potential role in HIV-1 inhibition. Studies have demonstrated that Serpin B8, as an endogenous furin inhibitor, can inhibit HIV-1 Env maturation and efficiently reduce infectious HIV-1 production when rerouted to the secretory pathway .

These findings highlight the importance of protein subcellular localization in determining functional outcomes and demonstrate how protein engineering of endogenous inhibitors can create novel antiviral strategies.

Association with Exfoliative Ichthyosis

Research utilizing SERPINB8 antibodies has uncovered a critical link between loss-of-function mutations in SERPINB8 and an autosomal-recessive form of exfoliative ichthyosis, a rare skin condition. In a groundbreaking study, three unrelated families with loss-of-function mutations in SERPINB8 were identified, providing strong evidence for this association .

The mutations affected different regions of the protein:

• A frameshift variant (c.947delA) resulting in complete loss of the reactive site loop

• A missense variant (c.2T>C) affecting the start codon

• Additional variants affecting protein stability

Despite the different mutation types and locations, all appeared to compromise Serpin B8's ability to function extracellularly, suggesting this protein plays a crucial role in regulating extracellular protease cascades in skin homeostasis .

Role in Desmosome Regulation

Research employing SERPINB8 antibodies has revealed that Serpin B8 plays an important role in epithelial desmosome-mediated cell-cell adhesion. Studies using siRNA knockdown of SERPINB8 in keratinocytes demonstrated increased levels of desmoplakin along the plasma membrane, with a notable shift from plasma membranous localization to increased cytoplasmic localization .

This altered desmoplakin distribution was particularly pronounced in keratinocytes subjected to mechanical stress, suggesting Serpin B8 helps maintain desmosomal integrity under mechanical load. Interestingly, while protein levels of desmosomal components increased following SERPINB8 knockdown, mRNA levels decreased, indicating Serpin B8 may influence post-translational regulation of these adhesion structures .