Ag85B
Description
Secretion Dynamics and Strain Variability
Key findings from in vitro and in vivo studies:
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Comparative secretion:
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In vivo kinetics: Lung Ag85B levels peak at 21 days post-infection in mice, then decline 10,000-fold as bacterial growth arrests
Humoral and Cellular Responses
Immune Evasion Mechanisms
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Extracellular Ag85B creates antigenic "decoys," reducing infected-cell recognition by T cells
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Released via:
Subunit Vaccines
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Hybrid-1 (Ag85B-ESAT6):
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Ag85B-TB10.4:
BCG Modifications
| Vaccine Construct | Macrophage Uptake | Protection vs Mtb |
|---|---|---|
| BCG(Δ85B) | ↓63% | No change |
| BCG(oex85B) | ↑41% | No improvement |
Prime-Boost Strategies
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Ag85B peptide boost ↑ IFN-γ (1,850 pg/mL) vs BCG boost (620 pg/mL)
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Sustained antigen release from amyloid aggregates improves immunogenicity (↑Th1 responses 4.7-fold)
Diagnostic and Therapeutic Potential
Current Research Frontiers
Product Specs
DDYNGWDINTPAFEWYYQSGLSIVMPVGGQSSFYSDWYSPACGKAGCQTYKWETF
LTSELPQWLSANRAVKPTGSAAIGLSMAGSSAMILAAYHPQQFIYAGSLSALLDP
SQGMGPSLIGLAMGDAGGYKAADMWGPSSDPAWERNDPTQQIPKLVANNTRLWVY
CGNGTPNELGGANIPAEFLENFVRSSNLKFQDAYNAAGGHNAVFNFPPNGTHSWE
YWGAQLNAMKGDLQSSLGAG.
Product Science Overview
Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis (TB), one of the deadliest infectious diseases worldwide. The antigen 85 (Ag85) complex, comprising Ag85A, Ag85B, and Ag85C, is a group of major secretory proteins of Mtb. Among these, Ag85B is the most abundant and immunodominant protein, playing a crucial role in the pathogenesis and immune response of TB.
Ag85B is a 30-kDa protein that is secreted by Mtb and is involved in the synthesis of the mycobacterial cell wall. It catalyzes the transfer of mycolic acids to the cell wall arabinogalactan, a critical step in maintaining the integrity and virulence of the bacterium. The protein is highly conserved among mycobacterial species, making it a prime target for diagnostic and therapeutic interventions.
Ag85B is known for its strong immunogenic properties. It elicits a robust immune response, particularly the activation of CD4+ T cells and the production of interferon-gamma (IFN-γ). This immune response is essential for controlling Mtb infection, as IFN-γ activates macrophages to kill the intracellular bacteria. However, Mtb has evolved mechanisms to exploit the immunogenicity of Ag85B to its advantage, promoting its own survival and spread within the host .
Recombinant Ag85B is produced using genetic engineering techniques, where the gene encoding Ag85B is cloned and expressed in a suitable host system, such as Escherichia coli. The recombinant protein is then purified and used in various applications, including vaccine development, diagnostic assays, and research studies.
Ag85B is a key component in several subunit vaccines under development for TB. These vaccines aim to enhance the protective immune response against Mtb by including Ag85B as an antigen. Studies have shown that immunization with Ag85B DNA or protein induces a strong antigen-specific CD4+ T cell and IFN-γ response, providing protection against TB .
Recombinant Ag85B is also used in diagnostic assays to detect TB infection. It serves as a biomarker for the presence of Mtb, and its detection can aid in the diagnosis of active TB. Various assays, such as enzyme-linked immunosorbent assay (ELISA) and immunoblot, have been developed using recombinant Ag85B to identify TB infection .
