Bacillus collagen-like protein A (BclA) (BclA)

Bacillus collagen-like protein A (BclA) is the primary surface glycoprotein located on the exosporium, the outermost layer of Bacillus anthracis spores (UniProt Q83WB0; NIH 1.2.1). It is characterized by a central collagen-like triple-helical domain and forms the hair-like projections that cover the spore surface, serving as the initial point of contact between the pathogen and the host immune system (NIH 1.2.3; NIH 1.3.4). BclA plays a significant role in pathogenesis by facilitating spore interaction with host cells, such as macrophages, and by recruiting host complement factor H to the spore surface to inhibit complement-mediated destruction (NIH 1.2.4; NIH 1.2.5). While not strictly required for germination, BclA is essential for spore persistence in the lungs and influences the efficiency of the host's innate immune response (NIH 1.2.3; NIH 1.2.4). Due to its high abundance and immunodominance, BclA is a major target for the development of recombinant vaccines and diagnostic assays designed to detect or neutralize the infectious spore form of anthrax (NIH 1.2.2; NIH 1.4.1).

Other names

Bacillus collagen-like protein of anthracisExosporium glycoprotein BclAMajor surface glycoprotein of Bacillus anthracis spores

Induction of opsonizing antibodies to enhance spore phagocytosis and neutralization; inhibition of complement factor H recruitment to the spore surface to prevent immune evasion (NIH 1.2.2, 1.2.4, 1.2.5).