Bacterial lysate (respiratory) (BL)

Bacterial lysates (respiratory) are polyvalent immunomodulatory preparations composed of inactivated bacterial components and antigens derived from common respiratory pathogens such as Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. These extracts function as pathogen-associated molecular patterns (PAMPs) that engage the host's innate immune system through pattern recognition receptors, including Toll-like receptors (TLR2, TLR4) and NOD-like receptors. This interaction triggers the maturation of dendritic cells and macrophages, promoting a balanced Th1/Th2 immune response and stimulating the production of secretory IgA (sIgA) at mucosal surfaces. Clinically, these lysates are primarily used for the prophylaxis of recurrent respiratory tract infections (RRTIs) and the management of chronic obstructive pulmonary disease (COPD) and asthma exacerbations. Recent evidence also indicates their potential in reducing viral susceptibility by downregulating host cell receptors like ACE2 and TMPRSS2.

Other names

Mixed respiratory bacterial antigensPolyvalent bacterial lysateBacterial extractsOM-85Broncho-VaxomLantigen BIsmigenLuivacRibomunylPolyvalent mechanical bacterial lysate (PMBL)

Activation of pattern recognition receptors (PRRs), specifically Toll-like receptors (TLR2, TLR4, TLR7/8, TLR9) and NOD-like receptors (NOD2), on dendritic cells and macrophages, leading to immune system priming, enhanced Th1 responses, and increased production of secretory IgA (sIgA) at mucosal surfaces.