Respiratory bacterial antigens (PBL)

Respiratory bacterial antigens refer to a complex mixture of inactivated or lysed components derived from common respiratory pathogens, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus (Esposito et al., 2020, Frontiers in Immunology). These antigens are primarily utilized in the form of polyvalent bacterial lysates (PBLs) to act as immunomodulators that enhance the host's defense mechanisms against recurrent respiratory tract infections (RRTIs) (Cazzola et al., 2022, Therapeutic Advances in Respiratory Disease). By interacting with pattern recognition receptors like Toll-like receptors (TLRs) in the gut-associated lymphoid tissue (GALT) or bronchus-associated lymphoid tissue (BALT), they stimulate both innate and adaptive immune responses (Kearney et al., 2015, American Journal of Respiratory and Critical Care Medicine). This stimulation leads to the maturation of dendritic cells, increased secretion of protective IgA at mucosal surfaces, and a balanced Th1/Th2 cytokine profile. Clinically, these antigens are used to reduce the frequency and severity of infections in patients with chronic bronchitis, COPD, and pediatric recurrent infections (Jurkiewicz et al., 2021, Nutrients). While generally well-tolerated, they are considered a therapeutic modality rather than a specific molecular target within the human body.

Other names

Bacterial lysatesPolyvalent bacterial extractsRespiratory bacterial lysatesOM-85PMBLBacterial immunomodulators

Stimulation of mucosal immunity through the activation of pattern recognition receptors, primarily Toll-like receptors (TLRs) such as TLR2, TLR4, and TLR9, on dendritic cells and macrophages. This interaction triggers the maturation of immune cells and the production of cytokines (e.g., IFN-gamma, IL-10), leading to increased secretion of protective secretory IgA (sIgA) at mucosal surfaces and the recruitment of T and B lymphocytes to the respiratory tract.