Moraxella catarrhalis antigens

Moraxella catarrhalis antigens are a diverse group of surface-exposed molecules, primarily consisting of outer membrane proteins (OMPs) and lipooligosaccharides (LOS), that play critical roles in the bacterium's pathogenicity. Key antigens include the ubiquitous surface proteins A1 and A2 (UspA1 and UspA2), which act as trimeric autotransporter adhesins and facilitate immune evasion by binding host complement regulators, as well as the Moraxella IgD-binding protein (MID/Hag). These antigens are essential for the bacterium's ability to colonize the human respiratory tract, attach to epithelial cells, and resist the host's innate immune clearance mechanisms. Clinically, M. catarrhalis is recognized as a leading cause of acute otitis media in children and a major driver of exacerbations in adults with chronic obstructive pulmonary disease (COPD). Due to the high prevalence of beta-lactamase-mediated antibiotic resistance in this species, these surface antigens have become the primary focus for the development of prophylactic vaccines. Investigational candidates, such as the multi-antigen vaccine GSK3277511A, target conserved proteins like UspA2 to induce protective humoral and cellular immunity, aiming to reduce the global burden of respiratory infections and the associated socioeconomic costs.

Other names

Moraxella catarrhalis surface proteinsMoraxella catarrhalis outer membrane proteinsM. catarrhalis vaccine candidatesMoraxella catarrhalis adhesins

Vaccine-mediated induction of antigen-specific humoral and cellular immune responses, leading to the production of bactericidal IgG and IgA antibodies that inhibit bacterial adherence and promote opsonophagocytosis.