Immunoglobulin a protease variants facilitate intracellular survival in epithelial cells by nontypeable haemophilus influenzae tat persist in the human respiratory tract in chronic obstructive pulmonary disease

Abstract

Background. Nontypeable Haemophilus influenzae (NTHi) persists in the airways in chronic obstructive pulmonary disease (COPD). NTHi expresses 4 immunoglobulin (Ig)A protease variants (A1, A2, B1, B2) with distinct cleavage specifcities for human IgA1. Little is known about the diflerent roles of IgA protease variants in NTHi infection. Methods. Twenty-six NTHi isolates from a 20-year longitudinal study of COPD were analyzed for IgA protease expression, survival in human respiratory epithelial cells, and cleavage of lysosomal-associated membrane protein 1 (LAMP1). Results. IgA protease B1 and B2-expressing strains showed greater intracellular survival in host epithelial cells than strains expressing no IgA protease (P