Surfactant proteins A and D enhance the phagocytosis of Chlamydia into THP-1 cells.
Chlamydiae are intracellular bacterial pathogens that infect mucosal surfaces, i.e., the epithelium of the lung, genital tract, and conjunctiva of the eye, as well as alveolar macrophages. In the present study, we show that pulmonary surfactant protein A (SP-A) and surfactant protein D (SP-D), lung collectins involved in innate host defense, enhance the phagocytosis of Chlamydia pneumoniae and Chlamydia trachomatis by THP-1 cells, a human monocyte/macrophage cell line. We also show that SP-A is able to aggregate both C. trachomatis and C. pneumoniae but that SP-D only aggregates C. pneumoniae. In addition, we found that after phagocytosis in the presence of SP-A, the number of viable C. trachomatis pathogens in the THP-1 cells 48 h later was increased approximately 3.5-fold. These findings suggest that SP-A and SP-D interact with chlamydial pathogens and enhance their phagocytosis into macrophages. In addition, the chlamydial pathogens internalized in the presence of collectins are able to grow and replicate in the THP-1 cells after phagocytosis.
Oberley
Rebecca E
RE
Department of Anatomy and Cell Biology, University of Iowa College of Medicine, Iowa City, IA 52242, USA.
Ault
Kevin A
KA
Neff
Traci L
TL
Khubchandani
Kavita R
KR
Crouch
Erika C
EC
Snyder
Jeanne M
JM
D000818:Animals; D002690:Chlamydia Infections / Q000276:immunology*; D002692:Chlamydia trachomatis / Q000254:growth & development / Q000276:immunology*; D016993:Chlamydophila pneumoniae / Q000254:growth & development / Q000276:immunology; D006801:Humans; D016676:Macrophages, Alveolar / Q000276:immunology / Q000382:microbiology; D010587:Phagocytosis / Q000187:drug effects*; D011014:Pneumonia / Q000276:immunology; D037662:Pulmonary Surfactant-Associated Protein A / Q000494:pharmacology*; D037663:Pulmonary Surfactant-Associated Protein D / Q000494:pharmacology*; D051381:Rats; D020298:U937 Cells
D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D