CYTOKINE STIMULATION BYPSEUDOMONAS AERUGINOSA—STRAIN VARIATION AND MODULATION BY PULMONARY SURFACTANT

Abstract

Pulmonary surfactant and its components are part of the first-line immune defense within the lung. Here the authors show that the surfactant protein (SP) SP-D, but not SP-A, agglutinates some clinical isolates of Pseudomonas aeruginosa and Stenotrophomonas maltophilia. No agglutination of Staphylococcus aureus or Burkholderia cepacia was observed. The SP-D-induced agglutination of P. aeruginosa was not dependent on a specific lipopolysaccharide (LPS) serotype. The authors also show that SP-D, but not SP-A, increased the tumor necrosis factor (TNF alpha) release from human monocytic cells in response to a subset of P. aeruginosa and P. aeruginosa LPS. A clinical preparation of surfactant (Alveofact) blocked the TNF alpha release from monocytic cells induced by P. aeruginosa or its LPS. SP-A reversed the inhibitory effect of Alveofact in 6/8 strains of P. aeruginosa and 2/9 preparations of P. aeruginosa LPS. SP-D did not significantly alter the TNF alpha production induced by vital P. aeruginosa in the presence of Alveofact but markedly increased the TNF alpha release induced by a preparation of rough and smooth P. aeruginosa LPS. In summary, this study shows that the immunomodulatory properties of SP-A and SP-D specifically depend on the colonizing strain of P. aeruginosa. In addition, the authors show that the function of SP-A and SP-D is modulated in the presence of surfactant lipids.

Surfactant protein D in human lung diseases

“…Surfactant protein D binds to most species of gram‐negative bacteria including Pseudomonas aeruginosa [20,21], Klebsiella pneumoniae [22,23], Stenotrophomonas maltophilia [24], E. coli and Haemophilus influenzae [25]. It also binds to some gram‐positive organisms including Streptococcus pneumoniae and Staphylococcus aureus [26] via binding of the CRD to the bacterial cell wall components lipoteichoic acid and peptidoglycan [27].…”

Surfactant Protein A in Cystic Fibrosis: Supratrimeric Structure and Pulmonary Outcome

“…[26], [30]) wide variation in agglutination is observed; (2) agglutination may be depended on the growth phase of the bacterial strain (own unpublished observation), and (3) the assay used has been investigated extensively previously in a previous study [19], allowing others to reproduce the findings independently. In addition, the purpose of the assay is to demonstrate the multi-valence of SP-A and compare it between subjects and not so much to assess different micro-organisms.…”

Review: Surfactant protein D: A lung specific biomarker in COPD?

“…In alveolar macrophages, but not in peripheral blood mononuclear cells, SP-D stimulates the chemotaxis and actin polymerization at concentrations ranging from 10 to 25 µg/ml (Tino and Wright, 1999). SP-D may also stimulate the release of TNF-α from human monocyte cells in response to Pseudomonas aeruginosa and to LPS (Bufler et al 2004). Alveolar macrophages participate in SP-D turnover by internalization and degradation of SP-D (Dong and Wright, 1998).…”