Elsevier

Immunobiology

Volume 212, Issues 4–5, 26 June 2007, Pages 381-416
Immunobiology

Surfactant protein A and surfactant protein D variation in pulmonary disease

https://doi.org/10.1016/j.imbio.2007.01.003Get rights and content
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Abstract

Surfactant proteins A (SP-A) and D (SP-D) have been implicated in pulmonary innate immunity. The proteins are host defense lectins, belonging to the collectin family which also includes mannan-binding lectin (MBL). SP-A and SP-D are pattern-recognition molecules with the lectin domains binding preferentially to sugars on a broad spectrum of pathogen surfaces and thereby facilitating immune functions including viral neutralization, clearance of bacteria, fungi and apoptotic and necrotic cells, modulation of allergic reactions, and resolution of inflammation. SP-A and SP-D can interact with receptor molecules present on immune cells leading to enhanced microbial clearance and modulation of inflammation. SP-A and SP-D also modulate the functions of cells of the adaptive immune system including dendritic cells and T cells.

Studies on SP-A and SP-D polymorphisms and protein levels in bronchoalveolar lavage and blood have indicated associations with a multitude of pulmonary inflammatory diseases. In addition, accumulating evidence in mouse models of infection and inflammation indicates that recombinant forms of the surfactant proteins are biologically active in vivo and may have therapeutic potential in controlling pulmonary inflammatory disease. The presence of the surfactant collectins, especially SP-D, in non-pulmonary tissues, such as the gastrointestinal tract and genital organs, suggest additional actions located to other mucosal surfaces. The aim of this review is to summarize studies on genetic polymorphisms, structural variants, and serum levels of human SP-A and SP-D and their associations with human pulmonary disease.

Keywords

Surfactant proteins A and D
Pulmonary diseases
Innate immunity
Inflammation
Phospholipid homoeostasis

Abbreviations

ALI
acute lung injury
BPD
bronchopulmonary dysplasia
CF
cystic fibrosis
COPD
chronic obstructive pulmonary disease
CTLD
C-type lectin domain
CVD
collagen vascular disease
IPF
idiopathic pulmonary fibrosis
MBL
mannan-binding lectin
PAP
pulmonary alveolar proteinosis
PRR
pathogen recognition receptors
PRM
pathogen recognition molecules
RDS
respiratory-distress syndrome
SNP
single nucleotide polymorphisms
SP-A and D
surfactant proteins A and D

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