Surfactant protein A integrates activation signal strength to differentially modulate T cell proliferation.

Journal Article

Pulmonary surfactant lipoproteins lower the surface tension at the alveolar-airway interface of the lung and participate in host defense. Previous studies reported that surfactant protein A (SP-A) inhibits lymphocyte proliferation. We hypothesized that SP-A-mediated modulation of T cell activation depends upon the strength, duration, and type of lymphocyte activating signals. Modulation of T cell signal strength imparted by different activating agents ex vivo and in vivo in different mouse models and in vitro with human T cells shows a strong correlation between strength of signal (SoS) and functional effects of SP-A interactions. T cell proliferation is enhanced in the presence of SP-A at low SoS imparted by exogenous mitogens, specific Abs, APCs, or in homeostatic proliferation. Proliferation is inhibited at higher SoS imparted by different doses of the same T cell mitogens or indirect stimuli such as LPS. Importantly, reconstitution with exogenous SP-A into the lungs of SP-A(-/-) mice stimulated with a strong signal also resulted in suppression of T cell proliferation while elevating baseline proliferation in unstimulated T cells. These signal strength and SP-A-dependent effects are mediated by changes in intracellular Ca(2+) levels over time, involving extrinsic Ca(2+)-activated channels late during activation. These effects are intrinsic to the global T cell population and are manifested in vivo in naive as well as memory phenotype T cells. Thus, SP-A appears to integrate signal thresholds to control T cell proliferation.

Full Text

Duke Authors

Cited Authors

  • Mukherjee, S; Giamberardino, C; Thomas, J; Evans, K; Goto, H; Ledford, JG; Hsia, B; Pastva, AM; Wright, JR

Published Date

  • February 1, 2012

Published In

Volume / Issue

  • 188 / 3

Start / End Page

  • 957 - 967

PubMed ID

  • 22219327

Electronic International Standard Serial Number (EISSN)

  • 1550-6606

Digital Object Identifier (DOI)

  • 10.4049/jimmunol.1100461

Language

  • eng

Conference Location

  • United States