| First Author | Yang L | Year | 2010 |
| Journal | J Immunol | Volume | 184 |
| Issue | 2 | Pages | 975-83 |
| PubMed ID | 20007532 | Mgi Jnum | J:159418 |
| Mgi Id | MGI:4442565 | Doi | 10.4049/jimmunol.0900650 |
| Citation | Yang L, et al. (2010) Surfactant protein B propeptide contains a saposin-like protein domain with antimicrobial activity at low pH. J Immunol 184(2):975-83 |
| abstractText | Surfactant protein B (SP-B) proprotein contains three saposin-like protein (SAPLIP) domains: a SAPLIP domain corresponding to the mature SP-B peptide is essential for lung function and postnatal survival; the function of SAPLIP domains in the N-terminal (SP-BN) and C-terminal regions of the proprotein is not known. In the current study, SP-BN was detected in the supernatant of mouse bronchoalveolar lavage fluid (BALF) and in nonciliated bronchiolar cells, alveolar type II epithelial cells, and alveolar macrophages. rSP-BN indirectly promoted the uptake of bacteria by macrophage cell lines and directly killed bacteria at acidic pH, consistent with a lysosomal, antimicrobial function. Native SP-BN isolated from BALF also killed bacteria but only at acidic pH; the bactericidal activity of BALF at acidic pH was completely blocked by SP-BN Ab. Transgenic mice overexpressing SP-BN and mature SP-B peptide had significantly decreased bacterial burden and increased survival following intranasal inoculation with bacteria. These findings support the hypothesis that SP-BN contributes to innate host defense of the lung by supplementing the nonoxidant antimicrobial defenses of alveolar macrophages. |
