Surfactant protein D (SP-D) is an important innate immune collectin involved in uptake and clearance of microbes and allergens in the lungs. SP-D has been shown to ameliorate allergic asthma reactions in mice; however, the mechanisms for this are not fully understood. We investigated the role of SP-D in the uptake and clearance of the model allergen ovalbumin (OVA) by macrophages. We discovered that SP-D does not bind OVA but binds fractions with contaminating proteins; ovomucin and ovomacroglobulin. We extended these findings to show that SP-D binds human alpha-2-macroglobulin (A2M) in its cleaved or intact state, in a concentration-, calcium-, and carbohydrate-dependent manner. A2M increases the innate immune potential of SP-D by increasing its ability to agglutinate the bacteria Escherichia coli and Bacillus subtilis. We found that SP-D does not increase the uptake of OVA by murine macrophage cell lines, or by alveolar macrophages in vivo in BALB/cJ mice.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/18266 |
| Date | 13 January 2010 |
| Creators | Craig-Barnes, Hayley A. |
| Contributors | Palaniyar, Nades |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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