Role of Membrane Synthesis in Macrophage Function (Abstract)
Christopher Sage and Suzanne Jackowski

Macrophages are a type of white blood cell and are part of the first-line response to an infection. Bacteria and other foreign bodies are ingested by macrophages and broken down into peptides that are presented as antigens by specialized molecules on the cell’s surface. Phagocytosis by the macrophage requires phospholipids within the cell membrane, due to the development of the phagosomes, vesicles that contain the foreign body in the macrophage. Two mammalian genes encode isoforms of CTP:phosphocholine cytidyltransferase (CCT), a key rate-controlling step in membrane phospholipid biogenesis. CCTa is the most ubiquitously-expressed and well-studied, while the CCTß form is present at significantly lower levels. We investigated the role(s) of the CCTa in macrophages by generating knockout microphages in mice. The CCTa gene knockout macrophages had a slower proliferation rate compared to the wild-type macrophages which doubled in number in seven days. The CCTa gene knockout macrophages also were limited in the amount of bacteria that they were able to ingest. These data suggest that replication and phagocytosis were impaired, but not absent, from the CCTa-deficient cells.

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