VAMP-8/Endobrevin negatively regulates bacteria uptake by dendritic cells.

Phagocytosis is a specialized mechanism utilized by mammalian cells, particularly the cells of the immune system, such as the dendritic cells (DC) and macrophages to protect the host against infection. The process involves a complex cascade of pathways, from the ligation of surface receptors of phagocytes with components of the microorganism's surface, formation of phagosomes and subsequently phagolysosomes, to the eventual presentation of foreign antigens. VAMP-8/endobrevin has been shown previously to function in the endocytic pathways. Our results showed that VAMP-8 co-localized with LAMP-2 and a significant amount of VAMP-8 was recruited to the phagosomes during bacterial ingestion. However, overexpression of VAMP-8 significantly inhibited phagocytosis in DC. We also found that the phagocytic activity of VAMP-8^-/- DC was significantly higher than wild-type VAMP-8^+/+ DC, thus further confirming that VAMP-8 negatively regulates phagocytosis in immature DC. This work was supported by grants from the Microbiology Vaccine Initiative (R182-005-067-731 to S.H.W) and Academic Research Council, Singapore Ministry of Education (R182-000-099-112 to S.H.W). [ABSTRACT FROM AUTHOR]