Investigators reporting in The JCI discovered that HBP and HNP1-3 trigger enhanced uptake of microbes by macrophages.
A group of scientists found that a number of proteins secreted by neutrophils (PMNs) enhance uptake of bacteria by macrophages, which are capable of destroying the microbes.
In the study, proteins secreted by human PMNs, specifically HBP and HNP1-3, were found to enhance the in vitro ability of human and mouse macrophages to take up bacteria coated in the immune molecule IgG.
These two proteins activated the macrophages to secrete soluble factors, TNF-a and IFN- ?, that in turn induced the macrophages to express proteins to which IgG can bind (CD32 and CD64). The use of blocking antibodies and knockout mice revealed that HBP acts viaß2 integrins, but the receptor for HNP1–3 remained unclear.
Researchers from University of Ulm, Lund University, and Karolinska Institutet collaborated on this experiment. The study was detailed in the September 11 online version of The Journal of Clinical Investigation.
