Different Requirements for Early and Late Phases of Azurophilic Granule-Phagosome Fusion

Nordenfelt, PontusLund University,Lunds universitet,Infektionsmedicin,Sektion III,Institutionen för kliniska vetenskaper, Lund,Medicinska fakulteten,Kvantitativ immunbiologi,Forskargrupper vid Lunds universitet,Infection Medicine (BMC),Section III,Department of Clinical Sciences, Lund,Faculty of Medicine,Quantitative immunobiology,Lund University Research Groups (author)

Phagocytosis and killing of microorganisms are complex processes that involve tightly regulated membrane traffic events. Because many signaling molecules associate with membrane rafts and because these structures can be found on azurophilic granules, we decided to investigate raft recruitment and the signaling requirements for azurophilic granule secretion during phagosome maturation. At the site of phagocytosis of immunoglobulin G-opsonized prey in human neutrophils, we found that early secretion of azurophilic granules was both raft- and calcium-dependent. Subsequently, rafts at the phagocytic site were internalized with the prey. At the fully formed phagosome, the fusion of azurophilic granules was no longer dependent on rafts or calcium. These findings were found to be true also when using Streptococcus pyogenes bacteria as prey, and depletion of calcium affected the kinetics of bacterial intracellular survival. These findings suggest that the mechanisms for delivery of azurophilic content to nascent and sealed phagosomes, respectively, differ in their dependence on calcium and membrane rafts.

Winberg Tinnerfelt, MartinLinköpings universitet,Medicinsk mikrobiologi,Hälsouniversitetet(Swepub:liu)marwi07 (author)
Lönnbro, PerLund University,Lunds universitet,Infektionsmedicin,Sektion III,Institutionen för kliniska vetenskaper, Lund,Medicinska fakulteten,Infection Medicine (BMC),Section III,Department of Clinical Sciences, Lund,Faculty of Medicine(Swepub:lu)medk-pl0 (author)
Rasmusson, BirgittaLinköpings universitet,Medicinsk mikrobiologi,Hälsouniversitetet(Swepub:liu)birra51 (author)
Tapper, HansLund University,Lunds universitet,Infektionsmedicin,Sektion III,Institutionen för kliniska vetenskaper, Lund,Medicinska fakulteten,Infection Medicine (BMC),Section III,Department of Clinical Sciences, Lund,Faculty of Medicine(Swepub:lu)medk-hta (author)
Winberg, Martin E (author)
InfektionsmedicinSektion III (creator_code:org_t)

By the author/editor: Nordenfelt, Pont ...; Winberg Tinnerfe ...; Lönnbro, Per; Rasmusson, Birgi ...; Tapper, Hans; Winberg, Martin ...

About the subject

MEDICAL AND HEALTH SCIENCES: MEDICAL AND HEAL ...; and Clinical Medicin ...; and Infectious Medic ...

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