Mycobacterium tuberculosis H37Rv induces ectosome release in human polymorphonuclear neutrophils

summary Ectocytosis, the cellular process by which ectosomes (Ects) are released, is an important phenomenon by which eukaryotic cells exchange molecular information. Ects released from N-formylmethionyl-leucylphenylalanine (fMLP)-activated human polymorphonuclear neutrophils (PMNs) have recently been characterized. Molecules such as CD35 and phosphatidylserine (PS), and enzymes such as myeloperoxidase and elastase were found in these vesicles, suggesting that Ects from PMNs could function as ectoorganelles with anti-microbial activity. Here we show for the first time that human PMNs release ectosomes in response to Mycobacterium tuberculosis H37Rv infection. We found that the release of ectosomes was not associated exclusively with mycobacterial infection since infection with other microorganisms (e.g., Leishmania mexicana, Staphylococcus aureus, and Escherichia coli or activation with phorbol myristate acetate (PMA)) also induced ectocytosis. Ects release started as early as 10 min after infection or activation. Expression of CD35, PS, Rab5, Rab7 and gp91 Phox , a subunit of Cyt b555 was