Studies on the interaction of human neutrophils with plaque spirochetes

Abstract

Polymorphonuclear leukocytes (PMNs) encounter spirochetes in the diseased gingival crevice. The purpose of this investigation was to learn more about the nature and potential consequences of in vitro PMN‐spirochete interactions. Isolated spirochetes (various strains of Treponema denticola and T. vincentii) were incubated with human peripheral blood PMNs. PMNs were able to interact with these organisms demonstrating increased oxygen consumption, chemoluminescence, and phagocytosis. Serum was not an absolute prerequisite for phagocytosis, but oxygen consumption and chemoluminescence were generally not observed unless organisms were preopsonized with fresh serum. In spite of the fact that large numbers of spirochetes could be identified within PMN phagosomes, biochemical and ultrastructural evidence indicated limited degranulation on the part of the phagocytic cells. This can be contrasted to other plaque organisms which stimulated dose‐dependent degranulation in association with the phagocytic process. In fact, PMNs pretreated with soluble extracts of spirochetes, but not with non‐spirochetal organisms, were generally less responsive to zymosan‐induced degranulation. The data suggest that spirochetes may limit fusion of lysosomes to phagosomes and thereby influence the course of the inflammatory process in response to these as well as other organisms. These findings may be relevant in explaining the mechanisms of infection associated with the colonization of the gingival crevice by spirochetes.

Surface protease of Treponema denticola hydrolyzes C3 and influences function of polymorphonuclear leukocytes

“…denticola [17,18,21]. Our results indicate that, in addition to with other stimulants such as Msp, this microorganism activates PMNs with dentilisin via activation of complement.…”

“…It has been reported that T. denticola adheres to PMNs and is ingested into phagosomes [18,21]. Observations indicate that phagocytosed treponemes remain inside the phagosome, even after 60 min [21].…”

“…It has been reported that T. denticola adheres to PMNs and is ingested into phagosomes [18,21]. Observations indicate that phagocytosed treponemes remain inside the phagosome, even after 60 min [21]. It has been suggested that the humoral immune response to T. denticola is not capable of resolving T. denticola infection [29], and it has also been shown that mouse antibody against T. denticola only slowed initial T. denticola replication and did not alter the maximum growth in vitro.…”

The peptidolytic capacity of the spirochete system

“…Human ECs were quite receptive immediately after mitosis [24,25,52] 2. Inhibition of fibroblast proliferation, lymphocyte blastogenesis, Observed in vitro, but suggests that the treponemes neutrophil degranulation, and free radical production can inhibit host reparative processes [3,4,61,62] (oral treponemal extracts) 3. Distortion of cell morphology; adhesion to fibronectin (FN);…”

Physical map of the Treponema denticola circular chromosome

“…Many features of this bacterium are indicative of its potential to destroy host tissue and evade the host immune response. These include motility (6), the production of proteolytic enzymes (25,36), the synthesis of a factor that inhibits polymorphonuclear leukocyte function (6), and the ability to attach to host epithelial cells (16,27).…”