Polymorphonuclear neutrophils deliver activation signals and antigenic molecules to dendritic cells: a new link between leukocytes upstream of T lymphocytes

Abstract

Polymorphonuclear neutrophils (PMNs) are rapidly recruited to tissues upon injury or infection. There, they can encounter local and/or recruited immature dendritic cells (iDCs), a colocalization that could promote at least transient interactions and mutually influence the two leukocyte populations. Using human live blood PMNs and monocytederived iDCs, we examined if these leukocytes actually interacted and whether this influenced DC function. Indeed, coculture with live but not apoptotic PMNs led to up-regulation of membrane CD40, CD86, and human leukocyte antigen (HLA)-DR on DCs. Whereas CD40 up-regulation was dependent on soluble factors released by PMNs, as determined in cultures conducted in different chambers, cell contact was necessary for CD86 and HLA-DR up-regulation, a process that was inhibited by anti-CD18 antibodies, indicating that CD18 ligation was required. We also found that via a cell contact-dependent mechanism, DCs acquired Candida albicansderived antigens from live as well as from apoptotic PMNs and could thus elicit antigen-specific T lymphocyte responses. Altogether, our data demonstrate the occurrence of cross-talk between human PMNs and DCs and provide new insights into the immune processes occurring upstream of the interactions between DCs and T lymphocytes. J. Leukoc. Biol. 79: 977-988; 2006.

Spontaneous or Mycobacterium tuberculosis‐induced apoptotic neutrophils exert opposite effects on the dendritic cell‐mediated immune response

“…It has been previously demonstrated that both viable and PMNapo could modulate DC maturation [21][22][23][24]. Therefore, we examined whether PMN that underwent spontaneous apoptosis (PMNapo) could affect Mtbinduced maturation of iDC in culture.…”

Injection of lipopolysaccharide induces the migration of splenic neutrophils to the T cell area of the white pulp: role of CD14 and CXC chemokines

“…This interaction was driven by the binding of the DC-specific, C-type lectin DC-specific ICAM-grabbing nonintegrin to the ␤2-integrin membrane-activated complex 1 [36]. Interestingly, a recent report demonstrates that live neutrophils can deliver activating signals to immature DC, whereas via cell contact, live and apoptotic neutrophils can transfer heat-killed Candida albicans antigens to DC, allowing the latter to stimulate T lymphocytes [5]. We did not obtain any evidence suggesting that neutrophils may direct the migration of DC in our experimental setting.…”

Mycobacterium bovis BCG‐infected neutrophils and dendritic cells cooperate to induce specific T cell responses in humans and mice

“…Indeed, the role of neutrophils goes well beyond simply being recruited to kill microorganisms and then die (for a review [15]). These cells can also migrate to draining lymph nodes [11,25,26] and establish contacts with DC [27], helping the latter cells to stimulate T cells [10]. We investigated the cooperation between neutrophils and DC and its impact on antigen presentation to T cells in the context of BCG vaccination against TB.…”

“…They can help macrophages to eliminate highly adapted intracellular pathogens, such as Mycobacterium tuberculosis [6][7][8] and Leishmania major [9]. They may be key partners of DC; we have shown that live human neutrophils activate DC and transfer Candida albicans antigens for T cell presentation in vitro [10]. We have also shown in vivo, in mice, that neutrophils migrate via afferent lymphatic vessels to draining lymph nodes, where they shuttle live M. bovis Bacillus Calmette GuØrin (BCG) and get in the vicinity of resident DC and T cells [11].…”