Dynamics of Neutrophil Migration in Lymph Nodes during Infection

Ellen A. Robey et al., Immunity, 29, 3, 487-496(2008)

Student: Yun-Ju Song (宋昀儒)                                       Time: 14:10~15:00 May. 13, 2009

Commentator: Dr. Bei-Chang Yang (楊倍昌 老師)       Place: Room 601

Abstract:

        Neutrophils are not simply scavenging phagocytes that clear extracellular spaces of rapidly proliferating microbes. They are also active in the control of infections by intracellular pathogens¹. Recent reports have showed that neutrophils traffic to the lymphoid organs via lymphatic in response to Mycobacterium bovis BCG infection². There is very little evidence about their migration patterns within lymph nodes and how entering the action site following by affecting the ensuing immune response. In order to address these questions, the authors used two-photon scanning-laser microscopy and LysGFP reporter mice to observe the dynamic migration pattern of neutrophils in intact lymph node during infection with intracellular parasite, Toxoplasma gondii. After earflap or oral injection with live fluorescent T. gondii, parasites can be found within the CD169⁺macrophages, that line the subcapsulary sinus. In addition, neutrophils form dynamic swarms coincided with the location of parasites. There are two type of distinct swarm formation: transient swarms are small in size and persistent swarms are large. Swarm formation is initiated by pioneer neutrophils in response to parasite egress and then followed by entering of large-scale directed, coordinated migration of neutrophils toward swarm centers. Nevertheless, CD169⁺ macrophages are removal at the transient swarm location site of infected subcapsulary sinus of lymph node. The recruitment of neutrophils and swarming behavior in lymph node are also observed in Listeria monocytogenes infection indicating that they are general responses of neutrophils during infection in lymph node.

References:

1.          Bliss, S.K. et al. (2001) Neutrophil depletion during Toxoplasma gondii infection leads to impaired immunity and lethal systemic pathology. Infect. Immun. 69, 4898–4905.

2.          Abadie, V. et al. (2005) Neutrophils rapidly migrate via lymphatics after Mycobacterium bovis BCG intradermal vaccination and shuttle live bacilli to the draining lymph nodes. Blood 106, 1843–1850