Subcapsular sinus macrophages in lymph nodes clear lymph-borne viruses and present them to antiviral B cells.
Lymph nodes prevent the systemic dissemination of pathogens such as viruses that infect peripheral tissues after penetrating the body's surface barriers. They are also the staging ground of adaptive immune responses to pathogen-derived antigens. It is unclear how virus particles are cleared from afferent lymph and presented to cognate B cells to induce antibody responses. Here we identify a population of CD11b+CD169+MHCII+ macrophages on the floor of the subcapsular sinus (SCS) and in the medulla of lymph nodes that capture viral particles within minutes after subcutaneous injection. Macrophages in the SCS translocated surface-bound viral particles across the SCS floor and presented them to migrating B cells in the underlying follicles. Selective depletion of these macrophages compromised local viral retention, exacerbated viraemia of the host, and impaired local B-cell activation. These findings indicate that CD169+ macrophages have a dual physiological function. They act as innate 'flypaper' by preventing the systemic spread of lymph-borne pathogens and as critical gatekeepers at the lymph-tissue interface that facilitate the recognition of particulate antigens by B cells and initiate humoral immune responses.
Junt
Tobias
T
Immune Disease Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Moseman
E Ashley
EA
Iannacone
Matteo
M
Massberg
Steffen
S
Lang
Philipp A
PA
Boes
Marianne
M
Fink
Katja
K
Henrickson
Sarah E
SE
Shayakhmetov
Dmitry M
DM
Di Paolo
Nelson C
NC
van Rooijen
Nico
N
Mempel
Thorsten R
TR
Whelan
Sean P
SP
von Andrian
Ulrich H
UH
D000818:Animals; D000917:Antibody Formation / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D039481:CD11b Antigen / Q000378:metabolism; D002460:Cell Line; D008196:Lymph / Q000821:virology*; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology* / Q000821:virology*; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D011971:Receptors, Immunologic / Q000378:metabolism; D063267:Sialic Acid Binding Ig-like Lectin 1; D018116:Vesiculovirus / Q000276:immunology*
D039481:CD11b Antigen; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; D063267:Sialic Acid Binding Ig-like Lectin 1; C571167:Siglec1 protein, mouse