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Is early repopulation of macrophage‐depleted lymph node independent of blood monocyte immigration?
Author(s) -
Mebius Reina E.,
Martens Gratia,
Brevé John,
Delemarre Frans G. A.,
Kraal Georg
Publication year - 1991
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/eji.1830211221
Subject(s) - liposome , population , lymph node , biology , medulla , macrophage , mononuclear phagocyte system , hindlimb , lymph , andrology , pathology , immunology , anatomy , medicine , biochemistry , environmental health , in vitro
Abstract Popliteal lymph nodes (LN) of mice were depleted of their macrophage (Mϕ) populations in the subcapsular sinus and medulla by subcutaneous injection of dichloromethylene diphosphonate (Cl 2 MDP)‐containing liposomes into the footpads. Complete restoration of both Mϕ populations could be observed as late as 5 months after liposome administration. This relatively long repopulation time could be due to a depot of liposomes, directly killing all Mϕ precursors after extravasation into the interstitial tissue of the footpad. On the other hand, local interstitial precursors with very low turnover rates may have been depleted in the interstitial tissue of the hind leg. Therefore, two different types of experiments were performed; one in which Mϕ‐depleted LN were replaced by control LN at various time points after liposome treatment, and another whereby Mϕ‐depleted LN were transplanted into control animals. When liposome‐treated, Mϕ‐depleted LN were transplanted into control animals, a complete restoration of both populations in the subcapsular sinus and medulla could be observed within 5 weeks. Control LN transplanted into a Cl 2 MDP‐liposome‐treated leg showed a rapid disappearance of Mϕ from the subcapsular sinus and medulla and these cell populations remained absent for at least 7–8 weeks after liposome treatment, when the first cells started to reappear. Complete repopulation of these areas by Mϕ took as long as 15 weeks. Using labeled liposomes the presence of a continuous liposome depot was found to be very unlikely. These results suggest that the population of precursor cells that will give rise to Mϕ in the subcapsular sinus and medulla of a LN is probably contained within the interstitial tissue and is almost independent of precursor supply from the blood compartment.