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Mice lacking expression of secondary lymphoid organ chemokine have defects in lymphocyte homing and dendritic cell localization.

Gunn MD, Kyuwa S, Tam C, Kakiuchi T, Matsuzawa A, Williams LT, Nakano H - J. Exp. Med. (1999)

Bottom Line: Secondary lymphoid organ chemokine (SLC) is expressed in high endothelial venules and in T cell zones of spleen and lymph nodes (LNs) and strongly attracts naive T cells.DC migration to LNs after contact sensitization is also substantially reduced.The plt mutation maps to the SLC locus; however, the sequence of SLC introns and exons in plt mice is normal.

View Article: PubMed Central - PubMed

Affiliation: Cardiovascular Research Institute, University of California San Francisco, San Francisco, California 94143, USA. michael.gunn@duke.edu

ABSTRACT
Secondary lymphoid organ chemokine (SLC) is expressed in high endothelial venules and in T cell zones of spleen and lymph nodes (LNs) and strongly attracts naive T cells. In mice homozygous for the paucity of lymph node T cell (plt) mutation, naive T cells fail to home to LNs or the lymphoid regions of spleen. Here we demonstrate that expression of SLC is undetectable in plt mice. In addition to the defect in T cell homing, we demonstrate that dendritic cells (DCs) fail to accumulate in spleen and LN T cell zones of plt mice. DC migration to LNs after contact sensitization is also substantially reduced. The physiologic significance of these abnormalities in plt mice is indicated by a markedly increased sensitivity to infection with murine hepatitis virus. The plt mutation maps to the SLC locus; however, the sequence of SLC introns and exons in plt mice is normal. These findings suggest that the abnormalities in plt mice are due to a genetic defect in the expression of SLC and that SLC mediates the entry of naive T cells and antigen-stimulated DCs into the T cell zones of secondary lymphoid organs.

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Migration of DCs out of skin explants is normal in plt mice.  Dorsal ear skin was floated on medium and cultured (reference 31). After  72 h, dermal and epidermal whole mounts were prepared and stained  with anti–I-Ad followed by SA-FITC. The density of DCs is similar in  the epidermis of +/+ (A) and plt (B) mice after 72 h of culture. DC  cords form within dermal lymphatics of both +/+ (C) and plt (D) mice  after 72 h of culture. (E) The density of DCs in epidermis decreases similarly in +/+ and plt mice over 72 h of culture. I-A+ cells were counted  in 20 fields/slide over 4 slides and calculated as the mean ± SD of cells/ HPF. (F) Emigration of DCs out of cultured skin is normal in plt mice.  Nonadherent cells were collected from the bottom of wells in which ear  skin had been cultured for 72 h. Total cell number was determined by  counting on a hemocytometer. The proportion of DCs was calculated by  examining anti–I-Ad–stained cytospins of nonadherent cells. Results represent the mean ± SD of DCs/well over four wells.
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Figure 6: Migration of DCs out of skin explants is normal in plt mice. Dorsal ear skin was floated on medium and cultured (reference 31). After 72 h, dermal and epidermal whole mounts were prepared and stained with anti–I-Ad followed by SA-FITC. The density of DCs is similar in the epidermis of +/+ (A) and plt (B) mice after 72 h of culture. DC cords form within dermal lymphatics of both +/+ (C) and plt (D) mice after 72 h of culture. (E) The density of DCs in epidermis decreases similarly in +/+ and plt mice over 72 h of culture. I-A+ cells were counted in 20 fields/slide over 4 slides and calculated as the mean ± SD of cells/ HPF. (F) Emigration of DCs out of cultured skin is normal in plt mice. Nonadherent cells were collected from the bottom of wells in which ear skin had been cultured for 72 h. Total cell number was determined by counting on a hemocytometer. The proportion of DCs was calculated by examining anti–I-Ad–stained cytospins of nonadherent cells. Results represent the mean ± SD of DCs/well over four wells.

Mentions: SLC is expressed (and therefore has the potential to mediate DC migration) at two points along the migration route of DCs from skin to LNs: in lymphatic endothelium and within the T cell zone. To determine if plt mice have a defect in the peripheral mobilization of DCs, we examined the migration of DCs out of cultured skin. Similar to our findings in abdominal epidermis, dorsal ear epidermis from plt mice contains a normal number of DCs (Fig. 6 E). When segments of dorsal ear skin were placed in culture, the number of DCs within the epidermis of +/+ and plt mice decreased to a similar extent over 72 h (Fig. 6, A, B, and E). Over the same time period, the number of DCs within the dermis increased similarly in plt and +/+ mice (not shown). As described previously (31), migrating DCs formed cords within the dermal lymphatics of +/+ mice (Fig. 6 C). A similar formation of cords was seen in plt mice (Fig. 6 D), demonstrating that the plt mutation does not inhibit the entry of DCs into lymphatics. When the cells migrating out of dorsal ear skin were collected over 72 h and counted, the number of DCs released from the skin of plt and +/+ mice was similar (Fig. 6 F).


Mice lacking expression of secondary lymphoid organ chemokine have defects in lymphocyte homing and dendritic cell localization.

Gunn MD, Kyuwa S, Tam C, Kakiuchi T, Matsuzawa A, Williams LT, Nakano H - J. Exp. Med. (1999)

Migration of DCs out of skin explants is normal in plt mice.  Dorsal ear skin was floated on medium and cultured (reference 31). After  72 h, dermal and epidermal whole mounts were prepared and stained  with anti–I-Ad followed by SA-FITC. The density of DCs is similar in  the epidermis of +/+ (A) and plt (B) mice after 72 h of culture. DC  cords form within dermal lymphatics of both +/+ (C) and plt (D) mice  after 72 h of culture. (E) The density of DCs in epidermis decreases similarly in +/+ and plt mice over 72 h of culture. I-A+ cells were counted  in 20 fields/slide over 4 slides and calculated as the mean ± SD of cells/ HPF. (F) Emigration of DCs out of cultured skin is normal in plt mice.  Nonadherent cells were collected from the bottom of wells in which ear  skin had been cultured for 72 h. Total cell number was determined by  counting on a hemocytometer. The proportion of DCs was calculated by  examining anti–I-Ad–stained cytospins of nonadherent cells. Results represent the mean ± SD of DCs/well over four wells.
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Related In: Results  -  Collection

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Figure 6: Migration of DCs out of skin explants is normal in plt mice. Dorsal ear skin was floated on medium and cultured (reference 31). After 72 h, dermal and epidermal whole mounts were prepared and stained with anti–I-Ad followed by SA-FITC. The density of DCs is similar in the epidermis of +/+ (A) and plt (B) mice after 72 h of culture. DC cords form within dermal lymphatics of both +/+ (C) and plt (D) mice after 72 h of culture. (E) The density of DCs in epidermis decreases similarly in +/+ and plt mice over 72 h of culture. I-A+ cells were counted in 20 fields/slide over 4 slides and calculated as the mean ± SD of cells/ HPF. (F) Emigration of DCs out of cultured skin is normal in plt mice. Nonadherent cells were collected from the bottom of wells in which ear skin had been cultured for 72 h. Total cell number was determined by counting on a hemocytometer. The proportion of DCs was calculated by examining anti–I-Ad–stained cytospins of nonadherent cells. Results represent the mean ± SD of DCs/well over four wells.
Mentions: SLC is expressed (and therefore has the potential to mediate DC migration) at two points along the migration route of DCs from skin to LNs: in lymphatic endothelium and within the T cell zone. To determine if plt mice have a defect in the peripheral mobilization of DCs, we examined the migration of DCs out of cultured skin. Similar to our findings in abdominal epidermis, dorsal ear epidermis from plt mice contains a normal number of DCs (Fig. 6 E). When segments of dorsal ear skin were placed in culture, the number of DCs within the epidermis of +/+ and plt mice decreased to a similar extent over 72 h (Fig. 6, A, B, and E). Over the same time period, the number of DCs within the dermis increased similarly in plt and +/+ mice (not shown). As described previously (31), migrating DCs formed cords within the dermal lymphatics of +/+ mice (Fig. 6 C). A similar formation of cords was seen in plt mice (Fig. 6 D), demonstrating that the plt mutation does not inhibit the entry of DCs into lymphatics. When the cells migrating out of dorsal ear skin were collected over 72 h and counted, the number of DCs released from the skin of plt and +/+ mice was similar (Fig. 6 F).

Bottom Line: Secondary lymphoid organ chemokine (SLC) is expressed in high endothelial venules and in T cell zones of spleen and lymph nodes (LNs) and strongly attracts naive T cells.DC migration to LNs after contact sensitization is also substantially reduced.The plt mutation maps to the SLC locus; however, the sequence of SLC introns and exons in plt mice is normal.

View Article: PubMed Central - PubMed

Affiliation: Cardiovascular Research Institute, University of California San Francisco, San Francisco, California 94143, USA. michael.gunn@duke.edu

ABSTRACT
Secondary lymphoid organ chemokine (SLC) is expressed in high endothelial venules and in T cell zones of spleen and lymph nodes (LNs) and strongly attracts naive T cells. In mice homozygous for the paucity of lymph node T cell (plt) mutation, naive T cells fail to home to LNs or the lymphoid regions of spleen. Here we demonstrate that expression of SLC is undetectable in plt mice. In addition to the defect in T cell homing, we demonstrate that dendritic cells (DCs) fail to accumulate in spleen and LN T cell zones of plt mice. DC migration to LNs after contact sensitization is also substantially reduced. The physiologic significance of these abnormalities in plt mice is indicated by a markedly increased sensitivity to infection with murine hepatitis virus. The plt mutation maps to the SLC locus; however, the sequence of SLC introns and exons in plt mice is normal. These findings suggest that the abnormalities in plt mice are due to a genetic defect in the expression of SLC and that SLC mediates the entry of naive T cells and antigen-stimulated DCs into the T cell zones of secondary lymphoid organs.

Show MeSH
Related in: MedlinePlus