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Alveolar macrophages lack CCR2 expression and do not migrate to CCL2.

Opalek JM, Ali NA, Lobb JM, Hunter MG, Marsh CB - J Inflamm (Lond) (2007)

Bottom Line: The recruitment of mononuclear cells has important implications for tissue inflammation.In contrast to peripheral blood monocytes, alveolar macrophages did not express the CCL2 receptor, CCR2, and did not migrate toward CCL2.The addition of anti-CCR5 blocking antibodies completely abrogated CCL3-induced migration in alveolar macrophages, but did not affect the migration of peripheral blood monocytes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, The Ohio State University and Dorothy M, Davis Heart and Lung Research Institute, Columbus, Ohio, USA. clay.marsh@osumc.edu.

ABSTRACT

Background: The recruitment of mononuclear cells has important implications for tissue inflammation. Previous studies demonstrated enhanced CCR1 and CCR5 expression and decreased CCR2 expression during in vitro monocyte to macrophage differentiation. To date, no study examined the in vivo differences in chemokine receptor expression between human peripheral blood monocytes and alveolar macrophages.

Methods: We examined the expression of these receptors in human peripheral blood monocytes and alveolar macrophages using microarray analysis, reverse-transcriptase PCR, flow cytometry and migration analyses.

Results: In contrast to peripheral blood monocytes, alveolar macrophages did not express the CCL2 receptor, CCR2, and did not migrate toward CCL2. In contrast, monocytes and freshly isolated resident alveolar macrophages both migrated towards CCL3. However, up to 6-fold more monocytes migrated toward equivalent concentrations of CCL3 than did alveolar macrophages from the same donor. While peripheral blood monocytes expressed the CCL3 receptor, CCR1, alveolar macrophages expressed the alternate CCL3 receptor, CCR5. The addition of anti-CCR5 blocking antibodies completely abrogated CCL3-induced migration in alveolar macrophages, but did not affect the migration of peripheral blood monocytes.

Conclusion: These data support the specificity of CCL2 to selectively drive monocyte, but not alveolar macrophage recruitment to the lung and CCR5 as the primary macrophage receptor for CCL3.

No MeSH data available.


Related in: MedlinePlus

Blocking antibodies to CCR5 decrease CCL3-induced chemotaxis in alveolar macrophages, but not fresh monocytes. Freshly isolated monocytes and alveolar macrophages (4.5 × 104/condition) were pre-incubated with 1 μg/ml CCR5 blocking antibodies and subjected to a migration assay using CCL3 (1–100 ng/ml) as the chemoattractant. The addition of anti-CCR5 antibodies did not significantly alter monocyte chemotaxis (left panel) at any concentration of CCL3 compared to the IgG control (p > 0.05 at all concentrations). In contrast, the addition of anti-CCR5 antibodies decreased CCL3-induced alveolar macrophage chemotaxis (right panel) at all tested concentrations of CCL3 (**p < 0.001). Results represent mean ± SEM for three independent studies.
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Figure 6: Blocking antibodies to CCR5 decrease CCL3-induced chemotaxis in alveolar macrophages, but not fresh monocytes. Freshly isolated monocytes and alveolar macrophages (4.5 × 104/condition) were pre-incubated with 1 μg/ml CCR5 blocking antibodies and subjected to a migration assay using CCL3 (1–100 ng/ml) as the chemoattractant. The addition of anti-CCR5 antibodies did not significantly alter monocyte chemotaxis (left panel) at any concentration of CCL3 compared to the IgG control (p > 0.05 at all concentrations). In contrast, the addition of anti-CCR5 antibodies decreased CCL3-induced alveolar macrophage chemotaxis (right panel) at all tested concentrations of CCL3 (**p < 0.001). Results represent mean ± SEM for three independent studies.

Mentions: To verify that surface expression of CCR1 and CCR5 predicted biological responsiveness to CCL3 in these cells, we next examined the effect of anti-CCR5 blocking antibodies on CCL3-induced migration. Consistent with a lack of CCR5 surface expression on monocytes, anti-CCR5 blocking antibodies did not reduce monocyte chemotaxis in response to CCL3 compared to isogenic control IgG (Figure 6a). In contrast, anti-CCR5 blocking antibodies reduced the chemotaxis of alveolar macrophages at all tested doses of CCL3 (Figure 6b). CCR1 blocking antibodies are not commercially available.


Alveolar macrophages lack CCR2 expression and do not migrate to CCL2.

Opalek JM, Ali NA, Lobb JM, Hunter MG, Marsh CB - J Inflamm (Lond) (2007)

Blocking antibodies to CCR5 decrease CCL3-induced chemotaxis in alveolar macrophages, but not fresh monocytes. Freshly isolated monocytes and alveolar macrophages (4.5 × 104/condition) were pre-incubated with 1 μg/ml CCR5 blocking antibodies and subjected to a migration assay using CCL3 (1–100 ng/ml) as the chemoattractant. The addition of anti-CCR5 antibodies did not significantly alter monocyte chemotaxis (left panel) at any concentration of CCL3 compared to the IgG control (p > 0.05 at all concentrations). In contrast, the addition of anti-CCR5 antibodies decreased CCL3-induced alveolar macrophage chemotaxis (right panel) at all tested concentrations of CCL3 (**p < 0.001). Results represent mean ± SEM for three independent studies.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2099427&req=5

Figure 6: Blocking antibodies to CCR5 decrease CCL3-induced chemotaxis in alveolar macrophages, but not fresh monocytes. Freshly isolated monocytes and alveolar macrophages (4.5 × 104/condition) were pre-incubated with 1 μg/ml CCR5 blocking antibodies and subjected to a migration assay using CCL3 (1–100 ng/ml) as the chemoattractant. The addition of anti-CCR5 antibodies did not significantly alter monocyte chemotaxis (left panel) at any concentration of CCL3 compared to the IgG control (p > 0.05 at all concentrations). In contrast, the addition of anti-CCR5 antibodies decreased CCL3-induced alveolar macrophage chemotaxis (right panel) at all tested concentrations of CCL3 (**p < 0.001). Results represent mean ± SEM for three independent studies.
Mentions: To verify that surface expression of CCR1 and CCR5 predicted biological responsiveness to CCL3 in these cells, we next examined the effect of anti-CCR5 blocking antibodies on CCL3-induced migration. Consistent with a lack of CCR5 surface expression on monocytes, anti-CCR5 blocking antibodies did not reduce monocyte chemotaxis in response to CCL3 compared to isogenic control IgG (Figure 6a). In contrast, anti-CCR5 blocking antibodies reduced the chemotaxis of alveolar macrophages at all tested doses of CCL3 (Figure 6b). CCR1 blocking antibodies are not commercially available.

Bottom Line: The recruitment of mononuclear cells has important implications for tissue inflammation.In contrast to peripheral blood monocytes, alveolar macrophages did not express the CCL2 receptor, CCR2, and did not migrate toward CCL2.The addition of anti-CCR5 blocking antibodies completely abrogated CCL3-induced migration in alveolar macrophages, but did not affect the migration of peripheral blood monocytes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, The Ohio State University and Dorothy M, Davis Heart and Lung Research Institute, Columbus, Ohio, USA. clay.marsh@osumc.edu.

ABSTRACT

Background: The recruitment of mononuclear cells has important implications for tissue inflammation. Previous studies demonstrated enhanced CCR1 and CCR5 expression and decreased CCR2 expression during in vitro monocyte to macrophage differentiation. To date, no study examined the in vivo differences in chemokine receptor expression between human peripheral blood monocytes and alveolar macrophages.

Methods: We examined the expression of these receptors in human peripheral blood monocytes and alveolar macrophages using microarray analysis, reverse-transcriptase PCR, flow cytometry and migration analyses.

Results: In contrast to peripheral blood monocytes, alveolar macrophages did not express the CCL2 receptor, CCR2, and did not migrate toward CCL2. In contrast, monocytes and freshly isolated resident alveolar macrophages both migrated towards CCL3. However, up to 6-fold more monocytes migrated toward equivalent concentrations of CCL3 than did alveolar macrophages from the same donor. While peripheral blood monocytes expressed the CCL3 receptor, CCR1, alveolar macrophages expressed the alternate CCL3 receptor, CCR5. The addition of anti-CCR5 blocking antibodies completely abrogated CCL3-induced migration in alveolar macrophages, but did not affect the migration of peripheral blood monocytes.

Conclusion: These data support the specificity of CCL2 to selectively drive monocyte, but not alveolar macrophage recruitment to the lung and CCR5 as the primary macrophage receptor for CCL3.

No MeSH data available.


Related in: MedlinePlus