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Updated: Jan 14, 2026
Competitive Homing Assays to Study Gut-tropic T Cell Migration
Published on: March 1, 2011
Bexarotene signaling in human B and T lymphocytes induces gut-homing receptor expression
Sina Kaiser1, Ina Suhrkamp1, Jinru He2
1Department of Dermatology, Venereology, and Allergy, University Hospital Schleswig-Holstein, Kiel, Germany.
Background:
Retinoic acid (RA) receptors (RARs) in human lymphocytes modulate the humoral and intestinal immune response by regulating target genes, including CD38, TGM2, and gut-homing markers. The impact of retinoid X receptors (RXRs) on this process is elusive.
Objective:
To determine the impact of the RXR ligand bexarotene (BXR) on the activation and differentiation of human B and T lymphocytes.
Methods:
In vitro BXR stimulation of human CD19+ B cells and CD4+ T helper cells was investigated regarding retinoid target gene expression using qPCR and flow cytometry and validated in peripheral B and T lymphocytes of patients with cutaneous T-cell lymphoma (CTCL) with and without BXR treatment.
Results:
BXR induced the canonical retinoid target gene CD38 in B cells and T cells (sixfold and threefold, respectively). BXR increased CD38 surface protein expression on B cells twofold and plasmablast differentiation threefold. The frequency of the gut-homing receptors CCR9 and integrin β7 was doubled on T and B cells after BXR stimulation, while cutaneous leucocyte-associated antigen (CLA) expression was decreased in B cells. Under BXR treatment, a reduced frequency of cells with these gut-homing receptors was observed in the blood of CTCL patients regarding memory T cells (mean off: 1.9%; on: 0.6%) and B cells (mean off: 5.7%, on: 4%).
Conclusion:
BXR via RXRs directly targets B and T lymphocytes, inducing retinoid target gene expression, including gut-homing receptors.
Insights
Bexarotene (BXR) activates retinoid X receptors (RXRs) in human B and T lymphocytes. This immune cell modulation impacts gut-homing receptors and CD38 expression, influencing immune responses.
Area of Science:
- Immunology
- Molecular Biology
- Pharmacology
Background:
- Retinoic acid receptors (RARs) influence human lymphocyte function, affecting humoral and intestinal immunity.
- The role of retinoid X receptors (RXRs) in these processes remains unclear.
Purpose of the Study:
- To investigate the effect of the RXR ligand bexarotene (BXR) on human B and T lymphocyte activation and differentiation.
- To elucidate the molecular mechanisms underlying BXR's impact on lymphocyte populations.
Main Methods:
- In vitro studies using human CD19+ B cells and CD4+ T helper cells stimulated with BXR.
- Quantitative PCR (qPCR) and flow cytometry to assess retinoid target gene expression and protein levels.
- Validation in peripheral blood lymphocytes from cutaneous T-cell lymphoma (CTCL) patients undergoing BXR treatment.
Main Results:
- BXR significantly upregulated the retinoid target gene CD38 in both B and T cells.
- BXR increased CD38 surface protein expression and promoted plasmablast differentiation in B cells.
- BXR stimulation enhanced gut-homing receptors (CCR9, integrin β7) on lymphocytes while decreasing cutaneous lymphocyte-associated antigen (CLA) on B cells.
- In CTCL patients, BXR treatment correlated with reduced frequencies of gut-homing receptors on memory T and B cells.
Conclusions:
- Bexarotene (BXR), acting through retinoid X receptors (RXRs), directly modulates human B and T lymphocytes.
- BXR induces retinoid target gene expression, including key gut-homing receptors, thereby influencing lymphocyte trafficking and immune responses.
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