Research article

Human palatine tonsil: a new potential tissue source of multipotent mesenchymal progenitor cells

Sasa Janjanin^{* 1,2} , Farida Djouad^{* 1} , Rabie M Shanti^1,3 , Dolores Baksh¹ , Kiran Gollapudi^1,3 , Drago Prgomet² , Lars Rackwitz¹ , Arjun S Joshi⁴ and Rocky S Tuan¹

¹Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Department of Health and Human Services, 9000 Rockville Pike, Bethesda, MD 20892, USA

²Department of Otorhinolaryngology, Head & Neck Surgery, Zagreb Clinical Hospital Center, Zagreb University School of Medicine, Kispaticeva 12, 10000 Zagreb, Croatia

³Howard Hughes Medical Institute-National Institutes of Health, Research Scholars Program, 1 Cloister Court, Bethesda, MD 20814-1460, USA

⁴Division of Otolaryngology – Head and Neck Surgery, George Washington University, 2150 Pennsylvania Ave. N.W., Washington, DC 20037, USA

author email corresponding author email* Contributed equally

Arthritis Research & Therapy 2008, 10:R83doi:10.1186/ar2459

Published:	28 July 2008

Abstract

Introduction

Mesenchymal progenitor cells (MPCs) are multipotent progenitor cells in adult tissues, for example, bone marrow (BM). Current challenges of clinical application of BM-derived MPCs include donor site morbidity and pain as well as low cell yields associated with an age-related decrease in cell number and differentiation potential, underscoring the need to identify alternative sources of MPCs. Recently, MPC sources have diversified; examples include adipose, placenta, umbilicus, trabecular bone, cartilage, and synovial tissue. In the present work, we report the presence of MPCs in human tonsillar tissue.

Methods

We performed comparative and quantitative analyses of BM-MPCs with a subpopulation of adherent cells isolated from this lymphoid tissue, termed tonsil-derived MPCs (T-MPCs). The expression of surface markers was assessed by fluorescent-activated cell sorting analysis. Differentiation potential of T-MPCs was analyzed histochemically and by reverse transcription-polymerase chain reaction for the expression of lineage-related marker genes. The immunosuppressive properties of MPCs were determined in vitro in mixed lymphocyte reactions.

Results

Surface epitope analysis revealed that T-MPCs were negative for CD14, CD31, CD34, and CD45 expression and positive for CD29, CD44, CD90, and CD105 expression, a characteristic phenotype of BM-MPCs. Similar to BM-MPCs, T-MPCs could be induced to undergo adipogenic differentiation and, to a lesser extent, osteogenic and chondrogenic differentiation. T-MPCs did not express class II major histocompatibility (MHC) antigens, and in a similar but less pronounced manner compared with BM-MPCs, T-MPCs were immunosuppressive, inhibiting the proliferation of T cells stimulated by allogeneic T cells or by non-specific mitogenic stimuli via an indoleamine 2,3-dioxygenase-dependent mechanism.

Conclusion

Human palatine T-MPCs represent a new source of progenitor cells, potentially applicable for cell-based therapies.