Altered CD45 isoform combination in C77G carriers influences the function of CD4+CD25high FoxP3+ regulatory T cells

ABSTRACT: Disorders in regulatory T cell (Treg) function can result in the break-down of immunological self-tolerance. Thus, the identification of mechanisms controlling the activity of Treg is of great relevance. We used Treg from individuals carrying the C77G polymorphism as human models to study the role of CD45 molecules. The C77G mutation occurs with low frequency in healthy individuals and prevents splicing of CD45 exon A thereby leading to an aberrant expression pattern of CD45 isoforms in affected individuals. Resting and in vitro expanded/activated CD4+CD25highFoxp3+ Treg from carriers of C77G strongly expressed CD45RA isoforms whereas they were almost absent in cells from individuals with wild-type CD45. The expression patterns of CD45RB and CD45RC did not differ between C77G and control Treg but CD45R0 molecules were reduced in C77G cells. Resting C77G Treg showed diminished upregulation of activation markers and a reduced proliferative potential when stimulated with anti-CD3/TcR or anti-CD3/CD28 mAb suggesting decreased responsiveness to activating stimuli. This is in line with the observation that CD3/CD28-mediated activation of in vitro expanded Treg resulted in lower levels of TGF-? and IL-10 transcripts in C77G cells compared to controls. Furthermore, microarray studies revealed distinct gene expression patterns in Treg from C77G carriers and individuals with wild-type CD45. In addition, the capacity to suppress proliferation of conventional CD4+ T cells was reduced in C77G Treg. These data suggest that the changes in CD45 isoform combination resulting from C77G alter the responsiveness of Treg to CD3/TcR- and/or CD28-mediated signalling. Targeting of CD45 isoforms might be an approach to modulate Treg function. Total RNA was isolated from expanded and stimulated (2h with 1:5 CD3/CD28 beads) Treg of wild-type and C77G carriers using RNeasy Plus Micro Kit (Qiagen). Two pools of three wild-type individuals and three C77G individuals were prepared using equal amounts of RNA from each single donors. The two samples were each hybridised twice on an Agilent human Gene Expression Microarray 4x44K. cell type comparison

ORGANISM(S): Homo sapiens

SUBMITTER: Robert Geffers 

PROVIDER: E-GEOD-31209 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress