Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The molecules that define human regulatory T cells (Tregs) phenotypically and functionally remain to be fully characterized. We recently showed that activated human Tregs express mRNA for a transmembrane protein called glycoprotein A repetitions predominant (GARP, or LRRC32). Here, using a GARP-specific mAb, we demonstrate that expression of GARP on activated Tregs correlates with their suppressive capacity. However, GARP was not induced on T cells activated in the presence of TGFbeta, which expressed high levels of FOXP3 and lacked suppressive function. Ectopic expression of FOXP3 in conventional T cells was also insufficient for induction of GARP expression in most donors. Functionally, silencing GARP in Tregs only moderately attenuated their suppressive activity. CD25+ T cells sorted for high GARP expression displayed more potent suppressive activity compared with CD25+GARP- cells. Remarkably, CD25+GARP- T cells expanded in culture contained 3-5 fold higher IL-17-secreting cells compared with either CD25+GARP+ or CD25-GARP- cells, suggesting that high GARP expression can potentially discriminate Tregs from those that have switched to Th17 lineage. We also determined whether GARP expression correlates with FOXP3-expressing T cells in human immunodeficiency virus (HIV) -infected subjects. A subset of HIV+ individuals with high percentages of FOXP3+ T cells did not show proportionate increase in GARP+ T cells. This finding suggests that higher FOXP3 levels observed in these HIV+ individuals is possibly due to immune activation rather than to an increase in Tregs. Our findings highlight the significance of GARP both in dissecting duality of Treg/Th17 cell differentiation and as a marker to identify bona fide Tregs during diseases with chronic immune activation.
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PMID:Expression of GARP selectively identifies activated human FOXP3+ regulatory T cells. 1966 73

Using the feline immunodeficiency virus (FIV) model for AIDS-lentivirus infection, our laboratory has previously demonstrated that T regulatory (Treg) cell-mediated immune T and B cell dysfunction contributes to lentivirus persistence and chronic disease through membrane bound transforming growth factor beta (mTGFb). Studying Treg cells in the context of infection has been problematic as no inducible marker for activated Treg cells had been identified. However, recent reports in human Treg studies have described a novel protein, glycoprotein A repetitions predominant (GARP), as a unique marker of activated human Treg cells that anchors mTGFb. Herein we extend these studies to the feline Treg system, identifying feline GARP and demonstrating that human and feline GARP proteins are homologous in structure, expression pattern, and ability to form a complex with TGFb. We further demonstrate that GARP and TGFb form a complex on the surface of activated Treg cells and that these GARP(+)TGFb(+) Treg cells are highly efficient suppressor cells. Analysis of expression of this Treg activation marker in the FIV-AIDS model reveals an up-regulation of GARP expressing Treg cells during chronic FIV infection. We demonstrate that the GARP(+) Treg cells from FIV-infected cats suppress T helper cells in vivo and that blocking GARP or TGFb eliminates this suppression. These data suggest that GARP is expressed in complex with TGFb on the surface of activated Treg cells and plays an important role in TGFb(+) Treg-mediated T cell immune suppression during lentivirus infection.
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PMID:Feline glycoprotein A repetitions predominant anchors transforming growth factor beta on the surface of activated CD4(+)CD25(+) regulatory T cells and mediates AIDS lentivirus-induced T cell immunodeficiency. 2337 23

Although rollout of combined antiretroviral treatment (cART) has blunted human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) onset, there is increased development of cardiovascular diseases (CVDs) in HIV-infected individuals. While most HIV-infected individuals on cART achieve viral suppression, this may not necessarily result in complete immunological recovery. This study therefore evaluated T-cell-mediated changes and coagulation markers in HIV-positive individuals to ascertain their potential to increase CVD risk. Eighty participants were recruited (Worcester, South Africa), and fasted blood was collected to evaluate: 1) immune activation (CD38 expression on CD4+ and CD8+ T cells) and thrombus formation [tissue factor (CD142)] on CD4+ and CD8+ T cells; 2) monocyte subpopulations (nonclassical, intermediate, and classical); and 3) classical regulatory T (Treg) cells with activation markers [glycoprotein A repetitions predominant (GARP) and special AT-rich sequence-binding protein 1 (SATB-1)]. High- and low-density lipoprotein subclasses (Lipoprint) were also determined. This study revealed four key findings for HIV-positive patients: 1) coexpression of the CD142 coagulation marker together with immune activation on both CD4+ and CD8+ T cells during chronic infection stages; 2) Treg cell activation and upregulated GARP and SATB-1 contributing to Treg dysfunction in chronic HIV; 3) proatherogenic monocyte subset expansion with significant correlation between T-cell activation and macrophage activation (marker: CD163); and 4) significant correlation between immune activation and lipid subclasses, revealing crucial changes that can be missed by traditional lipid marker assessments (LDL and HDL). These data also implicate lipopolysaccharide-binding protein as a crucial link between immune activation, lipid alterations, and increased CVD risk. NEW & NOTEWORTHY With combined antiretroviral treatment rollout, HIV-AIDS patients are increasingly associated with cardiovascular diseases onset. This study demonstrated the significant interplay between adaptive immune cell activation and monocyte/macrophage markers in especially HIV-positive individuals with virological failure and on second line treatment. Our data also show a unique link between immune activation and lipid subclass alterations, revealing important changes that can be missed by traditional lipid marker assessments (e.g., LDL and HDL).
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PMID:HIV and cardiovascular diseases risk: exploring the interplay between T-cell activation, coagulation, monocyte subsets, and lipid subclass alterations. 3076 57