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)

Chemokines are proinflammatory cytokines that play a role in leukocyte migration and activation. Recent reports showed that RANTES (regulated on activation normal T-cell expressed and secreted chemokine), eotaxin, macrophage-derived chemokine (MDC), and stromal cell-derived factor-1 (SDF-1) are NH(2)-terminally truncated by the lymphocyte surface glycoprotein and protease CD26/dipeptidyl peptidase IV (CD26/DPP IV). Removal of the NH(2)-terminal dipeptide resulted in impaired inflammatory properties of RANTES, eotaxin, MDC, and SDF-1. The potential CD26/DPP IV substrate macrophage inflammatory protein-1beta (MIP-1beta) and the related chemokine, LD78alpha (ie, one of the MIP-1alpha isoforms), were not affected by this protease. However, CD26/DPP IV cleaved LD78beta, a most potent CCR5 binding chemokine and inhibitor of macrophage tropic human immunodeficiency virus-1 (HIV-1) infection, into LD78beta(3-70). Naturally truncated LD78beta(3-70), but not truncated MIP-1beta, was recovered as an abundant chemokine form from peripheral blood mononuclear cells. In contrast to all other chemokines processed by CD26/DPP IV, LD78beta(3-70) had increased chemotactic activity in comparison to intact LD78beta. With a minimal effective concentration of 30 pmol/L, LD78beta(3-70) became the most efficient monocyte chemoattractant. LD78beta(3-70) retained its high capacity to induce an intracellular calcium increase in CCR5-transfected cells. Moreover, on CCR1 transfectants, truncated LD78beta(3-70) was 30-fold more potent than intact LD78beta. Thus, CD26/DPP IV can exert not only a negative but also a positive feedback during inflammation by increasing the specific activity of LD78beta. CD26/DPP IV-cleaved LD78beta(3-70) is the most potent CCR1 and CCR5 agonist that retains strong anti-HIV-1 activity, indicating the importance of the chemokine-protease interaction in normal and pathologic conditions. (Blood. 2000;96:1674-1680)
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PMID:Cleavage by CD26/dipeptidyl peptidase IV converts the chemokine LD78beta into a most efficient monocyte attractant and CCR1 agonist. 1096 62

The interferon (IFN)-inducible chemokines, specifically, IFN-gamma-inducible protein-10 (IP-10), monokine induced by IFN-gamma (Mig), and IFN-inducible T-cell alpha-chemoattractant (I-TAC), share a unique CXC chemokine receptor (CXCR3). Recently, the highly specific membrane-bound protease and lymphocyte surface marker CD26/dipeptidyl peptidase IV (DPP IV) was found to be responsible for posttranslational processing of chemokines. Removal of NH(2)-terminal dipeptides by CD26/DPP IV alters chemokine receptor binding and signaling, and hence inflammatory and anti-human immunodeficiency virus (HIV) activities. CD26/DPP IV and CXCR3 are both markers for Th1 lymphocytes and, moreover, CD26/DPP IV is present in a soluble, active form in human plasma. This study reports that at physiologic enzyme concentrations CD26/DPP IV cleaved 50% of I-TAC within 2 minutes, whereas for IP-10 and Mig the kinetics were 3- and 10-fold slower, respectively. Processing of IP-10 and I-TAC by CD26/DPP IV resulted in reduced CXCR3-binding properties, loss of calcium-signaling capacity through CXCR3, and more than 10-fold reduced chemotactic potency. Moreover, IP-10 and I-TAC cleaved by CD26/DPP IV acted as chemotaxis antagonists and CD26/DPP IV-truncated IP-10 and Mig retained their ability to inhibit the angiogenic activity of interleukin-8 in the rabbit cornea micropocket model. These data demonstrate a negative feedback regulation by CD26/DPP IV in CXCR3-mediated chemotaxis without affecting the angiostatic potential of the CXCR3 ligands IP-10 and Mig.
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PMID:Amino-terminal truncation of CXCR3 agonists impairs receptor signaling and lymphocyte chemotaxis, while preserving antiangiogenic properties. 1173 56

Plasma levels of cytomegalovirus (CMV)-specific immunoglobulin G (IgG), soluble (s) CD30, sCD26 (dipeptidyl peptidase IV [DPP IV]) enzyme activity, and tumor necrosis factor receptor-I (TNFR-I) were assessed in human immunodeficiency virus (HIV)-infected patients who experienced CMV retinitis (CMVR) as an immune restoration disease (IRD) during their first 6 months of highly active antiretroviral therapy (HAART) and in CMV-seropositive, HIV-infected patients with similar baseline CD4(+) T cell counts who had uneventful immune reconstitution. Patients who experienced CMVR IRD had a significant increase in CMV-specific IgG during their first 12 months of HAART, indicating restored CMV-specific immune responses. They also had significantly higher levels of sCD30 both before HAART and for up to 12 months after start of treatment. sCD30 levels remained elevated during 48 months of HAART, suggesting persistence of a predominant Th2 cytokine environment. Levels of sCD26 (DPP IV) enzyme activity and TNFR-I did not differ significantly between the 2 groups at any time point.
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PMID:Cytomegalovirus (CMV) retinitis immune restoration disease occurs during highly active antiretroviral therapy-induced restoration of CMV-specific immune responses within a predominant Th2 cytokine environment. 1208 31

Hepatotoxicity was investigated, using plasma collected before and during treatment, in 16 human immunodeficiency virus (HIV)-hepatitis C virus (HCV)-coinfected patients who responded to highly active antiretroviral therapy (HAART), during a retrospective longitudinal study. Eleven patients experienced hepatotoxicity (i.e., a >3-fold increase in alanine aminotransferase level) while receiving HAART, including 4 patients with clinical hepatitis. Control subjects were 5 patients without hepatotoxicity. Markers of HCV-specific immune responses (HCV core-specific immunoglobulin G [IgG] antibody), T cell activation (soluble [s] CD26 dipeptidyl peptidase IV [DPP IV] enzyme activity), and inflammation (nitrate/nitrite and soluble tumor necrosis factor receptor I [sTNFRI] levels) were correlated with liver damage and immune reconstitution. All patients with hepatotoxicity had increased HCV core-specific IgG antibody and sCD26 (DPP IV) activity but did not have increased nitrate/nitrite or sTNFRI levels. Hepatotoxicity without clinical hepatitis was associated with increased CD8 T cell counts. Thus, hepatotoxicity in HIV-HCV-coinfected patients who respond to HAART is associated with increased HCV-specific immune responses and T cell activation.
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PMID:Association of increased hepatitis C virus (HCV)-specific IgG and soluble CD26 dipeptidyl peptidase IV enzyme activity with hepatotoxicity after highly active antiretroviral therapy in human immunodeficiency virus-HCV-coinfected patients. 1240 69

Recent studies have shown that nondividing primary cells, such as hepatocytes, can be efficiently transduced in vitro by human immunodeficiency virus-based lentivirus vectors. Other studies have reported that, under certain conditions, the liver can be repopulated with transplanted hepatocytes. In the present study, we combined these procedures to develop a model system for ex vivo gene therapy by repopulating rat livers with hepatocytes and hepatoblasts transduced with a lentivirus vector expressing a reporter gene, green fluorescent protein (GFP). Long-term GFP expression in vivo (up to 4 months) was achieved when the transgene was driven by the liver-specific albumin enhancer/promoter but was silenced when the cytomegalovirus (CMV) enhancer/promoter was used. Transplanted cells were massively amplified ( approximately 10 cell doublings) under the influence of retrorsine/partial hepatectomy, and both repopulation and continued transgene expression in individual cells were documented by dual expression of a cell transplantation marker, dipeptidyl peptidase IV (DPPIV), and GFP. In this system, maintenance or expansion of the transplanted cells did not depend on expression of the transgene, establishing that positive selection is not required to maintain transgene expression following multiple divisions of transplanted, lentivirus-transduced hepatic cells. In conclusion, fetal hepatoblasts (liver stem/progenitor cells) can serve as efficient vehicles for ex vivo gene therapy and suggest that liver-based genetic disorders that do not shorten hepatocyte longevity or cause liver damage, such as phenylketonuria, hyperbilirubinemias, familial hypercholesterolemia, primary oxalosis, and factor IX deficiency, among others, might be amenable to treatment by this approach.
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PMID:Repopulation of rat liver by fetal hepatoblasts and adult hepatocytes transduced ex vivo with lentiviral vectors. 1271 80

An inhibitor of the metallo-ectoenzyme, pyroglutamyl aminopeptidase II (PPII), a thyrotropin releasing hormone-specific peptidase, was identified by screening extracts from marine species of the Cuban coast-line belonging to the phylla Chordata, Echinodermata, Annelida, Mollusca, Cnidaria, Porifera, Chlorophyta and Magnoliophyta. Isolation of the inhibitor (HcPI), from the marine annelide Hermodice carunculata, was achieved by trichloroacetic acid treatment of the aqueous extract, followed by ion-exchange chromatography on DEAE Sephacel, gel filtration on Sephadex G-25 and reverse phase-HPLC. HcPI had a small apparent molecular weight (below 1000 Da) and was not a peptide. It inhibited rat PPII (a membrane preparation with 8.5mg protein/ml) with an apparent K(i) of 51 nM. HcPI did not inhibit serine (trypsin, chymotrypsin, elastase and dipeptidyl aminopeptidase IV), cysteine (papain, bromelain and pyroglutamyl aminopeptidase I), aspartic (pepsin and recombinant human immunodeficiency virus 1 protease (HIV1-PR)) nor other metallo proteinases (collagenase, gelatinase, angiotensin converting enzyme, aminopeptidase N and carboxypeptidase A). HcPI was non-toxic and active in vivo. Intraperitoneal injection of HcPI reduced mouse pituitary and brain PPII activity. Potency of the effect was higher in hypophysis and hypothalamus than in other brain regions. Intrathecal administration to male rats reduced PPII activity in the spinal cord. In conclusion we have identified a specific inhibitor of PPII that is the first M1 family zinc metallo-peptidase inhibitor isolated from marine invertebrates. It may be useful for elucidating the in vivo role of PPII in the pituitary and central nervous system.
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PMID:Purification of a specific inhibitor of pyroglutamyl aminopeptidase II from the marine annelide Hermodice carunculata. in vivo effects in rodent brain. 1459 39

CD26 or dipeptidyl-peptidase IV (DPPIV) is engaged in immune functions by co-stimulatory effects on activation and proliferation of T lymphocytes, binding to adenosine deaminase, and regulation of various chemokines and cytokines. DPPIV peptidase activity is inhibited by both Tat protein from human immunodeficiency virus (HIV)-1 and its N-terminal nonapeptide Tat-(1-9) with amino acid sequence MDPVDPNIE, suggesting that DPPIV mediates immunosuppressive effects of Tat protein. The 2.0- and 3.15-A resolution crystal structures of the binary complex between human DPPIV and nonapeptide Tat-(1-9) and the ternary complex between the variant MWPVDPNIE, called Trp(2)-Tat-(1-9), and DPPIV bound to adenosine deaminase show that Tat-(1-9) and Trp(2)-Tat-(1-9) are located in the active site of DPPIV. The interaction pattern of DPPIV with Trp(2)-Tat-(1-9) is tighter than that with Tat-(1-9), in agreement with inhibition constants (K(i)) of 2 x 10(-6) and 250 x 10(-6) m, respectively. Both peptides cannot be cleaved by DPPIV because the binding pockets of the N-terminal 2 residues are interchanged compared with natural substrates: the N-terminal methionine occupies the hydrophobic S1 pocket of DPPIV that normally accounts for substrate specificity by binding the penultimate residue. Because the N-terminal sequence of the thromboxane A2 receptor resembles the Trp(2)-Tat-(1-9) peptide, a possible interaction with DPPIV is postulated.
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PMID:Crystal structures of HIV-1 Tat-derived nonapeptides Tat-(1-9) and Trp2-Tat-(1-9) bound to the active site of dipeptidyl-peptidase IV (CD26). 1569 14


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