[Clinical analysis of fertility-sparing therapy of patients with complex atypical hyperplasia and endometrial cancer].

OBJECTIVE: To analyze the efficacy and prognosis of fertility-sparing therapy of the patient with complex atypical hyperplasia (CAH) and endometrial cancer (EC). METHODS: Clinical data of 191 EC and CAH patients who received fertility-sparing therapy in Peking University People's Hospital between January 2009 and September 2021 were recruited retrospectively. Outcomes of remission, recurrence and pregnancy were analyzed. RESULTS: (1) Efficacy and efficacy-related factors: The complete response (CR) rate was 86.1% (161/187) for all the patients, and the CR rate of the CAH patients were higher than that of the EC patients (92.7% vs. 79.1%, P=0.007), the CR rate was significant higher in the CAH patients (OR=2.786, P=0.035). (2) The recurrence rate was 19.3% (31/161), and the recurrence rate of the EC patients were much higher than that of the CAH patients (26.4% vs. 13.5%, P=0.039). The median recurrence time was 22.5 (9.0, 50.0) months. (3) The high risk factors of recurrence were pathological type of EC (χ2=4.880, P=0.027), without the use of metfor-min (χ2=7.075, P=0.008), longer time to complete remission (>7 months) (χ2=6.204, P=0.013), and no pregnancy (χ2=6.765, P=0.009). (4) Results of pregnancy and related factors: Among the patients who achieved CR, 108 patients had fertility willing with the pregnancy rate of 41.7% (45/108), and the live birth rate was 34.3% (37/108). The live birth rate was lower in EC than that in the CAH patients (28.6% vs. 42.4%, P=0.045). The median time to achieve pregnancy was 10.50 (5.75, 33.25) months. The pregnancy rate was significant higher in the patients with pregnancy history (OR=9.468, P < 0.001) and in those who received assisted reproductive therapy (OR=7.809, P < 0.001). CONCLUSION: Fertility-sparing therapy of CAH and EC patients is effective resulting in high disease remission and certain pregnancy. However, the high recurrence rate and low pregnancy rate are still key problems for EC and CAH patients, therefore close monitoring and follow-up are indicated.

Clinical impacts of sun exposures on the faces and hands of Japanese women of different ages.

OBJECTIVE: To assess the impacts of sun exposures on some skin signs on the faces and hands of differently aged Japanese women, according to their distinct behaviours towards vis à vis sun exposure. METHODS: Two comparable cohorts of Japanese women (aged 18-83 years) were created according to their usual behaviour towards sun exposure i.e. non-sun-phobic (N = 495) and sun-phobic (N = 516) and through their regular use(s) of a photo-protective product. Standard photographs (full-face and 45° lateral) allowed to focus on 18 facial signs that were graded by 15 experts, using a referential skin ageing Atlas. From these two cohorts, two sub-cohorts (114 and 122 women) were created with regard to the similar clinical aspects of the dorsal side of their hands (Left vs. Right) that were further graded. Absolute differences in the scores of each sign were used (non-sun-phobic minus sun-phobic), by age-ranges, to better ascertain the impact of sun exposures and photo-protection. RESULTS: Facial signs related to skin wrinkles/texture and pigmentary spots were found significantly more accentuated among non-sun-phobic women and show an early onset (20-30 years). Facial sagging and crow's feet wrinkles appear delayed (30-40 years). The severity of vascular disorders was found to be similar in the two cohorts. The absolute differences in the grading's of almost all signs were unsurprisingly found increased with advancing ages, illustrating the combination of chronological and photo-ageing processes. With regard to hands, differences in skin texture and pigmentary disorders are of a late onset (40-50 years) and were found much increased at older ages. The cutaneous signs of the hands of Japanese women can hardly be taken as reliable markers of their photo-ageing status. CONCLUSION: The present work illustrates, for the first time, some specificities of the impact of sun exposures on the facial skin of Japanese women, pinpointing the fact that some facial signs are of an early onset. Results significantly confirm the importance of both sun avoidance coupled with photo-protective measures.

OBJECTIF: D'évaluer les impacts de l'exposition solaire sur plusieurs signes du visage et des mains de femmes Japonaises d'âge différents, selon leurs différents comportements vis-à-vis de l'exposition solaire. MÉTHODES: Deux cohortes comparables de femmes Japonaises (âgées de 18 à 83 ans) ont été créées selon leur comportement habituel vis à vis de l'exposition solaire, phobique (N = 516) ou non (N = 495) et selon leur utilisation(s) régulière(s) de produits photo-protecteurs. Des photographies standardisées du visage de face et latérales (45°) ont permis de se focaliser sur 18 signes cliniques du visage dont la sévérité a été quantifiée par 15 experts, utilisant un Atlas de référence du vieillissement cutané. De ces deux cohortes, deux sous-cohortes ont été extraites (114 et 122 femmes) par les aspects cliniques similaires de la face dorsale de leurs mains (Gauche vs. Droite) pour être ensuite quantifiées. Les différences absolues de chaque signe (non-phobiques moins phobiques), par tranches d'âges, ont été utilisées pour mieux déterminer l'impact des expositions solaires et des routines de photo-protection. RÉSULTATS: Les signes du visage liés à la texture cutanée/rides et aux taches pigmentaires ont été trouvés significativement aggravés chez les femmes non-phobiques de l'exposition solaire et d'apparition précoce (20-30 ans) tandis que la ptose du visage ou les rides de la patte d'oie apparaissent plus tardivement (30-40 ans). La sévérité des désordres vasculaires du visage a été trouvée similaire dans les deux cohortes. Les différences absolues dans la sévérité de la plupart des signes ont été logiquement trouvées accrues avec l'âge, illustrant la combinaison du vieillissement chronologique et de celui photo-induit. Concernant les mains, les différences dans la texture cutanée et les désordres pigmentaires apparaissent significativement tardives (40-50 ans) et augmentent à des âges plus avancés. Les signes cutanés des mains des femmes Japonaises ne semblent donc pas être des marqueurs fiables du vieillissement photo-induit. CONCLUSION: La présente étude illustre, pour la première fois, quelques spécificités des impacts de l'exposition solaire sur les signes faciaux de femmes Japonaises, pointant le fait que certains sont d'apparition précoce. Les résultats confirment de manière significative l'importance d'éviter les expositions solaires et de recourir à des mesures photo-protectrices.

Hypoxia-inducible factor-1α inhibits interleukin-6 and -8 production in gingival epithelial cells during hypoxia.

BACKGROUND AND OBJECTIVE: Hypoxia has been widely studied in inflammatory diseases as it can modulate the inflammatory response, mainly via the hypoxia-inducible factor (HIF). However, little is known about the effects of hypoxia and the role of HIF in the inflammatory responses to periodontitis. In this study, we focused on the gingival epithelium that is exposed to relatively low levels of oxygen. We investigated whether hypoxic conditions have an impact on inflammatory responses in human gingival epithelial cells (HGECs). MATERIAL AND METHODS: Pimonidazole HCl, which accumulates in hypoxic cells, was administered intraperitoneally to C57BL/6 mice with or without Porphyromonas gingivalis infection. Immunohistochemistry was then performed to detect the hypoxic cells in periodontal tissue. Immortalized HGECs were cultured under hypoxic conditions with or without interleukin (IL)-1ß, and the expression levels of IL-6 and IL-8 were measured by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. HIF-1α expression was detected by western blotting. The DNA-binding activity of HIF-1α was determined by a DNA-binding enzyme-linked immunosorbent assay. The involvement of HIF-1α in the hypoxic response was examined by transfection with HIF-1α siRNA. RESULTS: Immunohistochemistry revealed pimonidazole HCl accumulation in the gingival epithelium of both normal and P. gingivalis-infected mice, with a slightly stronger signal in the P. gingivalis-infected mice than in the normal mice. The IL-1ß-induced IL-6 and IL-8 production by HGECs was suppressed under hypoxic conditions. HIF-1α accumulated during hypoxia, and this accumulation was further enhanced by IL-1ß treatment. The hypoxia-dependent suppression of IL-6 and IL-8 expression was reversed by treating the cells with HIF-1α siRNA. CONCLUSION: Our results suggest that the gingival epithelium is exposed to low oxygen tension in periodontal tissue and that this hypoxic condition modulates the local inflammatory response of gingival epithelial cells in an HIF-1α-dependent manner.

Regulation of somatostatin receptor 4-mediated cytostatic effects by CD26 in malignant pleural mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is an aggressive neoplasm arising from mesothelial lining of pleura. CD26 molecules preferentially expressed on epithelioid type of MPM. This study investigates the molecular mechanisms of CD26 regulating MPM cells in vitro and in vivo. METHODS: Biochemical and cell biological approaches were used for identifying a novel molecular target of MPM. Its contribution to tumour expansion has been also assessed using animal models. The clinical samples of MPM were also assessed for its expression. RESULTS: We identify that cytostatic effects in MPM are mediated by somatostatin (SST) receptor 4 (SSTR4), being inhibited by the interaction of CD26 molecules. We also indicates that SSTR4-mediated cytostatic effects are regulated by SHP-2 PTP, and that this inhibitory effect by SST agonist is enhanced via lipid raft clustering of associated molecules following crosslinking of anti-CD26 antibody. Finally, using an in vivo xenograft model, we demonstrate that the anti-tumour effect of anti-CD26 mAb is enhanced when combined with SSTR4 agonist treatment, and that SSTR4 is highly coexpressed with CD26 on epithelioid or biphasic types of MPM tissues obtained from patients' surgical specimens. CONCLUSIONS: Combination therapy with humanised anti-CD26 mAb and SSTR4 agonist may therefore potentiate anti-tumour effect on MPM.

Identification of the sequence required for expression of the 2H4 epitope on the human leukocyte common antigens.

The anti-2H4 antibody, which subdivides the T4+ population of human T lymphocytes into T4+, 2H4+ suppressor-inducer cells and T4+, 2H4- helper cells, recognizes an epitope on a subset of the human leukocyte common antigens (LCAs). LCAs are a family of cell surface glycoproteins generated from a single gene by the differential usage of three exons near the NH2-terminus. Using cDNA clones corresponding to four of the different forms of LCA molecules, extracellular domains of the LCA molecules were synthesized in vitro. Immunoprecipitation of these molecules with the anti-2H4 antibody demonstrated that exon A is required for the expression of the 2H4 epitope.

Direct association of pp125FAK with paxillin, the focal adhesion-targeting mechanism of pp125FAK.

Focal adhesion kinase (pp125FAK) is localized to focal adhesions and tyrosine phosphorylated by the engagement of beta 1 integrins. However, it is unclear how pp125FAK is linked to integrin molecules. We demonstrate that pp125FAK is directly associated with paxillin, a 68-kD cytoskeleton protein. The COOH-terminal domain of pp125FAK spanning FAK residues 919-1042 is sufficient for paxillin binding and has vinculin-homologous amino acids, which are essential for paxillin binding. Microinjection and subsequent immunohistochemical analysis reveal that glutathione S-transferase-FAK fusion proteins, which bind to paxillin, localize to focal adhesions, whereas fusion proteins with no paxillin-binding activity do not localize to focal adhesions. These findings strongly suggest that pp125FAK is localized to focal adhesions by the direct association with paxillin.

The subdivision of the T4 (CD4) subset on the basis of the differential expression of L-C/T200 antigens.

The T4 (CD4) subset of T lymphocytes has been subdivided into two major subsets, a suppressor/inducer subset (T4+,2H4+) and a helper subset (T4+,2H4-) on the basis of the differential expression of the L-C/T200 (CD45) antigens. The 2H4 antigen itself comprises at least three distinct polypeptides at 125,200, and 220 X 10(3) Mr, of which the 200 and 220 X 10(3) Mr polypeptides constitute the highest Mr isoforms of a pool of five distinct L-C/T200 antigens. The T4+,2H4+ subset expresses at least four of these isoforms at 180, 190, 200, and 220 X 10(3) on the cell surface, while the T4+,2H4- subset expresses only the 180 and 190 X 10(3) Mr forms. Pulse-chase analysis and endoglycosidase treatment revealed that the 125 X 10(3) Mr chain of the 2H4 antigen is nonglycosylated, while the 200 and 220 X 10(3) polypeptides are structurally related and derived by N- and O-linked glycosylation from two nascent subunits at 150 and 160 X 10(3) Mr. The function of the T4+,2H4+ subset could be blocked only by an antibody reactive with the L-C/T200 isoforms enriched with O-linked oligosaccharides at 200 and 220 X 10(3) Mr.

Human CD4 helper T cell activation: functional involvement of two distinct collagen receptors, 1F7 and VLA integrin family.

In the present study, we showed that activation of human CD4 T cells can be induced by anti-CD3 and collagen in a serum-free system. This activation was inhibited by the addition of peptides containing the RGD or Gly-Pro-X sequences. Significantly, we demonstrated that both the 1F7 (CD26) structure and the VLA integrin family, particularly the VLA-3 complex, contribute to the functional interaction between collagen and CD4 cells since anti-1F7 and anti-VLA-3 specifically inhibited this collagen-induced CD4 cell activation. Biochemical studies showed that the 1F7 structure is not a member of the VLA integrin family. These results thus indicated that two different families of antigens serve as functional collagen receptors for CD4 T cell activation.

Ligation of VLA-4 on T cells stimulates tyrosine phosphorylation of a 105-kD protein.

The VLA/integrins are a family of heterodimeric adhesion receptors shown to be involved in cell-to-cell and cell-to-extracellular matrix (ECM) interactions. Given recent evidence that VLA molecules can synergize with the CD3/T cell receptor (TCR) pathway to activate T cells, it is important to identify biochemical event(s) generated by these molecules. Here, we report that the engagement of VLA-4 on T cells with specific antibodies or its ligand activates protein-tyrosine kinase (PTK) activity as detected by antiphosphotyrosine immunoblotting. The crosslinking of VLA-beta 1 (CD29) with a specific monoclonal antibody (mAb) (anti-4B4) plus anti-mouse immunoglobulin resulted in the rapid tyrosine phosphorylation of a 105-kD protein (pp105) in the human T cell line H9, as well as in peripheral resting T cells. The increase in tyrosine phosphorylation of pp105 was specifically mediated by VLA-4, since mAbs against alpha 4, but not against other VLA alpha chains, could induce this phosphorylation. In addition, the binding of T cells with the CS1 alternatively spliced segment of fibronectin (the binding site recognized by VLA-4) induced pp105 tyrosine phosphorylation. Crosslinking the CD3 complex or VLA-4 molecules with mAbs demonstrated that each of these molecules stimulated the tyrosine phosphorylation of unique sets of proteins with different kinetics, suggesting that these two receptor systems are coupled to distinct PTKs. Since tyrosine phosphorylation of cellular proteins has been shown to be a crucial biochemical event in cell growth, our findings suggest that the induction of pp105 tyrosine phosphorylation via VLA-4 may play a role in the transduction of activation signals through this molecule.

Structure and function of Cas-L, a 105-kD Crk-associated substrate-related protein that is involved in beta 1 integrin-mediated signaling in lymphocytes.

Integrin/ligand binding evokes tyrosine phosphorylation of various proteins. We reported previously that a 105 kD protein (pp105) was tyrosine phosphorylated by the engagement of beta 1 integrins in T lymphocytes. We show here that pp105 is a novel p130Cas (Crk-associated substrate)-related protein. Deduced amino acid sequence revealed that pp105 contains conserved motifs with p130Cas, and both pp105 and p130Cas bind to focal adhesion kinase (pp125FAK) and Crk. However, pp105 has a clearly distinct structure from p130Cas, and pp105 is preferentially expressed in lymphocytes, whereas p130Cas is expressed in adherent cells. With these findings, we designate pp105 as Cas-L, lymphocyte-type Cas. Furthermore, we demonstrate that integrin/ligand binding results in the recruitment of Crk, Nck, and SHPTP2 to pp105. These findings further define the roles of pp105/Cas-L and pp125FAK in the integrin-mediated signaling pathways.

A cytotoxic T lymphocyte inhibits acquired immunodeficiency syndrome virus replication in peripheral blood lymphocytes.

CD8+ (suppressor/cytotoxic) lymphocytes block replication of HIV-1 or the simian immunodeficiency virus of macaques (SIVmac) in PBL of infected individuals. We now show that these CD8+ lymphocytes undergo clonal expansion in vivo after AIDS virus infection of the individual, suggesting they may be antigen-specific T cells. These CD8+ cells block replication of virus in autologous but not MHC class I-mismatched PBL. The inhibitory lymphocytes express the integrin family molecule 4B4 and the CTL-associated S6F1 epitope of LFA-1. Finally, physical contact is required for the CD8+ lymphocyte-mediated inhibition of AIDS virus replication, since this inhibitory function is blocked by anti-LFA-1 and anti-CD8 mAbs. These studies suggest that the cell that inhibits AIDS virus replication in PBL of infected individuals is a CTL.

Activation of CD4 cells by fibronectin and anti-CD3 antibody. A synergistic effect mediated by the VLA-5 fibronectin receptor complex.

In this study, fibronectin synergized with anti-CD3 antibody to promote CD4 cell proliferation in a serum-free culture system. The cell-adhesive domain plus additional regions of the fibronectin molecule are involved in this synergy. Anti4B4(CDw29) antibody blocked the activation of CD4 cells in this system. Furthermore, it is the VLA-5 protein within the set of molecules recognized by anti-4B4 that serves as a fibronectin receptor on the CD4 lymphocytes. The VLA-5 fibronectin receptor was mainly expressed on CD4+ CD45R-CDw29+ cells and may in part contribute to the unique function of these cells.

VLA-4 mediates CD3-dependent CD4+ T cell activation via the CS1 alternatively spliced domain of fibronectin.

We previously showed that fibronectin (FN) synergized with anti-CD3 in induction of CD4+ T cell proliferation, and that VLA-5 acted as a functional FN receptor in a serum-free culture system. In the present study, we showed that VLA-4 is also involved in this CD3-dependent CD4 cell activation through its interaction with the alternatively spliced CS1 domain of FN. When highly purified CD4 cells were cultured on plates coated with anti-CD3 plus synthetic CS1 peptide-IgG conjugate, significant proliferation could be observed. Neither CS1 alone nor anti-CD3 alone induced this activation. This proliferation was completely blocked by anti-VLA beta 1 (4B4) and anti-VLA-4 (8F2), while anti-VLA-5 (monoclonal antibody [mAb] 16 and 2H6) had no effect. These data indicate that VLA-4 mediates CD3-dependent CD4 cell proliferation via the CS1 domain of FN. Anti-VLA-4 also partially (10-40%) inhibited CD4 cell proliferation induced by native FN plus anti-CD3, implying that the CS1 domain is active in the native plasma FN. However, this native FN-dependent proliferation was entirely abolished by addition of anti-VLA-5 alone. Moreover, when native FN-coated plates were pretreated with anti-FN (mAb 333), which blocks RGDS sites but not CS1 sites, no CD4 cell activation could be observed. These results strongly suggest that CD4 cell activation induced by plasma FN/anti-CD3 may be dependent on both VLA4/CS1 and VLA5/RGDS interactions, although the latter interaction may be required for function of the former.

The cellular basis for lack of antibody response to hepatitis B vaccine in humans.

We had previously obtained evidence that among normal subjects the humoral antibody response to hepatitis B surface antigen (HBsAg) was bimodally distributed with about 14% of subjects producing less than 1,000 estimated radioimmunoassay RIA units. From the study of major histocompatibility complex (MHC) markers in the very poor responders who produced less than 36 estimated RIA units of antibody, it appeared that there was an excess of homozygotes for two extended haplotypes [HLA-B8, SC01, DR3] and [HLA-B44, FC31, DR7]. This finding suggested that a poor response was inherited as a recessive trait requiring nonresponse genes for HBsAg on both MHC haplotypes and was strengthened by finding a much lower antibody response among prospectively immunized homozygotes for [HLA-B8, SC01, DR3] compared with heterozygotes. In the present study, we have analyzed the cellular basis for nonresponse to this antigen by examining antigen-specific proliferation of T cells from responders and nonresponders in the presence and absence of autologous CD8+ (suppressor) cells. Peripheral blood cells from nonresponders to HBsAg failed to undergo a proliferative response to recombinant HBsAg in vitro, whereas cells from responders proliferated vigorously. This failure of cells from nonresponders to proliferate was not reversed in cell mixtures containing CD4+ and antigen-presenting cells devoid of CD8+ cells. There was no difference between responders and nonresponders with respect to the number of circulating T cells or their subsets, or the proliferative response to mitogens such as pokeweed or phytohemagglutinin or another antigen, tetanus toxoid. Our results indicate that our HBsAg nonresponding subjects have a very specific failure in antigen presentation or the stimulation of T helper cells, or both. Our evidence is against specific immune suppression as the basis for their nonresponsiveness. The failure of antigen presentation or T cell help is consistent with recessive inheritance of nonresponsiveness and suggests that response is dominantly inherited.

CD26 expression on T cell lines increases SDF-1-alpha-mediated invasion.

BACKGROUND: CD26 is a multifunctional membrane-bound glycoprotein that regulates tumour growth in addition to its other activities. Because disease aggressiveness is correlated with CD26 expression in several T-cell malignancies, we decided to investigate the invasiveness of cells expressing different levels of CD26. METHODS: To assess CD26 involvement in cell invasion, we performed in vitro invasion assays with human T cell lines expressing different levels of CD26. These included the parental CD26-positive T-lymphoblast cell line HSB-2 and clones infected with a retrovirus expressing siRNA vectors that either targeted CD26 or encoded a missense siRNA, and the parental CD26-negative T-leukaemia cell line Jurkat and clones expressing CD26. CD26 expression in these cell lines was evaluated by flow cytometry and western immunoblotting. CXCR4 expression, phosphorylation of signalling kinases, and MMP-9 secretion were also evaluated by western immunoblotting, whereas MMP-9 activity and the effect of kinase and CD45 inhibitors on activity were measured by zymography of conditioned media. RESULTS: The presence of CD26 enhanced stromal-cell-derived factor-1-alpha (SDF-1-alpha)-mediated invasion of T cell lines. This process was regulated in part by the PI-3K and MEK1 pathways, as indicated by increased phosphorylation of p44/42 MAP kinase and Akt in the presence of SDF-1-alpha and the effect of their respective inhibitors on MMP-9 secretion and in vitro invasion. In addition, CD26-associated enhancement of SDF-1-alpha-induced invasion was decreased when CD45 was inhibited. CONCLUSIONS: Our results indicate that the expression of CD26 in T cell lines leads to increased SDF-1-alpha-mediated invasion in an in vitro system and that this is controlled in part by the PI-3K and MEK1 pathways. The data also suggest that CD26 enhancement of invasion may be mediated by CD45, however, more studies are required to confirm this involvement.

Histamine H1-receptor antagonists with immunomodulating activities: potential use for modulating T helper type 1 (Th1)/Th2 cytokine imbalance and inflammatory responses in allergic diseases.

Being a first-line treatment for hypersensitivity allergic disease, histamine H1-receptor antagonists possess anti-inflammatory activity in addition to being H1-receptor antagonists. While it is not purely a histamine-related condition, hypersensitivity allergic disease is associated with an increase in the number of T helper type 2 (Th2) cells and Th2 cytokines, and a decrease in the number of Th1 cells and Th1 cytokines. Suppression of Th2-type cytokine production in addition to H1-receptor blockade may therefore represent a successful therapeutic strategy for the treatment of hypersensitivity allergic diseases. H1-receptor antagonists have been reported to modulate immune cascade at various points by acting on T cell-related inflammatory molecules, including adhesion molecules, chemokines and inflammatory cytokines. These effects of H1-receptor antagonists may be optimized for the treatment of allergic diseases. Besides their ability to regulate inflammatory molecules, some H1-receptor antagonists have been reported to down-regulate Th2 cytokine production. In particular, it has been shown that several H1-receptor antagonists specifically inhibit the production of Th2, but not Th1, cytokines. Accumulating evidence indicates a crucial role for Th1/Th2 cytokine imbalance on the development of allergic diseases. Accordingly, the use of H1-receptor antagonist with Th2 cytokine inhibitory activity to modulate Th1/Th2 cytokine imbalance might be a favourable strategy for the treatment of hypersensitivity allergic diseases. Furthermore, the identification of H1-receptor antagonists which possess immunoregulatory activities in addition to their anti-histamine activity will provide an important insight into the development of novel immunoregulatory drugs.

Direct association of adenosine deaminase with a T cell activation antigen, CD26.

CD26, the T cell activation molecule dipeptidyl peptidase IV (DPPIV), associates with a 43-kilodalton protein. Amino acid sequence analysis and immunoprecipitation studies demonstrated that this 43-kilodalton protein was adenosine deaminase (ADA). ADA was coexpressed with CD26 on the Jurkat T cell lines, and an in vitro binding assay showed that the binding was through the extracellular domain of CD26. ADA deficiency causes severe combined immunodeficiency disease (SCID) in humans. Thus, ADA and CD26 (DPPIV) interact on the T cell surface, and this interaction may provide a clue to the pathophysiology of SCID caused by ADA deficiency.

Adhesion of human B cells to germinal centers in vitro involves VLA-4 and INCAM-110.

Human B lymphocytes localize and differentiate within the microenvironment of lymphoid germinal centers. A frozen section binding assay was developed for the identification of those molecules involved in the adhesive interactions between B cells and lymphoid follicles. Activated human B cells and B cell lines were found to selectively adhere to germinal centers. The VLA-4 molecule on the lymphocyte and the adhesion molecule INCAM-110, expressed on follicular dendritic cells, supported this interaction. This cellular interaction model can be used for the study of how B cells differentiate.

Crk-associated substrate lymphocyte type regulates transforming growth factor-beta signaling by inhibiting Smad6 and Smad7.

Crk-associated substrate lymphocyte type (Cas-L) is a 105 kDa docking protein with diverse functional properties, including regulation of cell division, proliferation, migration and adhesion. Cas-L is also involved in beta1 integrin- or antigen receptor-mediated signaling in B and T cells. In the present study, we demonstrate that Cas-L potentiates transforming growth factor-beta (TGF-beta) signaling pathway by interacting with Smad6 and Smad7. Immunoprecipitation experiments reveal that single domain deletion of full-length Cas-L completely abolishes its docking function with Smad6 and Smad7, suggesting that the natural structure of Cas-L is necessary for its association with Smad6 and Smad7. On the other hand, both N-terminal and C-terminal deletion mutants of Smad6 and Smad7 still retain their docking ability to Cas-L, suggesting that Smad6 and Smad7 possess several binding motifs to Cas-L. Moreover, Cas-L interaction with Mad-homology (MH)2 domain, but not with MH1 domain of Smad6 or Smad7, ameliorates TGF-beta-induced signaling pathway. Finally, depletion of Cas-L by small-interfering RNA oligo attenuates TGF-beta-induced growth inhibition of Huh-7 cells, with a concomitant reduction in phosphorylation of Smad2 and Smad3. These results strongly suggest that Cas-L is a potential regulator of TGF-beta signaling pathway.

Urushiol (poison ivy)-triggered suppressor T cell clone generated from peripheral blood.

Allergic contact dermatitis to Toxicodendron radicans (poison ivy) is mediated by the hapten urushiol. An urushiol-specific, interleukin 2 (IL-2)-dependent T cell clone (RLB9-7) was generated from the peripheral blood of a patient with a history of allergic contact dermatitis to T. radicans. This clone proliferated specifically to both leaf extract and pure urushiol. Although the clone had the phenotype CD3+CD4+CD8+, proliferation to antigen was blocked by anti-CD8 and anti-HLA-A, B, C, but not by anti-CD4, suggesting that CD4 was not functionally associated with the T cell receptor. Furthermore, studies with antigen-presenting cells from MHC-typed donors indicated that the clone was MHC class 1 restricted. RLB9-7 was WT31 positive, indicating it bears the alpha beta T cell receptor. The clone lacked significant natural killer cell activity and produced only low levels of IL-2 or gamma-interferon upon antigen stimulation. Addition of RLB9-7 to autologous peripheral blood mononuclear cells in the presence of urushiol inhibited the pokeweed mitogen-driven IgG synthesis. This suppression was resistant to irradiation (2,000 rad) and was not seen when RLB9-7 was added to allogeneic cells, even in the presence of irradiated autologous antigen-presenting cells, suggesting that suppression was MHC restricted and not mediated by nonspecific soluble factors. However, RLB9-7 cells in the presence of urushiol inhibited the synthesis of tetanus toxoid-specific IgG by autologous lymphocytes, indicating that the suppression, although triggered specifically by urushiol, was nonspecific.