Protein tyrosine phosphatase PTPN22 regulates LFA-1 dependent Th1 responses.

A missense C1858T single nucleotide polymorphism within PTPN22 is a strong genetic risk factor for the development of multiple autoimmune diseases. PTPN22 encodes a protein tyrosine phosphatase that negatively regulates immuno-receptor proximal Src and Syk family kinases. Notably, PTPN22 negatively regulates kinases downstream of T-cell receptor (TCR) and LFA-1, thereby setting thresholds for T-cell activation. Alterations to the quality of TCR and LFA-1 engagement at the immune synapse and the regulation of downstream signals can have profound effects on the type of effector T-cell response induced. Here we describe how IFNγ+ Th1 responses are potentiated in Ptpn22-/- T-cells and in T-cells from mice expressing Ptpn22R619W (the mouse orthologue of the human genetic variant) as they age, or following repeated immune challenge, and explore the mechanisms contributing to the expansion of Th1 cells. Specifically, we uncover two LFA-1-ICAM dependent mechanisms; one T-cell intrinsic, and one T-cell extrinsic. Firstly, we found that in vitro anti-CD3/LFA-1 induced Th1 responses were enhanced in Ptpn22-/- T-cells compared to WT, whereas anti-CD3/anti-CD28 induced IFNy responses were similar. These data were associated with an enhanced ability of Ptpn22-/- T-cells to engage ICAM-1 at the immune synapse when incubated on planar lipid bilayers, and to form conjugates with dendritic cells. Secondly, we observed a T-cell extrinsic mechanism whereby repeated stimulation of WT OT-II T-cells with LPS and OVA323-339 pulsed Ptpn22-/- bone marrow derived dendritic cells (BMDCs) was sufficient to enhance Th1 cell development compared to WT BMDCs. Furthermore, this response could be reversed by LFA-1 blockade. Our data point to two related but distinct mechanisms by which PTPN22 regulates LFA-1 dependent signals to enhance Th1 development, highlighting how perturbations to PTPN22 function over time to regulate the balance of the immune response.

Lifitegrast: First LFA-1/ICAM-1 antagonist for treatment of dry eye disease.

Dry eye disease is an extremely common condition affecting millions worldwide. The underlying pathophysiological mechanism is thought to be localized inflammation of the ocular surface resulting in the localization of T cells at this surface followed by their activation and subsequent liberation of cytokines. This effect on T cells results from the binding of lymphocyte function-associated antigen-1 (LFA-1) located on T cells to intercellular adhesion molecule 1 (ICAM-1) expressed on inflamed epithelium and endothelium, and on T cells. Lifitegrast is a T-cell integrin antagonist designed to mimic ICAM-1, thus blocking the interaction of LFA-1 and ICAM-1. Lifitegrast enters the systemic circulation to a limited extent thus reducing the likelihood of unwanted systemic reactions. Clinical trials in over 2,500 subjects with dry eye disease have shown that 5.0% lifitegrast given by ocular instillation causes a significant reduction in objective and subjective signs and symptoms of the disease. These beneficial effects are associated with a relatively low incidence of unwanted effects, almost all local in nature. In light of these findings, lifitegrast was approved by the Food and Drug Administration (FDA) in 2016 for the treatment of dry eye disease, the first drug with this mechanism of action to be so approved.

Foot reflexology in feet impairment of people with type 2 diabetes mellitus: randomized trial / Reflexologia podal no comprometimento dos pés de pessoas com diabetes mellitus tipo 2: ensaio randomizado / Reflexología podal en el comprometimiento de los pies de personas con diabetes mellitus tipo 2: ensayo aleatorio

AbstractObjective: to evaluate the effect of foot reflexology on feet impairment of people with type 2 diabetes mellitus.Method: this is a randomized, controlled and blind clinical trial. The sample was comprised by people with type 2 diabetes mellitus who, after being randomized into Treated group (n = 21) and Control group (n = 24), received guidelines on foot self-care. To the Treated Group it was also provided 12 sessions of foot reflexology. The scores of impairment indicators related to skin and hair, blood circulation, tissue sensitivity and temperature were measured by means of the instrument for assessing tissue integrity of the feet of people with diabetes mellitus. Chi-square test, Fisher exact test, Mann-Whitney test and regression analyzes were applied to the data, considering a significance level of 5% (P value <0.05).Results: participants who received the therapy showed better scores in some impairment indicators related to skin and hair (hair growth, elasticity/turgor, hydration, perspiration, texture and integrity of the skin/ skin peeling).Conclusion: the foot reflexology had a beneficial effect on feet impairment of people with type 2 diabetes mellitus, which makes it a viable therapy, deserving investment. This study was registered in the Brazilian Registry of Clinical Trials - RBR-8zk8sz.

ResumoObjetivo:avaliar o efeito da reflexologia podal no comprometimento dos pés de pessoas com diabetes mellitus tipo 2.Método:trata-se de um ensaio clínico, randomizado, controlado e mascarado. A amostra foi composta por pessoas com diabetes mellitus tipo 2 que, após serem randomizadas em grupo Tratado (n=21) e Controle (n=24), receberam orientações de autocuidado com os pés. Ao Grupo Tratado também foram fornecidas 12 sessões de reflexologia podal. Foram mensurados os escores de comprometimento de indicadores relacionados à pele e pelos, circulação sanguínea, sensibilidade e temperatura tissular por meio do Instrumento para avaliação da integridade tissular dos pés de pessoas com diabetes mellitus. Aos dados foram aplicados os testes Qui-Quadrado, Exato de Fisher, Mann-Whitney e Análises de regressão, considerando-se nível de significância de 5% (Valor P<0,05).Resultados:os participantes que receberam a terapia apresentaram melhores escores de comprometimento em alguns indicadores relacionados à pele e pelos (crescimento de pelos, elasticidade/tugor, hidratação, transpiração, textura e integridade da pele/descamação cutânea).Conclusão:a reflexologia podal apresentou efeito benéfico sobre o comprometimento dos pés de pessoas com diabetes mellitus tipo 2, o que a torna uma terapia viável e que merece investimento. Este estudo foi registrado no Registro Brasileiro de Ensaios Clínicos - RBR-8zk8sz.

ResumenObjetivo:evaluar el efecto de la reflexología podal en el comprometimiento de los pies de personas con diabetes mellitus tipo 2.Método:se trata de un ensayo clínico, aleatorio, controlado y enmascarado. La muestra estuvo compuesta por personas con diabetes mellitus tipo 2 que, después de ser tratadas aleatoriamente en los grupos Tratado (n=21) y Control (n=24), recibieron orientaciones de autocuidado de los pies. También, al Grupo Tratado se le suministraron 12 sesiones de reflexología podal. Fueron medidos los puntajes de comprometimiento de indicadores relacionados a la piel y pelos, circulación sanguínea, sensibilidad y temperatura tisular por medio de instrumento para evaluación de la integridad del tejido de los pies de personas con diabetes mellitus. Los datos fueron sometidos a las pruebas Chi-cuadrado, Exacta de Fisher, Mann-Whitney y Análisis de regresión, considerando un nivel de significación de 5% (Valor p<0,05).Resultados:los participantes que recibieron la terapia presentaron mejores puntajes de comprometimiento en algunos indicadores relacionados a la piel y pelos (crecimiento de pelos, elasticidad/turgencia, hidratación, transpiración, textura e integridad de la piel/descamación cutánea).Conclusión:la reflexología podal presentó efecto benéfico sobre el comprometimiento de los pies de personas con diabetes mellitus tipo 2, lo que la torna una terapia viable y que merece inversiones. Este estudio fue registrado en el Registro Brasileño de Ensayos Clínicos - RBR-8zk8sz.

LFA-1 blockade induces effector and regulatory T-cell enrichment in lymph nodes and synergizes with CTLA-4Ig to inhibit effector function.

Despite encouraging results using lymphocyte function antigen-1 (LFA-1) blockade to inhibit BM and solid organ transplantation rejection in nonhuman primates and humans, the precise mechanisms underlying its therapeutic potential are still poorly understood. Using a fully allogeneic murine transplantation model, we assessed the relative distribution of total lymphocyte subsets in untreated versus anti-LFA-1-treated animals. Our results demonstrated a striking loss of naive T cells from peripheral lymph nodes, a concomitant gain in blood after LFA-1 blockade, and a shift in phenotype of the cells remaining in the node to a CD62LloCD44hi profile. We determined that this change was due to a specific enrichment of activated, graft-specific effectors in the peripheral lymph nodes of anti-LFA-1-treated mice compared with untreated controls, and not to a direct effect of anti-LFA-1 on CD62L expression. LFA-1 blockade also resulted in a dramatic increase in the frequency of CD4+ FoxP3+ regulatory T cells in graft-draining nodes. Our results suggest that the differential impact of LFA-1 blockade on the distribution of naive versus effector and regulatory T cells may underlie its ability to inhibit alloreactive T-cell responses after transplantation.

Secondary metabolites from marine cyanobacteria and algae inhibit LFA-1/ICAM-1 mediated cell adhesion.

An assay for inhibitors of LFA-1/ICAM-1 mediated cell-cell adhesion has been employed to identify new pharmacologically active compounds from marine cyanobacteria and algae. From a panel of sixty unusual marine natural products, seventeen compounds inhibited LFA-1/ICAM-1-based cell aggregation without showing significant cytotoxicity in the primary assay. Six compounds inhibited the cell-cell adhesion of HL-60 cells to CHO-ICAM-1 cells. The unusual oxylipin Cymathere aldehyde methyl ester (IC (50) 3.5 microM), cyanobacterial lipopeptides microcolins B (IC (50) 0.15 microM) and D (IC (50) 0.9 microM), bromophenol avrainvilleol (IC (50) 2.2 microM), sesquiterpene cymopol (IC (50) 2.7 microM), and cryptophyte derived compound styrylchromone hormothamnione diacetate (IC (50) 1.5 microM) significantly inhibited LFA-1/ICAM-1 mediated cell adhesion. The pharmacological activity and structure-activity relationships of selected marine algal metabolites are described. Abbreviations. LFA-1:Lymphocyte function-associated molecule-1 ICAM-1:Intercellular cell adhesion molecule-1 PMA:Phorbol 12-myristate 13-acetate HL-60:Promyelocytic human leukemia-60 CHO:Chinese hamster ovary

LFA-1 and ICAM-1 antibody-idarubicin conjugates separately prolong murine cardiac allograft survival.

Drug antibody conjugates can enhance the activity of monoclonal antibodies (MoAb) and idarubicin-MoAb conjugates have led to tolerance induction with antibodies which are inactive when used alone. It has been reported that, in mice, antibodies to ICAM-1 and LFA-1 have to be used together to induce tolerance to cardiac allografts; here we show that these monoclonal antibodies, conjugated to idarubicin, can lead to tolerance induction to cardiac allografts when used alone.

Effect of LFA-1beta antibody on leukocyte adherence in response to hemorrhagic shock in rats.

The activation and adherence of leukocytes to the venular endothelium are critical steps in the pathogenesis of generalized microvascular injury following hemorrhagic shock. Previous studies have shown that the integrins CD11/CD18 play a significant role in this interaction. The purpose of this study is to examine the efficacy of anti-LFA-1beta, an antibody to CD11a/CD18, in attenuating leukocyte adherence before, during, and after hemorrhagic shock. Following a control period, blood was withdrawn to reduce the mean arterial pressure to 40 mm Hg for 30 min in urethane-anesthetized rats. Mesenteric venules in a transilluminated segment of the small intestines were examined to quantitate leukocyte adherence using intravital microscopy. In sham-operated rats (control), there was minimal to no leukocyte adherence throughout the experiment. Hemorrhagic shock resulted in significant leukocyte adherence during resuscitation (10.8 +/- 1.7 cells/100 microm, P < 0.01) when compared to control. Anti-LFA-1beta, when given before hemorrhagic shock, significantly attenuated leukocyte adherence during resuscitation (1.1 +/- 0.8, P < 0.01) when compared with hemorrhagic shock alone. This protective effect of anti-LFA-1beta on leukocyte adherence was even demonstrated when it was given during (1.6 +/- 0.3, P < 0.01) and 10 min after hemorrhagic shock (5.8 +/- 0.4, P < 0.05). These results suggest that anti-LFA-1beta may be of potential therapeutic benefit against microvascular injury caused by hemorrhagic shock.

Treatment of an infected murine macrophage cell line (J774A.1) with interferon-gamma but not tumor necrosis factor-alpha or live Mycobacterium intracellulare alone modulates the expression of adhesion molecules.

In the present study, we evaluated whether the activation of a murine macrophage cell line (J774.1A) by treatment with recombinant murine tumor necrosis factor-alpha (rTNF-alpha) or recombinant murine interferon-gamma (rIFN-gamma) before or simultaneous with infection with Mycobacterium intracellulare would affect their ability to express lymphocyte function-associated antigen-1 (LFA-1) and to restrict growth and kill the ingested M. intracellulare. The data showed that the effect of lipopolysaccharide (LPS) in increasing the level of LFA-1 was the same in the presence or absence of M. intracellulare. The inability of M. intracellulare to affect the level of expression of LFA-1 was irrespective of the M. intracellulare to J774A.1 ratio. A significant increase in the expression of LFA-1 was observed when J774A.1 cells were prestimulated with IFN-gamma 1 day before the addition of the bacteria. The addition of IFN-gamma with M. intracellulare simultaneously, however, did not affect the expression of the adhesion molecules as compared with the IFN-gamma alone. Our results indicated no change in the level of LFA-1 on J774A.1 following exposure with TNF-alpha. We observed that preexposure with 10-10(4) IU/ml of TNF-alpha can significantly decrease the number of ingested M. intracellulare. Simultaneous addition of 10(3) and 10(4) IU/ml of TNF-alpha, however, did not have any mycobactericidal effect. This indicates that the TNF-alpha-induced killing by J774A.1 cells was relatively selective, depending on the concentration and the time of presence of TNF-alpha. The data may suggest that the uptake of M. intracellulare is carried out via other adhesion receptors when M. intracellulare and IFN-alpha are present simultaneously and that in the presence of TNF-alpha other surface receptors are involved in the uptake of M. intracellulare. Flow cytometry analysis of the spleen cells removed at various times from M. intracellulare-infected mice also indicated no change in the level of LFA-1 beta or MAC-1, a finding comparable with that of the J774A.1 cells.

High-level production of recombinant proteins in CHO cells using a dicistronic DHFR intron expression vector.

We have constructed expression vectors for Chinese hamster ovary (CHO) cells that produce both selectable marker and recombinant cDNA from a single primary transcript via differential splicing. These vectors produce stable CHO cell clones that, when pooled, produce abundant amounts of secreted recombinant proteins compared with the amounts produced by conventional expression approaches that have selectable marker and the cDNA of interest under control of separate transcription units. Our vectors divert most of the transcript to product expression while linking it, at a fixed ratio, to dihydrofolate reductase (DHFR) expression to allow selection of stable transfectants. Pools of clones with increased expression of the product gene can be efficiently generated by selection in methotrexate. The high level of expression from pools allows convenient and rapid production of milligram amounts of recombinant proteins.

Prevention of reovirus type 2-induced diabetes-like syndrome in DBA/1 suckling mice by treatment with antibodies against intercellular adhesion molecule-1 and lymphocyte function-associated antigen-1.

Reovirus type 2-induced diabetes-like syndrome in suckling mice is considered to be an animal model for human insulin-dependent diabetes mellitus. We have previously demonstrated that immunopathologic pancreatic islet cell damage might be relevant to reovirus type 2 infection. In this study the involvement of adhesion molecules in the development of reovirus type 2-induced diabetes-like syndrome was examined. In infected mice infiltration of mononuclear cells mixed with polymorphonuclear leucocytes in and around pancreatic islets (insulitis) was observed in association with abnormal glucose tolerance. The treatment with monoclonal antibodies against intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) prevented the development of insulitis with abnormal glucose tolerance in a dose dependent manner. These results suggest that ICAM-1 and LFA-1 molecules may, at least in part, participate in islet cell damage, resulting in reovirus type 2-induced diabetes-like syndrome. The role of ICAM-1 and LFA-1 molecules on the development of insulitis is discussed.

[The onset mechanism of experimental autoimmune uveoretinitis induced by interphotoreceptor retinoid-binding protein].

In order to analyze the onset mechanism of experimental autoimmune uveoretinitis (EAU), two experimental models were used; one was EAU induced by one injection of purified bovine interphotoreceptor retinoid-binding protein (IRBP) with complete Freund's adjuvant in Lewis rat, and the other was an IRBP-induced autoimmune uveoretinitis that occurred spontaneously in nude (nu/nu) mice at 4 weeks of age reconstituted by the grafting of rat embryonic thymus (TG nude mouse). EAU develops when the IRBP-reactive lymphocytes in the regional lymph-nodes are activated. Activation begins when the T lymphocyte recognizes the peptide for the epitope bound to a major histocompatibility complex (MHC) molecule in the antigen-presenting cell by way of the T-cell receptor (TCR). In EAU, ten peptide residues p1182-1191 of the IRBP amino acid sequence, were revealed to be sufficiently capable of lymphocyte activation for EAU, and it was also shown that amino acid positions 1182W (tryptophane), 1185G (glycine), 1186V (valine) and 1188P (proline) of IRBP play important roles as the epitopes or agretopes in developing EAU. On the other hand, two amino acids of IRBP, amino acid positions 1182W (tryptophane) and 1194P (proline) were shown to be the agretopes inducing autoimmune uveoretinitis in the TG nude mouse. A study of the variable region of the TCR with a residual p1182-1194 specific T-cell line from the TG nude mouse revealed that as many as 96% utilized the T-cell receptor V beta 6 gene and that the peptide-MHC molecule complex was recognized by restricted receptors. Adhesion molecules such as ICAM-1 and LFA-1 were also found to play an important role as cofactors in activation of lymphocytes in the antigen-recognition process of EAU. Uveoretinitis seemed to result from an immune reaction in the eye occurring when the T lymphocyte arrives there, activating the immunological process. ICAM-1 and LFA-1 were also found to be involved in the infiltration process of inflammatory cells: our immunohistological examination revealed that ICAM-1 was present in the retinal pigment epithelium and epithelium of the ciliary body composing the blood-ocular barrier. In contrast, LFA-1 was expressed in the infiltrating cells. Finally, the tolerance of IRBP was discussed and it was experimentally demonstrated that the absence of IRBP-induced uveoretinitis in human beings and certain experimental animals resulted from endogenous IRBP serving as a tolerogen; we assumed that the breakdown of this self-tolerance would induce EAU due to thymic dysfunction or IRBP antigen injection.