Synthetic integrin antibodies discovered by yeast display reveal αV subunit pairing preferences with ß subunits.

Integrins are cell surface receptors that mediate the interactions of cells with their surroundings and play essential roles in cell adhesion, migration, and homeostasis. Eight of the 24 integrins bind to the tripeptide Arg-Gly-Asp (RGD) motif in their extracellular ligands, comprising the RGD-binding integrin subfamily. Despite similarity in recognizing the RGD motif and some redundancy, these integrins can selectively recognize RGD-containing ligands to fulfill specific functions in cellular processes. Antibodies against individual RGD-binding integrins are desirable for investigating their specific functions, and were selected here from a synthetic yeast-displayed Fab library. We discovered 11 antibodies that exhibit high specificity and affinity toward their target integrins, i.e. αVß3, αVß5, αVß6, αVß8, and α5ß1. Of these, six are function-blocking antibodies and contain a ligand-mimetic R(G/L/T)D motif in their CDR3 sequences. We report antibody-binding specificity, kinetics, and binding affinity for purified integrin ectodomains, as well as intact integrins on the cell surface. We further used these antibodies to reveal binding preferences of the αV subunit for its 5 ß-subunit partners: ß6 = ß8 > ß3 > ß1 = ß5.

Synthetic integrin antibodies discovered by yeast display reveal αV subunit pairing preferences with ß subunits.

Eight of the 24 integrin heterodimers bind to the tripeptide Arg-Gly-Asp (RGD) motif in their extracellular ligands, and play essential roles in cell adhesion, migration, and homeostasis. Despite similarity in recognizing the RGD motif and some redundancy, these integrins can selectively recognize RGD-containing ligands including fibronectin, vitronectin, fibrinogen, nephronectin and the prodomain of the transforming growth factors to fulfill specific functions in cellular processes. Subtype-specific antibodies against RGD-binding integrins are desirable for investigating their specific functions. In this study, we discovered 11 antibodies that exhibit high specificity and affinity towards integrins αVß3, αVß5, αVß6, αVß8, and α5ß1 from a synthetic yeast-displayed Fab library. Of these, 6 are function-blocking antibodies containing an R(G/L/T) D motif in their CDR3 sequences. We report antibody binding specificity, kinetics, and binding affinity for purified integrin ectodomains as well as intact integrins on the cell surface. We further employed these antibodies to reveal binding preferences of the αV subunit for its 5 ß-subunit partners: ß6=ß8>ß3>ß1=ß5.

Feature Optimization Method of Material Identification for Loose Particles Inside Sealed Relays.

Existing material identification for loose particles inside sealed relays focuses on the selection and optimization of classification algorithms, which ignores the features in the material dataset. In this paper, we propose a feature optimization method of material identification for loose particles inside sealed relays. First, for the missing value problem, multiple methods were used to process the material dataset. By comparing the identification accuracy achieved by a Random-Forest-based classifier (RF classifier) on the different processed datasets, the optimal direct-discarding method was obtained. Second, for the uneven data distribution problem, multiple methods were used to process the material dataset. By comparing the achieved identification accuracy, the optimal min-max standardization method was obtained. Then, for the feature selection problem, an innovative multi-index-fusion feature selection method was designed, and its superiority was verified through several tests. Test results show that the identification accuracy achieved by RF classifier on the dataset was improved from 59.63% to 63.60%. Test results of ten material verification datasets show that the identification accuracies achieved by RF classifier were greatly improved, with an average improvement of 3.01%. This strongly promotes research progress in loose particle material identification and is an important supplement to existing loose particle detection research. This is also the highest loose particle material identification accuracy achieved to in aerospace engineering, which has important practical value for improving the reliability of aerospace systems. Theoretically, it can be applied to feature optimization in machine learning.

Loss of LRRC33-Dependent TGFß1 Activation Enhances Antitumor Immunity and Checkpoint Blockade Therapy.

TGFß has multiple roles and gene products (TGFß1, -ß2, and -ß3), which make global targeting of TGFß undesirable. Expression of TGFß requires association with milieu molecules, which localize TGFß to the surface of specific cells or extracellular matrices. Here, we found that LRRC33 was specifically associated with TGFß1, not TGFß2 and TGFß3, and was required for surface display and activation of TGFß1 on tumor-infiltrating myeloid cells. Loss of LRRC33-dependent TGFß1 activation slowed tumor growth and metastasis by enhancing innate and adaptive antitumor immunity in multiple mouse syngeneic tumor models. LRRC33 loss resulted in a more immunogenic microenvironment, with decreased myeloid-derived suppressor cells, more active CD8+ T and NK cells, and more skewing toward tumor-suppressive M1 macrophages. LRRC33 loss and PD-1 blockade synergized in controlling B16.F10 tumor growth. Our results demonstrate the importance of LRRC33 in tumor biology and highlight the therapeutic potential of dual blockade of the LRRC33/TGFß1 axis and PD-1/PD-L1 in cancer immunotherapy.

MiR-17-5p protects neonatal mice from hypoxic-ischemic brain damage by targeting Casp2.

Hypoxia-ischemia brain damage (HIBD) is a leading cause of neonatal death worldwide, which significantly influences the development of newborns; however, effective treatment strategies remain limited. Recent studies have discovered that microRNAs (miRNAs) play essential roles in the progression of HIBD. Our study was designed to explore whether miR-17-5p was involved in the pathological development of HIBD. In our study, HIBD mouse experimental model was established by carotid artery ligation combined with a hypoxic environment. RT-qPCR and western blot analyses found that Casp2 was high expressed while miR-17-5p was poorly expressed in the cerebral cortical tissue of HIBD mice. Knockdown of Casp2 significantly alleviated brain injury and cell apoptosis. Additionally, the luciferase reporter assay confirmed that miR-17-5p targeted the 3' UTR of Casp2 and negatively regulated Casp2 expression. The rescue experiment demonstrated that miR-17-5p mimic significantly relieved brain tissue damage and improved memory ability in the HIBD mouse model, while these functions of miR-17-5p were blocked by overexpression of Casp2. In summary, our results indicated that miR-17-5p exerted protective effects on HIBD by targeting Casp2.

Reactivation of the tumor suppressor PTEN by mRNA nanoparticles enhances antitumor immunity in preclinical models.

Increasing clinical evidence has demonstrated that the deletion or mutation of tumor suppressor genes such as the gene-encoding phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in cancer cells may correlate with an immunosuppressive tumor microenvironment (TME) and poor response or resistance to immune checkpoint blockade (ICB) therapy. It is largely unknown whether the restoration of functional PTEN may modulate the TME and improve the tumor's sensitivity to ICB therapy. Here, we demonstrate that mRNA delivery by polymeric nanoparticles can effectively induce expression of PTEN in Pten-mutated melanoma cells and Pten-null prostate cancer cells, which in turn induces autophagy and triggers cell death-associated immune activation via release of damage-associated molecular patterns. In vivo results illustrated that PTEN mRNA nanoparticles can reverse the immunosuppressive TME by promoting CD8+ T cell infiltration of the tumor tissue, enhancing the expression of proinflammatory cytokines, such as interleukin-12, tumor necrosis factor-α, and interferon-γ, and reducing regulatory T cells and myeloid-derived suppressor cells. The combination of PTEN mRNA nanoparticles with an immune checkpoint inhibitor, anti-programmed death-1 antibody, results in a highly potent antitumor effect in a subcutaneous model of Pten-mutated melanoma and an orthotopic model of Pten-null prostate cancer. Moreover, the combinatorial treatment elicits immunological memory in the Pten-null prostate cancer model.

Comparative analysis of the liver transcriptome in the red-eared slider Trachemys scripta elegans under chronic salinity stress.

The red-eared slider (Trachemys scripta elegans), identified as one of the 100 most invasive species in the world, is a freshwater turtle originally from the eastern United States and northeastern Mexico. Field investigations have shown that T. s. elegans can survive and lay eggs in saline habitats. In order to understand the molecular mechanisms of salinity adaptation, high-throughput RNA-Seq was utilized to identify the changes in gene expression profiles in the liver of T. s. elegans in response to elevated salinity. We exposed individuals to 0, 5, or 15 psu (practical salinity units) for 30 days. A total of 157.21 million reads were obtained and assembled into 205138 unigenes with an average length of 620 bp and N50 of 964 bp. Of these, 1019 DEGs (differentially expressed genes) were found in the comparison of 0 vs. 5 psu, 1194 DEGs in 0 vs. 15 psu and 1180 DEGs in 5 vs. 15 psu, which are mainly related to macromolecule metabolic process, ion transport, oxidoreductase activity and generation of precursor metabolites and energy by GO (Gene Ontology) enrichment analyses. T. s. elegans can adapt itself into salinity by balancing the entry of sodium and chloride ions via the up-regulation expression genes of ion transport (potassium voltage-gated channel subfamily H member 5, KCNH5; erine/threonine-protein kinase 32, STK32; salt-inducible kinase 1, SIK1; adiponectin, ACDC), and by accumulating plasma urea and free amino acid via the up-regulation expression genes of amino acid metabolism (ornithine decarboxylase antizyme 3, OAZ3; glutamine synthetase, GLUL; asparaginase-like protein 1b, ASRGL; L-amino-acid oxidase-like, LAAO; sodium-dependent neutral amino acid transporter B, SLC6A15s; amino acid permease, SLC7A9) in response to osmotic regulation. An investment of energy to maintain their homeostatic balance is required to salinity adaptation, therefore, the genes related to energy production and conversion (F-ATPase protein 6, ATP6; cytochrome c oxidase subunit I, COX1; cytochrome c oxidase subunit III, COX3; cytochrome b, CYTb; cytochrome P450 17A1, CYP17A1) were up-regulated with the increase of gene expression associated with lipid metabolism (apolipoprotein E precursor, APoE; coenzyme Q-binding protein, CoQ10; high-density lipoprotein particle, SAA) and carbohydrate metabolism (HK, MIP). These findings improve our understanding of the underlying molecular mechanisms involved in salinity adaptation and provide general guidance to illuminate the invasion potential of T. s. elegans into saline environments.

A Milieu Molecule for TGF-ß Required for Microglia Function in the Nervous System.

Extracellular proTGF-ß is covalently linked to "milieu" molecules in the matrix or on cell surfaces and is latent until TGF-ß is released by integrins. Here, we show that LRRC33 on the surface of microglia functions as a milieu molecule and enables highly localized, integrin-αVß8-dependent TGF-ß activation. Lrrc33-/- mice lack CNS vascular abnormalities associated with deficiency in TGF-ß-activating integrins but have microglia with a reactive phenotype and after 2 months develop ascending paraparesis with loss of myelinated axons and death by 5 months. Whole bone marrow transplantation results in selective repopulation of Lrrc33-/- brains with WT microglia and halts disease progression. The phenotypes of WT and Lrrc33-/- microglia in the same brain suggest that there is little spreading of TGF-ß activated from one microglial cell to neighboring microglia. Our results suggest that interactions between integrin-bearing cells and cells bearing milieu molecule-associated TGF-ß provide localized and selective activation of TGF-ß.

[Effects on cervical spondylosis of neck type treated with Hegu needling and Shu needling techniques at the positive reaction points].

OBJECTIVE: To observe the clinical effects on cervical spondylosis of neck type treated with the combined therapy of Hegu needling and Shu needling techniques at the positive reaction points as compared with the conventional acupuncture. METHODS: A total of 90 patients of cervical spondylosis of neck type were randomized into an observation group and a control group, 45 cases in each one. In the observation group, the combined therapy of Hegu needling and Shu needling techniques at the positive reaction points was adopted. The positive reaction points were selected in the neck, shoulder and back regions. In the control group, the conventional acupuncture therapy was provided. The main acupoints were Tianzhu (BL 10), Fengchi (GB 20), Quchi (LI 11), Waiguan (TE 5), Neck-Jiaji (EX-B 2) of C4 to C6 and ashi points. The supplementary acupoints were Yinxi (HT 6) and Geshu (BL 17). The treatment was given once every two days, 10 treatments as one course in the two groups. Separately, before treatment, after the 1st treatment and at the end of one course of treatment, the scores of symptoms and physical signs and the scores of visual analogous scale (VAS) were observed in the two groups. The comprehensive clinical effects were compared between the two groups at the end of treatment. RESULTS: After the 1st treatment and at the end of treatment, the scores of symptoms and physical signs and VAS scores were reduced obviously as compared with those before treatment in the two groups (all P<0.05). After the 1st treatment, the scores of symptoms and physical signs and VAS scores were not different significantly between the two groups (both P>0.05). At the end of treatment, the scores of symptoms and physical signs and VAS scores in the observation group were reduced more obviously as compared with the control group (both P<0.05). The curative and remarkably effective rate was 84.1% (37/44) in the observation group, better than 65.1% (28/43) in the control group (P<0.05). CONCLUSION: Either the combined therapy of Hegu needling and Shu needling techniques at the positive reaction points or the conventional acupuncture is effective in the treatment of cervical spondylosis of neck type. The combined therapy of Hegu needling and Shu needling techniques at the positive reaction points achieves the superior effects as compared with the conventional acupuncture.

[Clinical effects of different therapeutic regimens for Helicobacter pylori infection in children].

OBJECTIVE: To investigate the clinical effects of sequential therapy, triple therapy, sequential therapy combined with Lactobacillus, and triple therapy combined with Lactobacillus in the eradication of Helicobacter pylori (H.pylori) infection in children. METHODS: A total of 416 children with H.pylori infection were randomly assigned to sequential group (102 children), triple group (100 children), sequential-Lactobacillus group (109 children), and triple-Lactobacillus group (105 children). The clinical outcome, H.pylori eradication rate, cost-effect ratio, and incidence of adverse events were compared between the four groups. RESULTS: The sequential-Lactobacillus and triple-Lactobacillus groups had significantly better clinical outcomes than the sequential group and the triple group (P<0.05). The sequential-Lactobacillus group had the highest marked response rate, followed by the triple-Lactobacillus group. The triple group had the lowest marked response rate. The sequential-Lactobacillus group also had the highest H.pylori eradication rate, followed by the triple-Lactobacillus group. The triple group had the lowest H.pylori eradication rate (P<0.05). The sequential group had the lowest cost-effect ratio, followed by the sequential-Lactobacillus group. The triple group had the highest cost-effect ratio (P<0.01). The sequential-Lactobacillus group had the lowest incidence rate of adverse events, followed by the triple-Lactobacillus group. The triple group had the highest incidence rate. CONCLUSIONS: Sequential therapy combined with Lactobacillus seems to be the best regimen for the eradication of H.pylori infection in children.

HIV-1 gp120 Glycoprotein Interacting with Dendritic Cell-specific Intercellular Adhesion Molecule 3-grabbing Non-integrin (DC-SIGN) Down-Regulates Tight Junction Proteins to Disrupt the Blood Retinal Barrier and Increase Its Permeability.

Approximately 70% of HIV-1 infected patients acquire ocular opportunistic infections and manifest eye disorders during the course of their illness. The mechanisms by which pathogens invade the ocular site, however, are unclear. Under normal circumstances, vascular endothelium and retinal pigment epithelium (RPE), which possess a well developed tight junction complex, form the blood-retinal barrier (BRB) to prevent pathogen invasion. We hypothesize that disruption of the BRB allows pathogen entry into ocular sites. The hypothesis was tested using in vitro models. We discovered that human RPE cells could bind to either HIV-1 gp120 glycoproteins or HIV-1 viral particles. Furthermore, the binding was mediated by dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) expressed on RPE cells. Upon gp120 binding to DC-SIGN, cellular NF-κB signaling was triggered, leading to the induction of matrix metalloproteinases, which subsequently degraded tight junction proteins and disrupted the BRB integrity. DC-SIGN knockdown or prior blocking with a specific antibody abolished gp120-induced matrix metalloproteinase expression and reduced the degradation of tight junction proteins. This study elucidates a novel mechanism by which HIV, type 1 invades ocular tissues and provides additional insights into the translocation or invasion process of ocular complication-associated pathogens.

Human Blood-Circulating Basophils Capture HIV-1 and Mediate Viral trans-Infection of CD4+ T Cells.

UNLABELLED: Cell-associated HIV-1 infection has been proposed to play a pivotal role in the spread of HIV-1 infection. Granulocytes are a category of white blood cells, comprising mainly basophils, neutrophils, and eosinophils, and participate in various inflammatory reactions and defense against pathogens. Here, we investigated the role of human blood granulocytes in the dissemination of HIV-1. These cells were found to express a variety of HIV-1 attachment factors (HAFs). Basophils expressed HAFs dendritic cell (DC)-specific intercellular adhesion molecule 3 (ICAM3)-grabbing nonintegrin (DC-SIGN), DC immunoreceptor (DCIR), heparan sulfate proteoglycan (HSPG), and α4ß7 integrin and mediated the most efficient capture of HIV-1 on the cell surface. Neutrophils were found to express DCIR and demonstrated limited efficiency of viral capture. Eosinophils expressed α4ß7 integrin but exhibited little or no virus-binding capacity. Intriguingly, following direct contact with CD4+ T cells, viruses harbored on the surface of basophils were transferred to T cells. The contact between basophils and CD4+ T cells and formation of infectious synapses appeared necessary for efficient HIV-1 spread. In HIV-1-infected individuals, the frequency of basophils remained fairly stable over the course of disease, regardless of CD4+ T depletion or the emergence of AIDS-associated opportunistic infections. Collectively, our results provide novel insights into the roles of granulocytes, particularly basophils, in HIV-1 dissemination. Thus, strategies designed to prevent basophil-mediated viral capture and transfer may be developed into a new form of therapy. IMPORTANCE: Cell-associated HIV-1 infection has been proposed to play a pivotal role in the spread of HIV-1 infection. Here, we demonstrated that human blood-circulating granulocytes, particularly basophils, can capture HIV-1 and mediate viral trans-infection of CD4+ T cells. The expression of a variety of HIV-1 attachment factors, such as the C-type lectins, etc., facilitates viral capture and transfer. Intriguingly, the frequency of basophils in patients with different levels of CD4+ T counts remains fairly stable during the course of disease. Our results provide novel insights into the roles of granulocytes, particularly basophils, in HIV-1 dissemination. We suggest that strategies designed to prevent basophil-mediated viral capture and transfer may be a new direction for the development of anti-HIV therapy.

Human Mucosal Mast Cells Capture HIV-1 and Mediate Viral trans-Infection of CD4+ T Cells.

UNLABELLED: The gastrointestinal mucosa is the primary site where human immunodeficiency virus type 1 (HIV-1) invades, amplifies, and becomes persistently established, and cell-to-cell transmission of HIV-1 plays a pivotal role in mucosal viral dissemination. Mast cells are widely distributed in the gastrointestinal tract and are early targets for invasive pathogens, and they have been shown to have increased density in the genital mucosa in HIV-infected women. Intestinal mast cells express numerous pathogen-associated molecular patterns (PAMPs) and have been shown to combat various viral, parasitic, and bacterial infections. However, the role of mast cells in HIV-1 infection is poorly defined. In this study, we investigated their potential contributions to HIV-1 transmission. Mast cells isolated from gut mucosal tissues were found to express a variety of HIV-1 attachment factors (HAFs), such as DC-SIGN, heparan sulfate proteoglycan (HSPG), and α4ß7 integrin, which mediate capture of HIV-1 on the cell surface. Intriguingly, following coculture with CD4(+) T cells, mast cell surface-bound viruses were efficiently transferred to target T cells. Prior blocking with anti-HAF antibody or mannan before coculture impaired viral trans-infection. Cell-cell conjunctions formed between mast cells and T cells, to which viral particles were recruited, and these were required for efficient cell-to-cell HIV-1 transmission. Our results reveal a potential function of gut mucosal mast cells in HIV-1 dissemination in tissues. Strategies aimed at preventing viral capture and transfer mediated by mast cells could be beneficial in combating primary HIV-1 infection. IMPORTANCE: In this study, we demonstrate the role of human mast cells isolated from mucosal tissues in mediating HIV-1 trans-infection of CD4(+) T cells. This finding facilitates our understanding of HIV-1 mucosal infection and will benefit the development of strategies to combat primary HIV-1 dissemination.

Anti-HIV-1 activities of extracts and phenolics from Smilax china L.

Four extracts (EtOH, CHCl3, EtOAc, and BuOH) and five phenolics (dihydrokaempferol (1), resveratrol (2), kaempferol-7-O-ß-D-glucoside (3), dihydrokaempferol-3-O-α-L-rhamnoside (4), oxyresveratrol (5)) from Smilax china L. was evaluated for anti-HIV-1 activities and cytotoxicity activities in vitro. All these extracts and phenolics showed lower or no cytotoxicity at a concentration ranged from 0.8 µg/mL to 100 µg/mL, but some showed potential anti-HIV-1 activities, that is, BuOH extract and compound 2 showed higher anti-HIV-1 activities than other extracts and compounds in the tested concentrations. EtOAc extract and compound 1 and 3 showed moderate anti-HIV-1 activities at a concentration higher than 4 µg/mL. In the end, the structure-activity relationship of four extracts and five phenolics was discussed.

Histamine enhances HIV-1-induced modulation of dendritic cells to skew naïve T cell differentiation toward regulatory T cells.

Altered cytokine profiles and imbalanced frequencies of CD4(+) T helper cell subsets are thought to be linked with HIV-1/AIDS pathogenesis, but the causes need to be further clarified. Histamine, a biogenic amine with many functions, shows enhancement in HIV-1 infected individuals, which are considered to link with disease progression, but is poorly understood. This study investigated histamine-assisted HIV-1 modulation of dendritic cell (DC) functions. Histamine and HIV-1 showed a synergistic role in induction of interleukin-10; histamine inhibited HIV-1-induced IL-12 production from MDDCs (monocyte-derived DCs); notably, histamine augmented HIV-1-induced MDDC functional polarization and skewed naïve T cell differentiation toward regulatory T cells (Tregs). The results indicate the novel role of histamine in HIV-1-induced DC functional regulation, which promoted Treg cell differentiation and up-regulated immunosuppressive factors. These findings help to bridge the correlation between elevated histamine and increased Treg cell frequency in HIV-1 infected individuals, and add to our understanding of HIV-1-induced immunosuppression.

Stimulation of Cryptococcus neoformans isolated from skin lesion of AIDS patient matures dendritic cells and promotes HIV-1 trans-infection.

Dendritic cells (DCs) play a pivotal role in host defense against invaded pathogens including fungi, while DCs are targeted by fungi for deleterious regulation of the host immune response. A few studies have reported fungal modulation of DC function in these immunocompromised AIDS patients. Cryptococcus neoformans (C. neoformans) is referred as one of the opportunistic fungi of AIDS. Here, we isolated native C. neoformans from an AIDS patient and investigated its effects on DC activation and function. Stimulation of C. neoformans matured DCs, and enhanced DC-mediated HIV-1 trans-infection; moreover, C. neoformans-stimulated DCs promoted the activation of resting T cells and provided more susceptible targets for HIV-1 infection. Microbial translocation has been proposed as the cause of systemic immune activation in chronic HIV-1 infection. Understanding the potential effects of pathogens on HIV-1-DC interactions could help elucidate viral pathogenesis and provide a new insight for against the spread of HIV.

Genome-wide association study identifies two new susceptibility loci for atopic dermatitis in the Chinese Han population.

Atopic dermatitis is a chronic, relapsing form of inflammatory skin disorder that is affected by genetic and environmental factors. We performed a genome-wide association study of atopic dermatitis in a Chinese Han population using 1,012 affected individuals (cases) and 1,362 controls followed by a replication study in an additional 3,624 cases and 12,197 controls of Chinese Han ethnicity, as well as 1,806 cases and 3,256 controls from Germany. We identified previously undescribed susceptibility loci at 5q22.1 (TMEM232 and SLC25A46, rs7701890, P(combined) = 3.15 × 10(-9), odds ratio (OR) = 1.24) and 20q13.33 (TNFRSF6B and ZGPAT, rs6010620, P(combined) = 3.0 × 10(-8), OR = 1.17) and replicated another previously reported locus at 1q21.3 (FLG, rs3126085, P(combined) = 5.90 × 10(-12), OR = 0.82) in the Chinese sample. The 20q13.33 locus also showed evidence for association in the German sample (rs6010620, P = 2.87 × 10(-5), OR = 1.25). Our study identifies new genetic susceptibility factors and suggests previously unidentified biological pathways in atopic dermatitis.

Experimental investigation of subspace identification and LQ control of a pressure tank.

Many control studies of complex processes are limited to simulation studies. However, many real processes exhibit peculiarities and nonlinearities that are difficult to model. Also some control designs are difficult to implement online in practice. Because of the recent availability of economical real time software, more complex control algorithms will see real time testing and implementation. In spite of this, many compromises are often necessary when the final control is implemented. This paper follows the identification (using subspace methods) and real time linear quadratic control of a pressure tank system and points to some of the compromises in identification and control design that are often necessary. A multivariate control is implemented on a pressure tank process with rather good results in spite of these compromises.