Comparison between ica operon expression and biofilm formation in methicillin-resistant staphylococcus aureus isolated from central venous catheters under different environmental conditions

Methicillin-resistant Staphylococcus aureus [MRSA] infections are complicated by the ability of the organism to grow in surface-adhered biofilms on a multitude of inert synthetic surfaces including those involving indwelling medical devices. Intensive care unit [ICU] patients using central venous catheters [CVCs] are particularly at risk of acquiring device-related infections, which involve biofilms. This study was carried out to compare intercellular adhesion [ica] operon expression and biofilm formation in MRSA isolated from CVCs grown under different environmental conditions. Seven hundred sixteen central venous catheters tips were tested for MRSA colonization. Semiquantitative measurements of biofilm formation were determined for all MRSA isolates grown under different environmental conditions: Brain heart infusion [BHI] medium, BHI supplemented with 4% sodium chloride [NaCl] and BHI supplemented with 1% glucose [Glu]. The ica operon expression were compared in all MRSA isolates grown under different environmental conditions using RT-PCR. The overall catheter tip colonization rate was 36.87%. Staphylococci were isolated from 56.06%. The distribution of the isolated Staphylococci was as follow: Staphylococcus epidermidis [S. epidermidis] 34.8%, Staphylococcus aureus [S. aureus] 12.12% and other Coagulase negative Staphylococci CoNS 9.09%. Out of 32 S. aureus isolates 9 were MRSA [28.125%]. Under standard laboratory conditions in BHI medium 22.22% of MRSA isolates were capable of biofilm development. This number increases to 77.77% when grown in BHI supplemented with 1% glucose. In contrast, growth in BHI supplemented with 4% NaCl induces biofilm in 11.11%. Among the 9 MRSA isolates, growth in the presence of NaCl resulted in activation of ica transcription in 8 strains but failed to induce substantial biofilm development in any of these isolates [weak -but measurable- biofilm formation was detected in medium supplemented with NaCl by one strain]. Glucose-mediated induction of biofilm formation in the 9 MRSA isolates correlated with weakly to moderately increased ica operon expression in 6 isolates. Interestingly, ica operon transcription was more potently activated by NaCl than by glucose in all of the MRSA isolates examined except one strain. There appears to be little correlation between ica operon regulation and biofilm formation in MRSA, suggesting that the ica operon and polysaccharide intercellular adhesin, or poly-Nacetylglucosamine [PIA/PNAG] may not be required for biofilm development in MRSA

Cross-reactive anti-PfCLAG9 antibodies in the sera of asymptomatic parasite carriers of Plasmodium vivax

The PfCLAG9 has been extensively studied because their immunogenicity. Thereby, the gene product is important for therapeutics interventions and a potential vaccine candidate. Antibodies against synthetic peptides corresponding to selected sequences of the Plasmodium falciparum antigen PfCLAG9 were found in sera of falciparum malaria patients from Rondônia, in the Brazilian Amazon. Much higher antibody titres were found in semi-immune and immune asymptomatic parasite carriers than in subjects suffering clinical infections, corroborating original findings in Papua Guinea. However, sera of Plasmodium vivax patients from the same Amazon area, in particular from asymptomatic vivax parasite carriers, reacted strongly with the same peptides. Bioinformatic analyses revealed regions of similarity between P. falciparum Pfclag9 and the P. vivax ortholog Pvclag7. Indirect fluorescent microscopy analysis showed that antibodies against PfCLAG9 peptides elicited in BALB/c mice react with human red blood cells (RBCs) infected with both P. falciparum and P. vivax parasites. The patterns of reactivity on the surface of the parasitised RBCs are very similar. The present observations support previous findings that PfCLAG9 may be a target of protective immune responses and raises the possibility that the cross reactive antibodies to PvCLAG7 in mixed infections play a role in regulate the fate of Plasmodium mixed infections.

Relationship between ganglioside expression and anti-cancer effects of the monoclonal antibody against epithelial cell adhesion molecule in colon cancer

The human colorectal carcinoma-associated GA733 antigen epithelial cell adhesion molecule (EpCAM) was initially described as a cell surface protein selectively expressed in some myeloid cancers. Gangliosides are sialic acid-containing glycosphingolipids involved in inflammation and oncogenesis. We have demonstrated that treatment with anti-EpCAM mAb and RAW264.7 cells significant inhibited the cell growth in SW620 cancer cells, but neither anti-EpCAM mAb nor RAW264.7 cells alone induced cytotoxicity. The relationship between ganglioside expression and the anti-cancer effects of anti-EpCAM mAb and RAW264.7 was investigated by high-performance thin-layer chromatography. The results demonstrated that expression of GM1 and GD1a significantly increased in the ability of anti-EpCAM to inhibit cell growth in SW620 cells. Anti-EpCAM mAb treatment increased the expression of anti-apoptotic proteins such as Bcl-2, but the expression of pro-apoptotic proteins Bax, TNF-alpha, caspase-3, cleaved caspase-3, and cleaved caspase-8 were unaltered. We observed that anti-EpCAM mAb significantly inhibited the growth of colon tumors, as determined by a decrease in tumor volume and weight. The expression of anti-apoptotic protein was inhibited by treatment with anti-EpCAM mAb, whereas the expression of pro-apoptotic proteins was increased. These results suggest that GD1a and GM1 were closely related to anticancer effects of anti-EpCAM mAb. In light of these results, further clinical investigation should be conducted on anti-EpCAM mAb to determine its possible chemopreventive and/or therapeutic efficacy against human colon cancer.

Chronic Trypanosoma cruzi-elicited cardiomyopathy: from the discovery to the proposal of rational therapeutic interventions targeting cell adhesion molecules and chemokine receptors: how to make a dream come true

One hundred years ago, Carlos Chagas discovered a new disease, the American trypanosomiasis. Chagas and co-workers later characterised the disease's common manifestation, chronic cardiomyopathy, and suggested that parasitic persistence coupled with inflammation was the key underlying pathogenic mechanism. Better comprehension of the molecular mechanisms leading to clinical heart afflictions is a prerequisite to developing new therapies that ameliorate inflammation and improve heart function without hampering parasite control. Here, we review recent data showing that distinct cell adhesion molecules, chemokines and chemokine receptors participate in anti-parasite immunity and/or detrimental leukocyte trafficking to the heart. Moreover, we offer evidence that CC-chemokine receptors may be attractive therapeutic targets aiming to regain homeostatic balance in parasite/host interaction thereby improving prognosis, supporting that it is becoming a non-phantasious proposal.

CD99 activates T cells via a costimulatory function that promotes raft association of TCR complex and tyrosine phosphorylation of TCR zeta

We investigated the co-stimulatory role of a cell-surface protein, CD99. Co-ligation of CD99 and suboptimal CD3 induced T-cell activation to a level comparable to that obtained with optimal CD3 or CD3+CD28. We also noted concomitant enhancement of the earliest T-cell receptor (TCR) signaling events. In addition, co-ligation of CD99 and CD3 led to translocation of TCR complexes into the lipid raft, without concomitant migration of CD99 to the raft, and consequent enhancement of TCR zeta-mediated signal 1. These data demonstrate the unique properties of CD99 co-stimulation that distinguish this molecule from CD28 and other raft-resident co-stimulatory factors.

High expression of co-stimulatory and adhesion molecules are observed on eosinophils during human Schistosoma mansoni infection

Herein we have focused attention on major phenotypic features of peripheral blood eosinophils from chronic Schistosoma mansoni-infected patients. For this purpose, detailed immunophenotypic profiles of a range of cell surface markers were performed, including activation markers (CD23/CD69/CD25/HLA-DR), co-stimulatory molecules (CD28/CD80/CD86), chemokine receptors (CXCR1/CXCR2/CCR3/CCR5) besides L-selectin-CD62L and adhesion molecules (CD18/CD54). Our major findings pointed out increased frequency of CD23+-cells, besides decreased percentages of CD69+-eosinophils, suggesting a chronic activation status with low frequency of early activated eosinophils in chronic S. mansoni-infected patients (INT) in comparison to non-infected individuals (NI). Moreover, a dichotomic expression of beta-chemokine receptors was observed during human schistosomiasis mansoni with higher CCR5 and lower levels of CCR3 observed between groups. Enhanced expression of co-stimulatory receptors (CD28/CD86) and adhesion molecules (CD54/CD18), besides striking lower frequency of L-selectin+ were reported for eosinophils from INT group as compared to NI. Interestingly, the frequency of CD62L+-eosinophils and a range of cell activation related molecules pointed out an opposite pattern of association in NI and INT, where only INT patients that display lower frequency of CD62L+-eosinophils (first CD62L tertile) kept the unusual relationship between the expression of L-selectin and the CD23 activation marker. These findings suggest that distinct dynamic of activation markers expressed by eosinophils may occur during chronic S. mansoni infection.

Activated peripheral lymphocytes with increased expression of cell adhesion molecules and cytotoxic markers are associated with dengue fever disease

The immune mechanisms involved in dengue fever and dengue hemorrhagic/dengue shock syndrome are not well understood. The ex vivo activation status of immune cells during the dengue disease in patients was examined. CD4and CD8 T cells were reduced during the acute phase. Interestingly, CD8 T cells co-expressing activation marker HLA-DR, Q, P, and cytolytic granule protein-Tia-1 were significantly higher in dengue patients than in controls. Detection of adhesion molecules indicated that in dengue patients the majority of T cells (CD4 and CD8) express the activation/memory phenotype, characterized as CD44HIGH and lack the expression of the naïve cell marker, CD62L LOW. Also, the levels of T cells co-expressing ICAM-1 (CD54), VLA-4, and LFA-1 (CD11a) were significantly increased. CD8 T lymphocytes expressed predominantly low levels of anti-apoptotic molecule Bcl-2 in the acute phase, possibly leading to the exhibition of a phenotype of activated/effector cells. Circulating levels of IL-18, TGF-b1 and sICAM-1 were significantly elevated in dengue patients. Early activation events occur during acute dengue infection which might contribute to viral clearance. Differences in expression of adhesion molecules among CD4 and CD8 T cells might underlie the selective extravasation of these subsets from blood circulation into lymphoid organs and/or tissues. In addition, activated CD8 T cells would be more susceptible to apoptosis as shown by the alteration in Bcl-2 expression. Cytokines such as IL-18, TGF-b1, and sICAM-1 may be contributing by either stimulating or suppressing the adaptative immune response, during dengue infection, thereby perhaps establishing a relationship with disease severity.

Myositis in mixed connective tissue disease: a unique syndrome characterized by immunohistopathologic elements of both polymyositis and dermatomyositis

OBJETIVO: Caracterizar as células do infiltrado inflamatório, o padrão de expressão das moléculas de adesão (ICAM-1 e VCAM-1), complexo de ataque à membrana (C5b-9) e antígenos de histocompatibilidade maior (MHC) em biópsias musculares de patientes com doença mista do tecido conectivo (DMTC). MÉTODO: Foram estudados14 pacientes com DMTC e comparadas com 8 pacientes com polimiosite (PM), 5 com dermatomiosite (DM) e 4 com distrofias. As células inflamatórias foram caracterizadas como CD4+, CD8+, células T de memória (CD45RO+) e virgens, células "natural killer" e macrófagos. As expressões de MHC-I e ûII, ICAM-1, VCAM-1 e C5b-9 foram caracterizadas em fibras musculares e vasos. RESULTADOS:A análise morfológica demonstrou um padrão tipo PM. O estudo imuno-histoquímico revelou diminuição do número de capilares, predomínio de células CD4+ e B nas regiões perivasculares e predomínio de CD8+ e CD45RO+ nas regiões endomisiais. A expressão de MHC-I nos vasos e nas fibras degeneradas, MHC-II nos vasos e fibras perifasciculares e expressão de ICAM-1 / VCAM-1 no endotélio indicaram uma associação de processos vascular e imune-celular mediando a lesão muscular. CONCLUSAO: Os achados revelaram duplo mecanismo na DMTC, imune-celular como na PM e vascular como na DM.

Estudo da interação entre células endoteliais humanas e biomateriais utilizados em cirurgia buco-maxilo-facial / Interaction of human endothelial cells with biomaterials applied on maxillo-facial surgery

Neste estudo procuramos analisar a interação entre células endoteliais humanas e biomateriais utilizados em cirurgia oral, através de análises histológicas e ensaios imunocitoquímicos. Culturas primárias foram isoladas de veias de cordões umbilicais humanos. As células foram semeadas, em densidade determinada, sobre secções circulares de membrana colágena, placas de titânio e controles; foram mantidas por 1, 7 ou 14 dias. As células proliferaram, atingiram confluência e após 14 dias formaram camada plana e uniforme. Os resultados demonstraram que os materiais estudados permitem a proliferação e a adesão das células endoteliais. Esta adesão é mediada pela interação de integrinas e proteínas.With the present investigation, we examined the behavior of endothelial cells on two different biomaterials, using histological and immunocitochemical methods. The endothelial cells were isolated from umbilical cord veins. Cells, after two passages, were seeded in a standard density on a collagen membrane, on commercially pure titanium in the form of plates and on control surfaces. Then these were maintained for 1, 7 or 14 days. After 14 days, we could observe a confluent monolayer of cells. Our results showed that both studied materials support endothelial cells growth and attachment and this is most related to the binding through integrins and proteins...

Acute renal allograft rejection: progress in understanding cellular and molecular mechanisms.

The application of molecular biology tools to investigate the molecular basis of acute allograft rejection has unravelled many complex mechanisms and improved immunosuppressive therapies leading to significant improvements in graft survival. The "indirect" pathway of antigen presentation has emerged as more important, than the traditional "direct" pathway, for allorecognition by T cells. The recognition that CD28 costimulation is essential for allorecognition has provided novel targets for immunotherapy such as CTLA-Immunoglobulin. Understanding the role of Th1 and Th2 subsets of T helper cells, the cytokine network and cell adhesion molecules in the mediation or prevention of graft rejection has opened new avenues for research into therapeutic modalities. The ideal objective would be to identify the mechanisms of graft destruction and design specific inhibitors. This review highlights recent advances in the understanding of acute renal allograft rejection which may have future potential for rational design of new immunosuppressive strategies.

Efecto del extracto de Staphylococcus aureus en la expresión de L-selectina y LFA-1, en neutrófilos de pacientes con asma bronquial no alérgica / L-selectin and LFA-1 in neutrophils from moderate and non atopic asthma patients, before and after stimuli with and without Staphylococcus aureus

Objetivo. Comparar el número de neutrófilos que expresan en su superficie la molécula L-selectina y LFA-1, obtenidos de pacientes con asma bronquial moderada no alérgica, con y sin estímulo con extracto de Sa(Staphylococcus aureus). Material y método. Estudio experimental. Se estudiaron neutrófilos de 12 pacientes con asma bronquial moderada no alérgica y 12 sujetos controles sanos con y sin estímulo de Sa. Mediciones: se determinaron las moléculas de adhesión Cd 62-L y el CD 11 a mediante citometria de flujo expresadas en la superficie de neutrófilos. Resultados. La mediana de la expresión de la molécula Cd 62L aumentó con el estímulo del extracto bacteriano, en pacientes asmáticos de 2444 (Cl 1966, CS 3627, RC 1661) a 6285.5 (Cl 5243, CS 7203, RC 1960) y la mediana de la expresión de la molécula CD 1 la disminuyó con el estímulo del extracto bacteriano, en pacientes asmáticos 9910.5 (Cl 9765, CS 9961, RC 196) a 7670 (Cl 7125, CS 8291, RC 1166). La mediana de la expresión de la molécula CD 62L aumentó con el estímulo del extracto bacteriano, en sujetos sanos de 593 (Cl 361, CS 929, RC 568) a 1113 (a910, CS 1240, RC 330) y la mediana de la expresión de la molécula CD 11a disminuyó con el estímulo del extracto bacteriano, en sujetos sanos de 9850 (Cl 9741, CS 9898, RC 157) a 9808.5 (CL 9693, CS 9890, RC 197) [CL. Cuartil inferior, CS. Cuartil superior, RC. Rango cuartilar]

Integrin cell adhesion molecules on human spermatozoa.

The expression of integrin cell adhesion molecules (ITG-CAMs) by human ejaculated spermatozoa (fresh, capacitated and acrosome reacted) was evaluated by immunocytochemical, immunofluorescence and cell-ELIS methods, using monoclonal antibodies against alpha-6 and beta-3 subunits. Both the subunits were expressed on the acrosome region in fresh spermatozoa and post acrosomal region after acrosome reaction induced by calcium ionophore. The spermatozoa of the fertile men showed significantly (P < 0.001) higher expression of alpha-6 and beta-3 ITG subunits than the subfertile men. The percentage of spermatozoa reacting with alpha-6 and beta-3 mAbs increased significantly after the loss of acrosome when compared with fresh spermatozoa. Moreover, 35-40% of spermatozoa with normal shape and none of the spermatozoa with pathological shape showed a positive reaction. The quantitative analysis carried out by ELISA suggests that the levels of these ITG subunits decreased significantly (P < 0.001) in the subfertile subjects when compared with the fertile and the difference was more for alpha-6 than the beta-3. Hence our result suggests that alpha-6 subunit may be used as a clinical marker to evaluate the sperm quality in men.

Inmunorreacción de los anticuerpos monoclonales A3, E1 y P3 en tejido normal / Immunoreaction of the monoclonal antibodies A3, E1 and P3 in normal tissue

Conocer el reconocimiento tisular en órganos normales de estos anticuerpos monoclonales (AcMs) dirigidos contra moléculas de gangliósidos es importante como parte de su evaluación para uso diagnóstico. Las muestras fueron procesadas frescas y posteriormente fijadas en paraformaldehído. Los 3 sobrenadantes de cultivo se trabajaron puros y en todos los experimentos se utilizaron controles negativos y positivos. Los 3 AcMs reaccionaron con células del epitelio intestinal y el tejido conectivo de la submucosa. Los antígenos A3 y E1 se localizaron también en el epitelio traqueobronquial. El AcM E1 reaccionó con los epitelios renal y prostático que el A3 lo hizo en la epidermis y los ganglios autónomos mientéricos. La inmunotinción de las secreciones renales e intestinales con estos AcMs junto a las características del marcaje tisular pudieron sugerir la naturaleza de estos antígenos

Moleculas acessorias de adesao: breve revisao e provavel papel na etiopatogenia da asma / Acessory adhesion molecules: brief review and role probable in asthma etiology

O sistema imunitario, para poder exercer suas funcoes de defesa e homeostase do organismo frente aos diversos tipos de agentes patogenicos, necessita encontra-los e subsequentemente reconhece-los, de modo a poder efetuar um controle adequado desses patogenos, tanto intra quanto extracelulares. Para tanto, e necessario que as celulas imunocompetentes possam chegar aos locais de agressao inflamatoria rapidamente. Tal migracao e dependente de moleculas acessorias de adesao, pertencentes a diversas superfamilias genicas. Tal processo de direcionamento das celulas imunes e inflamatorias ocorre nao so nas doencas infecciosas mas em todos os tipos de resposta imunitaria. As doencas caracterizadas por hipersensibilidade caracterizam-se pelo desencadeamento de processos inflamatorios elicitados por antigenos ubiquitarios, nao patogenicos per se, decorrentes de uma desregulacao da resposta imunologica. A presente revisao nos mostra as funcoes exercidas por essas moleculas acessorias de adesao na asma bronquica, uma doenca frequentemente associada a hipersensibilidade mediada por IgE