Toll-like receptor 9 contributes to recognition of Mycobacterium bovis Bacillus Calmette-Guérin by Flt3-ligand generated dendritic cells

Recognition of mycobacteria by the innate immune system is essential for the development of an adaptive immune response. Mycobacterial antigens stimulate antigen presenting cells (APCs) through distinct Toll-like receptors (TLRs) resulting in rapid activation of the innate immune system. The role of TLRs during infection with Mycobacterium bovis Bacillus Calmette-Guérin (BCG) has been evaluated for TLR2 and TLR4 only. Surprisingly, despite the fact that immune stimulatory CpG-motifs have been originally derived from BCG, for the vaccine strain the role of TLR9 has not been addressed before. To identify the set of TLRs involved in the recognition of BCG, we infected bone marrow-derived macrophages and bone marrow-derived dendritic cells (Flt3-ligand generated DCs) from TLR2, TLR3, TLR4, TLR7, TLR9, MyD88 knockout, TLR2/4 and TLR2/4/9 multiple knockout mice. The degree of activation and stimulation was determined by TNFα, IL-6 and IL-12p40 ELISA. Activation of DCs was measured by surface expression of the costimulatory molecule CD86. We observed the most dramatic reduction of the inflammatory response for TLR2-deficient antigen presenting cells. Both macrophages and DCs produce markedly decreased amounts of TNFα and IL-6 in the absence of TLR2 whereas no significant reduction could be observed for TLR3, 4, 7, 9 single TLR-knockouts. However, IL-12 production in DCs appears not exclusively dependent on TLR2 and only in TLR2/4/9-deficient DCs BCG-induced IL-12 is reduced to background levels. Similarly, up-regulation of CD86 is abolished only in TLR2/4/9-deficient DCs supporting a role of TLR9 in the recognition of M. bovis BCG by murine dendritic cells.     

Selective inhibition of the transmembrane Ca conductivity of mammalian myocardial fibres by Ni,Co and Mn ions

Pflügers Archiv - European Journal of Physiology - According to earlier studies on mammalian papillary muscles, Ni and Co ions reduce the Ca dependent mechanical response whilst the action...     

Regulation and chance in the ontogeny of B and T cell antigen receptor repertoires

The adaptive immune system has to economically generate a large array of T and B cell antigen receptors (T cell receptors [TCRs], B cell receptors [BCRs]) that eliminate both longstanding and novel antigens from the host while preventing the production of deleterious (e.g., autoreactive) antigen receptors. Our studies focus on the mechanisms that shape the development of these antigen receptor repertoies during human ontogeny. The key to BCR and TCR diversity is the third complementarity determining region (CDR3) of the variable domain, which in the immunoglobulin heavy chain and TCR β chain, is created by the junction between the variable, diversity, and joining gene segments. The CDR3 diversity is constrained by overrepresentation of gene segments and lack of N regions during the first trimester of gestation and then increases exponentially during ontogeny until it reaches adult levels months after birth. This process parallels, and may contribute to, the stepwise acquisition of the ability to respond to specific antigens. Recent studies indicate that maturation of the CDR 3 repertoire is not accelerated by premature exposition to extrauterine antigen and thus appears to follow a strictly developmentally regulated program whose pacemaker(s) is still unknown.     

A transgenic mouse bearing an antisense construct of regulatory subunit type 1A of protein kinase A develops endocrine and other tumours: comparison with Carney complex and other PRKAR1A induced lesions

Background: Inactivation of the human type Iα regulatory subunit (RIα) of cyclic AMP dependent protein kinase (PKA) (PRKAR1A) leads to altered kinase activity, primary pigmented nodular adrenocortical disease (PPNAD), and sporadic adrenal and other tumours.

Methods and results: A transgenic mouse carrying an antisense transgene for Prkar1a exon 2 (X2AS) under the control of a tetracycline responsive promoter (the Tg(Prkar1a*x2as)1Stra, Tg(tTAhCMV)3Uh or tTA/X2AS line) developed thyroid follicular hyperplasia and adenomas, adrenocortical hyperplasia and other features reminiscent of PPNAD, including late onset weight gain, visceral adiposity, and non-dexamethasone suppressible hypercorticosteronaemia, with histiocytic, epithelial hyperplasias, lymphomas, and other mesenchymal tumours. These lesions were associated with allelic losses of the mouse chromosome 11 Prkar1a locus, an increase in total type II PKA activity, and higher RIIß protein levels; the latter biochemical and protein changes were also documented in Carney complex tumours associated with PRKAR1A inactivating mutations and chromosome 17 PRKAR1A locus changes.

Conclusion: We conclude that the tTA/X2AS mouse line with a downregulated Prkar1a gene replicates several of the findings in Carney complex patients and their affected tissues, supporting the role of RIα as a candidate tumour suppressor gene.

     

Effects of sorbent suspension dialysis on plasma amino acid levels in cirrhotic patients with refractory hepatic encephalopathy

In cirrhotic patients, plasma amino acid levels are severely deranged. A decreased ratio of branched-chain to aromatic amino acids (Fischer ratio) has been implicated in the pathogenesis of hepatic encephalopathy. In this prospective study, we investigated the effects of extracorporeal detoxification on amino acid levels using a sorbent suspension dialysis system. Twenty patients with documented cirrhosis and hepatic encephalopathy grade II-III not responding to standard treatment were randomized to receive either six hours of sorbent dialysis and standardized conventional medical treatment or ongoing medical treatment alone. In contrast to previous uncontrolled studies, no significant effect on amino acid levels, Fischer ratio or clinical grade of hepatic encephalopathy was detected in either treatment group. In conclusion, a 6-hour treatment with sorbent dialysis did not significantly influence plasma levels of amino acids and did not ameliorate the clinical grade of hepatic encephalopathy.     

Die Isolierung von Poliovirus in verschiedenen Gewebekulturen

Summary 100 stool extracts from patients with poliomyelitis or from individuals after oral poliomyelitis vaccination were inoculated simultaneously into HeLa, monkey kidney, and human thyroid cultures. In most cases (88 times) a cytopathic effect was seen in all three cultures. Failures were most frequently encountered in thyroid, rarely in monkey kidney cells. They were due either to thyroid culture lots with reduced viral susceptibility or to small amounts of virus in the stool specimens. No qualitative difference was found in the host range of individual virus strains. With attenuated viruses the cytopathic effect in HeLa cells as a rule was delayed for several days.

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Die Untersuchungen wurden mit Unterstützung der Deutschen Vereinigung zur Bekmpfung der Kinderlähmung e.V. durchgeführt.

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Wir danken Herrn Privatdoz. Dr. F.Müller, Düsseldorf, für die freundliche überlassung einiger virushaltiger Stuhlproben. Herr Dr. A. R.Ababio, Homburg, war uns bei der Beschaffung von Stuhlproben nach oraler Poliomyelitisimpfung behilflich. Wir danken schließlich Fräulein E.Baschleben, Frau H.Gelderblom, Frau H.Kaiser und Fräulein I.Lamy für ihre Hilfe bei den Untersuchungen.     

p38 Mitogen-activated protein kinase activation in endothelial cell is implicated in cell alignment and elongation induced by fluid shear stress.

Fluid shear stress is thought to be important in maintaining the phenotype of endothelial cells (ECs) in vivo. The purpose of the study was to determine the effect of varying levels of laminar shear stress on EC elongation and alignment and the role of p38 mitogen-activated protein kinase (MAPK) on the morphologic change induced by shear stress. Cultured bovine aortic ECs were subjected to 1, 4, 7, 14, or 20 dyne/cm(2) laminar steady shear stress. On morphometric analysis of static ECs, the average orientation angle was 41 degrees , whereas after 24 h shear stress at 1, 4, 7, 14, and 20 dyne/cm(2) the angles were 34 degrees, 33 degrees, 16 degrees, 11 degrees, and 10 degrees, respectively. The shape index of static ECs was 0.76, whereas the indexes of ECs exposed to shear stress were 0.72, 0.72, 0.65, 0.50, and 0.47, respectively. The time and the magnitude of activation of p38 MAPK were dependent on the level of shear stress. The results indicate that a minimum shear stress of 7 to 14 dynes/cm(2) is necessary for cell alignment and elongation and this correlates with activity of p38 MAPK. ECs exposed to shear stress in the presence of the p38 MAPK inhibitor SB-203580 did not orient in any manner and the shape index was similar to the static cells.     

The pregnancy-associated α2-glycoprotein (α2-PAG) A tumour marker?

Summary Long-term studies of 2-PAG in sera of patients with breast cancer, bronchial carcinoma, gynaecological carcinoma, melanoma and laryngeal carcinoma have proved that 2-PAG is a possible laboratory parameter for the assessment of recurrence of tumour and metastasis. The results published for trophoblastic tumour and gastrointestinal carcinoma are still divergent. Because of the large individual range of 2-PAG concentrations and the widely differing 2-PAG levels in men and women single determinations of this protein are without value. A detailed classification of the pathological mechanisms to which these proteins are submitted is still missing and consequently we have no fundamental knowledge of diseases that apart from pregnancy and neoplasia lead to changes in the physiological 2-PAG serum concentration.Dedicated to Prof. Dr. E. Schmiedt to his 60th birthday (20th of November 1980)