Diverse humoral autoimmunity to the ribosomal P proteins in systemic lupus erythematosus and hepatitis C virus infection

Autoantibodies to the three ribosomal P proteins (Rib-P) are specifically found in 10% to 40% of systemic lupus erythematosus (SLE) patients. Most anti-Rib-P autoantibodies bind to a C-terminal epitope shared by all three Rib-P proteins P0, P1 and P2. In the present study, we shed more light on the humoral autoimmune response to the Rib-P antigen as it occurs in autoimmunity and infectious disease. In a mutational analysis of the major C-terminal epitope, we verified the key role of phenylalanine residues Phe ( 111 ) and Phe ( 114 ) for binding of most anti-Rib-P serum autoantibodies present in SLE sera (n = 28). By nuclear magnetic resonance (NMR) investigation of a peptide comprising the C-terminal 22 amino acids, we observed hallmarks for alpha-helical secondary structure of the Rib-P epitope core (GFGLFD). Based on NMR data and on SPOT epitope analysis, we propose a structural model of the Rib-P major epitope, which displays Phe ( 111 ) and Phe ( 114 ) on one side of the helix. Apart from that, two sera from the hepatitis C virus (HCV) control group (n = 68) were found to contain antibodies specific for P2, but not for the other Rib-P proteins. Using a SPOT peptide array scanning the P2 amino acid sequence, we identified reactivity with two distinct epitopes (residues 21-35 and 41-55 of Rib-P2) shared by both HCV sera. We conclude that anti-Rib-P autoreactivity occurs in SLE, Chagas' disease (CD) and-as firstly described here-during HCV infection. Anti-Rib-P reactivity in SLE sera primarily depends on Phe ( 111 ) and Phe ( 114 ) of the alpha-helical C-terminal epitope. In contrast, anti-Rib-P autoantibodies in HCV infection mainly recognize epitopes within the N-terminal half of ribosomal P2.

A microarray enzyme-linked immunosorbent assay for autoimmune diagnostics

In order to quantify autoantibodies in the sera of patients with autoimmune disease, we have created a microarray-based immunoassay that allows the simultaneous analysis of 18 known autoantigens. The microarrays contain serial dilutions of the various antigens, thereby allowing accurate determination of autoantibody titer using minimal amounts of serum. The assay is very sensitive and highly specific: as little as 40 fg of a known protein standard can be detected with little or no cross-reactivity to nonspecific proteins. The signal intensities observed from serial dilutions of immobilized antigen correlate well with serial dilutions of autoimmune sera. Miniaturized and highly parallelized immunoassays like these will reduce costs by decreasing reagent consumption and improve efficiency by greatly increasing the number of assays that can be performed with a single serum sample. This system will significantly facilitate and accelerate the diagnostics of autoimmune diseases and can be adapted easily to any other kind of immunoassay.

Psychrotrophic, lactic acid-producing bacteria from anoxic waters in Ace Lake, Antarctica; Carnobacterium funditum sp. nov. and Carnobacterium alterfunditum sp. nov

Heterofermentative, lactic acid-producing, gram-positive, motile bacteria were isolated from the waters of Ace Lake, Antarctica. All strains produced virtually only L(+)lactic acid from D(+)glucose. D(--)-ribose was fermented to lactic, acetic, and formic acids, and ethanol. Cell walls contained meso-diaminopimaleic acid. The strains did not grow at 30 degrees C and were psychrotrophic. Whole cells contained 18:1 cis 9 as a major component of their fatty acids. At 20 degrees C, the strains grew better anaerobically than aerobically and all strains lacked catalase, oxidase and respiratory lipoquinones. DNA that coded for most of the 16S rRNA gene of one of the strains was amplified by the polymerase chain reaction and sequenced. The strain was phylogenetically most closely related to Carnobacterium mobile (Knuc = 0.0214). The isolates separated into two phenotypes. DNA/DNA homology studies determined on a representative from each phenotype showed low homology between the phenotypes (38 +/- 8%), and with Carnobacterium mobile (26 +/- 2%, 34 +/- 2%). Carnobacterium funditum sp. nov. produced acid from mannitol, trehalose, but not amygdalin. The G + C content of the DNA was 32-34%, and the Type strain is DSM 5970 (=ACAM 312). Carnobacterium alterfunditum sp. nov. produced acid weakly from amygdalin but not from mannitol trehalose. The G + C content was 33-34%, and the Type strain is DSM 5972 (=ACAM 313).

[(220,222Rn)radon exposure in indoor areas]

The inhalation of short-lived decay products of [220,222Rn]Radon accounts on the average for half of the effective dose equivalent from all natural sources of radiation. Sources of emanation/exhalation and subsequent mechanisms of indoor invasion of [220,222Rn]Radon are discussed. Both seasonality of [220,222Rn]Radon concentration (in- & outdoor) and the indoor ventilation rate are considered.

The 23S ribosomal RNA higher-order structure of Pseudomonas cepacia and other prokaryotes

A 23S ribosomal RNA gene of Pseudomonas cepacia has been cloned and sequenced. A general higher-order structure model based on earlier published models has been derived from comparative analysis of 23S-like rRNAs of eubacteria, archaebacteria, organelles and eukaryotes. Differences between the previous models were carefully analyzed and controversial regions evaluated. Moderately large insertions and deletions have been found at new points in the secondary structure. The analysis of 50 published as well as unpublished 23S rRNA sequences provide additional proof for six of the seven previously suggested tertiary interactions within the 23S rRNA. P. cepacia is the first representative of the beta subgroup of the Proteobacteria phylum whose 23S rRNA has been sequenced. A tree reflecting evolutionary relationships of prokaryotes was constructed. The topology of this tree is in good agreement with the 16S rRNA tree.