To generate a stable resource from which high affinity human antibodies to any given antigen can be rapidly isolated, functional V-gene segments from 43 non-immunized human donors were used to construct a repertoire of 1.4 x 10(10) single-chain Fv (scFv) fragments displayed on the surface of phage. Fragments were cloned in a phagemid vector, enabling both phage displayed and soluble scFv to be produced without subcloning. A hexahistidine tag has been incorporated to allow rapid purification of scFv by nickel chelate chromatography. This library format reduces the time needed to isolate monoclonal antibody fragments to under two weeks. All of the measured binding affinities show a Kd < 10 nM and off-rates of 10(-3) to 10(-4) s-1, properties usually associated with antibodies from a secondary immune response. The best of these scFvs, an anti-fluorescein antibody (0.3 nM) and an antibody directed against the hapten DTPA (0.8 nM), are the first antibodies with subnanomolar binding affinities to be isolated from a naive library. Antibodies to doxorubicin, which is both immunosuppressive and toxic, as well as a high affinity and high specificity antibody to the steroid hormone oestradiol have been isolated. This work shows that conventional hybridoma technology may be superseded by large phage libraries that are proving to be a stable and reliable source of specific, high affinity human monoclonal antibodies.

Systemic inflammation, as evidenced by elevated inflammatory cytokines, is a feature of advanced renal failure and predicts worse survival. Dialysate IL-6 concentrations associate with variability in peritoneal small solute transport rate (PSTR), which has also been linked to patient survival. Here, we determined the link between systemic and intraperitoneal inflammation with regards to peritoneal membrane function and patient survival as part of the Global Fluid Study, a multinational, multicenter, prospective, combined incident and prevalent cohort study (n=959 patients) with up to 8 years of follow-up. Data collected included patient demographic characteristics, comorbidity, modality, dialysis prescription, and peritoneal membrane function. Dialysate and plasma cytokines were measured by electrochemiluminescence. A total of 426 survival endpoints occurred in 559 incident and 358 prevalent patients from 10 centers in Korea, Canada, and the United Kingdom. On patient entry to the study, systemic and intraperitoneal cytokine networks were dissociated, with evidence of local cytokine production within the peritoneum. After adjustment for multiple covariates, systemic inflammation was associated with age and comorbidity and independently predicted patient survival in both incident and prevalent cohorts. In contrast, intraperitoneal inflammation was the most important determinant of PSTR but did not affect survival. In prevalent patients, the relationship between local inflammation and membrane function persisted but did not account for an increased mortality associated with faster PSTR. These data suggest that systemic and local intraperitoneal inflammation reflect distinct processes and consequences in patients treated with peritoneal dialysis, so their prevention may require different therapeutic approaches; the significance of intraperitoneal inflammation requires further elucidation.

The hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome is an autosomal dominant disorder caused by mutations of the dual zinc finger transcription factor, GATA3. The C-terminal zinc finger (ZnF2) binds DNA, whereas the N-terminal finger (ZnF1) stabilizes this DNA binding and interacts with other zinc finger proteins, such as the Friends of GATA (FOG). We have investigated seven HDR probands and their families for GATA3 abnormalities and have identified two nonsense mutations (Glu-228 3 Stop and Arg-367 3 Stop); two intragenic deletions that result in frameshifts from codons 201 and 355 with premature terminations at codons 205 and 370, respectively; one acceptor splice site mutation that leads to a frameshift from codon 351 and a premature termination at codon 367; and two missense mutations (Cys-318 3 Arg and Asn-320 3 Lys). The functional effects of these mutations, together with a previously reported GATA3 ZnF1 mutation and seven other engineered ZnF1 mutations, were assessed by electrophoretic mobility shift, dissociation, yeast twohybrid and glutathione S-transferase pull-down assays. Mutations involving GATA3 ZnF2 or adjacent basic amino acids resulted in a loss of DNA binding, but those of ZnF1 either lead to a loss of interaction with specific FOG2 ZnFs or altered DNA-binding affinity. These findings are consistent with the proposed three-dimensional model of ZnF1, which has separate DNA and protein binding surfaces. Thus, our results, which expand the spectrum of HDR-associated GATA3 mutations and report the first acceptor splice site mutation, help to elucidate the molecular mechanisms that alter the function of this zinc finger transcription factor and its role in causing this developmental anomaly.

The molecular diversity of rumen methanogens in sheep in Australia was investigated by using individual 16S rRNA gene libraries prepared from the rumen contents obtained from six merino sheep grazing pasture (326 clones), six sheep fed an oaten hay-based diet (275 clones), and five sheep fed a lucerne hay-based diet (132 clones). A total of 733 clones were examined, and the analysis revealed 65 phylotypes whose sequences (1,260 bp) were similar to those of cultivated methanogens belonging to the order Methanobacteriales. Pasturegrazed sheep had more methanogen diversity than sheep fed either the oaten hay or lucerne hay diet. Methanobrevibacter strains SM9, M6, and NT7 accounted for over 90% of the total number of clones identified. M6 was more prevalent in grazing sheep, and SM9, despite being found in 16 of the 17 sheep, was more prevalent in sheep fed the lucerne-based diet. Five new species were identified. Two of these species exhibited very little sequence similarity to any cultivated methanogens and were found eight times in two of the six sheep that were grazing pasture. These unique sequences appear to represent a novel group of rumen archaea that are atypical for the rumen environment.The rumen is a unique environment and is home to billions of microbes, including bacteria, methanogenic archaea, protozoa, and fungi. These different microbes form a complex community of organisms that interact with one another and play an important role in the digestion of feed and the supply of energy to the host in the form of volatile fatty acids and microbial protein. In the past decade, there has been an increasing amount of interest in the rumen methanogenic archaea. This has primarily resulted from the role of these organisms in global warming due to the production of methane by domesticated livestock.In Australia, ruminant livestock are the single largest source of agricultural greenhouse gas emissions and alone account for at least 12% of Australian's total anthropomorphic national emissions (3). In New Zealand, enteric emissions are responsible for approximately 60% of that country's total greenhouse gas emissions (27). Approximately 95.5% of the methane emitted by ruminants is produced in the rumen (3), and the associated loss of energy for the ruminant has been estimated to be between 2 and 15% of the gross energy intake (18,25,40).Methane production is influenced by feed intake and the digestibility of the dry matter in the feed that is consumed. The effects of diet on changes in the diversity and numbers of a wide range of bacterial species in the rumen are known (20,30,36,37,45), but there is little information available concerning the composition of the methanogen population and their numbers of methanogens with regard to diet. Therefore, it is necessary to understand the diversity of methanogens in the rumen.In the past, methanogens from the digestive tracts of domesticated ruminants were identified by classical microbiological techniques (46). However, because of the fastidious growth requirements of ru...