The availability of cost-effective high throughput screening assays combined with an enhanced understanding of oncogenesis has driven the development of more potent, specific, and less toxic anti-cancer agents. At the forefront of these advances are immunoglobulin molecules and their fragments. However, difficulties in producing antibodies in sufficient quantity and quality for commercial application have driven the development of alternative systems that can produce antibodies efficiently and cost-effectively. This thesis focuses on the engineering of an antibody fragment referred to as a single chain variable fragment (scFv), which consists of antibody light and heavy chain variable domains fused together by a peptide linker. Although the use of scFvs circumvents many of the issue of full-length antibody production, they still possess their own unique set of difficulties, including stability. In this thesis, we explored the following strategies to increase scFv stability. First, we increased the number of linkers used to join the variable light and heavy domains. We constructed two linear and two cyclic permutated scFvs that contained additional peptide linkers. Two linear permutated scFvs, named Model 1 and Model 3, showed increased stability with calculated melting temperatures (Tms) exceeding that of the unpermutated scFv. The two cyclic scFvs were less stable with Tms less than that of the unpermutated scFv. Second, we mutated light and heavy variable domains by introducing prolines or mutating glycine to alanine in the variable domain framework regions. Sites for proline mutations and glycine to alanine mutations were identified and scFvs containing the mutations were purified and their thermal stability tested. Unfortunately, there were no discernible differences between purified scFv mutants and the control scFv. Third, we designed a new selection/screening strategy using phage display and yeast two-hybrid assays to identify complementarity determining regions on scFvs that increased intracellular stability. We used this strategy to isolate anti-Abl-SH3 scFvs. Transient expression of scFvs in K562 cells indicated that two anti-Abl-SH3 scFv decreased viability.

Background: Genetic recombination is a driving force in genome evolution. Among viruses it has a dual role. For genomes with higher fitness, it maintains genome integrity in the face of high mutation rates. Conversely, for genomes with lower fitness, it provides immediate access to sequence space that cannot be reached by mutation alone. Understanding how recombination impacts the cohesion and dissolution of individual whole genomes within viral sequence space is poorly understood across double-stranded DNA bacteriophages (a.k.a phages) due to the challenges of obtaining appropriately scaled genomic datasets. Results: Here we explore the role of recombination in both maintaining and differentiating whole genomes of 142 wild double-stranded DNA marine cyanophages. Phylogenomic analysis across the 51 core genes revealed ten lineages, six of which were well represented. These phylogenomic lineages represent discrete genotypic populations based on comparisons of intra-and inter-lineage shared gene content, genome-wide average nucleotide identity, as well as detected gaps in the distribution of pairwise differences between genomes. McDonald-Kreitman selection tests identified putative niche-differentiating genes under positive selection that differed across the six well-represented genotypic populations and that may have driven initial divergence. Concurrent with patterns of recombination of discrete populations, recombination analyses of both genic and intergenic regions largely revealed decreased genetic exchange across individual genomes between relative to within populations. Conclusions: These findings suggest that discrete double-stranded DNA marine cyanophage populations occur in nature and are maintained by patterns of recombination akin to those observed in bacteria, archaea and in sexual eukaryotes.

The increase of multi-resistant bacteria highlights that the golden era of antibiotics is ending and that alternative treatmentsare urgently needed. Phages have been historically used to treat bacterial infections prior to the discovery of antibiotics and have gained renewed interest in the past decade. Despite the advantages of phage therapy over traditional antibiotic usage, a number of concerns persist over their clinical application centring on their efficacy and safety. This thesis presents four papers that focus on the isolation and characterization of phages that target reference strains and drug-resistant strains of E. coli as well as their infection dynamics and kinetics. In Paper I, six of thirty isolated phages were selected to be characterized for their growth parameters and host range using two commonly used methods. The study showed that the host range (an important selection criteria for phages) of the phages can change based on the assessment method and that the lysis efficiency of phages is host-dependent. The study suggests that standardised methods to assess the host range and lytic activity of phages are required to reduce result variability between research groups. Paper II investigated a rare phage with C3 morphotype from the Podoviridae family and characterised it via genomic, proteomic, morphologic and phylogenetic analysis. The study revealed previously unseen aspects including the formation of a honeycomb structure comprised of phage head during DNA packaging, the possible contractile nature of the tail and the 280 million year co-evolution between the major head protein and the scaffolding protein. Paper III highlights the need to take the immune system into consideration when designing phage therapeutics. In the study, four purified structurally distinct phages (selected from the three main phage families) were exposed to human cells (HT-29 and Caco-2 immortalised intestinal epithelial cell lines and donor-derived peripheral blood mononuclear cells) and the immunogenicity of the phages determined. Phage immunogenicity was shown to vary in a concentration and phage dependent manner with SU63 (a Myoviridae) being the most immunogenic phage and SU32 (a Siphoviridae) the least immunogenic. In the presence of human cells and a suitable host, phages were shown to maintain their killing efficacy as well as the ability to proliferate. Paper IV studies the infection dynamics of an experimental two-phage cocktail against a single bacterial host in vitro and in silico. However, in silico analysis and in vitro analysis produced conflicting results, in which mathematical modelling predicted the complete clearance of bacteria for all treatment scenarios whereas experimental results showed a 1-3log10 reduction in bacterial content. Practical experiments also showed increased anti-bacterial activity when the time between the additions of each phage was varied. This discrepancy suggests that the current mathematical model is unsuitable due to the inability to account for discrete variables such as interference. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p><p> </p>

Pseudomonas aeruginosa é um patógeno multirresistente capaz de produzir um biofilme protetor contra antibacterianos (ATB). O presente estudo avaliou estratégias terapêuticas contra biofilmes de cepas multirresistentes de P. aeruginosa representativas de clones e/ou genótipos de resistência endêmicos no Brasil. Os biofilmes foram formados in vitro utilizando um modelo adaptado do MBEC Assay e as estratégias terapêuticas utilizaram bacteriófagos líticos, combinação de ATB e/ou uso de força iônica alta (meio FIA). A aplicação de bacteriófagos líticos (&phi;SPM-1) e a combinação de Aztreonam (ATM) e Piperacilina/Tazobactam (PPT), não foram capazes de eliminar o biofilme. Biofilme formado em meio FIA possui CIM similar ao modelo planctônico, tanto para ATM (4 mg/mL) quanto para PPT (16 mg/mL). Ambos os ATB apresentaram CIM reduzida (inferior a 2 mg/mL) quando aplicados em conjunto com meio FIA. Dependendo da concentração de NaCl, a aplicação de meio FIA possui efeito bactericida sobre bactérias planctônicas e efeito bacteriostático sobre biofilmes já formados. / Multidrug-resistant Pseudomonas aeruginosa is a pathogen capable of producing a protective biofilm against antibiotics (ATB). The present study evaluated therapeutic strategies against biofilms of multidrug-resistant strains of P. aeruginosa representative of clones and/or exhibiting resistance genotypes endemic in Brazil. Biofilms were formed in vitro using an adapted model of MBEC Assay and the therapeutic strategies used lytic bacteriophages, combination of ATB and/or use of high ionic strength (HIS medium). The application of lytic bacteriophages (&phi;SPM-1) and the combination of Aztreonam (ATM) and Piperacillin / Tazobactam (PPT) were unable to remove the biofilm. The application of HIS during biofilm formation restored the bacteriostatic effect of both ATM (4 mg/mL) and PPT (16 mg/ml). Both ATB showed reduced MIC values (less than 2 mg/mL) when applied in conjunction with HIS medium. It was shown that HIS has a bacteriostatic or bactericidal effect on planktonic growth, which depend on the NaCl concentration, and bacteriostatic activity against mature biofilm.

Background Shiga toxin producing Escherichia coli (STEC) O157 causes severe gastrointestinal disease and haemolytic uremic syndrome, and has a major impact on public health worldwide with regular outbreaks and sporadic infection. Phage typing, i.e. the susceptibility of STEC O157 strains to a bank of 16 bacteriophages, has been used in the UK to differentiate STEC O157 for the past 25 years and the phage type (PT) can be an epidemiological marker of strains associated with severe disease or associated with cases that occur from foreign travel. However, little is known about the molecular interactions between the typing phages (TP) and STEC O157. The aims of this thesis were to use whole genome sequencing to elucidate the genetic basis for phage typing of STEC O157 and through this understand genetic differences between strains relevant to disease severity and epidemiology. Results Sequencing the STEC O157 TPs revealed that they were clustered into 4 groups based on sequence similarity that corresponded with their infectivity. Long read sequencing revealed microevolutionary events occuring in STEC O157 genomes over a short time period (approximately 1 year), evidenced by the loss and gain of prophage regions and plasmids. An IncHI2 plasmid was found responsible for a change in Phage Type (PT) from PT8 to PT54 during two related outbreaks at the same restaurant. These changes resulted in a strain (PT54) that was fitter under certain growth conditions and associated with a much larger outbreak (140 as opposed to 4 cases). TraDIS (Transposon directed Insertion site sequencing) was used to identify 114 genes associated with phage sensitivity and 44 genes involved in phage resistance, emphasising the complex nature of identifying specific genetic markers of phage susceptibility or resistance. Further work is required to prove their phage-related functions but several are likely to encode novel phage receptors. Deletion of a Stx2a prophage from a PT21/28 strain led to a strain that typed as PT32, supporting the concept that the highly pathogenic PT21/28 lineage I strains emerged from Stx2c+ PT32 strains in the last two decades by acquisition of Stx2a-encoding prophages. Conclusions This body of work has highlighted the complexity of bacteriophage interaction and investigated the genetic basis for susceptibility and resistance in E. coli. The grouping of the TPs showed that resistance or susceptibility to all members of a typing group was likely to be caused by one mechanism. IncHI2 was identified as one of the markers for the PT54 phenotype. The Stx2a prophage region was associated with the switch from PT32 to PT21/28, although PT32 strains containing both Stx2a and Stx2c-encoding prophages have been isolated and can provide insights into phage variation underpinning the susceptibility to the relevant typing phages. The TraDIS results indicated that susceptibility or resistance was governed by multiple genetic factors and not controlled by a single gene. The significance of LPS for initial protection from phage adsorption was evident and a number of novel genes controlling phage susceptibility and resistance identified including the Sap operon and stringent starvation protein A respectively. While SNP-based typing provides an excellent indication of the evolution and relatedness of strains, phage typing can provide real insights into short term evolution of the bacteria as PTs can be altered by mobile elements such as prophages and plasmids. This study has shown that, although complex, genetic determinants for PT can be mined from the genome and allow us to understand the evolution of this zoonotic pathogen between host species and during outbreaks.

There are estimated to be 1030 virus-like particles in the world's oceans. Most are viruses that infect bacteria, called `bacteriophages' or simply `phages'. Phages exert tremendous influence on marine biogeochemical cycling because they are responsible for about half of all bacterial death in the oceans, causing nutrient release into the dissolved and particulate organic matter pools. Traditional paradigms of phage biology held that most of these ocean phages belonged to the Caudovirales group: phages that contain a double-stranded DNA genome within a geometric capsid `head' to which a `tail' is joined, in one of several morphological variants, that is the main structure allowing the phage to interact and infect a host bacterium. Compared to tailed phages, small, non- tailed, single-stranded DNA-containing phages have been an historical afterthought; believed to exist only in specialized, niche environments. However, recent studies harnessing advances in technology have revealed that single-stranded DNA phages are ubiquitous to nearly every marine environment yet tested. Small, icosahedral, single-stranded DNA bacteriophages of the subfamily Gokushovirinae (family Microviridae) exemplify the difficulty that viruses can present as study subjects. They are difficult to visualize by epifluorescence microscopy and contain a paucity of genetic and protein material. As a result, recognition of their importance in marine environments has lagged behind that of tailed, double-stranded DNA bacteriophages. This thesis seeks to redress this knowledge gap. The first chapter expands knowledge of gokushovirus diversity in the environment by developing a degenerate PCR assay to amplify a portion of the major capsid protein (MCP) gene of gokushoviruses. Over 500 amplicons were sequenced from ten diverse environmental samples (sediments, sewage, seawater and freshwater), revealing the ubiquity and high diversity of this understudied phage group. The data was aggregated in several informative ways. Multiple alignments were combined with a predicted 3D-structure to reveal regions of both high and low conservation. Viewed in a phylogenetic framework, many gokushovirus MCP clades contained samples from multiple environments, although distinct clades dominated the different sample types. Some environments, particularly pelagic sediments, appear as hotbeds of gokushovirus diversity, while freshwater springs were the least diverse. The second chapter used the same primer set to detect gokushovirus communities at 0 m and 100 m depth in two seasons from three years at the Bermuda Atlantic Time- series Study (BATS) site. As a result of twenty-six years of constant sampling, the annual hydrodynamic cycling of BATS is very well understood. This wealth of knowledge allows us to hypothesize that the winter deep mixing layer will act to connect the viral communities between 0 m and 100 m. Conversely, in summer when stratification occurs, viral communities at the two depths will become divergent. We find compelling evidence to support this hypothesis. The final chapter of this thesis details continuing efforts to characterize the first non-tailed, single-stranded DNA, temperate phage to infect a member of the globally important genus of marine autotroph, Synechococcus. Efforts undertaken have spanned genomic, metagenomic and proteomic methodologies. The lack of culturable, phage-host model systems for small, single-stranded DNA phages is today one of the most glaring impediments to increased understanding of these viruses. In combination with the data presented on environmental diversity, steps taken towards establishing this Synechococcus phage as a culturable model system makes this thesis a major contribution to the understanding of environmental ssDNA phages.

Salmonella enterica serovar Typhimurium is a common cause of salmonellosis among humans and animals worldwide. In Australia, Typhimurium is responsible for over half of the salmonellosis cases. The Anderson phage-typing scheme is the primary means of long-term surveillance of Typhimurium outbreak isolates, and has played an important role in epidemiology. However, there exist quite a number of strains of Typhimurium that cannot be defined by the phage-typing scheme. Furthermore, the knowledge of evolutionary relationships among isolates of different phage types is still very limited and the genetic basis of phage type variation remains largely unknown. To address these issues, this study focused on molecular typing and evolution of Typhimurium. Fluorescent amplified-fragment length polymorphism (AFLP) was applied to 46 Typhimurium isolates comprising nine phage types in Australia using the restriction enzymes MseI and EcoRI and MseI +1 / EcoRI +1 primer pair combinations. The selected phage types, DT9, DT135, DT64, DT44, DT126, DT12a, DT1, DT141 and DT108, have been dominant or frequent phage types in animal and human infections in Australia in recent years. AFLP in the present study showed a very good discrimination power with Simpson index of diversity of 0.98, 35 different AFLP patterns were observed in the 46 isolates studied. The tree based on AFLP patterns showed good correlation with phage type, grouped most Typhimurium isolates by phage type, and differentiated all nine phage types. Furthermore, 84 phage-type specific polymorphic AFLP fragments, for which presence or absence correlated with phage type (including 25 with one exception to phage-type specificity) were observed in the 46 strains studied. Eighteen phage-type specific AFLP fragments were cloned and sequenced. Sixteen are of known genes or have a homologue in the databases. It was found a predominance of phage and plasmid genes rather than mutational changes in the AFLP fragments studied. Of the 18 cloned and sequenced AFLP fragments, only four relate to mutational changes in the S. enterica chromosome, the other 14 comprise DNA of mobile elements: nine are phage related, three are plasmid related and two are gain of DNA from unknown origin. Twelve of the 18 sequenced phage-type specific AFLP markers are polymorphic because the DNA is present or absent as indicated by Southern hybridization. Two of these markers were successfully used in preliminary PCR-based typing of 30 DT9 and 29 DT135 isolates from worldwide collections. 27 of the 30 DT9 isolates and all DT135 isolates tested were correctly categorized. The results implied a good potential to use the sequence of these fragments as the basis for a multiplex PCR or a microarray based molecular �phage� typing method for Typhimurium. This thesis also studied the molecular evolutionary relationships among the same set of 46 Typhimurium isolates using mutational changes detected by AFLP, or analysis of intergenic regions and their flanking genes in genome sequences. The complete genome sequence of Typhimurium LT2 was analysed by computer modelled AFLP. The polymorphic AFLP fragments, which matched with the modelled LT2 AFLP fragments, were amplified and sequenced by LT2 genome based primers to determine the changes. Forty-nine intergenic regions with higher pairwise differences between LT2 and Typhi CT18 were amplified and sequenced using LT2 genome based primers for one isolate of each phage type. 51 polymorphic sites were detected consisting of 18 in AFLP fragments and 33 in intergenic regions or their flanking genes. PCR-RFLP (restriction fragment length polymorphism) and SNaPshot were used to further investigate the distribution of the single nucleotide polymorphisms (SNPs) detected in intergenic regions in all isolates studied. Of the 18 mutational changes detected in AFLP fragments, eight were indels (insertions / deletions) and ten single base substitutions. Of the eight indels, four were in genes, three in intergenic regions, and one covered adjacent intergenic and coding regions. The four indels in genes all caused frameshift mutations, including three single base indels and one 19 bp deletion. Of the ten substitutions, one was in an intergenic region and nine in genes comprising three synonymous and six non-synonymous substitutions. Of the 33 polymorphic sites detected from sequences of 23 intergenic regions and their flanking genes, one was IS200 insertion and 32 single nucleotide polymorphisms (SNPs), of which 30 were single base substitutions and two were single base indels. Nine of the 33 variations were found in the flanking genes, which were all single base substitutions comprising four synonymous, four non-synonymous substitutions and one non-sense mutation. More non-synonymous than synonymous substitutions were found for those in coding regions within Typhimurium, indicating that slightly deleterious intraspecies mutations can be fixed within clones, such as various lineages of Typhimurium. The 51 polymorphic sites, which were inferred from sequences of both mutation related AFLP fragments, and intergenic regions and their flanking genes, gave a single phylogenetic tree of the 46 Typhimurium isolates studied. All sequences involved were compared with the homologous sequences in the available S. enterica genome sequences for serovars Typhi, Paratyphi A, Gallinarum, Enteritidis and Pullorum and this enabled the determination of the direction of the mutational changes in the isolates studied and the root of the phylogenetic tree. There were only two events inferred to have occurred twice, the remaining 49 polymorphisms can be explained by a single event. The data indicated that Typhimurium has a very strong clonal structure with a very low level of recombination over the time for diversification of Typhimurium as majority of clonal variations are from point mutations rather than recombination. The phylogenetic tree based on mutational changes showed that most Typhimurium isolates of a given phage type are in the same evolutionary group, but that some phage types appear to have arisen more than once. Comparison of the phylogenetic tree with AFLP data gave examples of unrelated isolates of a given phage type having common AFLP fragments comprising plasmid or phage genes, supporting the view that phage type can be determined by presence of specific phages or plasmids. The mutation-based tree showed that six of the nine phage types studied appeared to have a single origin, at least for the isolates studied. It also found that DT1 and DT44 had two independent origins even for the limited set of strains used. The distribution of DT12a isolates into two groups could be explained that the group of three DT12a isolates were derived from the other group of four DT12a isolates, where the root of the tree might be. The data also confirmed that DT64 arose from DT9. The phylogenetic tree that was generated based on essentially mutational changes provides clear relationships of the closely related Typhimurium isolates with high level of consistency and reasonable confidence. This study provided one of the few analyses of relationships of isolates within a clone. Matching actual AFLP with computer modeled AFLP and sequencing intergenic regions provide very good new strategies to identify mutational polymorphisms and to study the molecular evolutionary relationships in the closely related isolates.

<p>Heparan sulfates (HSs) are a class of anionic carbohydrate chains found at cell surfaces and in the extracellular matrix where they interact with a number of proteins. HS is characterized by extreme structural heterogeneity, and has been implicated in a number of biological phenomenon like embryogenesis, morphogen gradient formation and signalling of growth factors such as FGF, PDGF etc. Despite the characteristic structural heterogeneity, evidence from compositional studies show that the HS structure is expressed in a tightly regulated manner, implying a functional significance, which is most likely in the modulation of cell behaviour through HS-protein interactions. The lack of molecular tools has, however, hampered the understanding of HS structures with functional significance. This work therefore aims at characterizing the structural requirements on HS involved in the interaction with the anti-HS phage display antibodies HS4C3, AO4B08 and HS4E4 and a selected growth factor PDGF-BB. The characterization was done with the help of tailored oligosaccharide libraries generated from sources bearing structural resemblance to HS.</p><p>The work has thus made available tools that preferentially recognize certain structural features on the HS chain and will aid in the further study of HS structure and its regulation. Evidence is also provided to support the notion that HS protein interactions can occur in multiple manners, utilizing any of the structural features on the HS chain.</p>

Les DD-peptidases sont des enzymes impliquées dans la synthèse de la paroi bactérienne. Elles sont aussi appelées "Penicillin Binding Proteins" (PBPs) car elles forment des acyl-enzymes stables avec des antibiotiques de type beta-lactames comme la pénicilline, la stabilité de ces complexes étant à l'origine de l'effet antibiotique. Certaines bactéries sont résistantes aux b-lactames grâce à la production de beta-lactamases, capables d'hydrolyser ces antibiotiques jusqu'à 10E8 fois plus rapidement que les PBPs selon un mécanisme impliquant deux étapes, d'acylation puis de désacylation. Il est généralement accepté que les beta-lactamases ont évolué à partir d'une PBP ancestrale en intégrant au site actif un mécanisme catalytique efficace pour la réaction de déacylation. L'objectif de cette thèse s'inscrit dans la compréhension des mécanismes d'évolution de la catalyse enzymatique au niveau moléculaire. Nous tenterons de reproduire un mécanisme évolutif en créant in vitro une activité b-lactamase à partir d'une DD-peptidase. La protéine de départ pour ce travail est la PBP-A de Thermosynechococcus elongatus, appartenant à une nouvelle famille de PBPs homologue aux beta-lactamases de classe A. L'analyse biochimique de cette protéine suggère que c'est une DD-peptidase, et une approche rationnelle par substitution d'un résidu dans le site actif de PBP-A a permis d'augmenter la vitesse de désacylation de l'acyl-enzyme formé avec la pénicilline d'un facteur 90. L'analyse des structures 3-D de PBP-A sauvage et mutante laisse ouverte la question de savoir comment évoluer cette PBP en beta-lactamase. Ainsi, pour l'évolution dirigée de cette protéine, deux banques ont été construites par approches aléatoire et semi-rationnelle. Il a été possible de sélectionner par "phage display" des enzymes améliorées pour la réaction d'acylation. L'obtention de mutants améliorés pour l'acylation ou la désacylation constitue des premiers pas vers l'évolution de PBP-A en beta-lactamase.

This thesis describes the development and use ofnon-immunoglobulin affinity proteins denoted affibodies asalternatives to antibodies in different immunotechnologyapplications. A 58 aa IgG Fc binding three-helix bundle domainZ, derived from staphylococcal protein A has been used asframework for library constructions, in which the face of themolecule involved in the native binding activity has beenengineered by combinatorial protein engineering. Recruting 13surface-located positions for simultanenous substitutionmutagenesis, using degenerated oligonucleotides for libraryassembly at the genetic level, two libraries differing in thechoice of codons were constructed to serve as general sourcesof novel affinity proteins. The libraries were adapted fordisplay onE. colifilamentous phage particles allowingin vitroselection of desired variants capable ofbinding a given target molecule. In selections using human IgAas target, several new IgA specific affibodies could beidentified. One variant ZIgA1, was further investigated and showed binding toboth IgA1 and IgA2 human subclasses as well as to secretoryIgA. This variant was further demonstrated uesful as ligand inaffinity chromatography purification for recovery of IgA fromdifferent samples including unconditioned human plasma.Affibodies of different specificities were also fused to otherprotein domains to construct fusion proteins of relevance forimmunotechnology applications. Using Fc of human IgG as genefusion partner, "artificial antbodies" could be produced inE. colias homodimeic proteins, where the antigenbinding was confered by N-terminally positioned affibodymoieties of different valencies. One area of application forthis type of constructs was demonstrated through specificdetection of the target protein by Western blotting. Exploitingthe uncomplicated structure of affibody affinity proteins, genefusions between affibodies and the homotetrameric reporterenzyme β-galactosidase were constructed, which could beproduced as soluble proteins intracellularly inE. coli. The potential use of such recombinantimmunoconjugates in immunotechnology was demonstrated in ELISAdot-blot and immunohistochemistry, where in the latter case IgAdepositions in the glomeruli of a human kidney biopsy could bespecfically detected with low background staining ofsurrounding tissues. In a novel format for sandwich ELISA, thepossible advantage of the bacterial origin of the affibodyclass of affinity proteins was investigated. As a means tocircumvent problems associated with the presence of humanheterophilic antibodies in serum, causing bakground signals dueto analyte-independent crosslinking of standard capture anddetection antibody reagents, assay formats based oncombinations of antibody and affibody reagents for capture anddetection were investigated and found to be of potentialuse. <b>Keywords:</b>phage display, combinatorial, affinity, IgAligand, immunohistochemistry, affibody-fusions