Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2001. / Härtill 5 uppsatser.

Little is known about the virulence factors of Renibacterium salmoninarum, the causative agent of salmonid bacterial kidney disease. The predominant protein produced by R. salmoninarum in broth culture or during infection is a 57/58 kDa protein (p57) which is associated with strain virulence. In this study monoclonal antibodies (MAbs) to p57 were developed and used as tools to antigenically characterize and quantify the protein. Monoclonal antibodies 4D3 and 2G5 recognize p57 and appear to be species specific as they did not cross-react with proteins produced by bacterial species within the genera Streptococcus, Carnobacterium, Vibrio and Aeromonas, or with fish serum proteins. Further, these MAbs recognize conserved epitopes on p57 shared by 10 isolates from geographically diverse areas. In vitro activities attributed to p57 include the suppression of antibody production, and the agglutination of rabbit erythrocytes and salmonid spermatocytes. We described a novel in vitro agglutinating activity of p57 toward salmonid leukocytes that was inhibited by two of a panel of eight MAbs. The location of the putative epitopes recognized by the MAbs were determined by two-dimensional electrophoresis and Western blotting of proteolytic breakdown fragments of p57. Amino acid sequencing of several of the fragments suggested that the antibodies which inhibit agglutinating activity bind proximal to the amino terminus of the protein. To investigate the mechanism of leukocyte agglutination, p57 was purified to near homogeneity using anion-exchange and size-exclusion fastpressure liquid chromatography. P57 eluted as a protein monomer and retained leukoagglutinating activity. In addition, results of antibody-capture, enzyme-linked immunosorbent assays suggest that a monomer exists in culture supernatant and infected fish tissue. Antigenic analysis with MAbs has also been useful for developing immunoassays for detecting and quantifying p57 levels in vivo. Using a quantitative ELISA, the prevalence of salmon with antigen levels above 3 ng/ml of kidney homogenate varied from 12.8 to 36.6% in 740 adult spawning chinook salmon returning to an Oregon hatchery from 1989 to 1991. A rapid, semi-quantitative, Field ELISA was also developed for use under hatchery conditions, in addition to a sensitive chemiluminescent Western blot protocol for confirming ELISA positive samples. / Graduation date: 1992

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 91-111).

Renibacterium salmoninarum, the etiological agent of bacterial kidney disease (BKD) of salmonid fish, is a pathogen of great concern among fisheries and the aquaculture industry worldwide. Previous investigations have indicated the pathogenesis of BKD is complex. It is a chronic, multisystemic, granulomatous disease with a number of potential immunomodulatory effects on the host. Given the current limitations for treatment and control of BKD, it is imperative that the pursuit of development of methods of prevention, namely management strategies and vaccination, be continued. To do so, the immunology of BKD must be elucidated in order to better understand and manipulate the associated immune responses to our advantage. This dissertation is composed of four chapters which relate to BKD and the associated immune responses of three species of susceptible salmonid fish as follows: Exogenous stress factors, through stress-induced immunosuppression, have been shown to influence BKD development in cultured salmonids. Chapter 1 examines the effects of two environmental stressors common to fish culture, overcrowding and overfeeding, as they affect BKD development and R. salmoninarumantigen prevalence among juvenile chinook salmon (Oncorhynchus tshawytscha) Immunomodulatory interaction between pathogen and host in BKD is widely reported and merits further investigation. Particularly, the immunological parameters affected and the role of the extracellular protein (ECP) of R. salmoninarum are of interest. Chapter 2 examines the in vivo immune response of rainbow trout (Oncorhynchus mykiss) following exposure to the ECP in terms of both humoral and cell-mediated immunological parameters, including the immune response against another bacterial pathogen. Chapter 3 addresses the in vitro effects of the ECP upon specific splenic immunocyte functions, phagocytosis and respiratory burst activity, in brook trout (Salvelinus fontinalis). The immune-complex mediated hypersensitivity reported to occur with BKD has considerable ramifications for control measures involving immunostimulation via antigen exposure. Further investigation is warranted to discern the significance and consistency of immunological hypersensivity in BKD pathogenesis. Chapter 4 examines the renal lesions, including immunopathologic changes and indications of immune-mediated disease, of brook trout exposed to R. salmoninarum. / Ph. D.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2002. / Härtill 4 uppsatser.

Thesis (Ph. D.)--Oregon State University, 2011. / Printout. Includes bibliographical references (leaves 126-139). Also available on the World Wide Web.