http://hdl.handle.net/1903/2762 2013-05-25T15:19:50Z http://hdl.handle.net/1903/13577 Title: Review of the Molecular Biology and Epidemiology of Infectious Laryngotracheitis (Gallid Herpesvirus-1) Authors: Menendez, Kimberly Rae Abstract: A review of the molecular biology and epidemiology of avian infectious laryngotracheitis (ILT) is conducted due to the outdated state of current ILT review material. The objective of this review is to include updated information on the molecular biology of Gallid herpesvirus 1 (GaHV-1), the causative agent of ILT, and to present the latest information on the molecular epidemiology of ILT. Recent developments in molecular biology specific to GaHV-1 have been made and are highlighted in this review, and the role of current and historical use of live-attenuated vaccines is associated with the global and molecular epidemiology of ILT. Also, target genes for detection and strain differentiation are compiled by region of the world, and the global distribution of ILT is illustrated. Additionally, the field of epigenetics related to virus-host interactions is reviewed, and the molecular, epidemiologic, and epigenetic factors investigated are related to prospects for future eradication of ILT. 2012-01-01T00:00:00Z http://hdl.handle.net/1903/13504 Title: ROLE OF FUSION PROTEIN IN NEWCASTLE DISEASE VIRUS PATHOGENESIS Authors: Samal, Sweety Abstract: The fusion (F) protein of Newcastle disease virus (NDV) is a type I membrane glycoprotein that mediates the merger of the viral envelope to the host cell membrane. The F protein activation initiates a series of conformational changes in the F protein leading to membrane merge which occurs at the cell surface at neutral pH thus modulating NDV entry and spread. The present studies have given an insight to understand the role of F protein in NDV pathogenesis by using established reverse genetic techniques. The F gene of NDV has six glycosylation sites, two of which are present in heptad repeats that facilitate conformational changes during fusion process. To understand the importance of the glycosylation sites in NDV replication and virulence, each site was eliminated individually and in combination on a cDNA clone of NDV strain BC. Our results suggest that glycosylation of F protein plays a major role in virulence and some of the N-glycosylation sites are critical for fusogenicity of the F protein thus modulating NDV infectivity. The F protein is synthesized as an inactive precursor, F0, which is only fusogenic after cleavage into disulfide-linked F1 and F2 polypeptides by host cell proteases. The amino acid sequence surrounding the F protein cleavage site determines the virulence of NDV, since different host proteases that cleave the F protein of virulent strains are present in more tissues than those that cleave the F protein of non-virulent strains. The role of conserved glutamine residue in NDV F protein cleavage site in viral pathogenesis has been examined. This study has helped us to understand the requirement of F protein cleavage site conserved amino acids in proteolytic processing and viral infectivity. Further in this study, the role of F protein cytoplasmic domain and conserved cysteine residues in viral pathogenesis have been explored using reverse genetics. These regions have been suggested to play important roles in F protein conformation, stability and thus affecting the fusion process and viral infectivity. In summary, the purpose of this work is to determine the important domains and residues of the NDV F protein that facilitates fusion process and regulates viral pathogenesis and immunogenicity. An understanding of how NDV F protein fusion process are regulated may lead to the creation of more effective therapies and better vaccine against NDV and other paramyxoviruses in general. 2012-01-01T00:00:00Z http://hdl.handle.net/1903/13084 Title: CD23 MEDIATED IGE TRANSCYTOSIS IN AIRWAY INFLAMMATION Authors: Palaniyandi, Senthilkumar Abstract: CD23 (FceRII), a C-type lectin type II membrane glycoprotein, plays an important role in IgE homeostasis and development of allergic inflammation. I showed that CD23 was constitutively expressed in the established or primary human airway epithelial cells and its expression was significantly up-regulated by IL-4 stimulation. In a transcytosis assay, human IgE or IgE derived immune complex was transported and enhanced by IL-4 stimulation across a polarized Calu-3 monolayer. A CD23 specific antibody or soluble CD23 significantly reduced the transcytosis, suggesting a specific receptor-mediated transport by CD23. Transcytosis of both IgE and the immune complex was further verified in primary human airway epithelial cell monolayers. Furthermore, the transcytosed antigen-IgE complexes were competent in inducing degranulation of the cultured human mast cells. This study implies CD23-mediated IgE transcytosis in human airway epithelial cells may play a critical role in initiating and contributing to the perpetuation of airway allergic inflammation. To verify the above results in a mouse model, CD23 expression was detected in epithelial cells lining mouse airway and enhanced by IL-4 exposure as well as in ovalbumin (OVA) sensitized mouse. I showed that CD23 transported IgE and OVA-IgE derived immune complex across airway epithelial cells in wild-type, but not CD23 knockout (KO), mice. The chimeric CD23KO mice repopulated with wild-type myeloid cells, sensitized and challenged with OVA showed significant reduction in siglec-F+ cells, eosinophils, macrophages and IL-4 in bronchoalveolar lavage fluid recovered 24 hours later compared to the wild-type mice. Our finding of CD23-mediated IgE transport in airway epithelial cells suggest a possibility of CD23 transporting an IgE Fc-fused protein for immunotherapy. CTLA-4 (Cytotoxic T-Lymphocyte Antigen 4) which competitively binds CD80 and CD86 expressed on antigen presenting cells and inhibits CD28 mediated co-stimulation of T cell activation. A CTLA4-Fc (IgE) fusion protein produced in Chinese hamster ovary cells was intranasally administrated into mouse airway for assessing its specific transport by CD23. The effect of this fusion protein on the development of allergic inflammation is being fully investigated in wild-type, CD23-KO, and chimeric mouse model. 2012-01-01T00:00:00Z http://hdl.handle.net/1903/13081 Title: DETERMINATION OF GENETIC FACTORS INVOLVED IN THE VIRULENCE OF NEWCASTLE DISEASE VIRUS Authors: Paldurai, Anandan Abstract: Newcastle disease is economically the most important disease of poultry. The causative agent Newcastle disease virus (NDV) is a large, enveloped virus containing single stranded non-segmented negative-sense RNA genome. The genome of NDV contains six genes in the order of 3'Leader-N-P-M-F-HN-L-5'Trailer. NDV has at least three different genome size categories: 15,186, 15,192 and 15,198 nucleotides (nt) in length. The virulence of NDV is considered to be contributed by multiple genes. The importance of genome lengths and the roles of individual genes in virulence of NDV in its natural host, chickens, have not been determined. In this study, the effects of naturally occurring nucleotide insertions in NDV genome and roles of individual genes in the virulence of NDV in chickens were determined. To achieve this goal, reverse genetic systems for two strains of NDV were established for a highly virulent strain Texas GB (GBT) and a moderately virulent strain Beaudette C (BC). Both GBT and BC are isolated from chickens and belong to genotype II of class II NDV strains and have the genome length of 15,186 nt. The 6- and 12-nt insertions in the backbones of rBC and rGBT showed little attenuation in virus replication and in pathogenicity of the parental recombinant viruses. The reciprocal swap between NDV strains BC and GBT for the genes, nucleocapsid protein (N), phosphoprotein (P), matrix protein (M), fusion protein (F), hemagglutinin-neuraminidase protein (HN) and large polymerase (L) protein genes, showed that F protein gene is most important for NDV virulence, followed by the L protein gene. M, HN, N and P genes appeared not to affect the pathotypes of their parental recombinant viruses in chickens. The observations of the present study paves the way for future directions: to use the naturally occurring insertion site in the coding region of the phosphoprotein gene for insertion of potential marker sequences; to determine the amino acid residues important in fusion protein and polymerase protein for replication and pathogenesis of NDV. 2012-01-01T00:00:00Z