Research Assistant Professor
DVM, PhD, ACVM-Diplomate
My main research interests are the development and application of antiviral agents against the infection of various viruses including rotaviruses in food animals and humans and important pathogenic viruses in small animals. Rotaviruses (group A rotaviruses) are the most important cause of severe gastroenteritis in infants and children worldwide, responsible for over 500,000 deaths in children younger than 5 years of age, majority of them occurring in developing countries. The burden of disease, however, is also present in developed countries such as the U.S. where it is estimated that rotavirus is associated with approximately 5 % of all childhood hospitalizations. Also in calves, group A rotaviruses are one of the major causes of diarrhea, incurring up to 500 million dollars annual losses in North America. Although rotavirus vaccines for human uses are available for public use, their efficacy for heterotypical (different serotypes) protection and long term immunity are limited. In addition, limited availability of vaccines and vaccine failure also occur. However, there are no specific antivirals available for rotavirus infection, and information regarding therapeutic targets for antiviral development is limited. Therefore the development of novel antivirals effective for multiple serotypes is highly desirable to reduce the fatality and help minimize the length of rotavirus-associated hospitalization. Our research is focused on screening various compounds for their antiviral effects on important viral diseases and study to elucidate their mechanisms of actions, leading to antiviral drug development.
Y. Kim and K.O. Chang. Porcine enteric caliciviruses. Caliciviruses. Horizon Scientific Press. Book Chapter, In printing (2009).
K.O. Chang and Y. Kim. Reverse Genetics System and Replicon system of Caliciviruses. Caliciviruses, Horizon Scientific Press. Book Chaper, In printing (2009).
Chang, K.O., Sosnovtsev, S.V., Belliot, G., Kim, Y., Saif, L.J., and Green K.Y. Bile acids are essential for porcine enteric calicivirus replication in association with down-regulation of Stat1. Proc Natl Acad Sci USA. 101(23): 8733-8738 (2004)
Azevedo, M.S., Yuan, L., Iosef, C., Chang, K.O., Kim, Y., Nguyen, T.V., and Saif, L.J. Magnitude of serum and intestinal antibody responses induced by sequential replicating and nonreplicating retovirus vaccines in gnotobiotic pigs and correlation with protection. Clin Diag Lab Immunol 11(1): 12-20 (2004)
Nguyen, T.V., Iosef, C., Jeong, K., Kim, Y., Chang, K.O., Lovgren-Bengtsson, K., Morein, B,. Azevedo, M.S., Lewis, P., Nielsen, P., Yuan, L., and Saif, L.J.Protection and antibody responses by oral priming by attenuated human rotavirus followed by oral boosting with 2/6-rotavirus-like particles with immunostimulating complexes in gnotobiotic pigs. Vaccine 21(25-26): 4059-70 (2003)
Kim, Y., Chang, K.O., Kim, W.Y., and Saif, L.J. Production of hybrid double- or triple-layered virus-like particles of group A and C rotaviruses using a baculovirus expression system. Virology 302 (1): 1-8 (2002)
Kim, Y., Nielsen, P.R. Hodgins, D, Chang, K.O., and Saif L.J. Lactogenic antibody responses in cows vaccinated with recombinant bovine rotavirus-like-particles (VLPs) of two serotypes or inactivated bovine rotavirus vaccines. Vaccine 20(7-8):1248-58 (2002)
Chang K.O., Kim, Y., Green, K.Y., and Saif, L.J. Cell-culture propagation of porcine enteric calicivirus mediated by intestinal contents is dependent on the cyclic AMP signaling pathway. Virology 304(2): 302-10 (2002)
Iosef, C., Nguyen, T.V., Jeong, K.I., Kim, Y., Chang, K.O., Lovgren-Bengssor, K., Morein, B., Azevedo, M.S.P., Yuan, L., Nielsen, P., Lewis, P., and Saif, L.J. Systemic and intestinal antibody secreting cell responses in gnotobiotic pigs immunized per oral with Wa attenuated human rotavirus (HRV) and Wa 2/6-rotavirus-like-particles associated with immuno-stimulating complexes.Vaccine 20(13-14):1741-53 (2002)
Yuan, L., Geyer, A., Quan, Y., Iosef, C., Azevedo, M., Kim, Y., Chang, K.O., and Saif, L.J. Protective immunity and antibody-secreting cell responses elicited by combined oral attenuated Wa human rotavirus and intranasal administration of 2/6-VLPs with mutant Escherichia coli heat-labile toxin (LT-R192G) in gnotobiotic pigs. J Virol 75(19):9229-38 (2001)
Kim, Y., Chang, K.O., and Saif, L.J. Characterization of group C rotaviruses associated with diarrhea outbreaks in feeder pigs. J Clin Microbiol 37(5):1484-1489 (1999).
Chang, K.O, Kim, Y., and Saif, L.J. Comparisons of nucleotide and deduced amino acid sequences of NSP4 genes of attenuated and virulent group A and C rotaviruses. Virus Genes 18(3):229-33 (1999)