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Jaime M. Kean, Ph.D.

Garcea Lab: Human Polyomavirus



Complete Title of Thesis:

"Seroprevalence of Human Polyomaviruses and the Detection of Lymphotropic Polyomavirus DNA in Human Peripheral Blood"

Prepared under the direction of: Robert L. Garcea, M.D.



Lymphotropic polyomavirus (LPV) was first isolated in 1979 from a B-lymphoblastoid cell line derived from an African Green monkey (Med. Microbiol. Immunol., 167,137). Cellular tropism for LPV includes continuous lines of B lymphoblasts of both human and monkey origin. Antibodies to LPV are prevalent among primates. Recently, 15-25% of humans have been reported to be sero-positive for LPV (personal communication M. Pawlita; Adv Exp Med Biol, 577, 73; Kean), indicating that exposure to LPV or a virus antigenically similar to LPV (LPV-like) circulates in human populations. Furthermore,in addition to BKV and JCV, 3 new human polyomaviruses are now recognized: Kl (KIPyV), WU (WUPyV) and Merkel cell polyomavirus (MCPyV). To measure seroreactivity to the human polyomaviruses BKV, JCV, KIPyV, WUPyV, and MCPyV, and to the monkey polyomaviruses SV40 and LPV, an ELISA assay using recombinant VP1 capsid proteins was developed. To determine potential crossreactivity between
VP1 proteins, soluble heterologous VP1 pentamers were used to assess competition. To identify a tissue source for the characterization of the human LPV-like virus, PCR techniques were used to detect viral DNA in peripheral blood mononuclear cells(PBMCs) isolated from pediatric blood samples. The seroprevalence results indicate that human exposure to the 3 recently identified polyomaviruses is high. Furthermore, crossreactivity between the VP1 proteins of SV40 and BKV is frequent, however,although Kl and WU polyomaviruses and LPV and Merkel Cell polyomavirus are phylogenetically related to one another, competition assays suggest these viruses are serologically distinct. My results from the seroprevalence and PCR studies support the circulation of an LPV-like virus in the human population and the use of PBMCs from LPV sero-positive individuals as a possible source for characterizing the LPV human variant.