Bibhuti N Singh, Ph.D. Associate Professor, Biochemistry and Molecular Biology 1283 Weiskotten Hall Upstate Medical University 750 East Adams Street Syracuse, NY 13210 (315) 464-5398

Research Program and Department Affiliations

Research Abstract

Pathobiochemistry of Trichomonads: Trichomoniasis. With D. Beach, G. Elia and R. Gilbert

The trichomonad parasites Trichomonas vaginalis and Tritrichomonas foetus cause major sexually transmitted diseases (trichomoniasis) in humans and cattle, respectively. The ability of parasites to adhere to host cells plays an integral role in establishing infections. Such interactions may be mediated by cell surface glycoconjugates. The trichomonads possess novel lipophosphoglycan (LPG)-like glycoconjugates anchored on the cell surface (2-3x10⁶ copies of LPG/parasite), via an inositol-linked phosphoceramide. These molecules are antigenically unique and thus are ideal candidate antigens for development of a diagnostic test. Since trichomonads parasitize vaginal epithelial cells (VECs), we are investigating the interactions of parasites to VECs in vitro. Bovine trichomoniasis causes considerable economic loss in the U.S. as well as in other parts of the world. In cows, the disease is associated with infertility, endometritis, abortion and sometimes pyometra. We have been able to culture bovine VECs successfully in our laboratory to study host/parasite interactions in detail. Our results suggest that TF-LPG mediates the adhesion of parasites to BVECs. At present, we are investigating the biochemical / immunological nature of LPG and its relationships to other glycosylated adhesion antigens in order to define the pathobiochemistry of parasite.

T. vaginalis is the most common cause of vaginitis in women, and has been linked to several major pathological symptoms, such as severe vaginal inflammation and irritation, infertility, preterm delivery, invasive cervical carcinoma and increased susceptibility to human immunodeficient virus (HIV) infection. T. vaginalis may also serve as "vector" for other pathogenic organisms such as human papillomavirus and herpes simplex virus type-2. The specific objectives are a) to establish in vitro culture of human VECs to study the involvement of the LPG-like components in adhesion / invasion of T. vaginalis to HVECs; and, b) to define the biochemical/immunological nature of TV-LPG-like glycoconjugates. These studies will provide essential knowledge of the structure/function relationships of LPG-like glycoconjugates and will lead to a better understanding of the molecular mechanisms of pathogenesis involved in host-parasite interactions. Furthermore, the establishment of human VEC cultures will have significant implications in studying other disease processes in women.

Role of Glycosylated Antigen in Chlamydia Pathogenesis. With L. Stuart.

Chlamydia trachomatis is the leading cause of infectious blindness, and sexually transmitted disease, including non-gonoccocal urethritis and pelvic inflammatory disease and infertility. Recent research indicates that chlamydial infection may also be responsible for atherosclerosis and joint disorders. A genus-specific glycosylated antigen has been isolated from the supernatant of chlamydial infected cultures and named the exoglycolipid antigen (GLXA). This antigen is completely different from lipopolysaccharide (LPS). Studies have shown that a monoclonal anti-idiotypic antibody to the chlamydial GLXA in murine model of ocular chlamydial infection induced systemic immunity, which prevented clinical infection. Serum antibody from patients infected with either C. trachomatis, C. psittaci, or C. pneumoniae reacts strongly with GLXA. The main objective of our research is to define the biochemical/immunological nature of this chlamydial GLXA that will lead to a better understanding of the molecular mechanism of chlamydial pathogenesis.

Selected References

Singh, B.N. Lipophosphoglycan-like glycoconjugates of Tritrichomonas foetus and Trichomonas vaginalis. Mol. Biochem. Parasitol. 57:281-294, 1993.

Shaia, C.I., J.Voyich, S.J. Gillis, B.N. Singh and D.E. Burgess. Purification and expression of the Tf 190 adhesin in Tritrichomonas foetus. Infect. Immun. 66:1100-1105, 1998.

This profile was last updated on 12/05/2002

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