Survey of Chlamydial Inclusion Formation in a Range of Host Species.
Presented by: Laurel.A. Hall
Dept. of Microbiology, Oregon State University
Chlamydia, an obligate intracellular parasite, is unique in its nature of inclusion formation from the general endocytosis pathway. Unfortunately, this unexplained means of infection has created a gap in knowledge of biology about this pathogen. However, a technique using an immunofluorescence microscopy allows labeling of different proteins in either the inclusion membrane or the chlamydial outer membrane. This method has allowed a more careful study of the forming of the inclusion. Using the mammalian prototype of inclusion formation in both Chlamydia trachomatis and C. psittaci, the design is to survey a variety of cell lines. The purpose is to discover how conserved is the chlamydial pathogenic route. Although sufficient conclusive data has not been produced to date, epithelioma papillosum cyprini (EPC) cells, from carpe fish, can be infected with both species and show inclusion formation at as early as 32 hours after infecfion. A greater percentage of cells seem to be infected by C. trachonatis than cells infected with C. psittaci . In addition to general infection biology, fusion formation will also be addressed when cells are infected more than once. A South Pacific snail cell line, Biomphalaria glabrata embryo, has also been infected. Results were inconclusive due to the sensitivity of the cell line to the media and temperature. The importance of how chlamydial molecular mechanisms interact with host cells is crucial to understanding pathogenesis of the bacteria and for developing prevention strategies. The direction of future research will take advantage of the chlamydial inclusion. Through a heparin-induced binding of E. coli to Chlamydia , hypothetically both bacteria will be taken into the same inclusion. Following endocytosis, conjugation, along with other biological mechanisms, should occur between the two bacteria. This would provide one more link to the mystery behind chlamydial biology.