Members of the family Chlamydiae cause a wide range of diseases.
Chlamydia trachomatis and C. pneumoniae are most commonly associated with
human disease. C. psittaci and C. pecorum are largely animal pathogens, although
C. psittaci can cause pneumonia in the elderly and immunocompromised. A
vaccine against these pathogens is desirable, but although multiple vaccine
regimens have been examined, none have proven truly effective.
Studies were conducted to evaluate the use of recombinant vaccinia virus
(VV) vectors encoding chlamydial proteins as vaccine candidates using a guinea
pig model. In the first study, guinea pigs were immunized with varying amounts of
attenuated VV encoding either the M6 protein of Streptococcus pyogenes or
chloramphenicol acetyl transferase (CAT) from E. coli. The purpose of this study
was: (1) determine how much attenuated virus can be given intranasally to guinea
pigs without causing death; (2) characterize the humoral and secretory antibody
response to both the viral vector and M6 protein; and (3) develop a protocol for
animal manipulation, and sample collection and storage for use in future research.
The results obtained indicate that 10⁹ PFU of attenuated VV can be given
intranasally to guinea pigs. Serum IgG was detected against VV proteins, as
determined by immunoblotting. Antibodies against M6 could not be similarly
detected in serum, or by direct enzyme linked immunosorbant assay (ELISA). IgG
could not be detected by immunoblotting against either VV or M6 in saliva.
The purpose of the second part of this research was to evaluate the potential
efficacy of a vaccine using the C. psittaci guinea pig inclusion conjunctivitis
(GPIC) strain proteins IncA and TroA. Guinea pigs were immunized intranasally
with either PBS, control vaccinia virus, rVV:IncA, or rVV:TroA. Three weeks
after immunization animals were challenged by ocular infection with C. psittaci
elementary bodies (EBs). Eye swabs were taken following challenge and titered to
determine the chlamydial load.
Results indicate that rVV:TroA provides no protection against chlamydial
challenge. Titers from rVV:IncA immunized animals appeared to be somewhat
lower than those of the controls on day 4 post-challenge. This difference, however,
proved not to be statistically significant. A single immunization with rVV:IncA or
rVV:TroA was thus shown not lead to a protective immune response in guinea pigs
under the conditions tested. / Graduation date: 2002
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28803 |
| Date | 27 June 2001 |
| Creators | Werth, Eric P. |
| Contributors | Rockey, Daniel D., Hruby, Dennis E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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