Abstracts (complete list) - Wissenschaft Online

Nina Wantia, Tanja Ertl, Christine Cirl, Nuria Rodriguez, Hermann Wagner, Thomas
Miethke
Development of a protein and CpG-based vaccination against
Chlamydophila pneumoniae
Chlamydophila pneumoniae induces a pneumonia in C57/BL6 mice after nasal
application of 1,75x10 6 IFU (infectious units). Six days after infection the mice were
sacrificed, and chlamydial burden was measured in cell culture and by real-time PCR.
First we investigated whether protection is achievable, hence mice were low-dose
(0,5x10 6 IFU) infected three weeks before standard infection with 1,75x10 6 IFU. They
hardly lost weight and showed no clinical signs of infection. Chlamydial burden was
reduced to 0,2% in these mice compared to control mice. When we examined lung T
cells of these mice, we could show that after restimulation with infected dendritic cells
17,2% of CD4 + cells were IFN-γ positive (mock-infected mice: 0,055%). IFN-γ
producing T cells are known to be protective against chlamydial infection.
To generate a protective immunity against Cp. pneumoniae we tested several different
chlamydial proteins. Membrane proteins of Cp. pneumoniae are accessible to the
immune system and polymorphic membrane proteins (PMP) have been of
immunological interest recently. Although the exact function of this new protein family
is still unknown, it is known that they are able to induce neutralizing antibodies in
Chlamydia trachomatis and are promising candidates for vaccination, especially PMP21
and PMP10 and 11 are auspicious for protective vaccination.
Protein and CpG 1826 were injected subcutaneously, followed by the infectious
challenge three weeks later. Vaccination with OMP2 reduced chlamyidal burden to
10,0% compared to correspondig control mice. PMP21 could even decrease chlamydial
burden to 4,6%, whereas weight loss and lung weight was just slightly decreased in
both cases. To induce better protection including less weight loss and lung weight we
trapped the proteins in a organic polymer of Poly-DL-lactide-co-glycolide. This polymer
was shown to release the antigen slowly into the cell and induces robust T cell
responses.