This study investigated the role of the typhoid toxin in causing the symptoms of typhoid fever. The typhoid toxin is composed of two subunits, PltA and CdtB. Through in vivo and ex vivo experiments, the administration of purified typhoid toxin to mice induced similar symptoms to typhoid fever such as fever, weight loss, and increased inflammatory cytokines. Further experiments showed that the CdtB subunit has DNase activity that can cause DNA damage in macrophages, ultimately leading to apoptosis. This helps explain the symptoms and pathogenesis of typhoid fever.

1. ISABELLA SERNA ARBELAEZ
Tercer Semestre
Universidad Pontificia Bolivariana

2. SALMONELLA
TYPHI:
What is it?
Flagellated anaerobic bacilli
(bacteria)
Gram-negative coloration
Typhoid Fever
It is commonly associated with
pathologies such as:

3. THE TYPHOID
TOXIN
What is it?
- Is a proteín compossed of two
subunits (PltA and CdtB).
Whats it's function?
- Prinicipal virulence factor
- Subunit CdtB can cause DNA damage.
It's relationship with the disese:
- Responsible for causing the symptoms
of the TYPHOID FEVER.

4. "In this study, we have further investigated the role of
typhoid toxin in the symptomatology of typhoid fever
through in-vivo and ex-vivo studies. In mice, administration
of cloned and purified typhoid toxin induces similar
symptoms observed during typhoid fever such as fever,
weight loss with a decrease in peripheral leucocyte count
along with an increase in levels of pro-inflammatory
cytokines (Il-6, TNF-α)"
GENERAL OBJETIVE

5. 2.3. Plasmid construction
and transformation
BASIS: The plasmids were
constructed including the genes
for the proteins and then they
were transferred into E.coli
host cells.
CONTEXT: They were creating
a vector able to produce the
proteins that make up the toxin
BASIS: SDS-PAGE is a technique
used to identify proteins, is an
electrophoresis.
CONTEXT: They needed to
evaluate the presence of the
proteins PltA, PltB and CdtB
METHODS
2.4. Expression and
purification of PltA, PltB
and CdtB Proteins

6. BASIS: Macrophages were
treated with different
concentrations of the typhoid
toxin and PltA-PltB, and then
they did electrophoresis
CONTEXT: They were evaluating
the DNase-like activity of the
typhoid toxin
BASIS: They performed a dual
acridine orange/ethidium bromide
(AO/EB) co-staining to visualize
nuclear changes and the forming of
apoptotic body formation.
CONTEXT: This was done to detect
apoptosis in the typhoid toxin
treated macrophages.
METHODS
2.8.2. Macrophages DNA
analysis
2.8.3. Fluorescence
microscopy

7. The construction of recombinant plasmids were confirmed in A, B and C
The SDS-PAGE of the holotoxins revealed the presence of three brands
CdtB (31kDa), PltA (28kDa) and PltB (17kDa).
RESULTS

8. RESULTS
- In both treated
groups damage in
the DNA was
observed (Smearing)
indicating nuclease
activity of the CdtB
(DNase)
- 25% and 40% of cells in the treated
groups with T.T, showed early (Bright
green or yellow) or late (Red or orange)
apoptotic fases, compared to 96% of
live cells in controll group

9. J.Song et al
"After getting internalized, CdtB might have exerted its
genotoxic activity leading to DNA damage which ultimately
induces apoptosis (shown further) of the host cells that might
be the reason behind low WBCs count in treated groups"
DISCUSSION
"Similarly, we have also reported the DNase activity of
CdtB, a subunit of typhoid toxin"
"All these observations were recorded during our study
and found in accordance with the earlier reports thereby
strengthening and suggesting the contribution of typhoid
toxin to the acute symptomatology of typhoid fever"
AUTHOR AFIRMATION AGREE OR
DISAGREE
R. Thakur et al
T. Frisan et al

10. 1
This study helps us to better understand the
symptomatology of the typhoid fever and how it's
presentations are determined by the typhoid toxin
2
This study demonstarted the role of the CdtB
subunit as the principal factor of virulence in the
typhoid toxin
CONCLUSIONS

11. THANK YOU

12. CONCEPTUAL MAP