Biomedical Engineering Reference
In-Depth Information
a
b
2
3.5
λ i / σ i =1
λ i / σ i =1/ λ i
λ i / σ i =1
λ i / σ i =1/ λ i
3
1.5
2.5
2
1
1.5
1
0.5
0.5
0 0
0
1
2
3
0
1
2
3
Expression rate
Expression rate
Fig. 10 Optimal number of epitopes as a function of the expression rate. ( a ) Asynchronous model.
The virus budding time is normalized to 1. The early stage optimal solution is presented for a
set of ten proteins, each with a different expression rate:
λ i =
3
0
.
3
(
i
1
)
;1
i
10. Two
saturation levels are considered: a constant saturation level ( full line ):
λ
/ σ
=
1 and a saturation
i
i
level that is inversely proportional to expression rate ( dashed line ):
λ
/ σ
=
1
/ λ
i . The total epitope
i
i
5. The initial lymphocyte clone size was arbitrarily set to T i 0
number is C
=
=
1. The initial protein
concentration was x i 0
1. The optimization was solved analytically according to expression
( 10 ). In the two cases, early expressed proteins have a lower expected number of epitopes. ( b )
Synchronous model. The presented results follow the assumptions used for the asynchronous
model. The results follow the trend of the asynchronous stage, with the exception that the epitope
number can be zero for some of the proteins
=
0
.
This analysis represents the combined analysis of a large number of viruses and
represents an example of real-time evolution. The conclusions from this analysis
go beyond viral dynamics to the combination of elements in evolutionary compu-
tations. The proposed model can be expanded to other more complex evolutionary
scenario. The main advantages of the viral dynamics analysis are the high mutation
rate of viruses and their short life cycle. In contrast with other organisms, viruses
may have actually reached their optimal properties.
References
1. Abendroth, A., Arvin, A.: Varicella-zoster virus immune evasion. Immunol. Rev. 168 , 143-156
(1999)
2. Abendroth, A., Arvin, A.: Immune evasion mechanisms of varicella-zoster virus. Arch. Virol.
Suppl. (17), 99-107 (2001)
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