This paper analyzes the role of neutral viruses in the phenomenon of local immunodeficiency. We show that, even in the absence of altruistic viruses, neutral viruses can support the existence of persistent viruses and thus local immunodeficiency. However, in all such cases neutral viruses can maintain only bounded (relatively small) concentration of persistent viruses. Moreover, in all such cases the state of local immunodeficiency could only be marginally stable, while it is known that altruistic viruses can maintain stable local immunodeficiency. We also present an absolutely minimal cross-immunoreactivity network where a stable and robust state of local immunodeficiency can be maintained. It is now a challenge to synthetic biology to build such small networks with stable local immunodeficiency. Another important challenge for biology is to understand which types of viruses can play a role of persistent, altruistic and neutral ones and whether a role which a given virus plays depends on the structure (topology) of a given cross-immunoreactivity network.

中文翻译：

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局部免疫缺陷：中性病毒的作用

本文分析了中性病毒在局部免疫缺陷现象中的作用。我们表明，即使没有利他病毒，中性病毒也可以支持持久性病毒的存在，从而支持局部免疫缺陷。然而，在所有这些情况下，中性病毒只能维持有限（相对较小）浓度的持久性病毒。此外，在所有这些情况下，局部免疫缺陷的状态只能勉强稳定，而众所周知，利他病毒可以维持稳定的局部免疫缺陷。我们还提出了一个绝对最小的交叉免疫反应网络，可以保持局部免疫缺陷的稳定和稳健状态。现在，构建具有稳定局部免疫缺陷的小型网络对合成生物学来说是一个挑战。