Department of Mathematics, Southern Methodist University, Dallas, TX 75275-0156, USA.
J Biol Dyn. 2012;6:333-57. doi: 10.1080/17513758.2011.582169. Epub 2011 Jun 1.
We consider a deterministic intra-host model for Plasmodium falciparum (Pf) malaria infection, which accounts for antigenic variation between n clonal variants of PfEMP1 and the corresponding host immune response (IR). Specifically, the model separates the IR into two components, specific and cross-reactive, respectively, in order to demonstrate that the latter can be a mechanism for the sequential appearance of variants observed in actual Pf infections. We show that a strong variant-specific IR relative to the cross-reactive IR favours the asynchronous oscillations (sequential dominance) over the synchronous oscillations in a number of ways. The decay rate of asynchronous oscillations is smaller than that for the synchronous oscillations, allowing for the parasite to survive longer. With the introduction of a delay in the stimulation of the IR, we show that only a small delay is necessary to cause persistent asynchronous oscillations and that a strong variant-specific IR increases the amplitude of the asynchronous oscillations.
我们考虑了一种针对恶性疟原虫（Pf）疟疾感染的确定性宿主内模型，该模型考虑了 PfEMP1 的 n 个克隆变体之间的抗原变异和相应的宿主免疫反应（IR）。具体来说，该模型将 IR 分为两个组成部分，分别为特异性和交叉反应性，以证明后者可能是实际 Pf 感染中观察到的变体顺序出现的机制。我们表明，相对于交叉反应性 IR，较强的变体特异性 IR 以多种方式有利于异步振荡（顺序优势）而不是同步振荡。异步振荡的衰减率小于同步振荡的衰减率，从而使寄生虫能够存活更长时间。通过在刺激 IR 时引入延迟，我们表明仅需很小的延迟即可引起持续的异步振荡，并且较强的变体特异性 IR 会增加异步振荡的幅度。
