CD8A and infection: A model in which CD8+ T cells are assumed to kill infected cells typically has the following form:where T* is the number of virus-infected cells, V is viral load, β is the infection rate, T is the number of uninfected target cells, E is the number of virus-specific CD8+ T cells, k is the rate of CD8+ T cell killing, and δ is the (CD8+ T cell-independent) death rate of infected cells.