Determination of simian immunodeficiency virus production by infected activated and resting cells.

OBJECTIVE: To determine the relative amount of virus produced by activated and resting CD4+ T cells. DESIGN: The total quantity of virus produced by an activated cell relative to a resting cell in vivo was estimated from 'snap-shots' of virus production by infected cells at one time point. METHODS: Bayesian statistical methods were used to determine a credible interval for the desired ratio. RESULTS: The posterior mean of the ratio of virus produced by a typical activated cell to a typical resting cell is 0.82 to 4.28, depending on the half-lives of the resting infected cells. Simian immunodeficiency virus-infected resting cells could accordingly be responsible for 70 to 93% of peak virus production in the acute stage of infection. CONCLUSIONS: Whereas in 'snap-shots' the infected resting cells apparently produce much less virus than infected activated CD4+ T cells, the coincidence of peak SIV production with predominant infection of resting cells along with longer half-lives for productively infected resting cells point to a major contribution to virus production in early infection.