Immune checkpoints in viral latency

The dynamics of the relationship between the immune system and latent virus es are highly complex. Latent viruses not only avoid elimination by the hos t's primary immune response, they also remain with the host for life in the presence of strong acquired immunity, often exhibiting periodic reactivati on and recurrence from the latent state. The continual battle between reeme rgent infectious virus and immunological memory cells provides an essential virus-host regulatory loop in latency. In this review, we speculate on the critical importance of immune interference mechanisms by viruses contribut ing to the regulatory loop in viral homeostasis of latency. Central to the notion of viral homeostasis, we further invoke the concept of threshold lim its in naive and memory states of immunity to account for the failure of th e host to completely eradicate these intracellular parasites.