Abortive Infection

The term abortive infection was coined in the 1950s (N/A) to describe the observations that a fraction of the bacterial population did not support phage replication. This phenomenon, also called phage exclusion, was identified in multiple systems across the following decades

and reviewed extensively (N/A, N/A, N/A) . In the following years, and through the resolution of molecular mechanisms of key defense systems such as Rex or Lit, abortive infection became synonymous with infection-induced controlled cell-death. Controlled cell death upon detection of the phage infection stops the propagation of the phage and protects the rest of the bacterial population (N/A, N/A) . Abortive infection can thus be thought of as a form of bacterial altruism.

With the recent developments in phage-defense systems and microbial immunity (see (N/A) for a review), many newly identified anti-phage defense systems are thought to function through abortive infection. Abortive defense systems often detect the phage infection at a later stage through protein sensing or the monitoring of host integrity but can also be based on nucleic acid sensing. Upon sensing, a diverse set of effectors can be used to reduce metabolism or induce cell-death (e.g., NAD+ depletion, translation interruption or membrane depolarisation). The diversity of and mechanisms of abortive infection were recently reviewed here (N/A) , while the evolutionary success of this paradoxical altruistic form of immunity has recently been discussed here (N/A) .

Although abortive infection is currently often understood as leading to cell-death, it should be noted that its original definition appeared to be broader and that some mechanisms currently included as abortive infection may only lead to metabolic stalling or dormancy.