Table 1.

PTSD-relevant findings following immunization with Mycobacterium vaccae NCTC 11659

PTSD symptom based on DSM-5	Effects of M. vaccae NCTC 11659 in rodent models
Intrusions	N.A.
Avoidance (avoiding people, situations, circumstances resembling or associated with the event)	Decreased stress-induced anxiety-like defensive behavioral responses (avoidance) (Amoroso et al. 2019a, b; Frank et al. 2018; Reber et al. 2016; Loupy et al. 2021) Promotion of proactive behavioral responses to stress (Amoroso et al. 2019a, b; Frank et al. 2018; Reber et al. 2016; Loupy et al. 2021)
Negative alterations in mood and cognition	Antidepressant-like behavioral effects (Lowry et al. 2007; Siebler et al. 2018) Prevention of surgery-induced microglial priming (Fonken et al. 2018; Frank et al. 2018; Frank et al. 2019) and cognitive impairment (Fonken et al. 2018)
Alterations in arousal or reactivity (hypervigilance for threat, exaggerated startle response, irritability, difficulty concentrating, sleep problems)	Enhanced fear extinction in fear-potentiated startle (Fox et al. 2017; Hassell et al. 2019; Loupy et al. 2019) Enhanced fear extinction in models of stress-induced exaggeration of cued fear paradigms (Hassell 2019) Prevention of stress-induced cortical hyperarousal (Bowers et al. 2019) Prevention of stress-induced sleep and behavioral impairments (Bowers et al. 2021)