Crosstalk between the immune, endocrine, and nervous systems in immunotoxicology

Abstract

The interconnected nature of the endocrine, immune and nervous systems has been well established. The central nervous system innervates the primary and secondary immune organs and the endocrine glands through direct axonal contact. Hormonal signals from the endocrine system influence both the nervous and immune systems with differential effects based on sex and environmental exposures. Immune cells can communicate by either cytokine or neurotransmitter release to signal the endocrine, gastrointestinal, and nervous systems. This review focuses on the effects of environmental toxicants on the inter-play between these systems with inclusion of effects from the microbiome and exposome. Endocrine disrupting chemicals and xenoestrogenic compounds affect the hypothalamic-pituitary-adrenal or gonadal axis, which can lead to hormonal alterations of communication between the nervous and immune systems. Immune responses within the nervous system and the delicate balance between appropriate response to infection/disease and detrimental effects through inappropriate response are discussed. Environmental chemicals, maternal immune activation, the microbiome, post-traumatic stress disorder and traumatic brain injury are all discussed in relation to alteration of immune–neuroendocrine communications and immune responses to environmental cues.