Immunoendocrine host–parasite interactions during helminth infections: from the basic knowledge to its possible therapeutic applications

Abstract

Most of the current research on parasitic infections that affect humans and domestic animals has been focused on vaccines, diagnostic methods, epidemiology, new drug design, and recently, with the advancement of genomics and proteomics, on the evolutionary origins of parasites. However, the basic biology of many parasites of medical and veterinary importance has not been intensively studied. Some efforts have been made to obtain information on the parasite-host relationship; however, knowledge of the intricate neuroimmunoendocrine interactions of the host-parasite network, the consequences of this interaction on the host and parasite physiology, and its possible applications needs further investigation. We review here the literature, our own studies on the host-parasite neuroimmunoendocrine network, and how this basic knowledge can be used to design new treatments, by way of using hormones, antihormones, and hormone analogues as a possible novel therapy during parasitic diseases, with special emphasis on helminth parasites. Besides the biological interest, these investigations may contribute to the future identification of alternative treatments for several parasitic diseases. This complicated neuroimmunoendocrine network management during parasitic infections, and its physiological and behavioural consequences upon the host, may be operative in other mammalian infections. Such complexity may also help to explain the often conflicting results, observed between infections with respect to the role of the host sex and age, and hints to other avenues of research and strategies for their treatment and control.

In Vitro and In Vivo Effects of Tamoxifen against Larval Stage Echinococcus granulosus

“…Recent evidence revealed that estrogens can affect Taenia physiology (13,36). Within this line of evidence, the efficiency of chemoprotective TAM treatment suggests a possible role for the estrogens in Echinococcus development.…”

Endocrine Immune Interactions in the Host-Parasite Relationship: Steroid Hormones as Immune Regulators in Parasite Infections

“…In certain cases, hormones can regulate the innate immune response and the subsequent adaptive immune response [180].…”

Immunosuppression in Helminth Infection

“…Nonimmunological factors like sexual hormones, were proposed to influence the chronicity of the infection (Remoué et al, 2001). Hormones are strongly involved in immune suppression observed in stress-fully conditions which predispose to greater and longer infection or make the host susceptible to infection (Hernandez-Bello et al, 2010). Increases in gastrointestinal nematode egg production in sheep with age were greatest among individuals that had experienced the highest degree of stress (Hayward et al, 2009).…”

“…Neural pathways regulate immune response at regional, local and systemic levels through neurotransmitters and neuropeptides, and may have variable effects on immune cell activation and cytokine production. In turn, cytokines and chemokines produced both at peripheral inflammatory sites and/or locally in the CNS can modulate neural tissue function and hormonal secretion by endocrine glands (Delgado et al, 2004;Escobedo et al, 2005;Hernandez-Bello et al, 2010). One consequence of the invasion of nematode larvae is inflammation and tissue damage which provokes immunosuppression and analgesia.…”