Circadian rhythms in immunity and host‐parasite interactions

Abstract

The mammalian immune system adheres to a 24 h circadian schedule, exhibiting daily rhythmic patterns in homeostatic immune processes, such as immune cell trafficking, as well as the inflammatory response to infection. These diurnal rhythms are driven by endogenous molecular clocks within immune cells which are hierarchically coordinated by a light‐entrained central clock in the suprachiasmatic nucleus of the hypothalamus and responsive to local rhythmic cues including temperature, hormones and feeding time. Circadian control of immunity may enable animals to anticipate daily pathogenic threat from parasites and gate the magnitude of the immune response, potentially enhancing fitness. However, parasites also strive for optimum fitness and some may have co‐evolved to benefit from host circadian timing mechanisms, possibly via the parasites’ own intrinsic molecular clocks. In this review, we summarize the current knowledge surrounding the influence of the circadian clock on the mammalian immune system and the host‐parasitic interaction. We also discuss the potential for chronotherapeutic strategies in the treatment of parasitic diseases.

Role of Melatonin in Viral, Bacterial and Parasitic Infections

“…Human African trypanosomiasis is caused by the protozoan parasites Trypanosoma brucei , and it is transmitted by the bite of the tsetse fly. The disease is also called sleeping sickness because it is associated with the disruption of the circadian rhythms, possibly because it elicits a Th1-skewed immune response [ 99 ]. However, apart from a publication showing that MLT administration restored a normal sleep pattern in rats infected with T. brucei [ 100 ], no study has defined a possible therapeutic action of MLT against the infection.…”

Introduction to biological rhythms: A brief history of chronobiology and its relevance to parasite immunology

“…Parasitic infections often show rhythmic pathology and symptom severity; a result of rhythms in parasitaemia and in host immune responses (reviewed in Refs. [ 90‐92 ]). As discussed above, Plasmodium parasites show periodicity in their replication cycle, leading to rhythms in the resulting inflammatory response and associated fever 82 .…”

Вплив Зміни Режиму Освітлення На Морфофункціональну Активність Епіфізу Та Функціональний Стан Організму

“…У темряві сигнали від супрахіазматичних ядер посилюють синтез і вивільнення норадреналіну із симпатичних закінчень. У свою чергу, цей нейромедіатор збуджує рецептори на поверхні клітин шишкоподібної залози [1,23]. Функціонально активні пінеалоцити здатні селективно зв'язувати із кровообігу амінокислоту триптофан і послідовно піддавати її гідроксилюванню та декарбоксилюванню.…”