Tick attachment cement – reviewing the mysteries of a biological skin plug system

Abstract

The majority of ticks in the family Ixodidae secrete a substance anchoring their mouthparts to the host skin. This substance is termed cement. It has adhesive properties and seals the lesion during feeding. The particular chemical composition and the curing process of the cement are unclear. This review summarizes the literature, starting with a historical overview, briefly introducing the different hypotheses on the origin of the adhesive and how the tick salivary glands have been identified as its source. Details on the sequence of cement deposition, the curing process and detachment are provided. Other possible functions of the cement, such as protection from the host immune system and antimicrobial properties, are presented. Histochemical and ultrastructural data of the intracellular granules in the salivary gland cells, as well as the secreted cement, suggest that proteins constitute the main material, with biochemical data revealing glycine to be the dominant amino acid. Applied methods and their restrictions are discussed. Tick cement is compared with adhesives of other animals such as barnacles, mussels and sea urchins. Finally, we address the potential of tick cement for the field of biomaterial research and in particular for medical applications in future.

Wonders of tick saliva

“…This quickly polymerises to form a solid cement cone that acts as a gasket preventing loss of any fluids, and a holdfast securing the mouthparts and enabling the tick to remain attached for many days. Several other functions have been attributed to the cement cone including an antibacterial role [reviewed by (Suppan et al, 2018)]. The observation bioactive saliva molecules may stick to the cement cone, e.g.…”

“…in embryo development (Leal et al, 2018). Besides its potential as an anti-tick and pathogen transmission modulating vaccine, the natural glue and sealant properties of tick cement suggest the potential for developing new medical adhesives (Suppan et al, 2018).…”

Tick and Host Derived Compounds Detected in the Cement Complex Substance

“…Cement is a complex substance secreted by most ticks of the family Ixodidae including Rhipicephalus spp. to anchor their mouthparts to the host skin [29]. The cement has not only adhesive properties but has been proposed to have a possible role in antimicrobial properties, seals the lesion during feeding, facilitates feeding and pathogen transmission, and protects ticks from host immune and inflammatory responses [22,29].…”

Three-dimensional reconstruction of the feeding apparatus of the tick Ixodes ricinus (Acari: Ixodidae): a new insight into the mechanism of blood-feeding

“…In Movie 4, we animated both the food channel and the channel for the passage of saliva with associated structures and show how these structures function. The feeding process of most ixodid ticks begins with the secretion of cement-like substances, which allows the tick to be fixed in the host skin and seals the gap between the feeding lesion and inserted mouthparts [23][24][25] . The salivation period may be ended by a brief burst of saliva [16][17][18][19] .…”