Immunomodulatory and morphophysiological effects of Rhipicephalus sanguineus s. l. (Acari: Ixodidae) salivary gland extracts

Author(s)

de Abreu, Marina Rodrigues ^[1] ; Pereira, Melissa Carolina ^[1] ; Simioni, Patricia Ucelli ^{[1, 2]} ; Nodari, Elen Fernanda ^[1] ; Paiatto, Lisiery Negrini ^[2] ; Camargo-Mathias, Maria Izabel ^[1]

Affiliation

^[1] Sao Paulo State Univ UNESP, Biosci Inst, Dept Biol, Ave 24 A, 1515, BR-13506900 Rio Claro, SP - Brazil

^[2] FAM, Fac Amer, Dept Biomed Sci, Americana, SP - Brazil

• Document type: Journal article
• Source: VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY; v. 207, p. 36-45, JAN 2019.
• Web of Science Citations: 2

Abstract

Rhipicephalus sanguineus s. l. is popularly known as the ``brown dog tick{''} since dogs are its preferential hosts, but the species has been reported to parasitize other mammals, including humans, with significant medical-veterinary importance since it transmits several important pathogenic agents during the feeding period. The tick saliva is a complex mixture that has several functions, including the capability to modulate the hemostatic, inflammatory and immunologic systems of the host, allowing pathogens to settle. Despite knowledge about the immunosuppressive action of tick saliva, little is known about the mechanisms involved in this process and the morphophysiological effects caused by exposure to the salivary gland extract, taking into consideration the different periods of the glandular cycle. Thus, the objective of this study was to analyze the in vitro effects of salivary gland extracts obtained from R. sanguineus s. l. females fed on host rabbits for two (SGE2 - Salivary Gland Extracts of 2 days) and four days (SGE4 - Salivary Gland Extracts of 4 days) on J774 cells (monocyte macrophage cell line) and verify the occurrence of morphological and immunomodulatory alterations in these cells when exposed to different concentrations of these extracts. The results showed that: (i) SGE2 and SGE4 at the concentration of 4 mu g/mL presented cytotoxicity to the J774 cells exposed for 24 and 48 hours; (ii) SGE2 at the concentrations of 2 mu g/mL(48-hour exposure) and 1 mu g/mL (24-hour exposure) and SGE4 at the concentrations of 2 and 1 mu g/mL (48-hour exposure) showed proinflammatory activity, confirmed by the increased secretion of NO and proinflammatory cytokine (IL-2), and the presence of morphological characteristics detected by microscopy; and (iii) SGE2 and SGE4 at the concentrations of 0.5 and 0.1 mu g/mL had immunomodulatory activity, demonstrated by decreases in the secretion of NO and proinflammatory cytokines (IL2, IL-6 and TNF-alpha) and increase in the synthesis of IL-10, confirmed by the morphophysiological analysis. These unprecedented data are extremely relevant for future research to identify the processes involved in the ectoparasite-host relationship, as well to develop more efficient tick control strategies. (AU)

• FAPESP's process: 14/02843-8 - Hematophagy in female Rhipicephalus sanguineus L. S. (Acari: Ixodidae) and its relations: biochemical (bioactive gifts in extracts) and morphophysiological (salivary gland and gut)
• Grantee: Elen Fernanda Nodari
• Support type: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 18/02999-9 - In vitro and in vivo action of ozone on embryonic lineage cells (RML RSE and RML-15) and R. sanguineus s. l. semi engorged females
• Grantee: Marina Rodrigues de Abreu
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/20258-2 - Effects of oral tolerance and tolerogenic dendritic cell administration on the immune response in experimental colitis
• Grantee: Patricia Ucelli Simioni
• Support type: Regular Research Grants
• FAPESP's process: 15/20745-6 - Tumor cell line J774 (macrophage) exposure to extract from the salivary glands of Rhipicephalus sanguineus L.S. (Acari: Ixodidae) female ticks: morphophysiological assessment
• Grantee: Melissa Carolina Pereira
• Support type: Scholarships in Brazil - Scientific Initiation