Research Article
Karim Christina Scopinho Furqu
Abstract
This study presents the histochemical analysis of the glycoprotein, lipoprotein, enzyme (acid phosphatase) and mineral (calcium) contents of the secretion produced by salivary glands of Rhipicephalus sanguineus females fed for 2, 4 and 6 days on hosts (New Zealand White rabbits), which had been previously immunized with glandular extract obtained from 2-day fed females (SGE2). The results revealed that such glands present alterations in the secretory cycle, which occurred: a) by the inactivity of some c1 cells (in the glands of the 2-day fed females); c1 and c5 (in the glands of the 4-day fed females) and c1 and d (in the glands of the 6-day fed females), and b) by the modification in the constitution of secretion in relation to the glyco/lipoprotein, enzyme and mineral contents in the glands of 2 to 6-day fed females. Data clearly show that the most pronounced histochemical modifications were detected in 2-day fed females, since their hosts were inoculated with SGE2 extract, and therefore, developed resistance to the components of the glandular secretion present in this extract. In addition, it was verified that over the studied period (2-6 days), some cells underwent greater alterations due to the resistance acquired by the hosts, such as the f cells, demonstrating the great immunogenic capacity of the secretion synthesized by such cells, as well as the importance of the secretion in the modulation of the immune-inflammatory and hemostatic system of the host. Considering all the data obtained, this study clearly demonstrates that the modifications in the intensity of staining in the elements analyzed occurred because of different immunogenic capacities of the components present in SGE2 extract, which indicated that the greater the immunogenic capacity of the molecules present in SGE2, the greater the alterations in the cells responsible for the synthesis of such component. This study also demonstrated that the histochemical alterations here detected modified the salivary secretion, making it increasingly efficient over the process of modulation of the host, suggesting a possible compensation, or even an alternative route to overcome the resistance developed by the hosts, enabling the ectoparasites’ fixation, permanence and feeding.