Evaluation of glycoproteins purified from adult and larval camel ticks (Hyalomma dromedarii) as a candidate vaccine

In order to identify antigens that can help prevent camel tick infestations, three major glycoproteins (GLPs) about 97, 66 and 40 kDa in size were purified from adult and larval Egyptian ticks, Hyalomma (H.) dromedarii, using a single-step purification method with Con-A sepharose. The purified GLPs were evaluated as vaccines against camel tick infestation in rabbits. The rabbits received three intramuscular inoculations of GLPs (20 microg/animal) on days 0, 14, and 28. In the immunoblot analysis, Sera from the immunized rabbits recognized the native GLPs and other proteins from larval and adult H. dromedarii ticks along with those from other tick species such as Rhipicephalus sanguineus but not Ornithodoros moubata. The effects of immunity induced by these GLPs were determined by exposing rabbits to adult H. dromedarii ticks. These results demonstrated that GLP immunization led to a slightly decreased reproductive index and significantly reduced rates of egg hatchability. These results demonstrated that immunization with the purified GLPs can provide protection against infestation by H. dromedarii and some other tick species. Further studies are needed to confirm the effectiveness of immunization with GLPs against other tick species.

Assessment of the phospholipase A2 patterns of some Egyptian snakes venoms

Despite of the fact that functionally diverse phospholipase A2 variants of snake venoms are well characterized at the level of protein and gene sequences; the patterns of individual snake venom PLA2s are poorly known. We investigated the activity, molecular weights and isoelectric points of the phospholipase A2s of some medically important snake venoms in Egypt. Portrayal of the phospholipase A2 activity of the vipers, "Pseudocerastes persicus fieldi, Cerastes cerastes and Echis carinatus" and the elapids "Naja haje, Walterinnesia aegyptia and Naja nigricollis" venoms revealed that: 1- The elapid venoms, with the exception of Naja haje, displayed higher PLA2 activity than viper venoms; 2- The molecular weights of the phospholipase A2 variants were close to 14 kDa; 3- The major phospholipase A2s of Naja nigricollis were basic proteins while those of Walterinnesia aegyptia venom were acidic proteins; 4- The Naja nigricollis and Pseudocerastes persicus fieldi venoms possessed the highest phospholipase A2 activity while the Walterinnesia aegyptia and Pseudocerastes persicu fieldi had the highest hemolytic activity of the tested elapids and vipers, respectively; 5- The in vitro hemolytic activities of the venoms were inhibited by the heterologous antivenoms, suggesting that the venom hemolytic factor [s] have shared epitopes. The data provided biochemical information of snake venoms phospholipase A2 which allowed designing procedure for isolation of the phospholipase A2s to study their pharmacological effects

Purification and characterization of two larval glycoproteins from the cattle tick, Boophilus annulatus

The present study was conducted to identify new target immunogenic molecules from the larval stage of the cattle tick, Boophilus annulatus (Acari: Ixodidae). Two specific larval glycoproteins (GLPs) were isolated by two-step affinity chromatography. The larval immunogens were first purified with CNBr-Sepharose coupled to rabbit anti-larval immunoglobulins, and the glycoproteins were then purified with Con-A Sepharose. These glycoproteins have molecular weights of approximately 32 and 15 kDa with isoelectric points between 6.8 and 7.2. Antibodies against the two GLPs, labeled I and II, were detected in the anti-whole tick, -whole larval, and -gut antigens through immunoblot analysis. These results suggest that these GLPs are good immunogens and can be useful in the vaccination of cattle against tick infestation.