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.

Arylsulfatases in fresh water snails

The biodegradation of glycosaminoglycans [GAGS] was studied in an attempt to introduce more selectively into the control of the host snails for parasitic diseases. Characterization of sulfatase acting on GAGs from Biomphalaria alexandrina, Bulinus truncatus, Physa acuta and Lymnaea cailliaudi were carried out. Cell organelles were separated from B. alexandrina 7 weeks post infected with 10 S. mansoni miracidia and noninfected snails. Acid phosphatase [APase] and arylsulfatase [ARase] activation were found mainly in the lysosomal and cytosolic fractions. Their activity increased after infection with S. mansoni miracidia. The effect of pH, substrate concentration and inhibitors on the ARase activity were examined in the four snail species. The results point to the presence of more than one form of the ARase for the following observations: [a] The presence of pH optima at 5.0-5.6 and a shoulder between 6-7. [b] Plotting initial velocity versus substrate [p-nitrocatechol sulfate] concentration did not give the typical Michaelian behaviour [concave downward]. [c] The lysosomal enzyme is more sensitive to the known ARase inhibitors [sulfate, phosphate and cyanide]. Electrophoresis of the degradation products of chondroitin sulfate by the crude extract on agarose gel indicate that the extract contain sulfatase, beta-glucocuronidase and beta-N-acetylgalactosaminidase

Extraction and purification of proteoglycans of F. Hepatica adult worm

Proteoglycans [PG] from F. hepatica were sequentially extracted using 7M GnCl, 1% Triton X-100 and 1% SDS. Uronic acid, carbohydrate and protein were detected in the extracts. The presence of PG in the three extracts was examined using agarose acrylamide gel electrophoresis. A simple reproducible procedure for the purification of the main F. hepatica proteoglycan [FPG] included chromatography on DEAE-cellulose column under dissociative condition [4M GnCl] followed by chromatography on Sepharose C1-6B. Chemical analysis [uronic acid, hexosamine sulfate, carbohydrate and protein] and immunological characterization of peaks using different sera were carried out. The second peak of DEAE cellulose column [P2] was more specific to F. hepatica hyperimmune sera compared to the other peaks. Chromatography of P2 on Sepharose C1-6B column indicated the presence of three main uronic acid peaks. The first peak [A] exhibited high cross reactivity with hyperimmune sera against S. mansoni infected sera and chronically infected sera with S. mansoni cercariae. On the contrary of this behavior, the second peak [B] was more specific to FPG. Fraction B may be considered as a pure PG and more immunogenic and specific to F. hepatica