Immunological cross-reactivity between salivary gland proteins of Hyalomma anatolicum anatolicum and Boophilus microplus ticks

Immunological cross-reactivity was established between salivary gland extract antigens of Hyalomma anatolicum anatolicum (H.a.a) and Boophilus microplus (B.m.), using native-polyacrylamide gel electrophoresis (native-PAGE), immunoblotting, DOT-enzyme immunoassay (DOT-EIA) and in vivo intra-dermal skin test revealing immediate type hypersensitivity swelling reaction. Native-PAGE revealed six proteins in common of molecular weights of 60, 66, 148, 264, 300 and > 300 kDa in the salivary gland extract (SGE) of both the ticks. Four additional bands of molecular weights of 56, 64, 120 and 220 kDa were present in H.a.a. but absent in B.m. Immunoblot assay of native-PAGE transblotted proteins of H.a.a., using mice anti-H.a.a. SGE and anti-B.m. SGE immune serum revealed a common protein of 66 kDa. In DOT-EIA, anti-H.a.a. or anti-B.m. SGE immune serum gave similar antibody titres against the SGE antigens of either tick species. Intradermal inoculation of the SGE antigens of either species on cross-bred calves (Bos indicus × Bos taurus) immunized to H.a.a. or B.m. ticks produced a strong, immediate hypersensitivity skin swelling reaction.