Effect of feeding Stomoxys calcitrans (DIPTERA: MUSCIDAE) with blood from Bos taurus immunized with concealed antigens from the stable fly on the oviposition

Abstract

THE AIM OF THE PRESENT STUDY WAS TO EVALUATE THE EFFECT OF THE ANTIBODIES PRESENT IN BLOOD FROM BOS TAURUS IMMUNIZED WITH CONCEALED ANTIGENS FROM STOMOXYS CALCITRANS INTESTINE ON THE ADULT FL Y SURVIVAL OR ON THE OVIPOSITION CAPACITY. FIVE THOUSAND INTESTINES WERE COLLECTED FROM ADULT STABLE FL IES RECENTLY FED ON BOVINE NORMAL BLOOD TO PREPARE AN ANTIGENIC EXTRACT (AGIN-SC). A BOVINE WAS IMMUNIZED WITH AGIN-SC IN FREUND'S INCOMPLETE ADJUVANT ON DAYS 0, 14, 21, 28, 35 AND 40. ANOTHER BOVINE (CONTROL) WAS INOCULATED WITH SALINE SOLUTION ON THE SAME DATES. AT DAYS 40 AND 50 PERIPHERAL BLOOD WAS COLLECTED FROM THE TWO ANIMALS. SERUM WAS OBTAINED FROM ONE PART OF BLOOD AND FROZEN IN ALIQUOTS AT -70°C UNTIL USED, THE OTHER PART OF BLOOD WAS MAINTAINED IN SODIUM CITRATE AT 2% AND KEPT AT 4°C. BATCHES OF 200 RECENTLY EMERGED S. CALCITRANS FL IES/BOVINE WERE FED WITH THIS BLOOD DURING ONE WEEK AND MAINTAINED UNDER LABORATORY CONDITIONS. DURING DAYS 40 AND 50 POST-IMMUNIZATION, THREE DAILY OBSERVATIONS WERE PRACTICED TO EVALUATE FL Y MORTALITY AND NUMBER OF OVIPOSITED EGGS (OE). THERE WAS NO EFFECT ON SURVIVAL OF FL IES FED ON BLOOD FROM THE IMMUNIZED BOVINE; HOWEVER, OVIPOSITION WAS REDUCED. THERE WAS A SIGNIFICANT REDUCTION IN THE NUMBER OF OE, WHICH OSCILLATED BETWEEN 29% (P < 0.05, BLOOD FROM DAY 40) AND 65% (P < 0.01, BLOOD FROM DAY 50) IN RELATION TO THE NUMBER OF OE BY FL IES FED ON BLOOD FROM THE CONTROL ANIMAL. BY ELISA, THE IGG ANTI-INTESTINE ANTIBODY TITERS IN THE SERUM FROM THE IMMUNIZED ANIMAL WERE OF 1:1280 AND 1:2560 FOR DAYS 40 AND 50, RESPECTIVELY; WHILE, ON THE SAME DAYS, IN THE SERUM FROM THE CONTROL BOVINE WAS NEGATIVE TO SUCH ANTIBODIES. BY WESTERN BLOT, SERUM OF DAY 50 RECOGNIZED SEVEN COMPONENTS IN THE AGIN-SC WITH APPARENT MOLECULAR WEIGHTS WHICH RANGED BETWEEN 35 AND 205 KILODALTONS. ON THE BASIS OF THESE RESULTS, IT IS CONCLUDED THAT THE IMMUNIZATION PROCEDURE GENERATED THE PRODUCTION OF IGG ANTI-INTESTINE ANTIBODIES WHICH DID NOT AFFECT FL Y SURVIVAL; HOWEVER, THESE ANTIBODIES REDUCED THE NUMBER OF OE.