Induction of intradermal skin reactions in the bovine by fractionated proteins of Hypoderma lineatum.

Protein species found in crude extracts of Hypoderma lineatum (Villers) 1st-instar gullet-stage larval homogenates were fractionated by chromatography and further identified by conventional polyacrylamide gel electrophoresis (PAGE) and SDS/PAGE techniques. Seven major fractions were resolved by ion exchange chromatography. Conventional PAGE of the crude antigen preparation revealed a minimum of 14 protein species, while SDS/PAGE revealed 3 major protein species. The ability to elicit cutaneous reactivity by isolated proteins was determined by the intradermal skin test. An immediate-type hypersensitivity reaction was elicited in the skin of vaccinated and previously infested animals by the components of the 4 protein fractions tested. Only one protein fraction, fraction 4, elicited an apparent delayed reaction at 48 h in vaccinated and previously infested animals. A non-specific background reaction was elicited in control animals by the fractionated proteins and was most notable between 1- and 4-h post-injection.