Antigenic profile of Ixodes ricinus: effect of developmental stage, feeding time and the response of different host species.

Abstract

Antigens recognized by host species in response to ectoparasite infestation have been widely reported. Although differences in the immune responses of different host species have been described, only a very few of these studies compare the range of antigens recognized by different host species in response to infestation. We used Western blot analysis to investigate antigenic responses of different host species that were repeatedly infested with Ixodes ricinus ticks. Antigenic profiles of larval and nymphal whole tick homogenates were compared with the respective salivary gland extract (SGE) samples using sera from rabbits repeatedly infested with either adults, nymphs or larvae. SGE samples were also analysed using sera from hamsters infested with adults, nymphs or larvae. Sera from BALB/C mice, Apodemus flavicollis (yellow-necked mouse) or Clethrionomys glareolus (bank vole) repeatedly infested with larvae were used to compare the antigenic profiles of SGE and larval homogenate samples. We also investigated different sources of tick antigens, using rabbit sera, by comparing midgut extracts from female adult ticks and SGE from unfed ticks and from ticks throughout the 6-day feeding period with whole tick homogenates of female and male adults, nymphs and larvae. The pattern of antigenic tick-molecules recognized by infested host species varies with the period of feeding, developmental stage and the particular host species parasitized.