Abstract:
Ticks and tick-borne diseases have a negative impact on the quality and quantity of livestockderived
products. As such, effective control strategies against these parasites are needed.
Currently, acaricides are the most widely used control mechanism against ticks but due to the
increase in resistance to these chemicals, new control strategies, like vaccination, need to be
developed and improved. In cattle, increasing the understanding of the basic underlying variation
in immunological responses to tick infestation may constitute the basis of improved tick control
strategies in the future. While the identification of protective antigens is essential, the final
formulation of vaccines is pivotal in the efficacy of a future vaccine. As such, increasing the
understanding of the basic underlying variation in immunological responses to tick infestation may
constitute the basis of improved tick control strategies in the future. Chapter 2 describes the
differential regulation of T and B-lymphocyte subsets in the skin and lymph nodes amongst three
cattle breeds as potential mediators of immune-resistance to Rhipicephalus microplus tick. This
study has been the first to describe in detail the in vivo immune responses in lymph nodes of
cattle following Rhipicephalus microplus infestation, attachment and continued feeding. To further
compliment this study, Chapter 3 provides a temporal analysis of the bovine lymph node
transcriptome during cattle tick (Rhipicephalus microplus) infestation. Here a detailed description
on the specific transcriptional processes in the lymph nodes of Bonsmara cattle is given. These
processes include: (1) Leukocyte recruitment to the lymph node via chemokines and chemotaxis,
(2) Trans-endothelial and intranodal movement on the reticular network, (3) Active regulation of
cellular transcription and translation in the lymph node (including leukocyte associated cellular
regulatory networks) and (4) Chemokine receptors regulating the movement of cells out of the
lymph node. In addition to studying the immune response in cattle, the viability of a mouse model
was used for basic immune profiling during tick feeding and vaccination in Chapter 4. Here an in
vivo evaluation of Ixodes ricinus induced effects on T and B-cell maturation in the spleen and
lymph nodes of BALB/c mice is given.
