immunology of infectious and parasitic diseases - XXXVII Congress ...

Assessment of extracellular matrix proteins in the host skin from tick-resistant
and tick-susceptible bovine breeds
Nádia C. S. Gauna¹; Alessandra M. Franzin¹; Sandra R. Maruyama¹; Gustavo
R. Garcia¹; Lauren C. Ribeiro¹; Isabel K. F de M. Santos¹; Beatriz R. Ferreira²
1 School of Medicine of Ribeirão Preto, USP, Ribeirão Preto-SP, Brazil
2 School of Nursing of Ribeirão Preto, USP, Ribeirão Preto-SP, Brazil
Email: nadiagauna@usp.br
Introduction: Rhipicephalus boophilus microplus ticks are parasites that feed
for several days attached to their bovine hosts, which depends on the
inoculation of saliva into the skin feeding lesion. Composition of tick saliva is
complex and contains several molecules that modulate the innate and acquired
host immune response. The extracellular matrix (ECM) of the skin is a network
of components, which contribute to cell differentiation and proliferation, gives
tensile strength, as well as, facilitates the connection of chemokines that are
essential to recruit cells like basophils and eosinophils. In a previous study of
microarray, our group compared the Nelore bovine skin (tick-resistant breed)
with Holstein (tick-susceptible breed). We observed that a large profile of genes
were differentially expressed between the breeds, including genes coding for
ECM proteins, such as tenacyn, keratocan, collagen type I alpha 1, osteoglycin,
osteonectin, metalloproteinases and fibronectin. Our present work aimed to
evaluate some of these ECM proteins in the skin of tick-resistant and
susceptible bovine breeds. Methods and Results: We infested Nelore (n=4)
and Holstein (n=4) with 10,000 R. (B) microplus tick larva/animal and collected
skin biopsies containing attached tick larva and nymphs or without ticks. Using
qPCR and immunohistochemistry techniques we evaluated the gene expression
for keratocan, osteoglycin and collagen type I and their respective proteins. So
far, no statistical differences in the gene expression for keratocan, osteoglycin
and collagen type I was observed between the bovine breeds tick-infested skin.
In standardizing assays we did not detect collagen type I protein in Holstein
non-infested skin sections; on the other hand, this same skin was stained for
keratocan and strongly labeled for osteoglycin. The comparisons between the
skin of Nelore and Holstein breeds by immunohistochemistry are still ongoing.
Conclusion: The experiments are being repeated. This study will contribute to
a better understanding of the mechanisms by which resistant bovines can
prevent tick infestation.