Rhipicephalus (Boophilus) microplus: clotting time in tick-infested skin varies according to local inflammation and gene expression patterns in tick salivary glands.
Ticks deposit saliva at the site of their attachment to a host in order to inhibit haemostasis, inflammation and innate and adaptive immune responses. The anti-haemostatic properties of tick saliva have been described by many studies, but few show that tick infestations or its anti-haemostatic components exert systemic effects in vivo. In the present study, we extended these observations and show that, compared with normal skin, bovine hosts that are genetically susceptible to tick infestations present an increase in the clotting time of blood collected from the immediate vicinity of haemorrhagic feeding pools in skin infested with different developmental stages of Rhipicepahlus microplus; conversely, we determined that clotting time of tick-infested skin from genetically resistant bovines was shorter than that of normal skin. Coagulation and inflammation have many components in common and we determined that in resistant bovines, eosinophils and basophils, which are known to contain tissue factor, are recruited in greater numbers to the inflammatory site of tick bites than in susceptible hosts. Finally, we correlated the observed differences in clotting times with the expression profiles of transcripts for putative anti-haemostatic proteins in different developmental stages of R. microplus fed on genetically susceptible and resistant hosts: we determined that transcripts coding for proteins similar to these molecules are overrepresented in salivary glands from nymphs and males fed on susceptible bovines. Our data indicate that ticks are able to modulate their host's local haemostatic reactions. In the resistant phenotype, larger amounts of inflammatory cells are recruited and expression of anti-coagulant molecules is decreased tick salivary glands, features that can hamper the tick's blood meal.
Carvalho
Wanessa Araújo
WA
Departament of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP 14049-900, Brazil.
Maruyama
Sandra Regina
SR
Franzin
Alessandra Mara
AM
Abatepaulo
Antônio Roberto Rodrigues
AR
Anderson
Jennifer M
JM
Ferreira
Beatriz Rossetti
BR
Ribeiro
José Marcos Chaves
JM
Moré
Daniela Dantas
DD
Augusto Mendes Maia
Antonio
A
Valenzuela
Jesus G
JG
Garcia
Gustavo Rocha
GR
de Miranda Santos
Isabel K Ferreira
IK
D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood* / Q000235:genetics / Q000469:parasitology / Q000473:pathology; D019295:Computational Biology; D018076:DNA, Complementary / Q000737:chemistry; D005260:Female; D020869:Gene Expression Profiling; D015723:Gene Library; D006790:Host-Parasite Interactions; D007249:Inflammation / Q000097:blood / Q000469:parasitology / Q000662:veterinary; D008297:Male; D045726:Metalloproteases / Q000037:antagonists & inhibitors / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D048494:Rhipicephalus / Q000235:genetics / Q000502:physiology*; D012469:Salivary Glands / Q000201:enzymology / Q000502:physiology; D012471:Salivary Proteins and Peptides / Q000235:genetics; D012867:Skin / Q000098:blood supply / Q000469:parasitology* / Q000473:pathology; D013984:Tick Infestations / Q000097:blood / Q000235:genetics / Q000473:pathology / Q000662:veterinary*; D014914:Whole Blood Coagulation Time
D018076:DNA, Complementary; D012333:RNA, Messenger; D012471:Salivary Proteins and Peptides; D045726:Metalloproteases