Identification of Salp15 homologues in Ixodes ricinus ticks.
The 15-kDa Ixodes scapularis salivary gland protein Salp15 protects Borrelia burgdorferi sensu stricto from antibody-mediated killing and facilitates infection of the mammalian host. In addition, Salp 15 has been shown to inhibit T-cell activation. We determined whether Ixodes ricinus, the major vector for Lyme borreliosis in Western Europe, also express salp15-related genes. We show that engorged I. ricinus express salp15 and we have identified three Salp15 homologues within these ticks by reverse transcriptase-polymerase chain reaction (RT-PCR). One of the predicted proteins showed 80% similarity to I. scapularis Salp15, evenly distributed over the entire amino acid sequence, whereas the two other predicted proteins showed approximately 60% similarity, mainly confined to the signal sequence and C-terminus. Comparison of the DNA and protein sequences with those deposited in several databases indicates that these proteins are part of a Salp15 family of which members are conserved among different Ixodes species, all capable of transmitting B. burgdorferi sensu lato. This suggests that these Salp15 homologues could also play a role in the transmission of diverse Borrelia species and in inhibition of T-cell activation.
Hovius
J W R
JW
Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA. j.w.hovius@amc.uva.nl
Ramamoorthi
N
N
Van't Veer
C
C
de Groot
K A
KA
Nijhof
A M
AM
Jongejan
F
F
van Dam
A P
AP
Fikrig
E
E
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005260:Female; D018884:Ixodes / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012469:Salivary Glands / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
D012471:Salivary Proteins and Peptides