Immune recognition of the surface associated antigen, Tc-SAA-1, from infective larvae of Teladorsagia circumcincta.
A cDNA encoding a surface-associated antigen was amplified by reverse transcriptase polymerase chain reaction (PCR) from RNA extracted from Teladorsagia circumcincta exsheathed third stage larvae (xL3). The protein encoded by this cDNA, Tc-SAA-1, displays 77% identity over 162 amino acid residues to a surface associated antigen from Ancylostoma caninum (Ac-SAA-1). Antiserum raised against a bacterially-expressed recombinant form of Tc-SAA-1 reacted with a native protein in somatic and surface extracts of xL3 but not with L4 or adult parasites. Limited binding of anti-Tc-SAA-1 antibody was observed on the cuticular surface of xL3 s, however, regions of localization underlying the cuticle were observed. Incubation of xL3 T. circumcincta with anti-SAA rabbit serum failed to significantly inhibit penetration of the abomasal mucosa in vitro. IgA in abomasal mucus derived from sheep that had received a trickle infection of T. circumcincta bound recombinant Tc-SAA-1.
Nisbet
A J
AJ
Moredun Research Institute, Scotland, UK. alasdair.nisbet@moredun.ac.uk
Knox
D P
DP
McNair
C M
CM
Meikle
L I
LI
Smith
S K
SK
Wildblood
L A
LA
Matthews
J B
JB
D000595:Amino Acid Sequence; D000818:Animals; D000947:Antigens, Helminth / Q000235:genetics / Q000276:immunology*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D007070:Immunoglobulin A; D007814:Larva / Q000276:immunology; D008969:Molecular Sequence Data; D009092:Mucous Membrane / Q000469:parasitology; D009093:Mucus / Q000276:immunology; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012756:Sheep; D014251:Trichostrongyloidea / Q000235:genetics / Q000276:immunology*
D000947:Antigens, Helminth; D018076:DNA, Complementary; D007070:Immunoglobulin A