PrP conformational transitions alter species preference of a PrP-specific antibody.
The epitope of the 3F4 antibody most commonly used in human prion disease diagnosis is believed to consist of residues Met-Lys-His-Met (MKHM) corresponding to human PrP-(109-112). This assumption is based mainly on the observation that 3F4 reacts with human and hamster PrP but not with PrP from mouse, sheep, and cervids, in which Met at residue 112 is replaced by Val. Here we report that, by brain histoblotting, 3F4 did not react with PrP of uninfected transgenic mice expressing elk PrP; however, it did show distinct immunoreactivity in transgenic mice infected with chronic wasting disease. Compared with human PrP, the 3F4 reactivity with the recombinant elk PrP was 2 orders of magnitude weaker, as indicated by both Western blotting and surface plasmon resonance. To investigate the molecular basis of these species- and conformer-dependent preferences of 3F4, the epitope was probed by peptide membrane array and antigen competition experiments. Remarkably, the 3F4 antibody did not react with MKHM but reacted strongly with KTNMK (corresponding to human PrP-(106-110)), a sequence that is also present in cervids, sheep, and cattle. 3F4 also reacted with elk PrP peptides containing KTNMKHV. We concluded that the minimal sequence for the 3F4 epitope consists of residues KTNMK, and the species- and conformer-dependent preferences of 3F4 arise largely from the interactions between Met(112) (human PrP) or Val(115) (cervid PrP) and adjacent residues.
Zou
Wen-Quan
WQ
Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio 4410, USA. wenquan.zou@case.edu
Langeveld
Jan
J
Xiao
Xiangzhu
X
Chen
Shugui
S
McGeer
Patrick L
PL
Yuan
Jue
J
Payne
Michael C
MC
Kang
Hae-Eun
HE
McGeehan
John
J
Sy
Man-Sun
MS
Greenspan
Neil S
NS
Kaplan
David
D
Wang
Gong-Xian
GX
Parchi
Piero
P
Hoover
Edward
E
Kneale
Geoff
G
Telling
Glenn
G
Surewicz
Witold K
WK
Kong
Qingzhong
Q
Guo
Jian-Ping
JP
D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D000918:Antibody Specificity; D002417:Cattle; D006224:Cricetinae; D000939:Epitopes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D011328:Prions / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D012756:Sheep; D013045:Species Specificity
D000911:Antibodies, Monoclonal; D000939:Epitopes; D011328:Prions