Immunofluorometric assay of human kallikrein 10 and its identification in biological fluids and tissues.
BACKGROUND
The human kallikrein 10 gene [KLK10, also known as normal epithelial cell-specific 1 gene (NES1)] is a member of the human kallikrein gene family. The KLK10 gene encodes for a secreted serine protease (hK10). We hypothesize that hK10 is secreted into various biological fluids and that its concentration changes in some disease states. The aim of this study was to develop a sensitive and specific immunoassay for hK10.


METHODS
Recombinant hK10 protein was produced and purified using a Pichia pastoris yeast expression system. The protein was used as an immunogen to generate mouse and rabbit polyclonal anti-hK10 antisera. A sandwich-type immunofluorometric assay was then developed using these antibodies.


RESULTS
The hK10 immunoassay has a detection limit of 0.05 microg/L. The assay is specific for hK10 and has no detectable cross-reactivity with other homologous kallikrein proteins, such as prostate-specific antigen (hK3), human glandular kallikrein 2 (hK2), and human kallikrein 6 (hK6). The assay was linear from 0 to 20 microg/L with within- and between-run CVs <10%. hK10 is expressed in many tissues, including the salivary glands, skin, and colon and is also detectable in biological fluids, including breast milk, seminal plasma, cerebrospinal fluid, amniotic fluid, and serum.


CONCLUSIONS
We report development of the first immunofluorometric assay for hK10 and describe the distribution of hK10 in biological fluids and tissue extracts. This assay can be used to examine the value of hK10 as a disease biomarker.
Luo
L Y
LY
Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5 Canada.
Grass
L
L
Howarth
D J
DJ
Thibault
P
P
Ong
H
H
Diamandis
E P
EP
D000595:Amino Acid Sequence; D000653:Amniotic Fluid / Q000737:chemistry; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001826:Body Fluids / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D015200:Fluoroimmunoassay; D006801:Humans; D066298:In Vitro Techniques; D007610:Kallikreins / Q000032:analysis* / Q000097:blood / Q000134:cerebrospinal fluid; D008297:Male; D013058:Mass Spectrometry; D051379:Mice; D008895:Milk, Human / Q000737:chemistry; D008969:Molecular Sequence Data; D009928:Organ Specificity; D011817:Rabbits; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D012661:Semen / Q000737:chemistry; D012680:Sensitivity and Specificity; D014020:Tissue Extracts
D015415:Biomarkers; D011994:Recombinant Proteins; D014020:Tissue Extracts; C100936:KLK10 protein, human; D007610:Kallikreins