Applicability of ELISA detection of statherin for forensic identification of saliva

Abstract

Statherin is a low molecular-weight phosphoprotein secreted from the parotid gland. Statherin mRNA was previously reported to be a useful marker for mRNA-based saliva identification. In this study, applicability of ELISA detection of statherin for forensic identification of saliva was investigated. The specificity and sensitivity of ELISA for detection of statherin were compared with those of ELISA for α-amylase and the Phadebas® amylase test. Statherin was specifically detected in saliva but not in other body fluids. In addition, statherin was successfully detected in aged saliva stains, mixed body fluids-saliva stains, and simulated casework samples. On the other hand, although ELISA for α-amylase showed higher sensitivity than ELISA for statherin, it was not specific enough to identify saliva. The Phadebas® amylase test also showed positive results in other body fluids that are known to have α-amylase activity; however, it is easy to use for screening forensic casework samples. In conclusion, ELISA for detection of statherin developed in this study could be an effective tool for the forensic identification of saliva because of its specificity for saliva among other body fluids. Forensic casework samples should be tested by ELISA detection or mRNA-based analysis for statherin, depending on the condition of the sample, to supplement presumptive tests for α-amylase, such as the Phadebas® amylase test.

Identification and evaluation of potential forensic marker proteins in vaginal fluid by liquid chromatography/mass spectrometry

“…Notably, such absorbances were observed regardless of the dilution ratio of body fluid samples (data not shown). Using a cutoff value, the examination of vaginal fluids may be possible because of the marked difference in the absorbance values in body fluids, which is similar to that of statherin [5], TammHorsfall protein [29], and dermcidin [30].…”

“…Recombinant SPRR3 was diluted from 0.3 ng/mL to 30 μg/mL and recombinant FABP5 was diluted from 1.5 ng/mL to 15 μg/mL with BCB. The ELISA procedure was previously reported [5]. As primary antibodies, a monoclonal anti-human SPRR3 antibody (Abnova, Taipei, Taiwan) diluted 1:1000 with 0.05 % Tween-20 in phosphate buffered saline (PBST) or a polyclonal anti-human FABP5 antibody (R&D Systems, MN, USA) diluted 1:500 in PBST was used.…”

“…However, unlike hemoglobin in blood [3], prostate-specific antigen in Electronic supplementary material The online version of this article (doi:10.1007/s00216-015-8877-x) contains supplementary material, which is available to authorized users. semen [4], or statherin in saliva [5], no characteristic protein marker has been demonstrated for vaginal fluids, and an optimal method for identifying vaginal fluids has not been adequately established [6]. A method detecting cornulin and cornifin for discriminating vaginal fluids from other body fluids has been recently reported; however, this method involves time-consuming sample preparation for its use in practical forensic investigation, wherein rapidity is important.…”

Practical Issues of Inhibition in Forensic Body Fluid Identifications

“…These studies should present countermeasures against these inhibitors, such as methods to purify samples, methods of applying resistant testing, and methods for alternative testing. Several alternative approaches (e.g., enzyme-linked immunosorbent assay, PCR, mass spectrometry) have been studied for identifying the bodily fluids used in forensics [8,[11][12][13][14]; however, these methods are not widely used in casework because they are not as convenient or cost effective as conventional presumptive tests. The key point is that when dealing with samples that are suspected to be contaminated and inhibited, the samples should be evaluated using multiple tests when possible.…”

Detection of proline-rich proteins for the identification of saliva by enzyme-linked immunosorbent assay

“…However, a-amylase is also present in other body fluids including semen, vaginal fluid, blood, sweat, and urine [3,4]. Recently, methods for detecting histatin 3 (HTN3) mRNA [5] and bacterial DNA [6] have been reported.…”