Immunohistochemical Staining as a Potential Method for the Identification of Vaginal Epithelial Cells in Forensic Casework

Abstract

There is currently no accurate method to identify vaginal epithelial cells uniquely. This study aimed to use a cell extraction procedure compatible with routine forensic sampling methods, and to investigate the expression of cytokeratin (CK), estrogen receptor-alpha (ERalpha), and phosphodiesterase 5 (PDE5) in order to distinguish between skin, buccal, vaginal, and external penile epithelial cells. Seminal fluid samples were also examined. Epithelial cell samples were fixed in formalin, embedded in agarose, and processed using histological methods. Antigen-antibody reactions were detected using the DAKO Envision+ detection system. CK was present in all cells from all five sources confirming the origin of cells as epithelial. Both ERalpha and PDE5 positively labeled vaginal, buccal, and skin epithelial cells. Although an antigen unique to vaginal epithelial cells was not identified, we have described a cell extraction procedure for use in the immunohistochemical detection of a wide range of antigens, an approach compatible with forensic diagnostics.

Evaluation of genetic markers for forensic identification of human body fluids

“…These markers were proposed to be useful in biomarker research. Though there has been no report of a similar study with other body fluids, further optimization and validation of these miRNA markers could be a gold standard in saliva identification, especially when most importantly, when degraded samples are encountered Roeder and Haas, 2013;Fleming et al, 2013;Paterson et al, 2006;Jakubowska et al, 2013). Lin et al, (2015) described NGS methods as a useful technique to identify degraded forensic body fluids.…”

A novel histological technique for distinguishing between epithelial cells in forensic casework

“…The fixed cells were centrifuged at 400 Â g for 5 min, the supernatant was discarded and the pellet was resuspended in 500 ml of 4% (w/v) molten agarose (Type IX-A; ultra-low gelling temperature, Sigma-Aldrich, Auckland, New Zealand) and allowed to set at 4 8C for 20 min. The agarose cellblock was removed from the tube and processed by alcohol dehydration, clearing in xylene, wax impregnation and embedding in paraffin wax as described previously [5]. 4 mm-thick sections were mounted onto poly-L lysine (Sigma-Aldrich) coated slides, dewaxed and hydrated ready for subsequent histological staining.…”

“…To our knowledge there is currently no conclusive test to distinguish between these three cell types. Several previous studies have examined differential carbohydrate and protein expression including the immunohistochemical detection of cytokeratins, estrogen receptors and phosphodiesterases but no unique marker has been identified [4,5]. One of the most promising techniques, first reported in the 1970s, was Lugol's iodine that identified vaginal cells by the presence of glycogen granules [6][7][8].…”

Vaginal microbial flora analysis by next generation sequencing and microarrays; can microbes indicate vaginal origin in a forensic context?

“…For instance, indications whether the cell material of a female donor is of buccal, skin or vaginal origin may lead to a different evaluation at the activity level in a sexual assault case. In some cases, the cellular origin of a sample is determined using microscopic analysis, which can be assisted by histological or immunological staining to detect sperm or epithelial cells [1][2][3][4].…”