Detection of Saliva by Immunoaffinity and Mass Spectrometry

Summary

The identification of saliva in genital area during a criminal investigation can be a critical component in the prosecution of a sexual assault in France, as non-consensual oral-genital intercourses have been considered as crimes since 2021.The development of highly specific methods for saliva detection is therefore crucial as the commonly employed screening methods lack specificity. Protein mass spectrometry has proven to be a sensitive and specific method but is particularly time consuming. A faster and more sensitive hybrid approach using automated immunoaffinity mass spectrometry (IP-LC-MS/MS) has been recently developed and has been found to be particularly performant for the detection of a seminal fluid protein (semenogelin), allowing a high-throughput seminal fluid identification in semen samples. Like semenogelin, specific salivary proteins such as histatin type 1, cystatin D or proline-rich proteins (PRPs) could be detected using this promising approach, which has never been tested on saliva samples. In collaboration with the Clinical Proteomics Platform and the Department of Reproductive Medicine of the University Hospital of Montpellier, we aim to develop a protocol for the detection of specific saliva proteins by IP-LC-MS/MS in sexual assault-type samples.

Conditions

• Sexual Assault

Interventions

OTHER

Saliva collection

Collection of 2 samples of 1.5 to 2mL of saliva by passive salivation in healthy volunteers

OTHER

Vaginal secretion collection

Collection of vaginal secretions with 2 dry swabs in women

OTHER

IP-LC-MS/MS : immunoprecipitation enrichment with liquid chromatography coupled to tandem mass spectrometry

sample preparation and analysis : * Impregnation of the tips (absorbent cotton) of sterile dry swabs and vaginal swabs with controlled quantities of saliva. * Immunocapture of salivary proteins of interest (histatin type 1, cystatin D, PRPs) by protein A affinity purification * LC-MS/MS analysis of eluted purified peptides (Multiple Reaction Monitoring mode) Dilutions will be made from 10 to 10 (1/10, 1/100, 1/1000...), then after reaching a detectability threshold, specified by a second more precise analysis (e.g. if no signal at 1/1000, analysis at 1/500 then 1/250 etc.). Analytical sensitivity will be tested on three samples of each type (salivary, vaginal, vaginal + semen) to ensure reproducibility of results. Operators, unaware of the presence of saliva in the samples, will then carry out saliva-specific protein detection analysis using the IP-LC-MS/MS method.

Sponsors & Collaborators

• University Hospital, Montpellier

  lead OTHER

Principal Investigators

• Pierre-Antoine PEYRON, PI · University Hospital, Montpellier

Study Design

Allocation

NON_RANDOMIZED

Purpose

OTHER

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2024-01-15

Primary Completion

2024-07-15

Completion

2024-12-31

Countries

• France

Study Locations