Detection of Saliva by Immunoaffinity and Mass Spectrometry

Detection of Specific Salivary Proteins by Immunoaffinity and Mass Spectrometry

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.

Each participant will be contacted by a phone call the day before the visit, to present for a presentation of the study.The day of the visit, two types of samples will be collected :

• Saliva samples: on healthy volunteers in the Department of Legal Medicine (2 samples of 1.5 - 2 mL are collected for each volunteer).
• Vaginal samples : on women consulting in the Department of Reproductive Medicine (2 dry swabs on each patient). 2 groups, One group with vaginal secretion fluid samples only, and one group with vaginal secretion fluid + sperm samples.

Inclusion Criteria:

Saliva Samples

• Men and women aged 18 or more

Vaginal samples :

• Women aged 18 or more
• No unprotected vaginal sexual intercourse during the 10 days prior to the visit (group 1)
• Unprotected vaginal sexual intercourse with ejaculation in the 24 hours prior to the visit (group 2)

Exclusion Criteria:

Saliva Samples :

• Active pathology of the saliva glands (infection, tumor)
• Unprotected oral-genital sexual intercourse in the 24 hours prior to the visit
• Failure to obtain written informed consent after a reflection period
• Pregnant or breast feeding women
• Adult protected by law or under guardianship or curatorship
• No affiliation to the French Social Security System or no benefit from such a system

Vaginal Samples :

• Oral-genital sexual intercourse (cunnilingus) in the 24 hours prior to the visit
• Failure to obtain written informed consent after a reflection period
• Pregnant or Breastfeeding women
• Adult protected by law or under guardianship or curatorship
• No affiliation to the French Social Security System or no benefit from such a system