What are the handling and safety protocols for circulating CD117 (cluster of differentiation 117) in cynomolgus monkeys?

Handling and Safety Protocols for Circulating CD117 in Cynomolgus Monkeys

When working with circulating CD117 in cynomolgus monkeys, proper handling and safety protocols are essential to ensure accurate detection and measurement while maintaining sample integrity and laboratory safety.

Understanding CD117 in Cynomolgus Monkeys

• CD117 (also known as c-kit) is an important immunological marker that appears early in cynomolgus monkey development, with immunoreactivity detectable from embryonic days 40-45 onward 1
• CD117 is a critical marker in the identification of gastrointestinal stromal tumors (GISTs) in both humans and non-human primates, with approximately 95% of GISTs showing CD117 positivity 2
• In cynomolgus monkeys, CD117 plays a role in the developing immune system and can be detected in circulating immune cells 1

Sample Collection and Handling

• Blood samples should be collected in appropriate anticoagulant tubes (preferably EDTA or sodium citrate) to preserve CD117-expressing cells 3
• Samples should be processed within 24 hours of collection to maintain cell viability and prevent degradation of CD117 surface expression 3, 4
• When collecting samples:
  • Use sterile technique to avoid contamination
  • Minimize hemolysis which can interfere with accurate detection
  • Process samples at room temperature rather than refrigerated conditions 3

Laboratory Safety Considerations

• Standard biosafety level 2 (BSL-2) practices should be followed when handling cynomolgus monkey blood samples 1
• Personal protective equipment (PPE) should include:
  • Laboratory coat
  • Gloves
  • Eye protection
  • Face shield if risk of splashing exists 1
• All work should be performed in a certified biosafety cabinet to minimize exposure risk 1

Sample Processing and Analysis

• For immunohistochemical detection of CD117:
  • Fix samples in 4% buffered formalin (avoid Bouin's fixative as it interferes with molecular analysis) 2
  • Perform antigen retrieval carefully, as improper technique may result in false positive CD117 staining 2
• For flow cytometric analysis:
  • Use appropriate fluorochrome-conjugated anti-CD117 antibodies validated for cynomolgus monkeys 5
  • Include proper isotype controls to account for non-specific binding 5
• For detection of CD117 in immune complexes:
  • Consider using specialized immune complex assays that can detect drug-specific immune complexes in cynomolgus monkey serum 4
  • These assays can help identify potential immunogenicity issues in preclinical studies 3, 4

Special Considerations

• Be aware that cynomolgus monkeys show immunological polymorphisms (as demonstrated with CD3), which may affect antibody binding to surface markers including CD117 6
• When evaluating CD117 expression, consider that approximately 5% of GISTs may be CD117-negative despite having the typical morphological features 2
• For molecular analysis of CD117 (KIT gene):
  • Collect and store fresh frozen tissue samples when possible 2
  • Obtain appropriate informed consent for tissue storage according to institutional guidelines 2

Quality Control Measures

• Validate all antibodies and assays specifically for use with cynomolgus monkey samples before implementation 3, 5
• Include appropriate positive and negative controls in all assays 3
• Consider the potential for drug interference in CD117 detection assays, especially in toxicology studies where therapeutic antibodies are administered 3, 4
• For quantitative assays, establish the lower limit of quantitation (e.g., 15.6 ng/mL for some immune complex assays) 3

By following these handling and safety protocols, researchers can effectively work with circulating CD117 in cynomolgus monkeys while ensuring accurate results and maintaining laboratory safety.