Local Lymph Node Assay (LLNA)

A big variety of chemical components such as starting materials and processing aids including lubricants and mould-release agents used in the manufacture of medical device, adhesive/solvent residues from assembly process, and sterilant residues from sterilization process may be present in a finished product. It shall be taken into consideration that whether these components have the potential sensitization activity.

The local lymph node assay in mice is designed to evaluate the sensitizing potential of extract from medical device. In addition, the local lymph node assay can provide important information for human quantitative risk assessment.

STEMart offers several in vivo local lymph node assays for sensitization biocompatibility testing following the biocompatibility guidelines modified for medical devices.

Standard of LLNA

• ISO 10993-10: 2010
• OECD 442B
• OECD 429

LLNA Test Principle

The exposure of the dorsum of the ears of mice to a sensitizer induces a primary proliferation (induction phase) of lymphocytes in the lymph nodes that drain the site of test substance application. This proliferation is proportional to the dose applied and provides a quantitative dose-response assessment of sensitization.

Test Animal for LLNA

Female mice of the CBA/Ca or CBA/J strain

Test Methods of LLNA

• Local Lymph Node Assay (LLNA)

The LLNA is a radioactive method which determines the proliferating cells labelled by a radioactive label in the draining lymph nodes.

• Local Lymph Node Assay: BrdU-ELISA
• Local Lymph Node Assay: BrdU-FCM

Both LLNA: BrdU-ELISA and LLNA: BrdU-FCM are modified non-radioactive LLNA method for identification of potential skin sensitizing test substance. The LLNA: BrdU uses 5-bromo-2-deoxyuridine (BrdU) content as an indicator of lymph node cell proliferation, thereby eliminating the use of dangerous radioactive isotopes for labeling of DNA, which avoids occupational exposure to radioactivity and hazardous waste disposal.

Advantages of Local Lymph Node Assay

• Provide a quantitative endpoint
• Provide dose-responsive data
• Allow for prediction of potency
• Eliminate the need for an adjuvant

If you have additional questions about Local Lymph Node Assay or would like to find out more about our services, please feel free to contact us.

References

• International Organization for Standardization. Biological evaluation of medical devices — Part 10: Selection of tests for interactions with blood. ISO 10993-10; (2010).
• OECD Guideline for Testing of Chemicals. No 442B Local lymph node assay: BRDU-ELISA or -FCM (2018).
• OECD Guideline for Testing of Chemicals. No 429 Skin Sensitization local lymph node assay (2010).