YY/T 1465.4-2017Immunogenic evaluation method of medical devices - Part 4: Phagocytosis of mouse peritoneal macrophages on chicken erythrocytes- Ex-vivo method (English PDF)

1 Scope

This Part of YY/T 1465 gives the ex-vivo method for the determination of phagocytosis of mouse peritoneal macrophages on chicken erythrocytes.

This Part applies to the evaluation of the influence of medical devices/materials on phagocytic ability of macrophages.

2 Normative references

The following documents are indispensable for the application of this document.

For the dated references, only the versions with the dates indicated are applicable to this document. For the undated references, the latest version (including all the amendments) are applicable to this document.

GB/T 16886.1 Biological evaluation of medical devices - Part 1. Evaluation and testing within a risk management process (GB/T 16886.1-2011, ISO 10993-1:2009, IDT)

GB/T 16886.2 Biological evaluation of medical devices - Part 2. Animal welfare requirements (GB/T 16886.2-2011, ISO 10993-2:2006, IDT)

GB/T 16886.11 Biological evaluation of medical devices - Part 11. Tests for systemic toxicity (GB/T 16886.11-2011, ISO 10993-6:2006, IDT)

GB/T 16886.12 Biological evaluation of medical devices - Part 12. Sample preparation and reference materials (GB/T 16886.12-2005, ISO 10993- 12.2002, IDT)

GB/T 16886.20 Biological evaluation of medical devices - Part 20. Principles and methods for immunotoxicology testing of medical devices (GB/T 16886.20-2015, ISO/TS 10993-20:2006, IDT)

3 Terms and definitions

with reference to the requirements of acute, subacute, subchronic, and chronic systemic toxicity tests in GB/T 16886.11, and shall be stated in the final test report.

Note. The immunogens in medical devices are mostly macromolecular substances. If sample extracts are prepared, the effectiveness of the selective extraction method shall be explained.

6 Sample preparation and route of exposure

6.2 For degradable medical devices, it shall, according to intended clinical application mode, design the device-animal contact/immune mode. When there is available research literature, the method reported in the existing literature can be used for test design, to compare with the existing data. When there is no animal contact/immune mode which can be referenced, an implantation route similar to the intended clinical application mode may be considered.

6.3 The liquid test substance can be used directly or diluted.

7 Selection of control sample

8 Test procedures

9 Result calculation

The macrophages are counted under a microscope. Each slide is randomly counted for 200. The phagocytic percentage and the phagocytic index of each animal shall be calculated according to the formulas (1) and (2).

Note 1. If the drop slide is too dark, it can be decolored with 1% HCl. If it is too light, it can be re-dyed.

Note 2. If the fluid drawn out of the peritoneal cavity is bloody exudate, it shall not be used.

10 Result judgement

When the test group and the negative control group show statistically significant difference in the phagocytic percentage and the phagocytic index, it can be considered that the test substance has an impact on the phagocytic function of mouse macrophages. If a gradient-diluted material or its extract is used for the test, and there is dose-effect relationship between the phagocytic percentage and the phagocytic index, it suggests that the phagocytic function of macrophages may be affected.

11 Reliability inspection

11.1 The positive control is to, by using the substance which has been proven to promote or inhibit the phagocytic function of macrophages, confirm the suitability of the test. When it is necessary to verify that the laboratory is capable of performing this test and performing in-lab repeatability and interlaboratory reproducibility evaluations, positive control is recommended for each test.

11.2 For laboratories which frequently perform this test (Frequency is not less than once a month) and have long-term positive control data proving their ability Phagocytic percentage Phagocytic index Number of macrophages which phagocytose chicken erythrocytes Total number of macrophages counted Total number of chicken erythrocytes which are phagocytosed Total number of macrophages counted