[Abstract] Objective: To develop a new type of CD7 chimeric antigen receptor modified T cell (CD7-CAR-T) for the treatment of CD7 positive acute myeloid leukemia (AML), and to observe its killing effect on CD7 positive AML cells. Methods: The CD7-CAR lentiviral vector was constructed based on the CD7 Nanobody sequence and costimulatory domain sequence of CD28 and 4-1BB. The lentiviral particles were packaged and used to co-transfect human T cells with protein expression blocker (PEBL), so as to prepare CD7- CAR-T cells. Real time cellular analysis (RTCA) was used to monitor the cytotoxicity of CD7-CAR-T cells on CD7 overexpressed 293T cells. Flow cytometry assay was used to detect the effect of CD7-CAR-T cells on proliferation and cytokine secretion of AML cells with high, medium and low CD7 expressions (KG-1, HEL and Kasumi-1 cells, respectively). Results: CD7-CAR-T cell was successfully constructed and its surface expression of CD7 was successfully blocked. Compared with T cells, CD7-CAR-T cells could significantly inhibit the proliferation of CD7-293T cells and promote the release of TNF, Granzyme B and INF-γ; in addition, CD7-CAR-T cells also significantly promoted the apoptosis (t=147.1, P<0.01; t=23.57, P<0.01) and cytokine release (P<0.05 or P<0.01) in CD7 positive KG-1 and HEL cells, but had little effect on Kasumi-1 cells that only expressed minimal CD7 antigen (t=0.7058, P>0.05). Conclusion: CD7-CAR-T cells can specifically kill CD7-positive AML cells in vitro.

OBJECTIVETo improve the occupational health management levels in electroplating enterprises with quantitative classification measures and to provide a scientific basis for the prevention and control of occupational hazards in electroplating enterprises and the protection of workers' health.

METHODSA quantitative classification table was created for the occupational health management in electroplating enterprises. The evaluation indicators included 6 items and 27 sub-items, with a total score of 100 points. Forty electroplating enterprises were selected and scored according to the quantitative classification table. These electroplating enterprises were classified into grades A, B, and C based on the scores.

RESULTSAmong 40 electroplating enterprises, 11 (27.5%) had scores of >85 points (grade A), 23 (57.5%) had scores of 60∼85 points (grade B), and 6 (15.0%) had scores of <60 points (grade C).

CONCLUSIONQuantitative classification management for electroplating enterprises is a valuable attempt, which is helpful for the supervision and management by the health department and provides an effective method for the self-management of enterprises.

Electroplating ; Humans ; Occupational Exposure ; Occupational Health