OBJECTIVE: This study aimed to elucidate the polarization of M1 and M2 macrophage from CAD patients as well as to investigate the expression of MerTK in these macrophage phenotypes.
METHODS: A total of 14 (n) CAD patients were recruited and subsequently grouped into "no apparent CAD", "non-obstructive CAD" and "obstructive CAD" according to the degree of stenosis. Thirty ml of venous blood was withdrawn to obtain monocyte from the patients. The M1 macrophage was generated by treating the monocyte with GMCSF, LPS and IFN-γ while MCSF, IL-4 and IL-13 were employed to differentiate monocyte into M2 macrophage. After 7 days of polarization, analysis of cell surface differentiation markers (CD86+/CD80+ for M1 and CD206+/CD200R+ for M2) and measurement of MerTK expression were performed using flow cytometry.
RESULTS: Both M1 and M2 macrophage expressed similar level of CD86, CD80 and CD206 in all groups of CAD patients. MerTK expression in no apparent CAD patients was significantly higher in M2 macrophage compared to M1 macrophage [12.58 ± 4.40 vs. 6.58 ± 1.37, p = 0.040].
CONCLUSION: Differential polarization of macrophage into M1 and M2 was highly dynamic and can be varied due to the microenvironment stimuli in atherosclerotic plaque. Besides, higher expression of MerTK in patients with the least coronary obstructive suggest its vital involvement in efferocytosis.
OBJECTIVES: Preclinical studies with NK cells were promising and several clinical studies are ongoing to investigate their use in antibody therapies. However, more reliable ADCC assays are required for evaluating NK cell activity to optimise therapeutic antibodies. The therapeutic potential of NK cell therapy could then be improved by harnessing ADCC.
METHODS: This review discusses recent studies on key components of NK cell-mediated ADCC, current clinical trials involving NK cells, ADCC assay developments and various techniques to improve ADCC.
RESULTS: Improvements can be made to NK-mediated ADCC through modifications of antibodies, effector cells and target antigens. Different aspects of antibodies were studied extensively, including modifying glycosylation patterns, novel production methods, combination regiments, bispecific antibodies, and conjugated antibodies. Modification of NK cells and tumour surface markers could improve ADCC of even treatment-resistant cancer cells. Additives such as cytokines and other immunomodulatory agents can further augment ADCC to supplement NK cell-based therapies.
CONCLUSION: ADCC improvements could be incorporated with current biological techniques such as adoptive transfer of NK cells and chimeric antigen receptor (CAR) NK cells, to improve the outcome of NK cell-based therapy and pave the way for future immunotherapies.