Final answer:
HDL and VLDL are the main lipoproteins involved in cholesteryl ester transfer.
Step-by-step explanation:
The lipoproteins mainly involved in cholesteryl ester transfer are HDL (High-Density Lipoproteins) and VLDL (Very Low-Density Lipoproteins)
HDL takes up cholesterol from the tissues and transports it back to the liver, while VLDL transports newly synthesized triglycerides from the liver to the fatty tissues. In the process, cholesteryl ester is transferred to VLDL and LDL by a cholesteryl ester transfer protein (CETP).