How to pronounce“macras”in English

being able to visualize them myself but I as I mentioned I came to work in the laboratory of Dr zanville Cohen under Dr Ralph Steinman which was a laboratorythat worked on macras which were a cell that's related to dendritic cells and Ralph had just discovered dendritic cells and so I learned how to makethem it was the beginning of the AIDS epidemic and Ralph and his colleague Melissa Pope had demonstrated that