This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
The first cell culture vaccine was 
Select and explain. 
A. Human diploid cell ( HDC ) vaccine, B. Low egg passage ( LEP ) vaccine, C. Purified chick embryo cell ( PCEC ) vaccine, D. Purified vero cell ( PVC ) vacccine
A: Human diploid cell ( HDC ) vaccine
Answer: A: Human diploid cell ( HDC ) vaccine 
Explanation: An inactivated rabies vaccine for human use was first prepared in cell culture. It was shown that the human diploid cell (HDC) strain WI-38 was a suitable substrate for the propagation of the Pitman-Moore (PM) strain of fixed rabies virus. Ref : Ananthanarayana textbook of Microbiology 9th edition Pgno : 534