Venezuelan-born doctor Baruj Benacerraf, whose research on the human immune system won him a Nobel Prize for Medicine, has died.

Dr. Benacerraf was living in Boston, Massachusetts and had been suffering from pneumonia. He was 90 years old.

Dr. Benacerraf was born in Caracas and grew up in Paris, arriving in the United States in 1939 to study medicine.

His research into why some people are better able to fend off disease and infection than others brought him the 1980 Nobel Price for Medicine, which he shared with two fellow researchers.

Dr. Benacerraf also ran the Boston-based Dana-Farmer Cancer Institute.