[2] He and Maureen Howard discovered interleukin 4,[3][4] while an independent team led by Ellen Vitetta did the same in 1982.

While in America, Jack Paul met and married Sylvia Gleicher, a cousin of Norman Geschwind.

He joined the United States Public Health Service Commissioned Corps in 1962 and was assigned to the Endocrinology Branch of the NCI, where he worked for two years.

Paul trained at New York University with Baruj Benacerraf and later moved with him to the National Institute of Allergy and Infectious Diseases (NIAID).

[6] He received the 2002 American Association of Immunologists Lifetime Achievement Award[7] and the 2008 Max Delbrück Medal.