Immunity?
Bah.
Jesus did this.
Yes, but only a part of it.
http://jcem.endojournals.org/cgi/content/abstract/39/6/1045
The Metabolism of Vitamin D3 and 25-Hydroxyvitamin D3 in Normal and Anephric Humans
RICHARD W. GRAY, HUGO P. WEBER, JESUS H. DOMINGUEZ and JACOB LEMANN, JR.