Time for a little science lesson on how cells that secrete things work.
The DNA in a cell is kept inside the nucleus. This is a problem because the pores in the nuclear membrane are way too small to let the DNA through. Thats were messengerRNA(mRNA) and reverse transcriptase come in. Between the two of them the take a copy of a small segment of DNA and carry it out to the Rough Endoplasmic Reticulum(Rough ER) which takes that small genetic blueprint and creates a series of amino acids from it. When they are linked together amino acids are proteins, proteins are pretty much everything you're build up from in one way or another. This protein then makes its way to the smooth ER which packages it and sends it on its way out of hte cell.
I find this process incredible. Its one of the fundamental requirements for life and it happens in much of our body every millisecond.