passages.id: split_4_test_2698_passage
passages.type: progene_text
passages.text: Three closely positioned genes on human chromosome 19 encode distinct but paralogous proteins , which we designate interferon-lambda1 ( IFN-lambda1 ) , IFN-lambda2 and IFN-lambda3 ( tentatively designated as IL-29 , IL-28A and IL-28B , respectively , by HUGO ) .