HISTOCOMPATIBLE MINIATURE BOAR MODEL - SELECTION OF TRANSFORMED-CELL LINES OF B-LINEAGES AND T-LINEAGES PRODUCING RETROVIRUS

A lymphoblastoid cell line (BI) was isolated in culture following a brief exposure to 5‐azacytidine from peripheralblood mononuclear cells of a boar previously injected with cells (Shimozuma) producing porcine retrovirus (Tsukuba‐I) and suffering a severe non‐neoplastic syndrome at autopsy. BI cell line and 5 of its sublines were propagated for more than 100 generations, retaining doubling times comprised between 16.8 and 27.5 hr and growing readily in agarose or agar (plating efficiency: 5 to 50%). Karyotype analyses showed that 4 sublines were nearly diploid, except for cells of L14, which displayed a monosomy affecting chromosome 18 pair. Two sublines (L35 and L45) were considered as being of T‐cell lineage, since MSA antigen was observed on the surface of approximately 30% of cells. Three sublines (L23, L14 and L52) were considered of B‐cell lineage, since membrane immunoglobulins were observed on the cell surface. In addition, sublines L23 and L52 were actively secreting immunoglobulin of μ isotype. Retrovirus particles were evidenced in gradient purified preparation of 200‐fold‐concentrated cell culture supernatants of the BI cell line, L14, L35 and L52 sublines, using both a reverse transcriptase activity assay and electron microscopic observation. These cell lines can be used to select for porcine retrovirus variants with transforming potential for lymphocytes of B and T lineages. Copyright © 1990 Wiley‐Liss, Inc., A Wiley Company