Cell lines derived from avian lymphomas exhibit two distinct phenotypes.

Lymphoid cell lines were derived from three avian leukosis virus (ALV)-induced lymphomas. These cell lines contained proviral DNA sequences integrated upstream from the c-myc proto-oncogene, expressed increased levels of c-myc RNA, and were tumorigenic in syngeneic animals. While cell surface immunoglobulin (IgM) was expressed by all three cell lines, only one of the lines secreted IgM into the culture medium. Further, analysis by light microscopy and flow cytometry demonstrated that these cell lines exhibited two distinct morphological and light-scattering profiles. The two nonsecreting lines exhibited a lymphoblastoid phenotype, whereas, the secreting line possessed a more differentiated plasmacytoid phenotype. These findings implicate the activation of c-myc in the pathogenesis of tumors representing two distinct stages of B-cell differentiation within a single animal species.