High‐ and low‐leukemogenic variants of the radiation leukemia virus (RadLV): Immunogenic, suppressive and genetic properties in relation to leukemogenic activity

Abstract

C57BL/6 (B6) mice inoculated with the highly leukemogenic variant of the radiation leukemia virus (A-RadLV) develop suppressor cells capable of abrogating potential anti-tumor immunity in vitro and in vivo. Inoculation of B6 animals with the low-leukemogenic D-RadLV variant does not result in suppressor cell generation but induces antitumor reactive lymphocytes. A-RadLV and D-RadLV are not leukemogenic in BALB/c or (B6 X BALB/c)F1(F1) mice, and reactive but not suppressor lymphocytes could be demonstrated in F1 animals inoculated with either virus. Infectivity assays and fingerprint analysis revealed that A-RadLV and D-RadLV contain viruses with N and B tropism. In addition, thymoma cells induced by A-RadLV produced another virus with a fingerprint pattern containing X-MuLV elements. The possible implications of the different virus types on the immunogenic and leukemogenic properties of the RadLV variants are discussed.

Potentiation of T cell immunity against radiation-leukemia-virus-induced lymphoma by polysaccharide K

“…The experimental system chosen for these studies was RadLV-induced leukemogenesis in Bö mice because (a) this virus induces a long premalignant state in the mouse, characterized by the appearance ofpreleukemic cells [6,7]; (b) RadLV-infected cells are potentially immunogenic ow-60 ing to expression of virus structural proteins in the cells [18][19][20], and (c) virus-specific Ts lymphocytes that emerge early in the preleukemic latency arbrogate the elicitation of anti-RadLV immune responses, which otherwise would interfere in the progression of the premalignant evolution process [16,18,19,21].…”

A highly leukemogenic radiation leukemia virus isolate is a thymotropic, immunosuppressive retrovirus with a unique rna structure

“…This technique is suitable for detecting resemblance vs. diversity among genetically related RNA viruses (Coffin et al, 1980). The oligonucleotide distribution of TV RNA was different from that of a fibrotropic retrovirus isolated from 127 or 136.5 cells which exhibited a fingerprint map typical of murine B-tropic viruses (Yefenof et al, 1984). Sixteen RNase T1-resistant oligonucleotides of TV and D-RadLV-derived fibrotropic virus were identical, as evident from their simultaneous co-migration in the 2-dimensional electrophoretic gel.…”

“…Medium was harvested daily for 4 days following the beginning of labelling and the radioactive virus was pelleted by centrifugation. The 70s viral RNA was extracted and digested with RNase T1, and the digestion products were separated by 2-dimensional PAGE (Yefenof et al, 1984).…”

“…2a,b) was similar to that of B-tropic viruses derived from either A-RadLV or D-RadLV \ C-78 (b) viral RNA cloned from A-RadLV. (Yefenof et al, 1984) The RNase T1-resistant oligonucleotide distribution of TV RNA (released by TIM-I cells) is shown in Figure 2c,d. Its pattern clearly deviated from that of viruses produced by the 127 cells ( Fig.…”