Nonproducer malignant tumor cells with rescuable sarcoma virus genome isolated from a recurrent Moloney sarcoma.

Abstract

The characteristic features of sarcomas induced in mice by Moloney murine sarcoma virus (MSV-M), 1 namely rapid development and spontaneous regression, have prompted extensive investigations on humoral and cell immune response in this model (1). A cause-and-effect correlation between immune response and tumor regression can be concluded from observations in immunologically incompetent hosts. In X-ray-irradiated (2), thymus-deprived (3, 4), or congenitally athymic mice (5, 6), Moloney sarcomas always show progressive growth. In immunocompetent mice, the majority of Moloney sarcomas completely regress, though few may continue to grow or recur later (7-12). It has been proposed that this recurrence is due to the disappearance of a resistance state acquired during tumor regression (10), although the possibility that the recurrent tumor may differ from the primary one with respect to, for instance, immunosensitivity and]or antigenicity, was not considered. We have therefore studied the virological, oncogenic, and antigenic properties of a transplantable tumor that reappeared at the site of a primary regressed Moloney sarcoma. Also, two oncogenic cell lines derived from this tumor, and for comparative purposes, ascitic MSV-M-producing cells (13) and a Moloney helper virusproducing cell line established from these ascitic cells were included in these studies. The purpose of this investigation was to obtain information on the escape mechanism of tumor cells from immune destruction. Materials and Methods Animals, Virus and Cells. STU-inbred mice, MSV-M, ascitic MSV-M-producing cells (asc-MSV-M), and its helper-virus-producing culture derivative (Bc) were the same as those described in preceding studies (13-15

Genetic Variation of Neurotropic and Non-neurotropic Murine Coronaviruses

“…The strains MHV A59, MHV 1 and MHV 3 were a gift from P. Carthew, MRC Laboratory Animal Centre, Surrey, U.K. and originated from the American Type Culture Collection. All stock virus strains were propagated on monolayers of Sac(-) cells (Weiland et al, 1978) grown in minimal essential medium containing 5 % foetal calf serum at an m.o.i, of 0.1 TCIDs0/cell. The infected cell cultures were incubated at 37 °C and harvested 20 to 24 h post-infection (p.i.…”

Monoclonal Antibody Detects a Common Surface Antigen on Two Independently Established Murine Moloney Sarcoma Virus Non-producer Transformants

“…Superinfection of these NP cells with Moloney helper virus derived from the syngeneic Bc cells (Weiland & Mussgay, 1976) generated the Sac producer cell line producing both Mo-MSV and helper virus. Details of their origin have been described previously (Weiland et al, 1978). More recently, the derivation of transformants from tumours induced in adult STU mice after intramuscular (i.m.)…”

“…In previous communications, we have reported the expression of a serologically and biochemically defined surface antigen on Moloney sarcoma virus (Mo-MSV) non-productively transformed Sac cells of STU mouse origin (Weiland et al, 1978;Hunsmann et al, 1980). This antigen was not found on untransformed Moloney helper virus (Mo-MLV)-producing cells and was neither related serologically to structural polypeptides of murine C-type viruses nor to components of embryonal STU mouse fibroblasts and foetal bovine serum.…”

“…Only transplantation of Mo-MLV-infected Sac cells led to anti-46K antibody development (Weiland et al, 1978). In order to obtain more information about this antigen, further transformants of different aetiology were tested for expression of an antigen identical or related to 46K antigen.…”

“…Application of these monoclonal antibodies led to the det~ection of only one further Mo-MSV NP transformant, PV-TC-77, induced with the progressor strain of Mo-MSV 0000-6524 © 1985 SGM (Weiland & Mussgay, 1980, 1982 which expressed a surface antigen with the same molecular weight and biological properties as the Sac cell surface antigen. Therefore, two independently established Mo-MSV transformants (Weiland et al, 1978;Weiland & Mussgay, 1980)expressed a cell surface antigen detectable by monoclonal antibodies against the 46K antigen.…”