A Transmissible Antigen Detected in Two Cell Lines Derived from Human Tumours

Abstract

SUMMARYVesicular stomatitis virus (VSV) can form 'pseudotype' particles with neutralization antigen(s) derived from mouse or chicken leukaemia viruses. These pseudotype particles contain the genome of VSV, but show neutralization, host-range and interference specificity of the corresponding oncornavirus. Pseudotypes were also detected following the growth of VSV in two established cell lines derived from human tumours: in MaTu derived from mammary carcinoma and in Tu-I35 derived from a sarcoma. No virus-like particles were detected in these cells by labelling with pH]-uridine followed by sucrose density gradient sedimentation. Media from these cultures did not contain DNA polymerase. Nevertheless, the capacity to produce VSV pseudotype was transmitted to some pseudotype-negative cells following their co-cultivation with X-irradiated, pseudotype-positive cells. Cell-free filtrates did not transmit the property. An antigen detected by immunofluorescence was also consistently transmitted. The VSV pseudotype produced in cells infected by co-cultivation possessed the same neutralization specificity as VSV pseudotype produced in the original tumour cells.

An unusual transmissible agent ? MaTu

“…Considering together all the observations on MaTu described previously [15,16] and in the present paper, we are coming to the conclusion that the most salient feature of MaTu is accumulation of paradoxes. In fact, every single of its known properties is in apparent contradiction to another, or to properties of known viruses.…”

“…We have previously reported [16] that MaTu agent was transmissible only to HeLa, but not to human embryo cells or to any of several animal cell lines tested. In these experiments we were detecting the presence of MaTu by the capacity to give rise to VSV pseudotype, or to specific interference with plaque formation by this pseudotype.…”

“…SIRC (a line from rabbit cornea, both control and X-MLVinfected) and Vero (African green monkey cell line) were used previously [ 17]. MaTu agent [15,16] was from original MaTu cells [12] transferred into our stock of HeLa by cocultivation with MaTu cells treated with mitomycin C, to ensure that control and MaTuinfected cells are comparable. MaTu cells were incubated for 3 h at 37 °C in media with 5 gg/ml of mitomycin C (Calbiochem).…”

“…Its origin and some properties have been described [15,16]. Briefly summarized, its only known biological manifestation in infected cells is the capacity to donate surface antigen for efficient formation of VSV (MaTu) pseudotypes.…”

Lymphocytic choriomeningitis virus: invisible but not innocent

“…The MaTu agent can be transmitted only by cell-to-cell contact, but not by filtered media from infected cells (Zavada et al, 1972(Zavada et al, , 1974. It has an extremely restricted host range and is transmissible to HeLa and HEF cells, but not to various human tumor cell lines or animal cell cultures.…”