Anti-tumour cell-mediated immune reactions were studied by the chromium release test (CRT) in mice bearing autochtonous Murine Sarcoma Virus (MSV)-induced sarcomas or syngeneic transplants of lymphomas with various antigenic specificities. Cytotoxic lymphoid cells were detected during tumor growth, but disappeared rapidly after day 13–15 in “progressors”, and more slowly in mice which were able to reject the tumor (“regressors”). The level of cytolytic activity of lymphoid cells in the spleen of “regressors” did not parallel the immune protection. No blocking of the cytotoxic activity of lymphoid cells was detected in CRT using either “progressor”, or “regressor” sera. The discrepancies which exist between these results and those which were obtained in the same tumor system by colony inhibition test or microcytotoxicity assay may suggest that different phenomena, possibly involving different lymphoid cell populations, were studied by the various methods. The antigenic specificity of the immune reactions which were evidenced by the CRT was not identical to those revealed by serological methods, cross-reactivity being regularly observed in CRT between FMRGi+ and G+lymphomas.



REACTION D'IMMUNITE CELLULAIRE CONTRE LES TUMEURS INDUITES PAR LES ONCORNAVIRUS. I. CINETIQUE ET SPECIFICITE DE LA REPONSE IMMUNE DANS LES TUMEURS INDUITES PAR LE VIRUS DU SARCOME DE LA SOURIS ET DANS LES LYMPHOMES TRANSPLANTES



Les reactions antitumorales a mediation cellulaire ont ete etudiees par le test de liberation de chrome (C.R.T.) chez des souris portant des sarcomes induits par le virus du sarcome de la souris (MSV) ou des lymphomes syngeniques transplantes ayant differentes specificites antigeniques. Les lymphocytes cytotoxiques ont ete detectes au cours de la croissance tumorale, mais ils disparaissent rapidement apres le 13e-15e jours chez les “progresseurs”, et plus lentement chez les souris qui ont rejete leur tumeur (“regresseurs”). L'activite cytotoxique des cellules spleniques des “regresseurs” n'etait pas parallele a la protection immune. Aucun blocage de l'activite cytotoxique des cellules lymphoides par les serums de “progresseurs” ou de “regresseurs” n'a ete detecte par le C.R.T. Les differences entre ces resultats et ceux qui ont ete obtenus dans le měme systeme tumoral par les techniques d'inhibition des colonies ou de microcytotoxicite suggerent que differents phenomenes, comprenant peut-ětre plusieurs populations de cellules lymphoides, ont ete etudies par ces techniques. La specificite antigenique des reactions immunes mises en evidence par C.R.T. n'est pas identique a celle que l'on a observe par des methodes serologiques, une reaction croisee entre les lymphomes FMRGi+ et les lymphomes G+ etant regulierement detectee par le C.R.T.

Cell‐mediated reaction against tumors induced by oncornaviruses. I. Kinetics and specificity of the immune response in Murine sarcoma virus (MSV)‐induced tumors and transplanted lymphomas

The nature of the target antigen, expressed on murine sarcoma virus (MSV) and related murine tumors which reacts with T killer lymphocytes, remains ill-defined. The experiments reported here show that: (a) the previously described H-2 restriction phenomenon is found under all experimental conditions including 3–4 and 16–20-h chromium release tests. With 16–20 h tests and highly efficient T lymphocytes however, quantitative methods are necessary to demonstrate the H-2 restriction. These results support the hypothesis that H-2 molecules may be determinant in the structure and/or in the function of the cytolytic T lymphocyte (CTL) reactive antigen. (b) Under syngeneic conditions (i.e. using H-2-identical immune lymphocytes, stimulators and target cells), the pattern of specificities recognized by anti-MSV or anti-Friend T killer cells on 20 different lymphomas suggests that the main reactive antigen is an “FMR-like” substance. Identical conclusions were drawn from competition experiments. (c) Blockings were obtained by pre-incubation of the target cells with a goat anti-gp70, suggesting a possible role of the viral gp70 in the antigen recognized. However, this could be due to nonspecific reactions as two other anti-gp70 sera as well as with antisera directed against the viral components gp45, pr60, p30, p15, p12 and p10 did not block. The CTL/tumor cell interaction was not inhibited by virion-associated antigens added to the medium. Lysostrip and co-capping experiments have failed to reveal an association between H-2 and gp70. The nature of the viral protein bearing the “FMR-like” substance therefore remains to be established.

Studies on the nature of the cell surface antigen reacting with cytolytic T lymphocytes in murine oncornavirusinduced tumors

WI-38 cells were used as indicators of toxicity in comparison to in vivo animal tests. Cell culture tests included 1) elution with cell culture medium, 2) direct contact with an agarose overlay, 3) elution with saline on an agarose overlay, and 4) elution with cottonseed oil on an agarose overlay. Animal tests performed were 1) systemic injection tests in mice, 2) intracutaneous tests in rabbits, and 3) intramuscular implantation in rabbits. Materials tested included rubber, polypropylene, polyvinyl chloride, copolymers, paper, polyethylene, and silicone rubber. WI-38 cell testing, by elution with cell culture medium, was the most sensitive indicator of toxicity followed in descending order by the intracutaneous rabbit test and the direct contact (agarose overlay) cell culture test. The other tests proved relatively insensitive measures of toxicity. Positive results were obtained with rubber, polyvinyl chloride, copolymers, and paper. The degree of correlation between in vitro and in vivo tests was rubber...

Human Cell Culture Toxicity Testing of Medical Devices and Correlation to Animal Tests

The biocompatibility of a wide variety of biomaterials was quantitatively assessed, in a physiologically normal environment" as to cytotoxicity induced in WI-38 cells by cell culture medium extracts. Materials tested included PVC plastic, rubber, silicone rubber, polyethylene, polypropylene, acetal, polyurethane, Teflon, nylon, epoxy, and polystyrene. Cell culture test results were correlated to U.S.P. animal tests. Potential test artifacts, lead, barium, cadmium, and endotoxin were tested for cytotoxicity in WI-38 cells. Cell culture methods yielded more positive tests, particularly rubber, PVC plastic and silicone rubber compounds, than observed in U.S.P. animal tests. Positivity in animal tests did not correlate quantitatively to cytotoxic titers in cell culture. Discrepancies between cell cultures tests and animal tests, specifically rubber compounds, were attributable, in some instances, to differentials in elution efficiency between saline, cottonseed oil, and complete MEM cell culture medium. In other instances, particularly PVC plastics, differences between cell culture and animal test results were due to an inherent difference in the two indicator systems to respond to specific toxic moieties.

Quantitative cell culture biocompatibility testing of medical devices and correlation to animal tests.

Human-mouse somatic cell hybrids, containing chromosome 7 from an SV40-transformed human cell line as the only human chromosome, were injected into the same inbred strain of mouse as the mouse parental cell, and the humoral immune response assayed A cell-surface antigen(s) coded for by the chromosome 7 common to all human fibroblastic cell lines tested and also found on African green monkey kidney cell lines was demonstrated No reactivity to SV40-induced TSTA was detected

Cell surface antigens coded for by the human chromosome 7.

Summary Analysis of a normal tissue culture cell line (L strain) by serological methods and by induction of transplantation immunity revealed three antigens associated with murine leukemias present in these nonleukemic cells: ( a ) the group-specific antigen of murine leukemia viruses; ( b ) an antigen common to Friend, Moloney, Rauscher, and Graffi leukemias (FMRGi) The group-specific and FMRGi antigens are probably related to the nonleukemogenic type C virus present in L cells The nature of this agent is briefly discussed; ( c ) a new antigen which is also present in various virus-induced leukemias of several strains and in the dimethylbenzanthracene-induced EL4 leukemia It was called L antigen L antigen was shown to be different from other already described murine leukemia antigens No tumor rejection of L + tumors was observed in hyperimmune mice despite the presence of cytotoxic antibodies in the blood Enhancement of tumor growth was frequently observed in this situation The origin of L antigen and its role in tumor immunity are briefly discussed

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J. C. Leclerc

Papers

Antigenic Analysis of L Strain Cells: A New Murine Leukemia-associated Antigen, “L”