Host resistance directed selectively against H-2-deficient lymphoma variants. Analysis of the mechanism.

Abstract

Three independent variants with a profound reduction of cell surface H-2 have been selected from the C57BL/6 mouse-derived RBL-5 and EL-4 T lymphomas. After subcutaneous inoculation of low cell doses in syngeneic mice, the H-2- variants failed to grow out, whereas the H-2+ control lines showed progressive growth. No difference in growth rate or cloning efficiency was detectable in tissue culture. The in vivo difference in tumor outgrowth was analyzed in detail for one of the H-2-low lines. The outgrowth difference remained after the H-2-low variant and the control line had been injected subcutaneously in opposite flanks of the same mouse, and it was not dependent upon activity of mature T cells, since the same result was seen in athymic nude mice. The difference was partially sensitive to irradiation of the hosts. When mice were pretreated with anti-asialo GM1 antiserum, known to depress natural killer (NK) cell activity, the difference in outgrowth was abolished, and both the control line and the H-2- variant showed progressive growth in vivo. Experiments comparing the distribution and survival of isotope-prelabeled variant and wild type cells indicated that a rapid elimination of the former took place within 24 h after intravenous injection. These differences in tumor elimination were not seen in mice treated with anti-asialo GM1 antiserum. We conclude that the reduced tumorigenicity of sublines with impaired H-2 expression is largely, if not exclusively due to rapid elimination by NK cells. These findings may reflect an inverse, indirect relation between factors controlling H-2 expression and NK sensitivity. Another possible explanation is that major histocompatibility complex (MHC)-encoded gene products are directly involved in a regulatory signal in the NK cell system. According to this interpretation, immunological selectivity in the NK cell system would be achieved by the failure to recognize self-MHC, irrespective of the presence of foreign antigens, i.e. by detection of no-self rather than of nonself. This may also explain previous observations on H-2-linked hybrid resistance against lymphoid grafts and changes in H-2 phenotypes associated with tumor progression.

In vivo tumor cell rejection induced by NK cell inhibitory receptor blockade: Maintained tolerance to normal cells even in the presence of IL‐2

“…RMA-S is a TAP-2-deficient variant of RMA, generated by mutagenesis followed by selection for MHC class I deficiency [4,48,49]. The cells were cultured in complete RPMI 1640 (100 U/mL penicillin, 100 mg/mL streptomycin, 2 mM L-glutamine, 50 mM 2-ME (2-mercaptoethanol), 1 mM sodium pyruvate, non-essential aa and 10% heat inactivated FBS) in 7% CO 2 at 371C.…”

CD8α/α homodimers fail to function as co‐receptor for a CD8‐dependent TCR

“…Peptides were reconstituted in PBS to a concentration of 2 mM and stored at -20 C. All peptides were generated by ProImmune (Oxford, UK). Cell lines and mice RMA-S cells (H2 b ) are derived from a Rauscher virus-induced C57BL/6N T cell lymphoma and are TAP-deficient due to a point mutation in the TAP2 gene [20]. P1HTR (H2 d ) is a mastocytoma cell line that expresses Fc receptors on the cell surface.…”

Prolonged exposure of dendritic cells to maturation stimuli favors the induction of type‐2 cytotoxic T lymphocytes

“…After 3 days, cells were analyzed by flow cytometry for CFSE expression and intracellular cytokine production (upon stimulation by phorbol 12-myristate 13-acetate (PMA)/ionomycin triggering) after staining with cytokine (IFN-c or IL-4) and CD8 antibodies. Alternatively, on day 6 of culture, unmarked Tc1 and Tc2 cells were analyzed for cell surface molecule expression and intracellular cytokine production (upon antigen-specific stimulation by RMA cells [63] pulsed with 1 nM SIINFEKL, or PMA/ionomycin triggering) by staining with FITC-labeled anti-CD44, anti-CD62L, anti-CD137, anti-Va2, anti-IFN-c, PE-labeled anti-CD8, anti-CD28, anti-CD25, anti-OX40, anti-Vb5, anti-IL-4, and biotinlabeled anti-CD40L, anti-IL-10 antibodies, followed by Cychrome-labeled streptavidin as described in [29,43]. Dead cells were excluded by physical parameter and, when possible, by the addition of propidium iodide immediately before sample acquisition.…”

“…Tc1 and Tc2 cells were also evaluated for their cytolytic activity in a standard 4-h 51 Cr-release assay, using as targets RMA cells [63] unpulsed or pulsed with SIINFEKL (from 0.1 to 1000 nM).…”