Enrichment of effector T lymphocytes specific to H-2 antigens by elution from allogeneic target cells and characterization of the eluted lymphocyte population

Utilization of the MHC class I (H-2Kb) purified molecule and its synthetic peptides for inhibition of Kb-specific suppressor T cells and their induction in vivo by the MHC peptides

Six synthetic peptides of the MHC class I molecule corresponding to individual H-2Kb participants in amino acid sequences of domains alpha 1 (peptide 1 and 2) and alpha 2 (peptides 3, 4, 5, 6) were selected. Kb-specific suppressor T cells (Ts) were induced in vivo in mice, then pretreated with a set of peptides and assayed by proliferation decrease in a three-cell lymphocyte culture (MLC). The effector function of Ts was abolished by the complex of the alpha 2-domain peptides (but not by the alpha 1-domain peptides) and decreased by particular peptides separately (4, 5, 6) of the alpha 2-domain. Both alpha 1- and alpha 2-domain peptides, added in high concentration, decreased otherwise efficient enrichment of Ts during the absorption-elution procedure on the syngeneic macrophage (M psi) monolayers. A similar significant effect was observed using the purified Kb molecule (100 micrograms/ml) in the allogeneic M psi monolayer. Interaction between Ts receptors and some MHC peptides indicates in effector Ts activation in vivo by induction with peptides 5 and 6 of the alpha 2-domain. The fine mechanisms of interaction between MHC class I molecule epitopes and T-cell receptors of each of the T-cell subsets separately are presently being studied.

Special differentiation requirements of original and enriched secondary cytotoxic T lymphocyte precursors (pCTL-2 memory cell) specific for the class I histocompatibility molecule

The in vivo-induced pCTL-2 cells of the L3T4- Lyt-2+ phenotype specific for the H-2Kb molecule are converted into effector CTLs in mixed lymphocyte culture (MLC) in the presence of heat-treated donor stimulators much more efficiently when the donor and recipient differ from each other, not only in the major histocompatibility complex (MHC) class I (H-2Kb) (anti-B10.MBR B10.AKM) but also in the MHC classes I + II, i.e., Kb + Ib (anti-C57BL/6 B10.D2 (R101)). The differentiation of original pCTL-2 is enhanced as the result of a synergistic action of the Kb alloantigen and rIL-2 in small doses. The anti-Kb pCTL-2, after their separation from helper T cells non-adherent to the macrophage donor monolayer and their subsequent elution from it, give rise to pronounced differentiation in simplified conditions over 3 days in monoculture in the absence of both stimulators and rIL-2. It is suggested that spontaneous and highly efficient specific differentiation of the eluted pCTL-2 is due to a dramatically enhanced secretion of the CTL differentiation factor by pCTL-2 themselves, and in addition, rIL-2 can also contribute to the secretion of this factor.

Requirements for induction of specific suppressor T cells and detection of their H-2 antigen-binding receptors by fractionation on target cell monolayers

The MC-resistant specific suppressor T cells that inhibit DNA synthesis and CTL generation in MLC were induced in vivo by gamma-irradiated allogeneic lymphoid cells in a large dose. MLRs were inhibited only slightly when triggered by third-party cells, even neighbouring with the corresponding stimulators. Unlike the irradiated cells, intact allogeneic lymphoid cells induced a mixture of macrophage-like and T-cell suppressors with a pronounced non-specific component of the action. Syngeneic cells induced low active non-specific suppressors of macrophage type only. The suppression was not due to a cytotoxic effect, since specific T suppressors differed from CTL by conditions of induction and high sensitivity to gamma-irradiation and from CTL precursors by high sensitivity to CY and HC. The specific T-suppressors could be selectively removed by adherence to a macrophage monolayer of the corresponding donor. The subsequent elution of adherent lymphocytes with pronase resulted in enrichment of specific T suppressors by a factor of 30 and 2.6, as judged by reduction in the number of lymphocytes required for 50% inhibition of DNA synthesis and 33% inhibition of CTL generation, respectively. The high specificity of this enrichment is shown by using both syngeneic monolayers for fractionation and third-party stimulators in MLR for testing and by disappearance of slight non-specific suppression caused by non-fractionated suppression. Complete inactivation of the eluted suppressors with anti-Thy-1.2 and anti-T antibodies, their resistance to anti-Mls antibodies, carrageenin, and carbonyl iron, together with the data of autoradiographic study and total DNA synthesis in the population indicate that the eluted highly specific suppressors represent mainly DNA-synthesizing large and medium T lymphocytes.

Cross-reactivity of cytotoxic T-lymphocyte antigen-binding receptors immune to antigens of the H-2 system

Anti-B10 D2 (anti-KbDb) cytotoxic T lymphocytes (CTL) and monospecific anti-Kk and anti-Dd CTL, separated from their mixture in anti-A B10 lymphocytes and concentrated with the absorption-elution technique on the macrophage monolayers of various genotypes, gave rise to cross-lysis of third-party target cells. Anti-B6 R101 (anti-Kb) CTL, which display a cross-lysis of mutant Kbd (M505) and Kba (Hzl) target cells, were separated into two fractions, one of them being able and the other unable to adhere to the cell monolayer of the particular mutant. The fraction of anti-Kb CTL adherent to Kba antigen was isolated by elution from the Hzl cell monolayer. These anti-Kba CTL and CTL eluted from the B6 cell monolayer displayed a considerably higher cytotoxic effect on B6 than on Hzl target cells. This difference was not due to lower sensitivity of Hzl targets to lysis. The findings indicate that anti-Kb CTL are homogeneous in the specificity of their receptors. The H-2 molecule is presumed to bear a single CTL determinant only, which induces a CTL clone or a group of clones homogeneous in specificity but heterogeneous in the affinity of its receptors.

Specific separation of cytotoxic T lymphocytes on immunoadsorptive films

A method for the specific separation of cytotoxic T lymphocytes (CTL) on immunoadsorptive films is described. The films were prepared by polymerizing a mixture of gelatine and polyethyleneimine with glutaraldehyde on the bottom of plastic tissue culture flasks. By using an excess of glutaraldehyde unsaturated aldehyde groups on the film surface can react with other chemical groups predominantly with aliphatic amino groups. In this study detergent solubilized H-2 antigens were conjugated covalently to the films CTL, prepared by filtering spleen cells from alloimmunized mice through nylon wool columns, were incubated on immunoadsorptive films and the adsorbed cells were quantitatively recovered by mechanical detachment. The cells were functionally intact and tested in a microcytotoxicity assay using embryonic fibroblasts as target cells. Specificity adsorbed cells were enriched in specific cytotoxic cells up to 100 fold compared to the original fraction. Depending on the cell density per film area the non-adsorbed cells could be quantitatively depleted of CTL. The immunoadsorptive films are stabile at 37 degrees C and can be reused.