Cell mediated PPD specific cytotoxicity against human monocyte targets: II. IL-2 expansion improves the strength and discriminatory power of CTLs used for cellular typing

Self-nonself discrimination and repertoire selection of human T cells differentiated in an HLA-semiallogeneic environment following bone marrow transplantation for severe combined immunodeficiency

We have analyzed allorecognition, HLA restriction and T cell receptor (TcR) diversity in an HLA-heterozygous (HLA-DRw6,7) severe combined immunodeficiency (SCID) patient whose T cell system had been repopulated by HLA-homozygous (HLA-DRw6) paternal T cells following T cell-depleted bone marrow transplantation (BMT). Donor origin of T cells and host origin of antigen-presenting cells (APC) in peripheral blood and BM is shown by HLA typing of separated cell populations and two-color immunofluorescence using an anti-HLA monoclonal antibody (mAb). Peripheral blood lymphocytes (PBL) from the chimeric patient proliferate normally against PHA, anti-TcR/CD3 mAb, pooled allogeneic PBL, and also against the recall antigen (Ag) tetanus toxoid and purified protein derivative of tuberculin (PPD) following immunization, suggesting recognition by donor (DRw6) T cells of Ag presented by host (DRw6,7) APC. PPD-specific cytotoxic T lymphocytes generated in vitro from patient PBL post-BMT display specific cytotoxicity against targets expressing DRw6 and DR7, but not against DR-mismatched targets, suggesting that HLA restriction of Ag recognition may occur through determinants expressed by the host and not by the donor. Donor T cells differentiated in the HLA-semiallogeneic host show specific proliferative and cytotoxic responses against HLA-mismatched stimulators, but not against stimulators taken from the host, expressing the host-specific HLA-haplotype, or expressing the host-specific HLA-DR7 antigens. Compared to T cells directly taken from the donor, differentiation of donor T cells in the host is associated with a significant decrease of T cells expressing TcR V beta 5 and V alpha 2 determinants, while no differences in the abundance of of TcR V beta 6, V beta 8 and V beta 12 subsets were noticed. We conclude that allorecognition, major histocompatibility complex (MHC) restriction and TcR diversity generation of human T cells can be modulated through differentiation in an MHC-different environment, as had been previously shown to be the case in murine model systems.

Human T4+ T-lymphocyte clones specific for the B fragment of tetanus toxin

Two T4+ cloned T-lymphocyte lines specific for a papain digest product of tetanus toxin are functionally characterized. The two clones were obtained from peripheral blood mononuclear cells activated in vitro by tetanus toxoid, expanded with IL-2, and cloned in soft agar. Both clones could be induced to undergo blastogenesis with tetanus toxoid, tetanus toxin, and the B fragment but not the C fragment of tetanus toxin. In addition, both clones caused cytolysis of plastic adherent cell targets cocultured for 18 hr with either tetanus or the B fragment. Antigen specific proliferation and cytolytic activity were MHC-class I restricted.

Binding, uptake and degradation of human recombinant interleukin-2 (125 ala) in activated human T- and B-lymphocytes and in monocyte-macrophages

High-affinity receptors for IL-2 (ala 125) were demonstrated in PHA-, antigen- and/or alloantigen-activated human T-cells (both proliferative and cytotoxic), in PWM-activated human B-cells and in human monocyte-macrophages. Binding in PHA-blasts was irreversible and Ca++-independent, and labelled IL-2 (ala 125) bound at 4 degrees C could not be removed by trypsin treatment. Binding was strongly pH-dependent, and lowering of pH caused release of nearly all cell associated radioactivity at 4 degrees C. In T- and B-lymphocytes, additional binding at high ligand concentrations was accounted for by receptors of much lower affinity. Binding to low-affinity receptors appeared reversible. At 4 degrees C, 2.2 pM labelled IL-2 (ala 125) bound to PHA-blasts (3.6 X 10(6)/ml) with a half time of about 15 min, and the association rate constant was approximately 8 X 10(9) M-1 min-1. The number of high affinity receptors per T-cell was determined as 9.7 +/- 0.5 X 10(2). At 37 degrees C, 60% of the tracer bound at 4 degrees C was rapidly internalized (Kint = 0.89 X 10(-1) min-1), and radioactivity comprising small MW products and iodotyrosine was released following a sigmoidal curve after a 20 min lag period. Similar results were obtained in PWM-activated B-lymphocytes and in cultured monocytes. It is concluded that high-affinity receptors mediate binding, uptake and degradation of IL-2 in activated human T- and B-lymphocytes and in monocyte-macrophages.

Cytotoxic human HLA class II restricted purified protein derivative-reactive T-lymphocyte clones. IV. Analysis of HLA restriction pattern and mycobacterial antigen specificity

Human T-lymphocyte clones specific for antigenic components of purified protein derivative (PPD) of tuberculin were generated by limiting dilution using in vitro PPD-activated peripheral blood mononuclear cells from a single donor. The HLA restriction specificity of eight clones that were cytotoxic against autologous PPD-pulsed monocyte targets, was examined against a panel of allogeneic PPD pulsed targets. In agreement with our findings with bulk-expanded PPD-reactive cytotoxic T lymphocytes, all clones were restricted by HLA class II antigens: seven by HLA-DR 2 and one by HLA-DRw10--the other HLA-DR antigen of the donor. All clones were CD3+, CD4+, CD8-. One clone exhibited, in addition to HLA-DR2 restriction, unrestricted cytotoxic alloreactivity against HLA-DR1. In monoclonal antibody-blocking experiments the latter clone was the only one that was blocked. Its lytic ability was abolished by two monoclonal antibodies against monomorphic HLA-DR determinants. The antigen specificity of the clones was studied by using autologous monocyte targets pulsed with antigens prepared from a range of different mycobacterial species. All seven HLA-DR2-restricted clones reacted with the majority of antigens tested. In contrast, the HLA-DRw10-restricted clone reacted exclusively with an antigen unique to PPD.

Cell mediated PPD specific cytotoxicity against human monocyte targets: III. Cellular typing with CTLs restricted by class II HLA antigens

The HLA-restriction specificity of a set of Cytotoxic T-Lymphocytes (CTLs) derived from 20 different individuals and with specificity for antigenic components in Purified Protein Derivative of tuberculin (PPD) were examined against a panel of 50 unrelated target cell donors. PPD pulsed monocytes were used as antigen presenting target cells. CTLs were generated by Interleukin-2 (IL-2) expansion of in vitro PPD activated Peripheral Blood Mononuclear Cells (PBM). The results confirm our previous finding that PPD-specific CTLs are restricted by HLA-class II - and not by class I antigens. The 20 CTLs used together provide reliable cellular typing reagents for the antigens HLA-DR2, -3, -4 and -7 and less so for the antigens HLA-DR1 and -5. In contrast, sharing between CTL- and target cell donors of HLA-DRw6 and -w8 correlates poorly to PPD-specific cytotoxicity. A few consistent exceptional patterns were observed. In one case lack of lysis in spite of HLA-DR antigen sharing could be explained by a split of HLA-DR2 into a normal and a short variant. Positive reactions in combinations, where no HLA-DR antigens are shared, were only few and evenly distributed among CTLs. Thus our findings indicate that our bulk CTLs predominantly contain clones restricted by determinants strongly associated to the serologically defined HLA-DR antigens.