Class-II HLA restriction of antigen-specific human T-lymphocyte clones. Evidence of restriction elements on both DR and MT molecules

Direct detection and magnetic isolation of Chlamydia trachomatis major outer membrane protein-specific CD8+ CTLs with HLA class I tetramers

We recently identified HLA class I-presented epitopes in the major outer membrane protein (MOMP) of Chlamydia trachomatis that elicit CTL responses in human genital tract infections. T cells possessing cytolytic activities specific for these epitopes could be detected following in vitro stimulation of peripheral blood CD8(+) T cells with peptides. In the present study we used HLA-A2 tetramers for detailed characterization of MOMP-specific CTL responses. Ex vivo tetramer analysis detected MOMP-specific T cells in the peripheral blood of infected individuals at significant frequencies (0.01-0.20% of CD8(+) T cells). After in vitro stimulation with peptides, the frequencies of MOMP peptide-specific T cells increased up to 2.34% of CD8(+) T cells in bulk cultures. In contrast, HLA-A2/MOMP tetramer-binding T cells were virtually undetectable in the peripheral blood from uninfected individuals, either ex vivo or after 3 wk of in vitro peptide stimulation of their T cells. Magnetically sorted, tetramer-bound T cells specifically lysed peptide-pulsed targets as well as C. trachomatis-infected epithelial cells with nearly 50-fold greater per cell efficiency than that of unsorted populations. This study provides conclusive evidence of in vivo induction of HLA class I-restricted CD8(+) CTL responses to C. trachomatis MOMP. Direct detection of these cells with tetramers will allow their further characterization without prior manipulation and facilitate monitoring of CTL responses during infections and in immunization trials with MOMP-based vaccines.

T-cell receptor beta usage by 35 different antigen-specific T-cell clones restricted by HLA-Dw4 or -Dw14.1

We studied whether antigen-specific T cells being restricted by the very similar HLA-Dw4 and/or -Dw14.1 molecules might demonstrate homogeneities in parts of their TCR. TCCs were generated from three individuals who were all HLA-Dw4/Dw14.1 heterozygous. Thirty-five TCCs specific for PPD or TT and restricted by HLA-Dw4 and/or -Dw14.1 were selected for TCR beta gene sequencing. We found that 19 different V beta genes from 13 V beta families were expressed by these TCCs. Thus, it seems that many different TCRV beta genes may be used by TCCs restricted by these HLA molecules. For PPD-specific TCCs, a possible biased usage of V beta 8, as well as possible preferential usage of a CDR3 motif, were found.

Characterization of skin-infiltrating lymphocytes in patients with psoriasis

In this study, skin-infiltrating cells in psoriasis patients were characterized in biopsies from both involved and uninvolved skin. Histologic examination of biopsies showed the presence of both CD4+ and CD8+ T cells and the lack of B lymphocytes. Skin biopsies were also placed in tissue culture medium supplemented with human serum, interleukin-2 (IL-2), and irradiated autologous blood lymphocytes. T lymphocytes grew from both plaques and univolved skin biopsies and consisted of a heterogeneous population of T-cell subsets. The immunophenotypic analysis of cultured cells was comparable to the histologic examination on frozen section, i.e., there was a greater number of CD4/CDw29+ cells than CD8+/CD45+ cells. Cultures were tested in the primed lymphocyte test (PLT) and cell-mediated lympholysis (CML) assays. All cultures tested demonstrated secondary proliferative but not cytolytic reactivity. The PLT results indicate that the cell cultures generated are autoreactive. This autoreactivity was found to be directed against non-human leukocyte antigens (HLA), i.e., minor HLA with some restriction to major HLA antigens.

Differential expression of major histocompatibility complex class II antigens on human keratinocytes

Skin biopsies from 136 patients with 30 different dermatoses and eight biopsies of normal skin were investigated with the avidin-biotin-peroxidase complex method with regard to the expression of major histocompatibility complex class II antigens human leukocyte antigen (HLA) HLA-DR, HLA-DQ, HLA-DP on keratinocytes. In normal skin the expression of these antigens was restricted to acrosyringia and Langerhans cells. In the dermatoses investigated HLA-DR was found in 51.5% (70 of 136), HLA-DQ in 24.3% (33 of 136), and HLA-DP in 20.5% (8 of 39). In 37 cases (27.2%) only HLA-DR could be detected, whereas in 33 cases (24.3%) HLA-DR was expressed jointly with HLA-DQ. Coexpression of HLA-DR and HLA-DQ was found especially often in cutaneous T cell lymphomas, skin tumors, and inflammatory dermatoses.

Antigen presentation by adherent cells from human peripheral blood. Correlation between T-cell activation and expression of HLA-DQ and -DR antigens

The ability of cells with different amounts of HLA-DQ or -DR to support T-cell proliferation in response to foreign antigens was investigated. Adherent cells were stained with monoclonal antibodies and sorted in the fluorescence-activated cell sorter (FACS) into (a) DQ-positive and DQ-negative subsets, with monoclonal anti-DQ; or (b) subsets expressing different density of DR determinants. Expression of HLA-DQ correlated with increased density of DR. The subset of cells expressing detectable DQ and increased density of DR was found to be more efficient in presenting mumps or tetanus toxoid antigen to T cells than were the DQ-negative, low-DR density adherent cells. Similar results were obtained with primary cultures of T cells from blood and with cloned antigen-specific T-cell lines, restricted by a single DR-subregion specificity. Our results suggest that quantitative variation in DR/DQ molecules expressed on monocytes correlates with their ability to support T-cell responses to nominal antigens. It is not clear whether this is due to only class II antigen density on the surface of the accessory cells or whether other factors are involved.

Class II antigens in Hashimoto thyroiditis. I. Synthesis and expression of HLA-DR and HLA-DQ by thyroid epithelial cells

Aberrant expression of HLA-DR antigens on epithelial cells is seen in various organ-specific autoimmune disorders including Hashimoto thyroiditis (HT). Expression of HLA-DQ has so far not been demonstrated on these cells. We report here that thyroid epithelial cells (TEC) in HT, in addition to the known aberrant expression of HLA-DR, coexpress HLA-DQ antigens. Furthermore we provide evidence that class II antigens are synthesized by TEC themselves by demonstration of intracellular HLA-DR gamma-chain. These findings support the theory that TEC may be able to present (auto)antigens in vivo thus perhaps contributing to the perpetuation of thyroid destruction. As expression of class II antigens on TEC was never observed in non- or weakly infiltrated areas, we propose that infiltration by T cells is necessary to induce this aberrant expression of class II antigens.

Comparison of HLA-Dw1 and -Dw2 positive adherent cells in antigen presentation to heterozygous T-cell lines: a low rubella antigen-specific response associated with HLA-Dw2

T-cell lines specific for purified tuberculin (PPD), rubella, and herpes simplex virus (HSV) antigens were established from two Dw1/w2 heterozygous subjects. Fresh peripheral blood monocytes from healthy individuals with shared and non-shared D-antigens were used as presenting cells and the T-cell lines as responders in lymphocyte blast transformation assays with specific antigens. An HLA-restricted reaction was seen with all the antigens, although the PPD- and HSV-specific cell lines reacted stronger than rubella-specific lines when the specific antigens were presented by monocytes not sharing the D-antigens. A significantly lower response was seen when rubella antigen was presented by Dw2 positive monocytes as compared to response promoted by Dw1 positive monocytes (p less than 0.0001, Mann-Whitney U-test), whereas no such difference was seen in responses to PPD or herpes simplex antigen.

Despite lack of monospecific anti-DRw13 sera, a corresponding class II determinant can be defined by a DRw13 restricted anti-influenza virus T cell clone

The study of a T3+ T4+ T8- human T cell clone COTC2 with both specific proliferative response and cytolytic activity for influenza A virus infected cells reveals that: the restricting element of this clone is strongly associated with DRw13 molecule(s) as seen by the study of a large panel of antigen presenting cells (APC) and by the observation that monoclonal antibodies (MoAb) specific for DR molecules inhibit its proliferative activity while anti-DQ MoAb do not. These results indicate that there exists a DRw13 associated determinant that can be defined at the functional level by COTC2 recognition despite the absence of monospecific anti-DRw13 serum. In contrast to the results found by other groups, the restriction of this DRw13 restricted clone follows the DRw13 serological definition irrespective of the DW type of the APC. These results indicate that the polymorphism of HLA class II molecules can be further defined at the functional level by monoclonal populations of T cells in conjunction with molecular definition.

Identification, at the genomic level, of an HLA-DR restriction element for cloned antigen-specific T4 cells

Two T4 cell clones (TLC) specific for antigenic epitopes on Chlamydia trachomatis were studied. Using a panel of allogeneic antigen-presenting cells (APC), both TLC were found to be restricted by HLA class II elements closely associated with, but not identical to the DRw5S specificity, as determined by highly selected alloantisera, a monoclonal antibody (mAb), 109d6, and confirmed on the DNA level by determination of restriction fragment length polymorphisms (RFLP) with a DR beta probe. Furthermore, HLA-DR-specific mAb, including 109d6, but not other HLA class II- or class I-specific antibodies inhibited the two TLC, strongly suggesting that the restriction element is expressed by a DR molecule. Using digestion with Hind III restriction enzyme and a DR beta probe, we found a complete concordance between the appearance of a 9.3 kilobase band and the ability of allogeneic APC to restimulate the T cell clones. Thus, the restriction element for these T cell clones appear to be expressed by DR molecules, but can, at present, only be detected at the genomic level.

Characterization of Chlamydia trachomatis serotypes by human T-lymphocyte clones

T cells primed to Chlamydia trachomatis serotypes A, F, and K were cloned by limiting dilution. All T-lymphocyte clones obtained reacted only with C. trachomatis antigens. The proliferative capacity of 89 clones was studied with autologous non-T cells as antigen-presenting cells and the chlamydia serotypes A, B, D, F, K, and LGV-2 as antigens. Most of the clones reacted to several of the chlamydia strains, indicating common antigenic determinants. Other T-cell clones reacted with only a few serotypes. On the basis of the proliferation of the T-cell clones to the chlamydia strains and to interleukin-2, different reactivity patterns were obtained, which possibly can be used to differentiate among the chlamydia strains.

HLA-DR-, MB- and novel DC-related determinants restrict purified protein derivative of tuberculin (PPD)-stimulated human T cell proliferation

Class II major histocompatibility complex determinants restricting recognition of tuberculin antigens (purified protein derivative; PPD) were studied by using monoclonal antibodies (mAb) to block lymphoproliferative responses. Anti-class II mAb were shown to exert inhibitory effects at the level of the antigen-presenting cells, without inducing suppressive lymphocytes or macrophages. Using panels of HLA-typed antigen-presenting cells and nonalloreactive proliferative T cell lines, derived by limiting dilution, restriction elements for PPD responses appeared to correlate with the donor's HLA-DRw6 specificity (one clone), MB1 (one clone), MB3 (one clone), or no established class II (or class I) specificity (three clones). mAb TU22, reacting with nonpolymorphic DC-like determinants, strongly inhibited stimulation of all clones except that restricted by DR antigens, suggesting the DC-like character not only of the MB1- and MB3-associated, but also of the unassigned, restriction elements of these cloned lines. In contrast, stimulation of the DR-restricted line was strongly inhibited by DR/SB-specific mAb which only weakly inhibited the stimulation of clones restricted by DC-like determinants. These results suggest that clonally distributed PPD-reactive proliferative lymphocytes from a single donor may be restricted by at least three different class II determinants (HLA-DR, MB, or a second, novel, DC-related molecule).

Antigen-specific T cell clones restricted by DR, DRw53 (MT), or DP (SB) Class II HLA molecules. Inhibition studies with monoclonal HLA-specific antibodies

T lymphocyte clones (TLCs) specific for Chlamydia trachomatis were obtained after limiting dilution of activated T cells from a single donor, BS (HLA-A3; B7,15; DR1, 4; DRw53; DPw4). Most of the proliferative TLCs obtained apparently used restriction elements on DR1 or DR4 molecules, expressed in the antigen-presenting cells (APC). The restriction pattern of two TLCs, however, closely followed the DRw53 specificity, while one TLC seemed to be restricted by elements on DPw4 molecules. A panel of murine monoclonal antibodies (Mabs) was employed to further dissect the restriction specificities. The proliferative capacity of some of the TLCs was studied with and without Mabs directed against different HLA molecules, using non-T cells, monocytes, and peripheral blood dendritic cells as APC. Two Mabs, 7.2 and D-54, which seem to detect monomorphic determinants on HLA-DR, inhibited both DR- and DRw53-restricted TLCs. One Mab, 109d6 which reacts with DRw53 determinants, selectively inhibited the DRw53-restricted TLCs. The DP-restricted TLC was not inhibited significantly by any tested Mabs, including two Mabs with putative specificity for monomorphic determinants on the DP molecule.

Detection of HLA restricted anti-minor histocompatibility antigen(s) reactive cells from skin GVHD lesions

Recipients of marrow grafts from HLA-identical, (including MLC non-reactive) sibling donors have a 40-50% incidence of acute graft vs. host disease (GVHD); the involvement of non-HLA linked, minor histocompatibility antigens (miHA) has been implicated. One of the target tissues of GVHD is the skin where morphological analysis of biopsy specimens is often used to support this diagnosis. We have obtained skin biopsy specimens from the site of GVHD lesions, grown the cells in the presence of T cell growth factor (TCGF) and feeder cells, and tested these cultured cells in the primed lymphocyte test (PLT) and cell mediated lympholysis (CML) assay. Five of six cell cultures tested demonstrated secondary proliferative but not cytolytic reactivity; cells from one culture demonstrated both reactivities. The cell culture populations generated are presumably directed against non-HLA antigens, i.e., miHA whose expression is restricted by an HLA antigen of the recipient. The data are consistent with the suggestion that in the majority of these cultures, the restriction element may be a determinant encoded within the HLA-D region: DQ, DR, and possibly DP based on panel testing. Although the number of cases is small, these preliminary data demonstrate the feasibility of this type of culturing system and also suggest that the cellular immunological events leading to the manifestation of skin GVHD lesions may be predominantly a delayed type hypersensitivity reaction.

Major histocompatibility complex restriction of tetanus toxoid-specific human T lymphocyte clones

Peripheral blood mononuclear cells (PBMC) from an HLA DRw6/7 individual were stimulated with tetanus toxoid (TT). T cell blasts were cloned by the limiting dilution technique in the presence of TT and irradiated autologous PBMC (iPBMC). Twelve were propagated under interleukin 2 and restimulated weekly with TT and iPBMC. All proliferated specifically in response to TT or either the alpha or beta chain of the toxin molecule. HLA restriction of specific proliferative responses was analyzed using a panel of HLA-typed unrelated donors and selected families, and blocking experiments with anti-HLA class I and class II monoclonal antibodies (mAb). Three types of restriction were observed: (a) autologous restriction; the inhibition observed using anti-HLA DR mAb as well as family studies performed previously with a similarly restricted clone obtained from the same donor suggest an HLA DRw6-linked restriction; (b) an HLA DR7 restriction was found for 2 clones, specific for alpha or beta chain; the identical pattern of inhibition obtained with two different mAb belonging to the same cluster suggests that these clones may be restricted by the same (or a very close) epitope of the HLA DR7 molecule; (c) an unusual restriction pattern was found for one clone; PBMC from more than 80% of donors could present TT whatever their degree of HLA compatibility with the autologous donor. Family studies were unable to disclose any restriction with known class II (or class I) antigens. While no inhibition was observed with anti-DR or -DC reagents, a mAb that recognizes class I antigen when associated with beta 2-microglobulin did inhibit the proliferation of this clone.

Inhibition of soluble antigen-induced T cell proliferation by warm-reactive antibodies to activated T cells in systemic lupus erythematosus

One of the fundamental immunologic characteristics of systemic lupus erythematosus (SLE) is a depressed T cell proliferative response to various specific and nonspecific stimuli. Both intrinsic cellular defect(s) and inhibitory influences of humoral factors, e.g., antilymphocyte autoantibodies or immune complexes, have been postulated to underly this functional abnormality. Because patient serum can induce SLE-like T cell dysfunction in normal cells, an extrinsic mechanism is probably responsible, but the nature and site of action of this humoral activity has not been defined. This laboratory recently described a novel antibody specific for activated T cells in SLE, which raised the possibility that suppression of T cell proliferation by SLE serum involved antibodies directed to surface determinants expressed during the process of activation. In experiments to examine this concept further, relatively warm-reactive antibodies to T cell blasts were found to inhibit strongly the well-characterized T cell response to tetanus toxoid. These antibodies were distinct from conventional cold-reactive IgM antibodies to resting T cells, which exhibited little inhibitory activity. Inhibition involved noncytotoxic effects on early activation events at the level of the responding T cell, which markedly reduced the expression of receptors for interleukin 2. Inhibitory effects on antigen-pulsed macrophages or on T cells already committed to proliferate were not demonstrable. Anti-T blast antibodies were characteristic of active SLE and were detected only occasionally in patients with inactive disease or non-SLE rheumatic disorders. Although the exact antigenic specificity was not identified, considerable evidence was obtained against the presence of antibodies to Ia and certain other surface determinants of functional relevance. Our observations concerning the suppressive effects of anti-T blast antibodies in SLE serum on the T cell response to tetanus toxoid should provide new insight into mechanisms of in vivo T cell dysfunction in this and other immunologic disorders.

Role of Ia-positive cells in the lymphocyte responses to Yersinia

Activation of T lymphocytes by an antigen requires joint recognition of the antigen and the class-II HLA determinants on the membrane of the antigen-presenting cells (APC). Patients with reactive arthritis exhibit a depressed lymphocyte transformation response to Yersinia, suggesting a possible immunoregulatory disturbance in these patients. In this study the role of Ia (class-II HLA antigen)-positive APC in the lymphocyte response to a complex antigen, whole Yersinia bacterium, was evaluated. The results demonstrate that Ia-positive cells are necessary for the T-lymphocyte response to Yersinia. The role of APC in the pathogenesis of reactive arthritis is discussed.

Antigen-specific HLA-restricted human T-cell lines. II. A GAT-specific T-cell line restricted by a determinant carried by an HLA-DQ molecule

Human T-cell lines responsive to the polypeptide antigens GAT and (T,G)-A--L were developed. They were specific for the priming antigens and required the participation of accessory cells matched for HLA-linked determinants, as shown in family studies. In panel studies, the ability of accessory cells to present antigen was shown to be associated with HLA-D-region antigens. However, the specificity of these determinants did not fully correspond to any HLA antigens as currently defined. One GAT-specific subline, derived by limiting dilution, utilized a restriction determinant associated with, but distinct from, the DQw3 (MB3) allospecificity. Blocking studies with mouse monoclonal antibodies indicated that this restriction determinant was carried by HLA-DQ molecules. The epitopes recognized in these molecules appear to be distinct from the alloantigenic determinants currently defined by serology.