Expression Of HLA Antigens Research Articles

Lack of HLA (A, B and C) antigen expression on the cell surface of trophoblastic tumors (hydatidiform moles and choriocarcinoma).

AbstractTwo hydatidiform moles and a choriocarcinoma as well as three normal chorionic villi (control) were examined by an immunofluorescence method in order to investigate the expression of HLA (A, B and C) antigens on trophoblastic tumor cells.In the hydatidiform moles, HLA antigens were absent from trophoblastic cells of the molar villus, but present on cells in villous stroma in a manner similar to those in normal chorionic villus. In the choriocarcinoma, HLA antigens were virtually negative.These findings are consistent with a hypothesis that trophoblastic tumor does not express HLA antigens.

Effect of warm ischemia time and HLA (A and B) matching on renal cadaveric graft survival and rejection episodes.

In a retrospective single-center study the influence of warm ischemia time and simultaneous influence of HLA (A and B) matching on one-year renal graft survival was analyzed in 170 adult recipients of primary cadaveric renal grafts. One-year survival of grafts with warm ischemia times longer than 50 min was only 40% (n = 10). When warm ischemia time was shorter than 50 min, a 1-min increase of warm ischemia time correlated with 1% decrease in one-year graft survival as a result of rejection. This detrimental effect of warm ischemia time on graft survival was not yet significant one month after transplantation, but became more evident as follow-up time was lengthened. Warm ischemia time also correlated with the number of reversible rejection episodes in patients with a graft functioning for longer than one year (P less than 0.04). The beneficial influence of HLA (A and B) matching on one-year graft survival was significant (P less than 0.05 log linear test). This influence was even more evident with longer warm ischemia times. It is concluded that warm ischemia has a detrimental influence on graft survival that is mediated by rejection, and it is suggested that this might be due in part to altered presentation or expression of HLA-antigens of ischemically damaged kidney tissues.

Recognition by xenogeneic cytotoxic T lymphocytes of cells expressing HLA-A2 or HLA-B7 after DNA-mediated gene transfer.

Murine L cells expressing HLA-A2 or -B7 antigens were isolated after cotransformation of thymidine kinase-negative cells with the herpes simplex virus thymidine kinase gene and the genomic clones containing either the HLA-A2 or -B7 genes. Monoclonal antibody binding analyses demonstrated the stable cell surface expression of HLA antigens by these cells at levels of up to 40% of the amount expressed by the human B lymphoblastoid cell line, JY. The HLA-A2 and -B7 antigens expressed by the L cells retained all of the antibody-defined, heavy-chain-associated antigenic determinants but lacked those determinants associated with human beta 2-microglobulin. These HLA transformants were capable of functioning as targets for monoclonal cytotoxic T lymphocytes (CTL) that specifically recognize the HLA-B7 or -A2 antigens expressed by JY cells. However, the efficiency of lysis, relative to the JY cell line, was 50-99% for individual CTL. In addition, not all of these CTL were capable of lysing the appropriate transformants. Because the antigens appear by serological criteria to be structurally intact and expressed at high levels, these results suggest that the complementation of the HLA heavy chains with mouse, rather than human, beta 2-microglobulin may alter the antigenic determinants that are important for CTL recognition.

Lack of HLA(ABC and DR) antigen expression on the normal and abnormal (hydatidiform mole and choriocarcinoma) trophoblastic cells

To give insight on developing Rh-based superalloys, systematic investigations on mechanical and electronic properties of fcc Rh and L12 Rh3Zr are conducted by first-principles calculation. Basic mechanical parameters including bulk modulus, elastic constants, shear modulus, Young׳s modulus, Poisson׳s ratio, and elastic anisotropy are calculated. Additionally, the ideal strengths are investigated under tensile and shear loading. Our results reveal that L12 Rh3Zr has lower mechanical strength but higher ductility than fcc Rh. The analysis of density of states reveals that the Rh-d electrons in L12 Rh3Zr become more localized, whereas the Zr-d electrons become more delocalized, than in pure bulk, due to the interaction of Rh and Zr.

Cell culture density modulates the incorporation of HLA antigens by enveloped viruses

Uninfected, as well as feline leukemia virus (FeLV) infected human cells cultured under high cell density conditions undergo changes in the expression of major histocompatibility complex (MHC) antigens, as determined by indirect trace binding radio immunoassay (RIA) using monoclonal anti-HLA antibodies and by decreased sensitivity to complement mediated cytotoxicity by anti-HLA alloantibodies. FeLV particles produced by the viral infected cells are also sensitive to neutralization by anti-HLA antibodies, suggesting that enveloped viral particles incorporated MHC antigens in the viral envelope. The amount of HLA antigens expressed in the viral enveloped, closely reflects the expression of HLA antigens by the virus-producer lymphoid cells. FeLV-infected HsB-2 (T) and SB (B) lymphoid cells cultured under high cell concentration condition show decreased expression of some HLA antigens (A2, B12, B17), and the viral particles produced by those cells also incorporate lower amounts of such antigens. Our results, based on the findings that human lymphoid cells (uninfected, as well as FeLV infected) show decreased expression of some HLA membrane determinants when growth under high cell density conditions, indicate that no viral selective mechanism operates in the incorporation of HLA determinants by enveloped viruses. Instead, our results suggest that viruses pick up MHC antigens from the host cell membrane according to the concentration of those antigens on the surface of the cells at the time of virus budding.

HLA Antigen Expression on Urothelial Cells: Detection by Antibody-Dependent Cell-Mediated Cytotoxicity

Antibody-dependent cell-mediated cytotoxicity (ADCC) was used to detect HLA-A, -B and -C antigens on in vitro-cultured urothelial cells of normal or malignant derivation. Alloantisera induced specific lysis of 51Cr-labelled targets by effector lymphoid cells from non-immune donors. HLA antisera were routinely titred to dilutions greater than or equal to 10(-3) on urothelial cells in primary or long-term culture. The HLA phenotype was compared for lymphoid cells and urothelial cells from eight individuals. HLA antigens detected by complement mediated lymphocytotoxicity were also detected on urothelial cells. No deletions or gains in HLA antigens were found on normal or malignant urothelial cultures as compared with donor lymphocyte HLA typings. The results show that the established urothelial cells lines J82, TCCSuP and SCaBER have retained their donor HLA phenotype. The established cell lines T24 and RT4 derived from transitional cell carcinomas and HCV-29 from urothelium were found to have distinctive HLA profiles although donor lymphocytes were not available for comparison. The serological crossreactions seen in complement mediated lymphocytotoxicity were clearly observed in ADCC. In particular, HLA-Cw5 was found to crossreact with HLA-Cw8. HLA-Cw5 was detected on 6/8 cultures of transitional cell carcinomas and this was confirmed by absorption analysis.

Interferon-induced changes in expression of antigens defined by monoclonal antibodies on malignant and nonmalignant mononuclear hematopoietic cells.

The effect of alpha interferon (alpha IFN) on the expression of histocompatibility--as well as differentiation antigens on normal and malignant hematopoietic mononuclear cells--were investigated by cell cytofluorometry using a panel of monoclonal antibodies (MoAbs). An increase in the expression of HLA-antigens detected by beta 2-Microglobulin (beta 2-M) could be demonstrated for peripheral blood mononuclear cells, non-T cells, Null cells, activated T cells, fetal thymocytes, adherent cells, and on four malignant non-T lymphoblastoid cell lines. In contrast, no significant differences were observed in the expression of antigens specific for B-lymphocytes (B1), T-lymphocytes (T3, T4, T6, T8, T11), NK-cells (901) and adherent cells (Mo1-4). Likewise, the expression of Ia-antigens remained unaltered on non-T cells, Null cells, and monocytes. The only other effect of IFN was an increase in the number as well as the amount of lymphocytes expressing the T10 antigen. It thus seems that the enhancing effect of IFN on resting cells of the immune system is highly selective. On the four lymphoblastoid cell lines, the expression of the common acute lymphoblastic leukemia antigen (CALLA) was significantly decreased concomitantly with the increase in MHC-antigens. On the other hand, the density of both a HLA-D related Ia antigen (I2) and a B-lymphocyte differentiation antigen (B1) remained unaltered following IFN treatment. The implications of these findings are discussed.

Changes in the expression of HLA and β2-microglobulin by cultured lymphoid cells

Changes in the expression of HLA and β 2-microglobulin ( β 2-m) antigens by cultured human lymphoid cell lines were investigated. HLA expression was assayed by indirect trace binding radioimmunoassay (RIA) with monoclonal antibodies and by determining sensitivity to completement-dependent lysis by alloanitsera. Lymphoid cells in culture were found to undergo changes in the expression of HLA and β 2-m antigens characterized by decreased membrane expression of these antigens at high cell densities or after a prolonged period of cultivation. The decreased expression of HLA and β2-m antigens apparently is due neither to a masking phenomenon nor to a lack of nutrients or an accumulation of metabolites in the culture media but is perhaps mediated by a cell-to-cell contact mechanism. Human interferon was found to enhance the expression of HLA and β 2-m, apparently overriding the effects on major histocompatibility complex (MHC) expression induced by cell density.

Production of functional human T-T hybridomas in selection medium lacking aminopterin and thymidine.

The production of hybridomas between immunologically activated T cells and malignant T-cell lines offers a potentially unlimited source of soluble T-cell-derived products. Recently, human T-T hybrids have been described; however, their use has been hampered by slow growth and chromosomal instability due at least in part to the presence of thymidine in the traditional hypoxanthine/aminopterin/thymidine (HAT) selection medium. In this report, we describe the development of a rapidly growing hypoxanthine phosphoribosyltransferase-deficient human T-cell line designated J3R7, the use of azaserine/hypoxanthine (AH) medium as an alternative selection medium to HAT medium, and the production of functional T-T hybrids by using the J3R7 line and the AH selection technique. Hybrids selected in AH medium were 4-fold greater in number and 3-fold faster in growth rate than hybrids grown in HAT medium. No stable clones were obtained from HAT cultures whereas AH-derived hybrids could be readily cloned by the method of limiting dilution. Evidence for hybridization included (i) the presence of approximately twice the number of chromosomes in hybrids than in J3R7 cells; (ii) the presence on hybrid cells of the Leu-3a surface antigen, present on normal helper T cells but not on J3R7 cells; (iii) the expression of HLA antigens of both the normal T-cell partner and the J3R7 line; and (iv) the constitutive secretion of interleukin 2 from multiple hybrid clones but not from the J3R7 cell line. Thus far, these clones have maintained their rapid growth, chromosome number, surface phenotype, and constitutive secretion of interleukin 2 for 4 months.

HLA antigen expression at the single cell level on a K562 X B cell hybrid: an analysis with monoclonal antibodies using bacterial binding assays.

The influence of different genetic environments on the expression of HLA complex-controlled antigens has been investigated using cell lines with various defects in the synthesis of these molecules and a somatic cell hybrid derived from them. A very sensitive bacterial binding assay allowing simultaneous evaluation of the morphology of a given cell and the quantity of a surface molecule has been developed for these studies. The fetal erythroid cell line K562, the Burkitt's lymphoma-derived cell line DAUDI, and their hybrid DUTKO1 have been employed. K562 and the hybrid, but not DAUDI, expressed HLA-A,B,C heavy chains as detected by the monoclonal antibody W6/32.HL, while two monoclonal antibodies (TU48 and 2BC4) against the supertypic specificities HLA-Bw4 and Bw6 showed no reactivity. The presence of human Ia-like antigens on the cell surfaces was investigated with a panel of eight monoclonal antibodies. K562 cells were completely unreactive, and DAUDI cells gave the expected positive reaction, but about 1% or less of the cells in the DUTKO1 population appeared to express these antigens as well. We discuss possible reasons for the failure to detect HLA-B antigens with monoclonal antibodies and the lack of complete "dominance" of the K562 genome in the hybrid cell line.

Expression of HLA, eryhtroid and myeloid antigens on K.562 cells as defined by monoclonal antibodies

Expression of HLA, eryhtroid and myeloid antigens on K.562 cells as defined by monoclonal antibodies

Reciprocal expression of HLA and myeloid antigens by cells in the myeloid differentiation pathway, studied by monoclonal antibodies

Reciprocal expression of HLA and myeloid antigens by cells in the myeloid differentiation pathway, studied by monoclonal antibodies

Expression of HLA antigens by human thymic epithelial cells

Human thymuses were examined by tissue section staining with antibodies specific for monomorphic and polymorphic HLA-A, B, C, and DR determinants. The principal cell type expressing high levels of HLA antigens has the distribution of epithelial cells. Immunoelectron microscopy confirmed their epithelial nature. As in the mouse, both medullary and cortical epithelial cells express high levels of class II (DR) antigens, a finding that is remarkable in that these antigens were originally thought to be restricted to lymphoid and accessory cells. Class I (A, B, and C) antigens are also present on thymic epithelial cells. They are easily detectable on medullary epithelial cells, but two distinct patterns of cortical straining were observed. One group of antibodies produced intense dendritic staining throughout the cortex: the other group produced only faint or no corticol dendritic staining at all. These different staining patterns do not correlate with known properties of the antibodies and thus appear to be due to intrinsci properties of the different A, B, and C antigens.

HLA antigen expression on urothelial cells: detection by antibody-dependent cell-mediated cytotoxicity.

Antibody-dependent cell-mediated cytotoxicity (ADCC) was used to detect HLA-A, -B and -C antigens on in vitro-cultured urothelial cells of normal or malignant derivation. Alloantisera induced specific lysis of 51Cr-labelled targets by effector lymphoid cells from non-immune donors. HLA antisera were routinely titred to dilutions greater than or equal to 10(-3) on urothelial cells in primary or long-term culture. The HLA phenotype was compared for lymphoid cells and urothelial cells from eight individuals. HLA antigens detected by complement mediated lymphocytotoxicity were also detected on urothelial cells. No deletions or gains in HLA antigens were found on normal or malignant urothelial cultures as compared with donor lymphocyte HLA typings. The results show that the established urothelial cells lines J82, TCCSuP and SCaBER have retained their donor HLA phenotype. The established cell lines T24 and RT4 derived from transitional cell carcinomas and HCV-29 from urothelium were found to have distinctive HLA profiles although donor lymphocytes were not available for comparison. The serological crossreactions seen in complement mediated lymphocytotoxicity were clearly observed in ADCC. In particular, HLA-Cw5 was found to crossreact with HLA-Cw8. HLA-Cw5 was detected on 6/8 cultures of transitional cell carcinomas and this was confirmed by absorption analysis.

Heterogeneity of allogeneic restriction of human cytotoxic T cell clones specific for Epstein Barr virus.

Clones of human cytotoxic T cells (Tc) specific for Epstein Barr virus (EBV) were isolated from peripheral blood lymphocyte (PBL) cultures stimulated repeatedly with autologous EBV-transformed lymphoblastoid cell line (LCL) cells in vitro. The method employed to clone EBV-specific Tc was a limiting dilution technique utilizing T cell growth factor (TCGF). The EBV specificity of Tc clones was determined by showing that they were significantly cytotoxic for autologous LCL cells but not for either autologous PBL or (natural killer-sensitive) K-562 cells. Eight EBV-specific Tc clones derived from a single donor exhibited distinct cytotoxic patterns against allogeneic LCL targets. Two clones were cytotoxic to LCL targets sharing both HLA-A26 and B15 antigens with effectors, and killing by two other clones was strongly restricted to autologous LCL cells. The four remaining clones showed cytotoxicities against various allogeneic LCL targets irrespective of HLA antigen expression. Eight EBV-specific Tc clones derived from a second donor also exhibited a wide spectrum of cytotoxicity to allogeneic LcL targets. We conclude that EBV-specific Tc, induced in vitro, consist of a number of clones with respect to restrictions imposed by the major histocompatibility complex. The determinants regulating these restrictions may include not only private HLA antigenic determinants that are defined by the HLA serotyping, but also undefined HLA antigenic determinants.

Ability of thrombocytes to acquire HLA specificity from plasma

Thrombocytes from HLA-A1 and HLA-A2 negative donors were incubated with plasma obtained from respective HLA-positive donors. The plasma-treated thrombocytes were shown to acquire HLA specificity of the plasma as demonstrated by their ability to absorb lymphocytotoxic activity of monospecific anti-HLA sera. The data are consistent with the hypothesis that the expression of HLA antigens in cells of hematopoietic origin diminishes in the course of differentiation and maturation and that the expression of HLA antigens on thrombocytes is primarily due to absorption of these antigens from plasma.

Ability of Thrombocytes to Acquire HLA Specificity From Plasma

Thrombocytes from HLA-A1 and HLA-A2 negative donors were incubated with plasma obtained from respective HLA-positive donors. The plasma-treated thrombocytes were shown to acquire HLA specificity of the plasma as demonstrated by their ability to absorb lymphocytotoxic activity of monospecific anti-HLA sera. The data are consistent with the hypothesis that the expression of HLA antigens in cells of hematopoietic origin diminishes in the course of differentiation and maturation and that the expression of HLA antigens on thrombocytes is primarily due to absorption of these antigens from plasma.

Expression of HLA antigens, β2-microglobulin and enzymes by human amniotic epithelial cells

A monolayer of epithelial cells, endowed with unique secretory properties, lines the human amniochorion1,2. It has been shown that transplantation of these membranes into allogeneic hosts does not result in overt acute graft rejection3–6. We demonstrate here that HLA-A, -B, -C and -DR antigens and β2 microglobulin (β2m) cannot be detected by immunofluorescence on freshly collected or in vitro cultured amniotic epithelial cells, although small quantities of such antigens were detected when more sensitive radiobiological techniques were used. We also show that these cells, cultured in vitro, produce large quantities of enzymes absent in patients with lysosomal storage diseases and that their supernatants can correct glycosaminoglycan accumulation in cultured fibroblasts from patients with Hurler's and Hunter's syndromes.

Expression of HLA-A/B/C and -DR Locus Antigens on Epithelial, Stromal, and Endothelial Cells of the Human Cornea

ABSTRACT We studied class I (A/B/C) and class II (DR) HLA antigens on human corneal cells with monoclonal antibodies using immunofluorescence and immunoperoxidase techniques. Cryostat sections of freshly harvested human corneas expressed class I HLA antigens on the corneal epithelium. Class II antigens were not detected on these corneal specimens, except for occasional, scattered positive cells in the peripheral corneal epithelium and stroma near the corneoscleral limbus. Corneal endothelial whole flat mounts from freshly excised human corneas were negative for class I and class II HLA antigens. In tissue culture, however, growing human corneal endothelial cells expressed class I HLA antigens. Crowing human corneal fibroblasts in tissue culture similarly were shown, through immunofluorescent techniques using monoclonal antibodies, to express class I HLA antigens. Fibroblasts and endothelial cells in tissue culture were negative for class II HLA antigens. We believe the low-to-nondetectable HLA antigen expression on central corneal stroma and endothelium may partly explain the immunological tolerance enjoyed by most corneal allografts.

Effect of conditions of culture and mitogenic stimulation on HLA antigen expression in lymphocytes

Effect of conditions of culture and mitogenic stimulation on HLA antigen expression in lymphocytes