Surface Markers on Human B and T Lymphocytes

An association has been found between the Epstein-Barr virus (EBV) and complement (C3d) receptors on human lymphoid cells. The evidence was four-fold: there was a correlation between the expression of these two receptors; inhibition experiments showed that the binding sites probably are close to each other in the cell membrane, although not identical; EBV and complement receptors have been found to co-cap in either order; and lymphoid cell lines lacking complement receptors could not be superinfected with EBV.     

Surface Markers on Human B and T Lymphocytes

The response of human peripheral lymphocytes to phytohemagglutinin-. concanavalin A-, pokeweed mitogen-, and mitomycin-treated allogeneic lymphocytes was characterized according to the surface markers of the responding cells Almost all blast cells derived from these cultures could be classified as either B or T cells Phytohemagglutinin, concanavalin A, and allogeneic lymphocytes triggered exclusively T-tell stimulation, whereas pokeweed mitogen gave rise to a dual response. No shift in the proportion of responding B and T cells was found If different concentrations of pokeweed mitogen under the present conditions Purified T cells, isolated by sheep erythrocyte (SRBC) rosette sedimentation, responded slightly more strongly than unseparated cells, whereas purified non-SRBC-binding; cells were essentially unresponsive to all three lectins. The presence of monocytes was found to increase the lectin responses as well as to make them more re producible. It is suggested that the classification of proliferating lymphocytes by surface markers may yield clinical information as well as serve as a useful tool in the evaluation of in vitro cellular cooperation     

Surface Markers on Human B and T Lymphocytes

A procedure to assess the cellular adherence displayed by lymphocytes, at the level of the single cell, is described. Adherence is defined as the capacity of a cell to hind acrylic acid polymer beads. 0.5 μm: in size, under standardized conditions These beads were found to adhere readily to lymphocytes that have a high density of surface immunoglobulin Such cells can be distinguished from other leukocytes with the same binding capacity by the extracellular localization of the beads on these cells Furthermore, adherence, as presently defined, is briefly characterized.     

Surface Markers on Human B and T Lymphocytes

The distribution of surface immunoglobulin and receptors for Fc, C3, and sheep erythrocytes (SRBC) on resting and blast-transformed peripheral lymphocytes was investigated. The following conclusions were reached. [1] SRBC receptors were retained on all blast-transformed T lymphocytes. No such receptors were found on normal or neuraminidase-treated B lymphocytes. [2] Receptors for Fc and C3 were found to be expressed on the same resting lymphocytes, which formed a subpopulation that did not entirely overlap with surface immunoglobulin-positive B cells. Owing to this and the fact that Fc/C3 receptors were lacking on almost all B blast cells, as well as for other reasons elaborated in the text, it is argued that caution must be taken when these receptors are used as B-cell markers. [3] A comparison among C3 indicator cells prepared with human or mouse complement showed that these detected the same lymphocyte subpopulatiom [4] B blast cells, induced by 72-hr pokeweed mitogen cultures, were found to carry detectable amounts of surface immunoglobulin. [5] Phagocytic leukocytes were found to be conveniently detected by scoring the number of cells with internal C3 indicator cells after osmotic lysis of externally bound indicator cells.     

Surface Markers on Human B and T Lymphocytes

Almost 100% of peripheral T lymphocytes are shown to have the capacity to form rosettes with human lymphoblastoid B-cell lines, predominantly at 4°C and with lines having surface-bound IgG. Blast-transformed T cells retained this capacity and formed rosettes even at 37°C Unstimulated T cells bound less readily to B-cell blasts, stimulated by pokeweed mitogen for 72 hr. Even though rosettes, formed at 4°C, were stable for several hours at 72°C, no T-cell-mediated cytotoxicity could be detected during overnight incubation. Extreme pH values and trypsinization decreased rosette formation, whereas neuraminidase treatment enhanced the reaction. Rosette formation was independent of bivalent cations and unimpaired in the presence of inhibitors (NaF. NaN₃), undiluted human or fetal call sera, protein A, sonicated sheep erythrocyte membranes, and normal or heat-aggregated human IgG. Anti-Ig, anti β₂-microglobulin, or anti-T cell sera did not influence rosette formation.     

Evidence for a Receptor Recognizing Antigen Complexed Immunoglobulin on the Surface of Activated Mouse Thymus Lymphocytes

The distribution in the mouse of lymphoid cells carrying receptors for IgG or IgG-Ag was investigated. B lymphocytes were found to have receptors reacting with both IgG and IgG-Ag. Resting T lymphocytes did not react with IgG-Ag. T lymphocytes activated by passage through irradiated, allogeneic mice had a receptor reacting with IgG-Ag, but not with IgG.     

Functional Relationship of Human T Lymphocytes, Monocytes and Interleukins

The different requirements of human T lymphocytes of different densities for accessory cells and helper factors (Interleukin 1 (Il-1) and Interleukin 2 (Il-2) ) in the response to phytohaemagglutinin (PHA) were investigated. Human T lymphocytes were subfractionated by discontinuous density gradient centrifugation. The various T-cell subsets were stimulated by PHA to form colonies in an agar micro-culture in the presence or absence of additional adherent cells or crude preparations of Il-1 or Il-2. The results show that the higher the density of the fractionated T lymphocytes and the lower the number of cells cultured, the greater is the number of adherent cells or the amount of helper factors required for the stimulation of colony-forming T lymphocytes. The results are consistent with the assumption that monocytes provide positive modulating activity during mitogenic stimulation of colony-forming T lymphocytes. The number of monocytes necessary for exerting an optimal modulating activity depends on the number of T cells cultured and the density of the T-cell fraction. This may reflect a distinct susceptibility of T cells of different densities to monocyte-mediated helper effects.     

A New Surface Antigen on Human Lymphocytes Defined by the Murine Monoclonal Antibody IVF7

The murine monoclonal antibody (MoAb) IVF7 was produced against tumour cells from a patient with a CD3+, CD4+, CD8- T-cell chronic lymphatic leukaemia (T-CLL). The MoAb IVF7 showed reactivity with subpopulations of normal peripheral blood lymphocytes (PBL), as well as with a few cell lines of haematopoietic origin. Thirty-six per cent of PBL were stained with IVF7. Analysing subpopulations, we found that 80% of NK cells, 25% of T cells, and 10-20% of B cells were positive. The myelomonocytic cell line KG-1 was also stained. The molecular weight of the molecule was 40 kDa under reducing conditions. The antigen was found to be trypsin-sensitive. MoAb IVF7 could modulate the antigen from the cell surface. The antibody did not stimulate PBL to DNA synthesis, nor did it significantly influence NK cell-mediated killing.     

TCGF Production for Cloning and Growth of Functional Human T Lymphocytes

In an effort to increase the potency of T cell growth factor (TCGF), several variables were examined for their effects on the production of TCGF. The following manipulations enhanced the potency of TCGF: first, the removal of adherent cells and addition of indomethacin to the producing cultures; second, irradiation with 1000 rads of the cells used to produce TCGF; and, third, the addition of Epstein-Barr virus transformed lymphoblastoid (LCL) cells. It was also noted that the addition of irradiated feeder cells increased the efficiency of limiting dilution cloning.     

HSP_(70BCG)-Daudi肿瘤肽复合物对γδT细胞的活化作用

用固相抗体法[1] 体外扩增人PBMC的γδT细胞 ,静息化处理后用HSP70BCG Daudi肿瘤肽复合物再次刺激研究HSP70BCG Daudi肿瘤肽复合物对γδT细胞的活化作用。MTT检测γδT细胞的细胞毒作用及TNF α生物学活性。3 H TdR掺入法测定细胞增殖。HSP70BCG Daudi肿瘤肽复合物活化的γδT细胞在效靶比为 10∶1及 5∶1时对靶细胞Daudi的杀伤活性分别为 88 36 %±8 2 1%及 75 2 3%± 16 36 % ,与对照组有显著性差别。 2 4及 4 8h增殖结果各组间无差别 ;未检测出各刺激组的上清中TNF α生物学活性有何差别。结论表明HSP70BCG Daudi肿瘤肽复合物活化的γδT细胞对Daudi有较高的杀伤活性     

A Monoclonal Antibody, H2, Defines a New Surface Antigen Expressed on Human Lymphocytes

We have previously described a monoclonal antibody (MoAb), H2, which recognized a tumour-unique antigen on a human T-cell chronic lymphatic leukaemia (T-CLL, CD3,4+). However, further characterization of H2 has revealed a reactivity with the majority of T lymphocytes and a minority of B lymphocytes, some malignant T cells and a few cell lines of leukaemia or of hematopoietic tumour origin. The molecular weight of the antigen (80,000) precipitated by the MoAb H2 from the cell lines NALM-6 and Reh corresponded to that previously found. When PBL were stimulated with PHA, IL-2, or Con A a reduced reactivity of H2 could be seen. The MoAb H2 was submitted to the Fourth International Conference on Human Leucocyte Differentiation Antigens, Vienna, 1989. H2 did not cluster in any of the 78 clusters of differentiation (CD 1-78) discussed at the conference, indicating its unique reactivity. This suggests that we have defined a new antigen on lymphocytes with a possible role along the resting-proliferating axis.     

Biochemical Purification of Various Receptor Molecules Involved in Human T Lymphocyte Activation

The now classical major histocompatibility complex (MHC)-restricted receptor for antigen on human T lymphocytes has been identified as a 90 kDa disulphide-linked heterodimer composed of two glycoproteins termed alpha and beta. More recently, another type of T cell receptor for antigen has been described, which seems to mediate killing of target cells without any obvious requirement for MHC recognition. This T cell receptor for antigen is also a heterodimer composed of gamma, delta chains non-covalently associated with the three mon morphic CD3 subunits. Another disulphide-linked dimer capable of triggering T lymphocytes has been defined recently by a monoclonal antibody: the anti-human 9.3 antigen. In order to generate monoclonal or polyclonal reagents against variable and constant regions of the T cell receptor chains and against new epitopes of the 9.3 antigen, we have developed a biochemical method of purification of T lymphocyte disulphide-linked dimers. Our method relies on two biochemical properties of the 9.3 surface molecule and the T cell receptor for antigen. (1) They are disulphide-linked dimers and thus can be separated from the vast majority of the cell surface molecules by two-dimensional (non-reduced versus reduced) sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). (2) T cell receptor chains are less hydrophobic than the 9.3 antigen, and thus can be isolated from it on reverse-phase high-performance liquid chromatography (HPLC) at a lower concentration of acetonitrile. Microsomal preparations from T cell clones and leukaemia lines were prepared by nitrocavitation and lysed in sodium deoxycholate. After concentration, this lysate was electrophoresed on SDS-PAGE in non-reducing conditions. The gel slice corresponding to the molecular weight of the T cell receptor was cut out and run in reducing conditions in the second dimension. The T cell receptor spots were easily located on the gel by autoradiography as the microsomal lysate had been mixed with iodinated glycoproteins. The T cell receptor was eluted from the gel with about 85% yield. At this stage, the T cell receptor preparations also contained the 9.3 antigen, another disulphide-linked dimer. The separation of this antigen from the T cell receptor chains had been achieved on reverse-phase HPLC. This procedure allows the purification and separation of two disulphide-linked dimers which are both involved in T cell activation. The obtention of antibodies against new epitopes of these important molecules would be extremely useful for analysing their role in T cell function and ontogeny.     

HLA-D-restricted Antigen Activation of Sensitized T Lymphocytes: Studies on the Ability of HLA-D/DR-expressing B Lymphocytes to Substitute for Macrophages in Antigen Activation

The proliferative response of sensitized human T lymphocytes to purified protein derivative (PPD) and to trinitrophenyl (TNP)-conjugated autologous cells in vitro is restricted by self HLA-D/DR determinants. Here we report that the PPD-specific response is strictly related to the content of phagocytosing cells (macrophages, Mphi) in the cultures and that an optimal PPD response occurred at a T/Mphi ratio between 10:1 and 5:1. B-cell-enriched suspensions, which also express the HLA-D/DR determinants, were not able to replace the macrophages in this HLA-D/DR-restricted response. On the other hand, TNP-treated similarly prepared B cells were in most instances effective in inducing a secondary TNP-specific response of in vitro-sensitized T cells.