Four distinct antigen systems on human thymus and T cells defined by monoclonal antibodies: immunohistological and immunochemical studies.

Human thymus and T cell antigens were identified by using four distinct monoclonal antibodies (MoAb), designated 2D5, 5B3, 7A5 and 9D4. 2D5 antibody reacted with most human thymocytes and a few peripheral lymphocytes as well as with a subpopulation (20%) of bone marrow cells, and precipitated a 45K molecular weight (mol. wt.) component from 125I-labelled thymus cell lysate. 7A5 antibody also reacted with the majority (80%) of thymocytes but neither with peripheral lymphocytes nor with bone marrow cells. The antigen detected by 7A5 was a glycoprotein consisting of 48K and 12K mol. wt. components, which were non-covalently associated with each other. 5B3 reacted with virtually all of human thymus and T cells but not with the majority of B cells and bone marrow cells. This reagent precipitated a 72K mol. wt. glycoprotein from thymus and T cells. An additional 65K mol. wt. glycoprotein was precipitated by 5B3 together with the 72K mol. wt. component, but with poor reproducibility. 9D4 antibody, on the other hand, reacted with a 200K mol. wt. component from thymus and T cells as well as 220K and 210K components from the non-T cell fraction of tonsil lymphocytes. Whereas antigens detected by 2D5 and 7A5 appeared to be highly expressed on cortical thymocytes, the antigen defined by 5B3 occurred much more abundantly on medullary thymocytes and peripheral T cells than on cortical thymocytes. Based on the data described above, it is suggested that 7A5, 5B3 and 9D4 MoAb recognize human homologues of mouse TL, Ly-1 and Ly-5 antigens, respectively, whereas 2D5 antibody seems to resemble OKT10, as described by others.     

Molecular identification of T cell-specific antigens on human T lymphocytes and thymocytes

We have identified membrane glycoproteins which carry T cell-specific antigens on human T lymphocytes and thymocytes. Purified cells were surface-labeled with NaB³H₄ after treatment with neuraminidase and galactose oxidase. Immunoprecipitations were performed with rabbit anti-human T cell-specific antibodies using co precipitation with protein A-containing staphylococci strain Cowan I. The labeled membrane glycoproteins and the precipitates were subjected to polyacrylamide slab gel electrophoresis and visualized by fluorography. The antibodies specifically precipitated 4 proteins called GP200, GP180, GP165 and GP160 (mol. wts. = 200000, 180000, 165000 and 160000) from surface-labeled T lymphocytes and low-density (medullary) thymocytes. The GP200 and GP180 were not labeled on high-density (cortical) thymocytes. A protein with a mol. wt. of 45000 was precipitated from thymocytes. Another glycoprotein on T lymphocytes and thymocytes with a mol. wt. similar to that of mouse and rat Thy-1 or Θ antigen (mol. wt. 25000) reacted with the antibodies.     

Detection of antinuclear antibody in the serum of patients with multiple sclerosis

Extracellular products have been purified from group A Streptococcus pyogenes culture supernatant fluids and their mitogenicities have been tested on rabbit and mouse lymphocytes. Two fractions were mitogenic: the κ-fraction (pI = 4.8, mol. wt. = 30,000), a protein which was identified as the erythrogenic toxin, and the ?-fraction (pI = 10.3, mol. wt. = 17,000) a glycoprotein, both stimulated rabbit and CBA mouse spleen cells. The stimulation of rabbit thymocytes was weak unless macrophages or 2-mercaptoethanol were added. A third product, the γ-fraction ( a protein, pI = 4.2, mol. wt. = 72,000) was very weakly mitogenic and had the capacity to reduce the stimulation induced by a T-cell mitogen, such as Con A, but not by a B-cell mitogen such as Nocardia.     

Two distinct antigenic markers for rat thymus and T cells defined by monoclonal antibodies.

Rat thymus and T-cell antigens were defined by using two distinct monoclonal antibodies (R-1-3B3 and R-1-12C5). R-1-3B3 antibody, when tested for its reactivity with rat lymphoid cells by immunofluorescence, labelled virtually all thymus and T cells but not B cells and bone marrow cells. The antigen defined by this R-1-3B3 antibody occurred more abundantly on medullary thymocytes and peripheral T cells than on cortical thymocytes. Immunochemical data showed that R-1-3B3 antibody recognized a single glycoprotein with a molecular weight of 67,000, which were able to interact with Lens culinaris haemagglutinin. R-1-12C5 antibody, on the other hand, reacted with all of thymus and T cells as well as with a subpopulation (approximately 20%) of bone marrow cells. In contrast to the antigen defined by R-1-3B3, that detected by R-1-12C5 antibody existed largely on cortical thymocytes and to a much lesser extent on medullary thymocytes and peripheral T cells. R-1-12C5 antibody detected a single glycoprotein with a 95,000 molecular weight, which could also interact with Lens culinaris haemagglutinin. Based on these data described above and since both antigens defined by R-1-3B3 and R-1-12C5 antibodies were absent from rat brain tissue, we concluded that they were distinct from brain-associated thymic antigens in rats including Thy-1 and W3/13 antigen systems.     

Two distinct antigens on chicken thymocytes defined by monoclonal antibodies

Two distinct antigens expressed on chicken thymocytes were defined by monoclonal antibodies designated as Lc-1 and Lc-2. Lc-1 (IgGl) reacted with 80% of the thymocytes (mostly cortical and medullary thymocytes) and Lc-2 (IgM) reacted with 40% of the thymocytes (mainly cortical thymocytes). Lc-1 reacted with 1% of the spleen lymphocytes, but the antibody was nearly nonreactive with cells from peripheral blood leukocytes, bursa and bone marrow. Lc-2 reacted with only small percentages of spleen and bursa cells, and with very few cells from peripheral blood leukocytes and bone marrow. This antibody reacted with a portion of concanavalin A stimulated spleen lymphocytes. When Marek's disease-derived T-lymphoblastoid cell lines were tested for their reactivities with monoclonal antibodies, Lc-1 reacted with none of the cell lines tested, whereas Lc-2 reacted with four of the six cell lines tested. Antigens recognised by Lc-1 and Lc-2 were first found in chick embryonic thymus on day 13 of incubation, after which the number of cells positive for Lc-1 and Lc-2 rapidly increased, reaching young adult levels by days 15 and 14 of embryonic life, respectively. Lc-1 precipitated materials with apparent molecular weights of 60 and 120 kDa from radioiodinated thymocytes.     

Chicken thymocyte-specific antigens identified by monoclonal antibodies: characterization and distribution in normal tissues and in tumoral tissues from Marek's disease chicken

Monoclonal antibodies (MAbs) were obtained against purified thymocyte membrane extracts. Five MAbs TA3, TB1, TB6 (IgG1), TC4, and TA1 (IgG2a), were tested by immunofluorescence and by immunoperoxidase tests against normal cells from different organs, Marek's disease (MD) cell lines, and MD tumoral cells from chickens. Three of them, TA3, TB1, and TB6, reacted exclusively with lymphoid cells in both cortical and medullary areas of the thymus and with less than 8% bursa cells. They identified a protein of apparently 40 kD. The other two revealed antigenic determinants on most medullar thymocytes and some cortical thymocytes, and on some splenic and peripheral blood lymphocytes. They were positive with MD cell lines and cells deriving from MD tumors. TC4 and TA1 detected molecular masses of about 110 kD and 16 kD, respectively. No MAbs reacted with erythrocytes, bone marrow, liver, brain, and skin cells. Not all of the tested cells were stained after contact with an anti-chicken immunoglobulin serum. In this paper, we determine a specific antigen restricted to T cells from thymus and different markers belonging to the mature T cells. The latter are also present on MD cell lines and MD tumoral cells.     

Identification of Ia glycoproteins in rat thymus and purification from rat spleen.

A fraction of la-like glycoproteins was prepared from rat thymocytes by lentil lectin affinity chromatography and gel filtration in deoxycholate. Spleen cells from mice immunized with this preparation were fused with myeloma cells to produce antibody-secreting hybrid cell lines. Antibody from four lines called MRC OX, 3, 4, 5, 6 reacted with the la-like glycoproteins, and MRC OX 3 antibody recognized an antigenie determinant polymorphic in the rat. All four antibodies also bound to mouse spleen cells and all detected polymorphisms. Studies on recombinant mouse strains suggest that the determinants are coded by the I-A subregion of the H-2 complex. MRC OX 3 correlates with Ia specificity 9, while MRC OX 4, 5, 6 correlate with specificity 17 or 18. MRC OX 4 monoclonal antibody was used for affinity chromatography to purify Ia glycoproteins from rat spleen. The rat Ia glycoprotein complex was composed of two noncovalently linked polypeptide chains of apparent mol. wt. (unreduced) 30 000 and 24 000 as determined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The purified Ia glycoprotein partially inhibited the binding to thoracic duct lymphocytes of an alloantiserum which detects Ia antigens linked to the major histocompatibility complex. The monoclonal anti-la antibodies bound to the majority of peripheral B lymphocytes and 18% of thymocytes, but did not significantly bind to peripheral T lymphocytes. There were on average 150000 molecules of Ia glycoprotein per la-positive B lymphocyte, and 45 000 molecules per la-positive thymocyte. From the same fusion, another cell line was prepared called MRC OX 2 which secretes monoclonal antibody to a previously undefined thymus glycoprotein of apparent mol. wt. 60000. Preliminary studies showed that the antigen was expressed on all thymocytes and on peripheral B lymphocytes in smaller amounts. It was also present in brain, but not liver or kidney homogenate.     

Monoclonal antibody against a "Pan-T-cell" antigen expressed by thymocytes, peripheral T-lymphocytes and T-cell leukemias

A monoclonal antibody, LAU-A1, which selectively reacts with all cells of the T-lineage, was derived from a fusion between spleen cells of a mouse immunized with paediatric thymocytes and mouse myeloma P X 63/Ag8 cells. As shown by an antibody-binding radioimmunoassay and analysis by flow microfluorometry of cells labelled by indirect immunofluorescence, the LAU-A1 antibody reacted with all six T-cell lines but not with any of the B-cell lines or myeloid cell lines tested from a panel of 17 human hematopoietic cell lines. The LAU-A1 antibody was also shown to react with the majority of thymocytes and E-rosette-enriched peripheral blood lymphocytes. Among the malignant cell populations tested, the blasts from all 20 patients with acute T-cell lymphoblastic leukemia (T-ALL) were found to react with the LAU-A1 antibody, whereas blasts from 85 patients with common ALL and 63 patients with acute myeloid leukemias were entirely negative. Examination of frozen tissue sections from fetal and adult thymuses stained by an indirect immunoperoxidase method revealed that cells expressing the LAU-A1 antigen were localized in both the cortex and the medulla. From the very broad reactivity spectrum of LAU-A1 antibody, we conclude that this antibody is directed against a T-cell antigen expressed throughout the T-cell differentiation lineage. SDS-PAGE analysis of immunoprecipitates formed by LAU-A1 antibody with detergent lysates of radiolabeled T-cells showed that the LAU-A1 antigen had an apparent mol. wt of 76,000 under non-reducing conditions. Under reducing conditions a single band with an apparent mol. wt of 40,000 was observed. Two-dimensional SDS-PAGE analysis confirmed that the 76,000 mol. wt component consisted of an S-S-linked dimeric complex. The surface membrane expression of LAU-A1 antigen on HSB-2 T-cells was modulated when these cells were cultured in the presence of LAU-A1 antibody. Re-expression of LAU-A1 antigen occurred within 24 hr after transfer of the modulated cells into antibody-free medium.     

Different subpopulations of developing thymocytes are associated with adherent (macrophage) or nonadherent (dendritic) thymic rosettes.

Thymic rosettes (ROS), structures consisting of thymic lymphoid cells attached to a central stromal cell, were isolated from mouse thymus by collagenase digestion and unit-gravity elutriation. The ROS were then separated into those where the stromal cells were either macrophage-like (M-ROS) or dendritic cell-like (D-ROS), on the basis of the differences in adherence properties or in the level of MAC-1 surface antigen. The ROS were then dissociated and the thymocyte content analyzed by immunofluorescent staining and flow cytometry. M-ROS and D-ROS differed in thymocyte composition, although the major component of both was the CD4+CD8+ cortical thymocyte. D-ROS were enriched in thymocytes expressing high levels of surface T-cell antigen receptor (TcR) and the associated CD3 complex, and these included both CD4+CD8-CD3++ and CD4-CD8+CD3++ mature thymocytes. M-ROS were enriched in CD4-CD8- thymocytes and had a reduced content of thymocytes expressing high TcR-CD3 levels; they nevertheless contained some mature thymocytes, but only of the CD4+CD8-CD3++ category. Several lines of evidence indicated that the mature thymocytes in ROS were cells recently formed in the cortex, and were not from the medullary pool. ROS-associated mature thymocytes expressed lower levels of H-2K than free, mature thymocytes. The CD4+CD8+CD3++ subpopulation, believed to be a developmental intermediate between cortical thymocytes and mature T cells, was present in both ROS populations. Further, late intermediates leading to both mature T-cell categories were evident in D-ROS, but only those leading to CD4+CD8-CD3++ T cells were evident in M-ROS. The results are compatible with a role for ROS in TcR-specificity selection and in the final maturation steps in the thymic cortex.     

CD3+ T cells in severe combined immunodeficiency (scid) mice. VI. Rescue of scid-derived, IgM-producing B cells by transfer of CD4+ CD8- T cells from various lymphoid organs.

Intravenous injection of purified CD4+ CD8- T cells from thymus, spleen or lymph nodes of adult dm2 donor mice (H-2d, Ld-, IgMa) into young C.B-17 scid/scid (scid) mice (H-2d, Ld+, IgMb) partially and selectively reconstituted the splenic CD4+ T-cell compartment of recipient scid mice. This was demonstrated by cytofluorographic analyses, histological examinations, growing donor-derived CD4+ T-cell lines in vitro from spleens of transplanted scid mice, and serial passage of Ld-, CD3+CD4+CD8- T-cell lines through young scid recipients for more than 1 year. Host-derived IgMb appeared in sera of all CD4+ T-cell-transplanted young scid mice, while none of the sex- and age-matched, non-transplanted control scid mice was Ig+. B-cell leakiness was most efficiently induced by transfer of low numbers of adult CD4+ CD8- thymocytes: transfer of 10(3) purified CD4+ CD8- thymocytes efficiently rescued scid-derived B cells, while transfer of 2 x 10(7) non-fractionated thymocytes from the same donor mouse was inefficient. Serum antibodies of scid mice with T-cell-induced B-cell leakiness stained congenic 'double-positive' (CD4+ CD8+) thymocytes and immunoprecipitated protein bands with an apparent MW of 14,000, 28,000, 43,000, 65,000 and 80,000 from 125I-labelled thymocytes. These data indicate that repopulation of peripheral lymphoid organs with CD4+ T cells is always accompanied by partial co-reconstitution of the B-cell system, and raises the question of the interdependence of these two lymphocyte subsets.     

The role of E receptors in the attachment of thymocytes and T lymphocytes to human target cells

Human thymocytes, activated T lymphocytes, and neuraminidase-treated T cells possess the distinct capacity of forming conjugates with various human cell lines. The present study investigated whether E receptors, which endow human T cells with their capacity to bind sheep red blood cells (SRBC), are involved in this phenomenon. Monoclonal antibodies to human T cells and various simple sugars were studied for their effect on the attachment of human T cells to target cells. A-22, a monoclonal antibody to the E receptor, inhibited the formation of E rosettes by T cells and SRBC, and reacted in immunofluorescent-staining assays with the majority of human thymocytes and peripheral T cells, and with T-cell lines capable of forming E rosettes. When human thymus cells were treated with A-22 antibody they showed a reduction of up to 70% in their capacity to attach to the GM-4762 lymphoblast cell line and the K-562 myeloid line. Antibody treatment of the target cells, rather than of the thymus cells, had no effect on the formation of conjugates between thymus cells and target cells. Treatment of thymus cells with various monoclonal antibodies to T cells which do not react with the E receptor had no inhibitory effect. The exposure of human thymus cells to various simple sugars (D-mannose, D-fucose, galactose, and lactose) markedly reduced their capacity of forming conjugates with target cells. Exposure of neuraminidase-treated peripheral blood lymphocytes and of activated T cells to A-22 antibody inhibited their attachment to human target cells. The present study suggests that E receptors play a role in the attachment of human thymus cells and activated T cells to other human cells, and raises the possibility that these T-cell receptors may be involved in the process of recognition of "self" structures by human T lymphocytes.     

Expression on human thymocytes of the idiotypic structures (Ti) from two leukemia T cell lines Jurkat and HPB-ALL

The expression on a significant number of thymocytes of idiotypic structures (Ti) restricted to HPB-ALL or Jurkat cells is demonstrated. As many as 2-4% of thymocytes were stained with anti-Ti HPB-ALL or anti-Ti Jurkat monoclonal antibodies, when analyzed by flow microfluorometry. Immunohistochemical localization studies performed on frozen thymus specimens of either fetal or pediatric origin indicated a scattered distribution of Ti-positive cells in both the cortex and the medulla. From lysates of 125I-labeled pediatric thymocytes, anti-Ti HPB-ALL and anti-Ti Jurkat monoclonal antibodies precipitated disulfide-linked heterodimers comparable to those precipitated from 125I-labeled HPB-ALL or Jurkat cells as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis.     

Monoclonal antibodies to the murine Ly-2.1 cell surface antigen.

Six monoclonal anti-Ly-2.1 antibodies are described that arose from a single fusion using the spleen from a 129/ReJ mouse immunized with CBA/H thymus cells. The specificity was determined from the strain distribution, and testing of congenic strains where all six monoclonal antibodies detected the Ly-2.1 alloantigen. Furthermore, the antibodies fall into two groups: Group I (four antibodies) detected the expected number of Ly-2+ thymocytes and peripheral T cells, whereas Group II (two antibodies) detected 10% fewer peripheral T cells. Functional studies demonstrated that the Ly-2.1 determinant detected by a Group I antibody (49-31.1) was presented on cytotoxic T cells (Ly-1+2+), on concanavalin A (Con A)-induced suppressor T cells (Ly-1-2+), but absent from helper T cells (Ly-1+2-). One antibody (49-11.1) precipitated a 68,000-75,000 mol.wt glycoprotein, which on reduction yielded 30,000 and 35,000 mol.wt moieties. Thus, by functional, genetic and biochemical criteria these antibodies detected the Ly-2.1 specificity. In addition, a monoclonal, noncytotoxic, IgGl, anti-Thy-1.2 antibody is described.     

WUT6-抗人胸腺细胞共同性分化抗原来交瘤细胞系的建立

本文报导了用人胎儿胸腺细胞免疫BALB/c小鼠,取其脾细胞与小鼠骨髓瘤细胞系NS-1融合,获得一株能稳定分泌抗人共同性胸腺细胞单克隆抗体的杂交瘤细胞株,W_(?)T_(?)。它与72％胸腺细胞、皮肤Langerhan's细胞及部分T细胞系呈阳性反应;外周血T、D细胞、粒细胞、红细胞、血小板及B细胞系、Null细胞系均阴性。FACS检测结果及W_(?)T_(?)阳性细胞的组织分布特点均同HIT_6相似。在胸腺、皮质细胞及髓质中少数胞体较大呈树突状的细胞呈阳性反应。在扁桃体实质中少数散在细胞阳性。上皮基底层中的Langerhan's细胞则呈强阳性反应。用W_(?)T_(?)亲和层析柱提取胸腺细胞膜上相应的靶抗原分子,证明W_(?)T_(?)识别分子量为51KDa的抗原。免疫竞争抑制试验表明,W_(?)T_(?)同抗原的结合可被HIT_6完全阻断。说明W_(?)T_(?)与HIT_6识别相同的抗原决定簇。     

免疫组化技术分析人淋巴组织的多种分化抗原

用间接免疫过氧化物酶和PAP技术检测本室制备的31种抗人分化抗原单抗与淋巴组织的反应性.结果表明,CD3、CD5单抗与扁桃腺和淋巴结的T细胞、大部分成熟髓质胸腺细胞和脾白髓的中央动脉周围淋巴鞘呈非常强的反应.CD4~+细胞在扁桃腺的分布与CD3~+细胞类似,但数量稍少.只有少部扁桃腺和淋巴结T细胞与CD8单抗反应,CD8单抗主要染大部分胸腺皮质细胞,但抗CD8单抗与脾窦的内皮细胞呈强阳性交叉反应.Wu59单抗同时与扁桃腺、淋巴结和脾脏的T、B细胞呈非常强的膜染色,并与胸腺皮质和髓质细胞呈阳性反应,该单抗可能识别白细胞共同抗原或LFA-1.Wu 26.145单抗除与扁桃腺生发中心呈弱阳性反应外,还与脾红髓窦状结构内的血小板呈强阳性反应.此外,抗B细胞及其亚群单抗与扁桃腺、淋巴结、脾白髓生发中心呈强阳性反应.抗IL-2受体单抗与上述组织基本上呈阴性反应。     

Monoclonal anti-T-cell antibodies react with circulating myeloid leukemia cells and normal tissue macrophages

Rabbit and monoclonal antibodies to human myeloid leukemia cells, monocytic leukemia cells and human thymocytes have shown the existence of common T-cell/myeloid/monocyte antigens. For this reason, the specificity of a series of monoclonal antibodies to human T-cells (OKT 1, 3, 4, 5, 6, 8, 9, 10; and NA1/34) was tested by immunofluorescence (cytofluorograph) and complement-mediated cytotoxicity against human myeloid leukemia and normal blood cells and leukemic cell lines. In addition, an immunohistological analysis of the specificity of OKT4, 9.3, Leu 3a, OKT3 and NA1/34 antibodies was performed using normal lymphoid tissues and a sensitive immunoperoxidase technique. Normal human peripheral blood mononuclear cells reacted with OKT3 ("pan T-cell", mean 54%), OKT4 ("helper T-cell", mean 35%) and OKT 5/8 ("suppressor T-cell", mean 18%) as previously reported. However, OKT3 reacted with the cell lines K562 (myeloid), RC2a and THP-1 (monocytoid) and U937 (macrophage) as well as with cells from 9/65 myeloid leukemia patients. OKT4 reacted with the cell lines HL60 (promyelocyte), RC2a and U937 and also with cells from 6/60 myeloid leukemia patients. OKT5 reacted with the cell lines K562 and THP-1. OKT1 ("pan T-cell") reacted with THP-1 and with myeloid and monocytic leukemia samples (5/32) as did OKT6 ("cortical thymocyte") (3/32). OKT10 ("common thymocyte") reacted with a range of leukemia cell lines (B-cell, pre- B-cell and macrophage) as well as 7/21 myeloid leukemia samples. In tissue sections Leu 3a, (9.3 and OKT4 to a lesser extent), stained paracortical lymphocytes, plus subcapsular and medullary macrophages, and dendritic cells present within the paracortex.(ABSTRACT TRUNCATED AT 250 WORDS)     

Stimulation and expansion of a human T-cell subpopulation by a monoclonal antibody to T-cell receptor molecule

A murine monoclonal antibody (MAb) was obtained that showed unique specificity for the immunizing T-cell line HPB-ALL. This antibody, C37 (an IgG1,K) also reacted with a small (2-5%) population of normal peripheral blood T (PBL-T) cells. These C37-positive (C37+) cells were found in both the T4/Leu3+ and T8/Leu2+ subsets. Like OKT3 antibody, C37 induced T-cell mitogenesis with a peak proliferative response at day 3. In long-term cultures containing irradiated autologous feeder cells and IL-2, C37 antibody caused the selective expansion of C37+ T cells. On HPB-ALL cells C37 induced comodulation of the T3 molecule. C37 precipitated a disulfide-linked dimer characteristic of the T-cell antigen receptor consisting of an alpha-subunit (45-48 kD) and a beta-subunit (38-42 kD) from both C37+ T-cell blasts of a normal individual and HPB-ALL cells that were surface radioiodinated. However, the precipitated molecule isolated from C37 antibody-activated T-cell blasts exhibited a different pI from that isolated from HPB-ALL cells. Our studies indicate that C37 recognizes an epitope on the T-cell receptor molecule that is shared by a subpopulation of human T cells, which raises the possibility that multiple variable-region associated and/or framework-like determinants of the T-cell antigen receptor can be defined serologically and used in functional and molecular studies of T-cell subsets.     

Analysis of T-lymphocyte subpopulations in juvenile-onset diabetics.

The antigenic properties of leukaemic cells from five patients with adult T cell leukaemia were studied with rabbit anti-MOLT-4 and anti-human thymocyte antisera using indirect membrane immunofluorescent staining. The E rosette-positive, surface immunoglobulin (sIg) negative leukaemic cells from these patients gave a positive reaction with the appropriately absorbed antisera, which reacted specifically with thymocytes, cells from T cell acute lymphoblastic leukaemia (T-ALL) and T-ALL-derived lymphoblastoid cell lines (T-LCLs) and normal peripheral blood T cells. Nevertheless, the antisera further absorbed with fresh normal peripheral blood lymphocytes (FN-PBL) lost almost all the reactivities with the leukaemic cells as well as with normal peripheral blood T cells but still retained the reactivities with thymocytes, T-LCLs and T-ALL cells. The results suggest that adult T cell leukaemia cells possess a peripheral blood T cell antigen but not a thymocyte-specific antigen.     

Helix pomatia A hemagglutinin: selectivity of binding to lymphocyte surface glycoproteins on T cells and certain B cells

Human and mouse lymphocytes were surface-labeled by lactoperoxidasecatalyzed iodination, or by galactose oxidase oxidation followed by reduction with tritiated sodium borohydride. The labeled cells were lysed with Nonidet P-40. Proteins binding to Helix pomatia A hemagglutinin (HP) were isolated by affinity chromatography on HP-Sepharose and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography. A major cell surface glycoprotein (apparent mol. wt. 150000, using reducing conditions) on human lymphocytes was responsible for almost all binding of HP. This protein was present on normal and malignant thymus-derived lymphocytes, e.g. thymocytes, blood T cells and T leukemia cell lines. It was also found on chronic lymphocytic leukemia cells, one null cell leukemia line, one unidentified leukemia line, one lymphoblastoid cell line of B origin and on one stem cell lymphoma line. In contrast, this protein was not found on various B cells at different steps of differentiation, e.g. four B lymphoma lines or one myeloma line. It was also absent from a histiocytic leukemia line. However, two of the four B lymphoma lines and the myeloma line had another HP-binding surface glycoprotein (mol. wt. 200000) instead of the 150000 protein. Studies of mouse lymphocytes similarly showed that thymus-derived lymphocytes (normal and malignant) but not normal adult B cells expressed a major HP-binding surface glycoprotein of apparent mol. wt. 130000 (reducing conditions).