Adult acute lymphoblastic leukemia phenotypes defined by monoclonal antibodies

Pretreatment peripheral blood and/or bone marrow blasts from 90 adults with acute lymphoblastic leukemia (ALL) were analyzed as part of a prospective treatment protocol study. Specimens were tested by immunofluorescence cytofluorometry for reactivity with the following monoclonal antibodies (MoAbs): BA-1 (B cell antigen); T101, OKT11 (pan-T cell antigens [T]); 3A1 (T cell antigen); MCS-2 (myeloid antigen); J5 common ALL antigen (CALLA); BA4 (Ia antigen [Ia]); BA-2 (lymphohematopoietic antigen). Four major phenotypic groups were identified: B lineage ALL (BA-1+T-) (64%), T lineage ALL (T+BA-1-MCS-2-) (13%), unclassified ALL (BA-1-MCS-2-CALLA-T-) (9%) and myeloid antigen ALL (MCS-2+CALLA-T-) (7%). An additional group of patients, miscellaneous ALL (7%), was comprised of cases with unusual marker profiles. In B lineage ALL, all cases tested were Ia+MCS-2-, and the vast majority were CALLA+ (84%). In T lineage ALL, 42% expressed CALLA or Ia positivity. In unclassified ALL, the predominant phenotype was Ia+BA-2+. In myeloid antigen ALL, two of four tested were 3A1+ and all cases evaluated were BA-1-. Patients with myeloid antigen ALL were older (median age, 66 years) than patients in the other groups. The T lineage ALL group had higher leukocyte counts (median WBCs, 183,000/microL) and an increased incidence of anterior mediastinal mass at presentation. All patients received identical induction therapy. In CALLA+B lineage ALL, 30 of 46 (65%) achieved a complete remission. While the number of patients evaluated was small, 9 of 9 CALLA-B-lineage ALL and only two of six myeloid antigen ALL cases responded with a complete remission. The data suggest that these MoAbs are useful in the characterization of adult ALL.     

Human myeloma: several subsets of circulating lymphocytes express plasma cell-associated antigens

Peripheral blood lymphocytes from 9 monoclonal gammopathies of undetermined significance (MGUS) and 27 multiple myelomas (MM) were studied with a panel of monoclonal antibodies (MoAb) that recognize B and T lymphocytes and plasma cells. No difference in the percentage of B lymphocytes, identified by B1 and B4 MoAb, was observed in MGUS and MM patients versus normal controls. However, high percentages of circulating lymphocytes expressing plasma cell-associated antigens were detected in MM (HAN-PC1+ = 29.4 +/- 20.4%; TEC-T10+ = 27.8 +/- 19.2%) whereas they were in the normal range in MGUS (HAN-PC1+ = 8.8 +/- 5.8% p = 0.006; TEC-T10+ = 5.7 +/- 4.7% p less than 0.001). Almost identical results were obtained using PCA-1 MoAb in 17 of these patients. TEC-T10+ and PCA-1+ lymphocytes were sorted and re-analyzed with phycoerythrin conjugated MoAb in 3 healthy subjects, 2 MGUS, and 4 MM patients. In normal subjects and in MGUS the majority of PCA-1+ cells belonged to the B lineage (Leu 2-, Leu3-, Leu 15-, HLA-Dr+), whereas the majority of TEC-T10+ cells are represented by activated T cells and NK cells (Leu 15+). In MM an abnormal expansion of T lymphocytes was chiefly responsible for the high values of lymphocytes expressing plasma cell-associated antigens. Moreover, in MM a clinical evaluation showed a correlation between the presence of these lymphocytes and an aggressive disease. Indeed, they can be considered a useful prognostic marker.     

Normal cellular counterparts of B cell chronic lymphocytic leukemia

In an attempt to compare B cell chronic lymphocytic leukemia (B-CLL) with its normal cellular counterpart, the cell surface phenotype of 100 cases of B-CLL was determined by using a panel of monoclonal antibodies (MoAbs) directed against B cell-restricted and -associated antigens. The majority of B-CLL cells expressed Ia, B4 (CD19), B1 (CD20), B2 (CD21), surface immunoglobulin (sIg), and T1 (CD5) but lacked C3b (CD35) receptors. In contrast, the overwhelming majority of small unstimulated B cells expressed Ia, B4, B1, B2, sIg, and C3b receptors but lacked detectable T1. Small numbers of weakly sIg+ cells could be identified in peripheral blood and tonsil that coexpressed the B1 and T1 antigens. Approximately 16% of fetal splenocytes coexpressed B1, T1, weak sIg, B2, and Ia but lacked C3b receptors and therefore closely resembled most B-CLL cells. With the phenotypic differences between the majority of small unstimulated B cells and B-CLL cells, we examined normal in vitro activated B cells and B-CLL cells for the expression of B cell-restricted and -associated activation antigens. Of 20 cases examined, virtually all expressed B5, and approximately 50% of the cases expressed interleukin-2 receptors (IL-2R) and Blast-1. Normal B cells were activated with either anti-Ig or 12-0-tetradecanoylphorbol- beta-acetate (TPA) and then were examined for coexpression of B1, T1, and the B cell activation antigens B5 and IL-2R. Only cells activated with TPA coexpressed B1 and T1 as well as B5 and IL-2R. B cells activated with either anti-Ig or TPA proliferated in the presence of IL- 2, whereas B-CLL cells did not, although they all expressed the identical 60-kilodalton proteins by immunoprecipitation. These studies are consistent with the notion that B-CLL resembles several minor subpopulations of normal B cells including a population of B cells that are activated in vitro directly through the protein kinase C pathway.     

Cytochemically demonstrable B-glucuronidase activity in normal and neoplastic human lymphoid cells

Mononuclear cell suspensions were prepared from 40 normal peripheral blood and lymphoid tissue specimens and 42 neoplastic specimens obtained from patients with malignant lymphoma and lymphocytic leukemia. These suspensions were analyzed for la antigens, surface immunoglobulin (Slg), sheep erythrocyte (E) rosette formation and, in some instances, acid alpha-naphthyl acetate esterase (ANAE) activity. The results of these studies were correlated with the expression of cytochemically demonstrable BG activity. The percentage of BG+ lymphocytes was found to be comparable, within 10%, to the percentage of E+ (T) cells in the majority of normal, non-neoplastic peripheral blood, tonsil, spleen, and lymph node specimens examined. Occasionally, the percentage of E+ cells exceeded the percentage of BG+ cells by 20% or more, suggesting the presence of an E+BG- T cell subpopulation. BG+ B lymphocytes were only demonstrated in 1 of 40 non-neoplastic lymphoid specimens. The neoplastic B cells in each of 14 B cell (la+Slg+E-) lymphomas were BG-. However, a variable proportion of the neoplastic cells isolated from 6 cases of B cell chronic lymphocytic leukemia and neoplastic plasma cells isolated from 7 cases of multiple myeloma expressed BG activity. Thus, it appears that both normal and neoplastic BG- and BG+ B lymphocyte populations exist; the latter may be related to a state of activation or a stage of B cell differentiation. The neoplastic cells isolated from 4 T cell (la-Slg-E+) malignancies were BG+ while those isolated from 3 T cell malignancies were BG-. The variable expression of BG activity by T cell malignancies may be related to T cell differentiation. Investigation of BG expression by T cell derived malignancies may prove useful in sorting out T cell phenotypes.     

Cell cycle progression of B-chronic lymphocytic leukemia cells induced to differentiate by TPA

The cell cycle transition and differentiation-associated surface antigen expression was studied in a clone of B cell chronic lymphocytic leukemia (B-CLL) with phenotypic properties similar to those of resting B lymphocytes. Differentiation was induced with TPA (12-O-tetradecanoyl- phorbol-13-acetate) and defined and quantitated by morphological and functional markers. Changes in the cell cycle position were determined by flow cytometry of acridine orange-stained cells. The uninduced B-CLL cells represented a homogeneous population with the same cell cycle position (GO) as resting normal peripheral blood lymphocytes. After five days of TPA stimulation, 56% of the B-CLL cells were found in G1A, 9% in G1B, and 3% in the S + G2/M phase, of which 2% was accounted to proliferating T cells. The cell cycle transition of the differentiating B-CLL cells was also examined using cell cycle-associated surface antigens as markers. HLA-DR and CD23 antigens were present already on noninduced cells. The former had a high constant expression, while the amount of CD23 increased upon induction. The 4F2 antigen was absent on noninduced cells but present on 86% of the induced cells. HH1 (CD37) was expressed by the majority of the cells before TPA treatment and decreased to almost undetectable levels within 24 hours. Two antigens related to late stages of the cell cycle, the interleukin 2 (IL 2; CD25) and the transferrin receptor, were present on about 20% of the induced cells. Experiments with enriched T cells showed that T but not B cells incorporated 3H-thymidine. Taken together these results and previous work on the induction of the protooncogene c-myc and c-fos suggest that this B-CLL clone represents GO cells that undergo differentiation without concomitant proliferation when exposed to TPA.     

Interleukin 2 promotes growth and cytolytic activity in human T3+4-8- thymocytes.

Human thymocytes bearing T3 but neither T4 nor T8 antigens (T3+4-8- cells) were obtained after negative selection of thymocytes, either fresh or cultured in medium containing recombinant interleukin 2 (IL-2), by treatment with Na1/34, OKT4A and B9.4 monoclonal antibodies (which recognize T6, T4, and T8 antigens, respectively) and complement. Quantitative flow cytometry showed a 98% pure population of T3+4-8- lymphocytes, which included proliferating cells. The growth and maturation requirements of these thymocytes were characterized and related to the T3-receptor complex and IL-2 pathways, thought to be used by mature lymphocytes. The results show that addition of recombinant IL-2 promotes, in a dose-dependent way, proliferation and acquisition of effector functions by cultured T3+4-8- thymocytes, the growth being inhibitable by monoclonal antibody 33B73 (anti-Tac). Furthermore, cytolytic activity of T3+4-8- cells induced by recombinant IL-2 is specifically blocked by monoclonal antibody OKT3, showing that it operates via the T3-receptor complex and does not require either T4 or T8 molecules. The finding of in vitro responsiveness to recombinant IL-2 in T3+4-8- thymocytes suggests a role of IL-2 in the growth and maturation of cells committed to the T-cell lineage, during intrathymic differentiation, prior to expression of T4 and T8 molecules.     

Hairy cell leukemia: a tumor of pre-plasma cells

Monoclonal antibodies defining B-, T-, and myeloid-restricted cell surface antigens were used to characterize the lineage and state of differentiation of tumor cells isolated from 22 patients with hairy cell leukemia (HCL). These tumors were shown to be of B lineage because they strongly expressed the B cell-restricted antigens B1 and B4 and lacked T cell- and monocyte-restricted antigens. Moreover, the strong expression of the plasma cell-associated PCA-1 antigen on the majority of hairy cells suggested that these tumors correspond to later stages of B cell ontogeny. Dual fluorescence experiments further confirmed that HCL splenocytes that coexpressed B1 and PCA-1 demonstrated both the morphology and tartrate-resistant acid phosphatase positivity of hairy cells. The observation that some hairy cells either spontaneously produce immunoglobulin (Ig) or could be induced to proliferate and secrete Ig provides complementary support for the view that HCL is a pre-plasma cell tumor. However, staining of hairy cells with anti-IL2R1 monoclonal antibody, which is directed to the T cell growth factor receptor and/or with the anti-Mo1 reagent, directed to C3bi complement receptor, distinguish these cells from currently identified B cells.     

Phenotypic analysis of synovial tissue and peripheral blood lymphocytes isolated from patients with rheumatoid arthritis

Cytofluorometric analysis was performed to characterize the surface phenotype and activation status of freshly isolated synovial tissue lymphocytes (STL) and peripheral blood lymphocytes (PBL) from 7 patients with rheumatoid arthritis (RA). Proliferative synovium was enzymatically digested to obtain tissue-derived lymphocytes. Indirect immunofluorescent staining of patient PBL and STL with a variety of monoclonal antibodies failed to reveal a consistent alteration in the number of CD4+ (helper/inducer) PBL or STL. However, there was a significant decrease in the number of CD8+ (suppressor/cytotoxic) cells in rheumatoid STL (P less than 0.05). A significant reduction in the density of the T cell differentiation antigens CD3 and CD4 was observed in RA PBL and STL, compared with control PBL. These differences in antigen density were not seen when normal PBL were subjected to the same enzymatic digestion. Both RA PBL and STL manifested increased expression of HLA-DR antigens, without augmentation of interleukin-2 receptor expression. Alterations in the expression of the T cell differentiation antigens and activation antigens by patient PBL closely paralleled the abnormalities observed in STL. In contrast, STL of patients with RA exhibited an increase in the expression of the adhesion-related glycoproteins (leukocyte function-associated 1 [LFA-1] and very late activation 1 [VLA-1] antigens), not observed with autologous PBL. These studies demonstrate that lymphocytes isolated from the synovial tissues of RA patients bear an activated phenotype, exemplified by the modulation of CD3 and CD4 and the expression of HLA-DR.(ABSTRACT TRUNCATED AT 250 WORDS)     

Expansion of Vdelta1 T lymphocytes producing IL-4 in low-grade non-Hodgkin lymphomas expressing UL-16-binding proteins

Data on 23 patients with low-grade non-Hodgkin lymphomas (NHLs), 4 mantle (MT), 4 marginal zone (MZ), and 15 follicular (FL), were analyzed and compared with 10 high-risk (HR) B-cell chronic lymphocytic leukemias (B-CLLs) with lymph node involvement and 4 diffuse large-cell lymphomas (DLCLs). A significant increase in circulating Vdelta1 T lymphocytes producing interleukin-4 (IL-4) was found in patients with FL, MT, and MZ NHL, at variance with DLCL and HR B-CLL. IL-4 was also detectable in the sera and lymph nodes of the same patients. In 19 of the 23 patients with NHL with increased circulating Vdelta1 T lymphocytes, B cells expressing the UL-16-binding proteins (ULBPs) ULBP2 or ULBP3 or both were found in peripheral blood, bone marrow, or lymph nodes. Of note, in HR B-CLL or in DLCL, where leukemic cells were negative for ULBPs, no Vdelta1 T-cell increase was found. Moreover, Vdelta1 T lymphocytes from patients with FL NHL proliferate in response to ULBP2+ and ULBP3+ lymphoma cells. Finally, patients with high expression of ULBPs, increased circulating Vdelta1 T lymphocytes, and high levels of serum IL-4 showed stable disease in a 1-year follow-up in contrast to patients with low circulating Vdelta1 T cells and undetectable IL-4 or ULBPs.     

Expression of human B cell-associated antigens on leukemias and lymphomas: a model of human B cell differentiation

A series of monoclonal antibodies that define B cell restricted and associated antigens was utilized in an attempt to characterize tumors of B lineage and to relate these tumors to B cell differentiative stages. Antigens that were previously shown to be B cell restricted on normal B lymphocytes were similarly expressed only on B cell malignancies. In contrast, antigens that were B cell associated were also found on tumors of other lineages. Moreover, on the basis of cell surface phenotypes, tumors of B cell origin were divided into three major subgroups, which corresponded to the level of differentiation of the malignant tumor cell: pre-B cell stage (non-T acute lymphoblastic leukemia and chronic myelocytic leukemia in lymphoid blast crisis); the mid-B cell stage (chronic lymphocytic leukemia, poorly differentiated lymphomas); and secretory B cell stage (large cell lymphomas and plasma cell tumors). A hypothetical model is derived that relates the malignant B cell to its normal cellular counterpart on the basis of cell surface expression of this panel of B cell-restricted and B cell- associated antigens.     

Increase in CD95 (Fas/APO-1)-positive CD4+ and CD8+ T cells in peripheral blood derived from patients with autoimmune hepatitis or chronic hepatitis C with autoimmune phenomena

BACKGROUND: The expressions of CD95 (Fas/APO-1) and Bcl-2 are determinants of apoptosis in normal lymphocytes, and abnormalities in their expressions might contribute to the induction of autoimmunity. In this study, we examined the expressions of CD95 and Bcl-2 on freshly isolated T and B cells from patients with autoimmune hepatitis (AIH) or chronic hepatitis C associated with autoimmune phenomena (CH-C(AI)). METHODS: The CD95 and Bcl-2 expressions within CD4+ T, CD8+ T, and CD19+ B cell subsets were analysed by two-colour flow cytometry. RESULTS: The surface expression of CD95 was significantly high in both the CD4+ T and CD8+ T cell subsets derived from the patients with AIH and those with CH-C(AI), compared with expression in patients with CH-C and normal subjects. The increase in CD95 expression was associated with the phenotypic conversion of naive CD45RO- to primed CD45RO+ CD4+ T cells. Bcl-2 was detected in the vast majority of peripheral T and B cells. There was no significant difference in the percentage of Bcl-2-positive cells in the CD4+ T cell, CD8+ T cell and CD19+ B cell subsets among the patient groups and normal subjects. CONCLUSIONS: These results indicate that an increase in CD4+ T cells expressing CD45RO and CD95 marks an important subset of AIH and CH-C(AI) patients. These expanded CD95+ CD45RO+ primed T cells most likely reflect a continuous antigen-specific or non-specific activation of T lymphocytes, and/or the persistent presence of activated lymphocytes as a consequence of abnormalities in the peripheral deletion of activated lymphocytes. These persistently activated lymphocytes might play a role in the induction of autoimmunity in AIH and CH-C(AI).     

Acid hydrolase activities in B cell chronic lymphocytic leukaemia lymphocytes: correlation of cytochemical reactions with immunological phenotype

The cytochemical reactions of 5 acid hydrolases, alpha-naphthyl acetate esterase (ANAE), acid phosphatase (AP), beta-glucuronidase, beta-glucosaminidase and dipeptidylaminopeptidase IV (DAP IV) were investigated in lymphocytes from 30 patients with B cell chronic lymphocytic leukaemia (B-CLL). Based on ANAE and AP reactivities, 4 cytochemically distinctive subgroups were identified: Group 1: AP and ANAE less than 50% positive lymphocytes (5 cases); Group 2: AP greater than 50%, ANAE less than 50% positive lymphocytes (11 cases); Group 3: AP less than 50%, ANAE greater than 50% positive lymphocytes (7 cases); Group 4: AP and ANAE greater than 50% positive lymphocytes (7 cases). beta-Glucuronidase displayed similar patterns of reactivity to AP. beta-Glucosaminidase activity was observed in the majority of lymphocytes in most patients, whereas DAP IV activity was present in less than 20% of lymphoid cells. The study failed to establish any relationship between cytochemical grouping and patients' clinical status, peripheral lymphocyte counts, E or mouse rosette values, light or heavy chain cellular immunoglobulin (Ig) class. Attempts to correlate acid hydrolase and Ig heavy chain isotype expression, putative markers of B cell maturation, were unsuccessful and indicate that within the narrow spectrum of B cell differentiation seen in B-CLL these characteristics are unrelated.     

Characterization of a series of monoclonal antibodies against human T cells

A set of 6 monoclonal antibodies is characterized reacting only with human T-cells but not with B lymphocytes. The antibody BL-T1 binds to the E receptor, being there on all mature T cells and on the majority of thymocytes. All respectively the majority of peripheral T cells but only subpopulations of thymocytes are recognized by the monoclonals BL-T2, BL-T3, BL-T4 and BL-T5. For identification and quantification of mature human T cells especially the antibody BL-T2 is suitable. The antigen recognized by BL-E1 is missing on peripheral B lymphocytes but expressed not only on T cells but also on erythrocytes, monocytes and a fraction of granulocytes. The monoclonals discussed are compared with the monoclonals for identification of leucocyte differentiation antigens (cluster of differentiation) characterized on the 1st Int. Workshop on Human Leucocyte Differentiation Antigens (Paris, 1982).     

Cell surface markers in HTLV-1 pathogenesis

The phenotype of HTLV-1-transformed CD4(+) T lymphocytes largely depends on defined viral effector molecules such as the viral oncoprotein Tax. In this review, we exemplify the expression pattern of characteristic lineage markers, costimulatory receptors and ligands of the tumor necrosis factor superfamily, cytokine receptors, and adhesion molecules on HTLV-1-transformed cells. These molecules may provide survival signals for the transformed cells. Expression of characteristic surface markers might therefore contribute to persistence of HTLV-1-transformed lymphocytes and to the development of HTLV-1-associated disease.     

Expression of the G-protein--coupled receptor BLR1 defines mature, recirculating B cells and a subset of T-helper memory cells

The G-protein-coupled receptor BLR1 related to receptors for chemokines and neuropeptides has been identified as the first lymphocyte-specific member of the gene family characterized by seven transmembrane-spanning regions. Using a high-affinity anti-BLR1 monoclonal antibody (MoAb) and three-color flow cytometry it is shown that BLR1 expression on peripheral blood cells is limited to B cells and to a subset of CD4+ (14%) and CD8+ (2%) lymphocytes. T cells expressing BLR1 were positive for CD45R0, were negative for interleukin-2 receptors, show high levels of CD44, and show low levels of L-selectin. The majority of CD4+ cells originating from secondary lymphatic tissue, but none of cord blood- derived T cells, express BLR1. These observations suggest that BLR1 is a marker for memory T cells. Furthermore, BLR1 expression was detected on all CD19+ peripheral or tonsillar B lymphocytes, but only on a fraction of cord blood cells and bone marrow cells expressing CD19, sIgM, or sIgD. Interestingly, activation of both mature B and T cells by CD40 MoAb and CD3 MoAb, respectively, led to complete downregulation of BLR1. These data suggest that the G-protein-coupled receptor BLR1 is involved in functional control of mature recirculating B cells and T- helper memory cells participating in cell migration and cell activation.     

CD4+ CD25+ T cells responding to serologically defined autoantigens suppress antitumor immune responses

A variety of tumor-derived antigens have been defined by IgG antibodies in tumor bearers' sera with serological identification of antigens by recombinant expression cloning (SEREX), a serological expression cloning method. The majority of these antigens show no structural abnormality and seem to be wild-type autoantigens. Coimmunization with DNA encoding these autoantigens and tumor-specific cytotoxic T lymphocytes epitopes heightened CD8+ T cell responses and increased resistance to tumor challenge in a CD4+ T cell-dependent manner. In contrast, immunization with these SEREX-defined autoantigens alone leads to heightened susceptibility to tumor challenge. This suppressive effect of immunization is mediated by CD4+ CD25+ T cells. In mice immunized with one of the SEREX-defined autoantigens, Dna J-like 2, the number of alpha-GalCer/CD1d tetramer+ CD3+ T cells [representing natural killer T (NKT) cells] was reduced in the pulmonary compartment, whereas no evident change in the number of other T cell subsets was observed. Experiments with Jalpha281-/- mice lacking most NKT cells indicate that NKT cells are primarily responsible for metastasis suppression and that their activity is inhibited by immunization with Dna J-like 2. We propose that SEREX identifies a pool of autoantigens that maintains and regulates immunological homeostasis via CD4+ CD25+ regulatory T cells.     

Distribution of the CD45R antigen in the maturation of lymphoid and myeloid series: the CD45R negative phenotype is a constant finding in T CD4 positive lymphoproliferative disorders

We have compared the expression of the common leucocyte antigen (CD45) and the restricted leucocyte antigen (CD45R) on normal haematopoietic cells, cell lines, and a total number of 136 cases of myeloid and lymphoid proliferative syndromes. CD45, the conventional leucocyte antigen, presents a generalized distribution along the lymphoid and myeloid maturation pathway with the exception of some myelomas and pre-B leukaemias. In contrast, the expression of the CD45R determinant is more limited. Although it is found in the majority of the differentiation stages of B cells and monocytes, it is present only in the early stages of myeloid differentiation. On T cells it is expressed on mature thymocytes and in the majority of CD8+ lymphocytes and a subset of CD4+ cells on peripheral blood. Finally, our results also indicated that CD4+ T lymphoproliferative syndromes are derived from the CD4+ CD45R- subset (20/20 cases).     

Differentiation-dependent expression of sialyl stage-specific embryonic antigen-1 and I-antigens on human lymphoid cells and its implications for carbohydrate-mediated adhesion to vascular endothelium

Expression of two developmentally regulated carbohydrate antigens, the sialyl stage-specific embryonic antigen-1 (SSEA-1) and I-antigens, in human lymphocytes and lymphocytic leukemia cells was investigated using specific monoclonal antibodies. Sialyl SSEA-1 was expressed only on natural killer (NK) cells, and was essentially absent on resting mature T and B cells among normal peripheral lymphocytes. On the other hand, the I-antigen was strongly expressed on virtually all mature B cells, moderately expressed on most mature T cells, but not expressed on NK cells in normal donors. Expression of the two antigens on normal T and B cells was reversible; in vitro stimulation of normal lymphocytes with concanavalin A (Con A) resulted in the loss of I-antigen and appearance of sialyl SSEA-1 on CD3+ T blasts, whereas stimulation with pokeweed mitogen led to loss of I-antigen expression and appearance of sialyl SSEA-1 antigen on CD19+ B blasts. Among lymphocytic leukemia cells, sialyl SSEA-1 was detected primarily on leukemia cells having immature properties such as most common acute lymphocytic leukemia (cALL) blasts, while the I-antigen was frequently expressed on malignant cells having relatively mature properties, such as those found in adult T- cell leukemia or chronic lymphocytic leukemia, and only occasionally on cALL blasts. Among normal peripheral lymphocytes, the sialyl SSEA-1+I- antigen- NK cells selectively underwent E-selectin (ELAM-1, endothelial- leukocyte adhesion molecule-1)-dependent adhesion to endothelial cells, while the I-antigen+sialyl SSEA-1- mature T and B cells did not, in line with the recent finding that sialyl SSEA-1 serves as a specific ligand for E-selectin. Con A blasts, which are sialyl SSEA-1+I-antigen- , also exhibited significant E-selectin-dependent adhesion to endothelial cells. These results indicate that expression of the sialyl SSEA-1 and I-antigens varies alternately depending on the differentiation/activation status of the lymphocytes, and that this at least partly regulates the behavior of lymphocytes at the vessel wall.     

Distribution of antigens defined by OKB monoclonal antibodies on benign and malignant lymphoid cells and on nonlymphoid tissues

Monoclonal antibodies OKB1, OKB2, OKB4 and OKB7 have been previously shown to detect distinctive antigens displayed on B, but not on T, lymphocytes. Benign and malignant lymphoid cells were investigated for their reactivity with these antibodies in cell suspension by indirect immunofluorescence and in cryostat tissue sections by the avidin-biotin complex immunoperoxidase technique. Fetal liver pre-B cells and pre-B and common type acute lymphoblastic leukemia cells isolated from 15 patients were OKB1-OKB2+OKB4-OKB7-. All mature lymphoid tissue B cells and the neoplastic cell surface immunoglobulin-positive (SIg+) B cells isolated from each of 47 B cell neoplasms were OKB2+. OKB1 and OKB7 were expressed by interfollicular, follicular center, and many, but not all, mantle zone B cells. OKB4 was expressed by follicular center cells, but not by mantle zone or interfollicular B cells. The neoplastic SIg+ B cells isolated from 45 of 47 B cell malignancies were OKB1+OKB4+, and those isolated from 45 of 46 B cell malignancies were OKB7+. The neoplastic B cells of one mantle zone lymphoma were OKB1-, of one small lymphocytic cell lymphoma were OKB7-, of one large cell lymphoma were OKB4-, and of one small lymphocytic cell lymphoma with a monoclonal gammopathy were OKB1-OKB4-. Normal and myeloma plasma cells were OKB-. The malignant T cells isolated from 12 T cell neoplasms were OKB2-OKB4-, but were OKB1+ and/or OKB7+ in 3 cases. Thus, the OKB antibodies appear to detect distinctive antigens that may be expressed at different stages of B cell differentiation. In addition, OKB4 reacted with selected renal and respiratory epithelium, and OKB2 reacted with a wide range of epithelial tissues. The OKB antibodies should prove useful in the investigation of B cell differentiation and may aid in the identification and characterization of lymphoproliferative malignancies with significant therapeutic and prognostic differences not identifiable by conventional histopathologic and immunologic methods.