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PubMed1987

Bovine antibody dependent cell-mediated cytotoxicity (ADCC) effector cells.

ADCC effector cells from bovine blood were separated by centrifugation, adherence and rosetting techniques. Each enriched cell population, peripheral blood mononuclear cells (PBM), null lymphocytes, monocytes and neutrophils, was then examined for its capacity to mediate ADCC. Utilizing heterologous sensitizing antisera it was found that monocytes had approximately twice the ADCC activity of null lymphocytes and that neutrophils had essentially no activity. However, when homologous sensitizing antisera were used it was found that neutrophils possessed the greatest activity followed by monocytes and null cells. Results confirm the existence of an ADCC active null lymphocyte in the bovine.

Animals↗
PubMed1978

Serum amyloid A: evidence for its origin in polymorphonuclear leukocytes.

In this study the presence of an amyloid A, antigenically related material was determined in four subpopulations of human leukocytes. Monocytes, granulocytes, thymus-derived lymphocytes, and bone marrow-derived and null lymphocytes were isolated from the peripheral blood of five apparently normal subjects, two patients with secondary amyloidosis, three patients with acute infections, and seven patients with metastatic cancer. Mononuclear leukocytes, isolated from the interface of a Ficoll-Hypaque gradient, were separated into monocytes, thymus-derived lymphocytes, and bone marrow-derived plus null lymphocytes by glass adherence and depletion of sheep erythrocyte rosette-forming lymphocytes. Granulocytes were isolated by sedimentation in 2% methyl cellulose from the erythrocyte-rich pellet formed at the bottom of the Ficoll-Hypaque gradient. The four isolated leukocyte subpopulations were cultured and, at varying intervals, the amyloid A content of the culture medium and of sonicated, 2 x 10(6) cells was determined by radioimmunoassay. Our results indicated a 2-14 times greater amount of amyloid A-related material in the sonicated granulocytes compared with the individuals' serum amyloid A levels. The mononuclear subpopulations showed a low or negligible amyloid A content. The amount of amyloid A antigenic material was further found to increase in cultured granulocytes, reaching a peak value between the 16th and 30th h of culture. The granulocytes of only two out of eight individuals tested released amyloid A antigenically related material into the culture medium. This release was found to be blocked by the presence of colchicine, vincristine, puromycin, or cycloheximide in the culture medium. In contrast, only the presence of puromycin or cycloheximide was shown to significantly inhibit the intracellular increase of amyloid A in the cultured granulocytes. Thus, it appears that among the circulating blood cells, the granulocytes produce amyloid A antigenically related material and could release it under conditions that remain to be further defined.

Adult↗
PubMed1980

Human graft versus host disease.

Human graft versus host disease is composed of 2 distinct clinical entities, acute graft versus host disease and chronic graft versus host disease, which have different pathogenesis. Acute graft versus host disease is produced by the attack of donor immunocompetent T or null lymphocytes against recipient histocompatibility antigens. The null lymphocytes may attack antigens shared by the donor and recipient and are autocytotoxic lymphocytes which can produce acute graft versus host disease in recipients of identical twin transplants. The cessation of acute graft versus host disease occurs when suppressor lymphocytes appear in the recipient's peripheral circulation. Chronic graft versus host disease is produced by immunocompetent lymphocytes that differentiate in the recipient. Its control is unknown. Some patients with chronic graft versus host disease have in vivo activated suppressor lymphocytes which produce a secondary immunoincompetence and an increased susceptibility to bacterial sepsis and death.

Antibody Formation↗
PubMed1982

The role of autologous helper and suppressor T cells in the regulation of human granulopoiesis.

Helper and suppressor T cells play a physiological role in immunoregulation and possibly in other biological systems. Previous studies have suggested that unfractionated T cells influence human blood cell formation in vitro. Subpopulations of such cells (TM and TG cells) were prepared by immune ox erythrocyte rosetting techniques. Co-cultures were established in semi-solid agar with autologous null lymphocytes as a source of granulocyte-macrophage progenitor cells (CFU-GM). TM(helper) cells produced an increase and TG (suppressor) cells a decrease in the expression of CFU-GM as reflected in the number of GM colonies generated by comparison with cultures of null lymphocytes alone. These data point to a contribution from T lymphocyte subpopulations to the physiological regulation of human granulopoiesis.

Cell Separation↗
PubMed1984

The B cell IgM Fc receptor: further evidence for the B cell origin of "null" chronic lymphocytic leukemia.

Fifty-three cases of chronic lymphocytic leukemia (CLL) were studied for the presence of the B cell IgM Fc receptor (Fc microR) using an aggregated IgM reagent. Restricted surface immunoglobulin, using conventional immunofluorescent techniques and FACS analysis, was detected in 43 cases (81%). The cells in the remaining ten cases (19%) expressed negligible surface immunoglobulin (slg-) and did not form E rosettes (E-), but this "null" subset clearly expressed the B cell Fc microR. The coincident membrane expression of the B1 antigen and the la-like antigen, as well as serial studies showing surface membrane light chain acquisition (in one patient), provided additional evidence for the B cell origin of this slg-E- subset. This subgroup of CLL appears to correspond phenotypically to a normal counterpart at a stage of B cell differentiation between the pre-B cell and the slgM+ early B cell. The B cell Fc microR appears to be a consistent and potentially useful marker for sl gE ("null") CLL.

Antigens, Surface↗
PubMed1979

The role of the lymphocyte in haemopoiesis.

According to current dogma, circulating blood cells are all derived from the same progenitor, which therefore must be both pluripotent and capable of prolific self-replication. In the irradiated mouse, such haemopoietic stem cells (HSC) give rise to splenic colonies, and thus are designated as CFU-S (colony forming units-spleen). Definitive identification of a similar entity in man so far has proved elusive. However, primitive unipotent cells, committed to development along a single pathway, can be detected in human blood-forming tissues under appropriate culture conditions. Operationally defined as CFU-E (erythrocyte), CFU-GM (granulocyte/macrophage) etc., the ontogenetic relationships of these cells to each other and to the HSC have been the objects of exhaustive study. A population of lymphocytes, classed as "null" cells, do not exhibit the surface membrane markers which characterize commitment to differentiation in the thymus-dependent (T-cell) or bursa- equivalent (B cell) lineages. Accumulating evidence points to the null lymphocyte as a potential precursor of haemopoietic tissue. In bone marrow, the activity of terminal deoxynucleotidyl transferase (TdT) is concentrated in null cells, but the relevance of this unique enzyme to lymphocytic differentiation remains uncertain. Nevertheless, it appears that the functional heterogeneity, expressed within the family of lymphocytes, extends to haemopoiesis. The roles of various lymphocyte populations, in the generation and functional control of blood-forming tissue, are examined in this review.

Animals↗
PubMed1976

Isolation and immunologic characterization of a human. B-lymphocyte-specific, cell surface antigen.

In addition to HL-A antigens, another cell surface protein complex has been obtained from membranes of the human B-lymphoblast cell line IM-1. This complex which was solubilized with papain, consisted of polypeptides of 23,000 and 30,000 daltons (p23, 30). Rabbit antisera to this material precipitated from [35S]methionine-labeled detergent-solubilized cells, three proteins of 39,000, 34,000, and 29,000 daltons. These antisera were specifically cytotoxic for B lymphocytes of peripheral blood, for B-lymphoblast cell lines, and for EAC rosette receptor-positive surface Ig-negative (Null) lymphocytes. The p23,30 complex was not present on T lymphocytes, EAC rosette receptor-negative Null lymphocytes, or platelets. In addition, the p23,30 complex from several cell lines inhibited alloantisera from multiparous Amish women which had been shown to recognize non-HL-A, B-lymphocyte antigens. Some other properties of the anti-p23,30 sera antisera were described.

Antigen-Antibody Reactions↗
PubMed1995

Effects of Cryptosporidium parvum infection on lymphocyte phenotype and reactivity in calves.

Cryptosporidium parvum is a protozoan parasite now recognized as a significant cause of neonatal diarrhea in calves, and infection is also widespread in both immunocompetent and immunocompromised humans. No effective treatment or preventive measures against C. parvum infection are available, owing largely to the lack of understanding of immunologic mechanisms of resistance to and recovery from this parasite. In the present study, we compared phenotypes of lymphocytes from peripheral blood, spleen, mesenteric, and prescapular lymph nodes of calves infected or not infected with C. parvum. We also compared reactivity of these lymphocytes to mitogens and C. parvum antigen in vitro. There were more non-T, non-B (null) lymphocytes in all tissues of infected compared with control calves. The percent of CD8+ lymphocytes was significantly increased in spleens of infected compared with control calves, and there were markedly less CD4+ than CD8+ cells in spleens of both groups (i.e. low CD4/CD8 ratios). Splenic lymphocytes showed significantly decreased in vitro proliferation to pokeweed mitogen and C. parvum antigen stimulation compared with lymphocytes from other tissues. These findings suggest that null lymphocytes and CD8+ lymphocytes may be important in the expression and regulation of bovine immune responses to C. parvum in vivo.

Animals↗
PubMed1982

Non-Hodgkin's lymphoma: identification of the monoclonal B lymphocyte component in the presence of polyclonal immunoglobulin.

A high proportion of non-Hodgkin's lymphomas are neoplastic proliferations of B lymphocytes, and, as such, express integral membrane and/or cytoplasmic immunoglobulin (Ig). Because these cellular proliferations are monoclonal, the Ig of all neoplastic lymphocytes will have identical light chain type and idiotype. These tumors sometimes contain significant amounts of polyclonal Ig. In this study we demonstrate that the polyclonal non-B-lymphocyte-associated Ig may be removed by washing tissue at low pH to reveal either neoplastic B lymphocytes or neoplastic "null" lymphocytes. These observations should facilitate the application of immunohistology to the routine diagnosis of lymphoma.

B-Lymphocytes↗
PubMed1975

Interaction of plant lectins with purified human lymphocyte populations: binding characteristics and kinetics of proliferation.

With six purified plant lectins as probes of cell surface structure, human T, B, and Null lymphocytes have been examined for cell surface differences. The results of binding experiments with radioiodinated lectins indicate that these three lymphocyte populations, although functionally different, bind equivalent amounts of E- and L-PHA, lentil PHA, Con A, RCA-I, and WGA. Since these lectins are capable of binding to at least four different cell surface oligosaccharides, these data indicate that human T, B, and Null lymphocytes do not differ with respect to surface content of these carbohydrate structures. In addition, all six lectins were investigated for their ability to stimulate DNA synthesis in these human lymphocyte populations. Four of these lectins (E- and L-PHA, lentil PHA, and Con A) were mitogenic for human lymphocytes, whereas RCA-I and WGA failed to stimulate significant DNA synthesis in any lymphocyte population. When incubated with the mitogenic lectins, both B and Null cells displayed a delayed peak of DNA synthesis in comparison to T cells. Thus, despite virtually identical binding characteristics, the lectin-induced mitogenic response exhibited by B and Null cells was markedly different kinetically from that of T cells.

Adsorption↗
PubMed1980

Electrophoretic mobility of peripheral non-B human Fc gamma-receptors bearing lymphocytes.

The electrophoretic mobilities of separated "null" lymphocytes and of null and T cells bearing receptors for the fragment of immunoglobulins (Fc) portion of IgG have been studied in normal human blood. The data have been compared with those of other circulating subsets and with more conventional marker techniques. A large proportion of B cells was removed by nylon wool adherence. Further purification of the effluent cells separated 3 non-B populations using the property of sheep's red blood cells to form 2 types of rosettes with T cells on the basis of their relative affinity: "active" rosettes, and low affinity E-rosettes. A population of "null" cells was obtained which was effluent of the nylon wool column and non rosette-forming cells with SRBC (E-RFC). The average purity of this population was 85%; it was found to contain an increased proportion of rosette-forming cells with IgG coated erythrocytes (EA-IgG RFC) (41.3 +/- 10.4% vs. 11.9 +/- 3.8% in the total population) and exhibited high spontaneous incorporation of thymidine but low response to mitogens. The "null" cell population and its erythrocyte-antibody complex-rosette forming cells (EA-RFC) exhibited a defined electrophoretic mobility, centered between 1.05 and 1.15 micrometer. sec-1. v-1. cm in NaCl 0.145 M. The T populations, defined as ERFC, possessed different electrophoretic mobilities, and contained different proportions of Fc gamma receptor-bearing cells. Possessing an e. m. generally greater than 1.15 micrometer. sec-1. v-1. cm., high affinity "active" rosettes did not appear to contain EA-RFC, while the low affinity ERFC contained 18% (8 to 33) EA (IgG) RFC, and had an e.m. comprised between 1.00 and 1.15 micrometer. sec-1. v-1. cm. The presence of antibody-dependent cellular cytotoxicity was found to correlate with EA-RFC: mainly in EA-RFC of the "null" cells, but also to a lesser extent in EA-RFC of the low affinity ERFC. In normal human blood, these non-B Fc gamma receptor bearing cells appeared to possess a comparable electrophoretic mobility centered between 1.05 and 1.15 micrometer. sec-1. v-1. cm. in the "null" and low affinity ERFC subsets.

Adult↗
PubMed1989

Characterization of the blood mononuclear leucocytes producing alpha interferon after stimulation with herpes simplex virus in vitro, by means of combined immunohistochemical staining and in situ RNA-RNA hybridization.

A procedure is described for combined immunohistochemical staining and in situ RNA-RNA hybridization of human peripheral blood mononuclear leucocytes (PBMC). These cells were first stimulated in vitro by herpes simplex virus (HSV)-infected fibroblasts and after 6 h fixed and stained with a panel of antibodies against differentiation antigens. Alpha interferon (IFN-alpha)-producing cells (IPC) were identified by in situ hybridization by means of a 35S-labelled IFN-alpha 2 cRNA probe. The IPC were infrequent, one in 200-5000 PBMC, but heavily labelled with the cRNA probe. They lacked antigens typical of T and B lymphocytes, and were also essentially negative for the Leu-M5 antigen, present on a majority of monocytes. However, 50% of IPC expressed OKM5 antigens, corresponding to the thrombospondin receptor. The IPC lacked the antigens present on null lymphocytes detected by OKT16, but most of them expressed HLA-DR, -DP and -DQ antigens. The IPC may represent a small subpopulation in the monocyte/macrophage lineage, resembling cells described as antigen presenting and stimulators of autologous mixed lymphocyte reactions. Alternatively, they constitute a subpopulation among the null lymphocytes.

Antibodies, Monoclonal↗
PubMed1983

Changes in purine nucleoside phosphorylase activity during thymosin-induced human null cell differentiation.

Purine nucleoside phosphorylase (PNP) is a purine salvage pathway enzyme which we have found to be 8-10 times more active (per cell) in human peripheral blood null lymphocytes than in T lymphocytes. To test the hypothesis that null cells are, in part, pre-T lymphocytes we have defined an in vitro system for null cell differentiation into T cells and examined PNP activity during this differentiation process. We found that about 10% of human null cells could be driven to differentiate into T cells using thymosin fraction 5 (TF5) an extract of bovine thymus glands. The response to TF5 was dose related to up to 250 micrograms/ml with a maximum response occurring by 42-46 hr incubation. Exposure to TF5 was necessary for more than 4 hr but no more than 8 hr in order to obtain a maximum response. Both OKT4 and OKT8 positive cells were present in the newly differentiated T cell population but OKT8 positive cells appeared to predominate (OKT4/OKT8 = 0.698 +/- 0.30, mean +/- 1 SD). The differentiation process did not involve DNA synthesis but was inhibited at 4 degrees C. In the newly differentiated T cells PNP activity per cell was 8- to 10-fold lower (36 +/- 23 nm/hr/106 cells) than in null cells (311 +/- 136), and was at a level similar to mature T cells (56 +/- 7). Thus, human peripheral blood null cells can be induced to differentiate into T lymphocytes which can be characterized by both surface markers and biochemical parameters. Future studies will look at the function of TF5-induced T cells and the regulation of PNP activity during the differentiation process.

Adult↗
PubMed1982

Acid phosphatase and alpha-naphthyl acetate esterase in neoplastic and non-neoplastic lymphocytes. A statistical analysis.

Acid phosphatase and alpha-naphthyl acetate esterase reaction patterns were evaluated in lymphocytes from patients with a variety of neoplastic and non-neoplastic conditions: leukemia, 59; NHL, 53; and reactive follicular hyperplasia, 23. Fifteen individuals with normal peripheral blood were also studied. For both enzymes, statistical analysis showed a strong correlation between a globular reaction pattern and T lymphocytic origin in both non-neoplastic lymph nodes and normal peripheral blood specimens (P less than 0.0001). A similarly strong correlation was found between a granular acid phosphatase pattern and T lymphocytic origin in cell isolated from non-neoplastic lymph nodes (P less than 0.0001) but not in those obtained from normal peripheral blood where this pattern was observed with equal frequency in B, T, and "null" lymphocytes (P = 0.415). A granular alpha-naphthyl acetate esterase pattern was correlated with non-T lymphocytes from normal peripheral blood (P less than 0.0001), but was observed with equal frequency in B, T, and "null" lymphocytes fron non-neoplastic lymph nodes (P = 0.76). In the eight T cell neoplasias studied, a globular pattern was evident in the majority of cells for both enzymes. In the majority of the B cell neoplasias, however, a granular pattern was observed for both enzymes.

Acid Phosphatase↗
PubMed1978

[Use of thymus hormone in the demonstration of acute T-null cell lymphocytic leukemia].

The Authors studied the effect of the human serum thymic factor on the peripheral-blood leukocytes from ALL patients, by testing the frequency of the E+cells by means of the e rosette assay before and after cell incubation with the above mentioned factor. In 3 out of 24 patients tested, the thymic factor incubation of peripheral-blood mononuclears increased the number of E+cells. The shift from R to E+cells caused by the human serum thymic factor occurred among null cells (E-, SM-Ig-). The possible value of the test in investigating whether a T0 leukemia might really exists is pointed out, as well as its prospective importance in monitoring the variations of the immature T cell counts in relationship to the patient's treatment and his disease course.

Adult↗
PubMed1979

Studies of mixed lymphocyte reactions, surface B cell antigens, and intracytoplasmic immunoglobulins in "null cell" acute lymphocytic leukemia.

Lymphoblasts from "null cell" acute lymphocytic leukemia (ALL) were analyzed for the pattern of proliferation displayed in a mixed lymphocyte reaction (MLR), the presence of a B cell surface antigen, and for the presence of intracytoplasmic immunoglobulin (ICIg). "Null cell" ALL was defined by cytologic and cytochemical criteria and by the absence of spontaneous rosette formation and surface membrane immunoglobulin in cell suspensions of the malignant lymphocytes. In eleven of fourteen patients the proliferative characteristics of lymphoblasts in the MLR were similar to those observed with normal B enriched lymphocytes. In eleven cases studied, anti-B cell serum reacted with a majority of the lymphoblasts. None of the ten cases examined displayed ICIg in the lymphoblasts. We conclude that the "null" lymphoblast from most cases of ALL is a B cell in an early stage of development.

Adolescent↗