Isolation and electrophoretic characteristics of 3 lymphocyte populations of normal human blood]

Cell electrophoresis allows separation of normal human blood lymphocytes into two main groups which are a function of their relative rates of migration, with regard to the reference speed (1 mum.sec.-1V-1.cm): the lymphocytes which have a greater mobility than this value seem to be T-lymphocytes (80,1 per cent for 42 healthy adults); on the contrary, B-lymphocytes have an inferior mobility (19,9 per cent). Two known methods are used for the selection of the lymphoid populations: spontaneous rosetting with sheep's red blood cells, which are characteristic of T lymphocytes, and adherence to nylon wool columns, which is dominant in the case of B-lymphocytes. This method confirms the fact that T-lymphocytes have a rapid migration and B-lymphocytes a slow migration. We have isolated a third population, having neither the T markers, nor the B markers. It has a very homogeneous migration, centered on the two classes 1,05 and 1,10 mum.sec.-1.V.-1.cm.     

Characterization of the normal lymphocyte population cytolytic to Burkitt's lymphoma cells of the EB2 cell line.

The normal human lymphocyte population which exhibits "spontaneous" cytolysis of EB2 Burkitt's lymphoma cells has been characterized. The effector cell has EA and EAC' receptors but lacks E receptors and probably surface Ig. "Spontaneous" anti-EB2 cytotoxicity was not reduced by preincubation of the effector cells with plastic or iron carbonyl or by passage through cotton wool or agarose columns but was reduced by passage through nylon wool columns. Thymocytes were not cytotoxic to EB2 cells, and chronic lymphocytic leukaemia cells (of B cell characteristics) had reduced cytotoxicity compared with normal lymphocytes. Cells from various lymphoid organs of rats and guinea-pigs were also cytotoxic to EB2 cells with reactivity in spleen greater than or equal to blood greater than lymph nodes. Spleen cells from neonatally thymectomized rats had increased cytotoxicity compared with normal rat spleen cells, suggesting that T lymphocytes are not essential. The effector cell in rat spleen did not adhere to cotton wool or agarose columns, indicating some resemblance to its counterpart in human peripheral blood.     

Participation of cyclophosphamide-sensitive T cells in graft-vs-host reactions.

Cyclophosphamide (CY)3 is toxic for a population of mouse T cells which is active in graft vs host (GVH) responses. This observation contrasts with previous reports which indicate that treatment of mice with CY regimens, similar to those used in this study, enhances the reactivity of T cells which mediate delayed type hypersensitivity to sheep red blood cells. The GVH-inducing capacity of T cells is not altered by removal of B cells by nylon wool columns. We suggest that CY-sensitive T cells may be "regulatory cells," and that the effect they have depends on, among other things, the nature of the stimulating antigen to which the cells are responding and/or the assay used for study.     

Human Antigen-Presenting Cells: Characterization of the Cells in the T-Lymphocyte Proliferative Response

Human antigen-presenting cells (APC) which present the antigen to T lymphocytes resulting in a T-lymphocyte proliferative response were found among peripheral mononuclear cells (MNC), by employing purified protein derivative (PPD) as soluble antigen. To assess the adherence capacity of human antigen-presenting cells, MNC were separated by plastic Petri dishes or nylon wool columns. Plastic nonadherent cells were almost equivalent to unseparated cells in antigen-presenting ability. Plastic adherent cells, however, showed better antigen-presenting ability than unseparated cells. On the other hand, cells passed over nylon wool columns showed essentially no ability to present PPD to T lymphocytes. Removal of phagocytic cells by carbonyl iron resulted in about 50–70% reduction in antigen-presenting ability. Carrageenan, which is known to be toxic to macrophages, had no effect on APC. By using both rabbit anti-human Ia-like antiserum and alloantiserum specific for HLA-DR phenotype and complement, it was shown that APC possessed Ia-like antigens, whereas they did not bear surface immunoglobulins. These results indicate that the human APC is probably a cell in the monocyte-macrophage lineage. Allogeneic MNC were used as APC in order to determine whether any genetic restriction exists between MNC as APC and responding T lymphocytes. Optimal stimulation was shown to require identity of mixed leukocyte reaction (MLR)-activating determinants between APC and T lymphocytes. It is, however, obscure whether an HLA-D region restriction exists in these combinations because PPD-pulsed allogeneic MNC lost their ability to elicit even MLR. It is possible that this failure to elicit MLR was caused by T lymphocytes among the MNC used as APC.     

Changes in the electric charge of blood lymphocyte populations after secondary immunization with tetanus antitoxin in man]

The electrophoretic mobility of circulating lymphocytes has been studied in normal human subjects after immunization by tetanus toxoid. The mean migration speed was shown to increase, particularly two and three days after secondary immunization. This increase appeared to be due to the elevation of percentage of T cells migrating at 1.20 and 1.35 micrometer. sec.-1v.-1 cm. (active rosettes-forming cells), with a decrease of the percentage of B cells and T lymphocytes migrating at 1.10 micrometer. sec.-1v.-1 cm. The return to the anterior status was observed between day 4 and 8 after immunization.     

Natural anti-bacterial activity against Salmonella typhi by human T4+ lymphocytes armed with IgA antibodies

Peripheral blood mononuclear cells from normal volunteers possess natural anti-bacterial (NA) activity against S. typhi that can be measured in a 2-hr in vitro assay. Employing fractionation on nylon wool columns, Percoll gradients, plastic adherence, and E rosetting, the effector cell of NA activity appeared to be a lymphocyte of the T lineage rather than a macrophage, a B lymphocyte, or a large granular cell. Moreover, complement-dependent killing with monoclonal antibodies such as OKM1, OKB7, OKT8, 5.9 and the anti-natural killer cells AB8.28 did not reduce NA activity. On the contrary, this was completely inhibited when OKT3, OKT11, or OKT4 antibodies and complement were used to pretreat the effector lymphocytes. Indeed, T4+ cells sorted with a FACS displayed an extremely high NA activity against S. typhi. By pretreatment of peripheral lymphocytes with F(ab')2 fragments against human IgA, the NA activity was blocked. It is therefore suggested that NA activity by human cells might be a mechanism of defense against infections, acting as antibody-dependent cellular cytotoxicity expressed by T4+ lymphocytes coated with preexisting anti-Salmonella IgA antibodies.     

Cytotoxic T-lymphocyte and spontaneous killer cell activity against human T- and B-lymphoid cell lines.

We have investigated cell-mediated immune responses to cultured human T- and B-cell lines. Two effector mechanisms were explored and found to have different capabilities for mediating cytotoxic reactions. Cytotoxic T lymphocytes were generated by stimulation with irradiated B-cell lines and demonstrated cross-reactive cytotoxicity against these lines but not against T-cell lines. Unseparated mononuclear cells showed spontaneous cytotoxicity for both T- and B-cell lines; however, T-cell lines appeared more susceptible. Cell separation procedures were employed to determine functional differences in effector cells. In contrast to cytotoxic T lymphocytes induced in vitro, spontaneous killer cells (SKC) were shown to be nylon wool adherent, non-T lymphocytes with receptors for IgG-coated sheep erythrocytes.     

In vitro induction of lymphocyte responsiveness by a Strongylus vulgaris-derived mitogen

Proliferation in vitro of peripheral blood lymphocytes both from horses infected with Strongylus vulgaris and from helminth-free ponies was observed in the presence of extracts of the fourth and fifth stage larvae and adults of S. vulgaris. In addition, S. vulgaris extracts induced transformation in cultures of peripheral blood lymphocytes from sheep and dogs and in mouse spleen cell cultures. Nylon wool non-adherent, T cell enriched fractions of lymphocytes from both mice and horses were stimulated by the S. vulgaris larval mitogen while no proliferation was observed in cultures containing nylon wool adherent, B cell enriched fractions. Macrophage co-operation appeared not to be necessary for S. vulgaris mitogen-induced transformation of spleen cells. The S. vulgaris mitogen stimulated a subpopulation of mouse spleen cells different from those responsive to PHA, Con A and LPS. These cells might be T helper cells since B cells were stimulated to proliferate in the presence of both T cells and S. vulgaris larval mitogen. In addition, the supernatant of in vitro cultured larvae of S. vulgaris induced slight, but significant transformation of equine peripheral blood lymphocytes. Therefore, it is possible that the S. vulgaris mitogen released by both viable parasites and degenerating larvae might induce T cell dependent production of immunoglobulin in vivo and account for the beta-globulinaemia, of which IgG(T) is a major component, in S vulgaris infected horses.     

Homologous antigen for T cell receptor in axial organ cells from the asterid Asterias rubens.

The axial organ (A.O. cells) of the sea star Asterias rubens is a primitive immune organ. The total population was fractionated into two populations: adherent (B-like) and non-adherent (T-like) to nylon wool. The adherent cells resemble mammalian B lymphocytes and bear homologous human T cell receptor (beta chain) to a higher degree than T-like cells which resemble T lymphocytes.     

Regulation of experimental allergic encephalomyelitis. II. Appearance of suppressor cells during the remission phase of the disease

Lewis rats are susceptible to experimental autoimmune encephalomyelitis (EAE). Most rats recover from paralysis and are subsequently resistant to the disease. In an adoptive transfer system, we found that lymph node cells (LNC) from rats that had recovered from EAE protect syngeneic recipients from the disease when the latter are challenged with encephalitogenic myelin basic protein and adjuvant after receiving donor cells. Suppression is antigen-specific and requires viable LNC. In contrast to the suppressor cells we previously studied in tolerized rats, which were nonadherent T lymphocytes, the suppressor cells found in rats that have recovered from EAE adhere to glass wool. However, they are not retained on Sephadex G-10 columns to which macrophages adhere. Suppressor activity is enriched in the nylon wool-adherent LNC population (which consists of approximately 80% Ig+ cells). Our findings suggest that activation of adherent suppressor cells may be implicated in recovery from EAE. These may be adherent T cells, or B cells that produce anti-BP blocking antibodies.     

Cellular mechanisms of suppression of T-lymphocyte proliferation by lung cells in experimental tuberculosis]

The ability of interstitial lung cells from mice, infected with Mycobacterium tuberculosis H37Rv, to suppress proliferative responses of immune lymphocytes to mycobacterial (PPD) and unrelated (Staphylococcus aureus cytoplasm) antigens was studied. Two types of suppression were observed: the specific one, which was characteristic of the PPD-response only; and non-specific. The latter was mediated mainly by prostaglandins, since it could be abolished by indomethacin. Both types of suppression depended on the presence of plastic and nylon wool adherent phagocytes from infected lung. Though the depletion of T or B lymphocytes from the lung cell population have not abrogated the suppressive effect, some intercellular interactions were required for antigen-specific suppression, since the presence of nylon wool adherent cells in the population of responder lymph node cells was necessary for its development.     

Activation of human lymphocyte subpopulations by protein A from Staphylococcus aureus bacteria.

Cowan I strain Staphylococcus aureus bacteria were found to be mitogenic for human peripheral and cord blood lymphocytes. Experiments with lymphocyte supopulations otained by nylon wool filtration and/or E-rosette separation revealed that T-lymphocytes are the main target cells, whereas isolated B cells did not respond significantly. Further experiments suggested that B cells could be activated in the presence of mitomycin-treated T cells. Null cell-enriched lymphocyte suspensions could be stimulated by Con A but not by the bacteria or by PHA.     

A Method for the Differentiation of T And B Lymphocytes and Monocytes Migrating Under Agarose

This report describes alterations in the agarose lymphocyte migration technique which resulted in satisfactory differentiation of T and B lymphocytes and monocytes which have migrated as a monolayer for 1-3 days. The Wright-Giemsa staining used in the original method did not permit identification of individual migrating cell types. The most important modifications were changing from a plastic to a glass migration surface, and significantly reducing the overlying thickness of agarose which permitted a short fixation time and easy preparation of permanent slides ruined for nonspecific esterase. The esterase staining of monocyte cytoplasm was intense and diffuse. One or two small, discrete areas of cytoplasmic esterase activity were identified in the majority of T lymphocytes B lymphocytes showed either a trace or no evidence of esterase activity. The modified method should prove useful for the histochemical differentiation of migrating subpopulations of mononuclear cells.     

A method for the differentiation of T and B lymphocytes and monocytes migrating under agarose.

This report describes alterations in the agarose lymphocyte migration technique which resulted in satisfactory differentiation of T and B lymphocytes and monocytes which have migrated as a monolayer for 1-3 days. The Wright-Giemsa staining used in the original method did not permit identification of individual migrating cell types. The most important modifications were changing from a plastic to a glass migration surface, and significantly reducing the overlying thickness of agarose which permitted a short fixation time and easy preparation of permanent slides stained for nonspecific esterase. The esterase staining of monocyte cytoplasm was intense and diffuse. One or two small, discrete areas of cytoplasmic esterase activity were identified in the majority of T lymphocytes. B lymphocytes showed either a trace or no evidence of esterase activity. The modified method should prove useful for the histochemical differentiation of migrating subpopulations of mononuclear cells.     

T Lymphocytes Orient against the Direction of Fluid Flow during LFA-1-Mediated Migration

As they leave the blood stream and travel to lymph nodes or sites of inflammation, T lymphocytes are captured by the endothelium and migrate along the vascular wall to permissive sites of transmigration. These processes take place under the influence of hemodynamic shear stress; therefore, we investigated how migrational speed and directionality are influenced by variations in shear stress. We examined human effector T lymphocytes on intercellular adhesion molecule 1 (ICAM-1)-coated surfaces under the influence of shear stresses from 2 to 60 dyn.cm⁻². T lymphocytes were shown to respond to shear stress application by a rapid (30 s) and fully reversible orientation of their migration against the fluid flow without a change in migration speed. Primary T lymphocytes migrating on ICAM-1 in the presence of uniformly applied SDF-1α were also found to migrate against the direction of shear flow. In sharp contrast, neutrophils migrating in the presence of uniformly applied fMLP and leukemic HSB2 T lymphocytes migrating on ICAM-1 alone oriented their migration downstream, with the direction of fluid flow. Our findings suggest that, in addition to biochemical cues, shear stress is a contributing factor to leukocyte migration directionality.     

Heterogeneity of human natural killer cell populations.

Natural killing (NK) in human donors was determined by the ability of peripheral blood subpopulations to lyse the myeloid target, K562, in a 2 to 4 hr ⁵¹Cr release assay. The most active cell was a non-T cell which passed through nylon columns (representing 10 to 25% of column passed cells). A second column passed cell population, with characteristics of T lymphocytes (75 to 90% of column passed cells), was also capable of mediating natural killing. Non-T cells which were retained by the nylon columns (45 to 55% of adherent cells) lacked NK activity. However, nylon adherent T cells (45 to 55% of adherent cells) were consistently active in NK assays, illustrating an important subset of NK effector cell often overlooked. Both column passed and adherent T cells were further separated according to their ability to bind IgG or IgM immune complexes, showing that those mediating NK have receptors for IgG (Tγ+) but not for IgM (Tμ+).     

Migration of recently divided B and T lymphocytes to peritoneum and lung

It is recognized that a population of newly divided (or young) cells migrate preferentially to inflamed foci. It has been shown that a large proportion of lymphocytes residing in the bronchoalveolar airspaces of rat are recently divided cells and that blood may be an important source of these cells. To further delineate how blood may contribute to lymphocyte subpopulations in inflamed peritoneum and lung, a comparison of the capacity of recently divided T and B cells to migrate from blood to inflamed peritoneum and lung was made. To label young lymphocytes, DA strain donor rats were given Initiated thymidine by vein in vivo for 7 days. After thoracic duct drainage, the following labeled cell populations were adoptively transferred by vein into syngeneic recipients: (i) unseparated thoracic duct lymphocytes (TDL), (ii) enriched T cells (>90%) or B cells (>80%) recovered after passage of TDL through nylon columns, and (iii) thoracic duct lymphocytes (> 99% B cells) obtained from “B rats” that were prepared by X irradiation, thymectomy, and bone marrow reconstitution. T and B cells were identified by specific heterologous antisera. The percentage recovery of labeled lymphocytes in the recipients with inflamed peritoneum or lung aspirates was determined from cell counts and autoradiographs. The studies indicated that (a) both labeled T and B cells migrated to inflamed peritoneum and lung; (b) labeled B cells migrated to peritoneum and lung better than did labeled TDL or T cells; and (c) labeled lymphocytes did not migrate to unstimulated peritoneum. The enhanced migration of newly divided B lymphocytes to inflamed peritoneum and normal lung (a site that is likely under chronic antigenic stimulation) was unexpected, but may provide additional information on the relative contribution of these subpopulations in the immune inflammatory response.     

Th1 and Th2 CD4+ T cells provide help for B cell clonal expansion and antibody synthesis in a similar manner in vivo

The relative ability of Th1 and Th2 T cells to help B cells remains controversial as do the mechanisms by which both T cell subsets provide help in vivo. Whether this help affects the clonal expansion and/or differentiation of B cells has been difficult to assess due to the low frequency of Ag-specific T and B lymphocytes. We have employed a novel technique to directly monitor the clonal expansion of Ag-specific T and B lymphocytes in vivo. OVA-specific TCR transgenic T lymphocytes were polarized toward a Th1 or Th2 phenotype in vitro. These cells were then transferred into syngeneic recipients, along with B cell receptor transgenic hen egg lysozyme-specific B lymphocytes. Our results indicate that Th1 and Th2 cells support B cell responses to a similar extent in vivo and that they achieve this in the same manner by migrating into B cell follicles to promote CD154-dependent B cell clonal expansion and Ab production.     

In vitro studies of the rabbit immune system. IV. Differential mitogen responses of isolated T and B cells.

The mitogenic responses of separated rabbit lymphocyte populations functionally analogous to mouse T and B cells have been tested in vitro. Purified T cells were prepared by passage over nylon wool (NW) and purified B cells prepared by treatment with antithymocyte serum and complement (ATS + C). ATS + C kills 70% of peripheral blood lymphocytes (PBL's) and 50% of the spleen cells while passage over NW yields 40% of the applied PBL's and 5–23% of the applied spleen cells. NW-purified T cells from the spleen or PBL's respond fully to concanavalin A (Con A) but have a reduced response to phytohemaglutinin (PHA) and little or no response to goat anti-rabbit immunoglobulin (anti-Ig). PBL's that survive ATS + C (B cells) are stimulated by anti-Ig but not by Con A or PHA. B cells purified from spleen do not respond to Con A or PHA but will respond to anti-Ig under appropriate conditions. A full spleen B-cell response to anti-Ig required removal of Ig produced by the cultures that blocked anti-Ig stimulation. It is concluded that, for rabbit lymphocytes, Con A and PHA are primarily T-cell mitogens and that anti-Ig is primarily a B-cell mitogen. However, the mitogen response of unfractionated PBL or spleen cell populations indicates an overlap in reactivity. This could be due to cells sharing T and B properties, alteration of cell populations by the fractionation procedures used, or recruitment of one population in the presence of a mitogenic response of the other population.     

In vitro sensitization of human lymphocytes against histiocytic lymphoma cell lines. I. Primary sensitization of lymphocyte subpopulations.

Peripheral blood lymphocytes from normal donors expressed spontaneous cytotoxic activity against human diffuse histiocytic lymphoma cell lines. In the unfractionated state, they could not be further sensitized in vitro against these cell lines. By applying cell separation techniques before culture, subpopulations of lymphocytes were obtained which could be sensitized in vitro and manifested cytotoxic activity against human histiocytic lymphoma cells. Three methods of separation were found effective: E rosette enrichment; elimination of Fc receptor positive cells; and removal of nylon wool adherent cells. Under these conditions, cross-reactive cytotoxicity was observed against non-neoplastic lymphoblastoid cell lines, but not against normal lymphocytes.