Cell surface energy and membrane associated actin in lymphocytes

We have shown previously that membrane associated actin correlates with the migratory abilities of lymphocytes during recirculation, and that cell surface energy correlates with the adhesiveness of lymphocytes to other cells. In this study, measurements of actin content and cell surface energy have been made for various lymphocyte subpopulations to examine the possibility that recirculation ability may be related to nonspecific adhesiveness. We have found that: both cell surface energy and actin content combine to provide a consistent explanation for the relative rates of recirculation of various lymphocyte subpopulations, and cell surface energies and actin contents vary independently in these lymphocyte subpopulations. Comparison of the actin contents and cell surface energies of metastatic and nonmetastatic lymphoma cell lines indicated that the differences in metastatic potential were more likely attributable to specific receptor-ligand interactions than to nonspecific adhesiveness. Cell surface energy and actin content are consistent with the greater adhesiveness of B cells than T cells to nylon wool, providing a physical basis for this common cell separation technique.     

Characteristics of lymphoid subpopulations isolated from healthy subjects and those suffering from nonspecific ulcerative colitis

Results of the studies of functional activity of lymphocyte subpopulations T+G, T-G, "O" subpopulations isolated peripheral blood of healthy persons and those with nonspecific ulcerative colitis (NUC) have been presented in this paper. The functional activity of the cells was assessed by means of local xenogeneic graft-vs-host reaction performed on CBA mice and by determination of nonspecific esterase enzyme. It has been established that analogous lymphocyte subpopulations influence the graft-vs-host reaction development in different ways depending on the condition of cell donor state: health/pathology. "O" subpopulations isolated from healthy persons hampered the graft-vs-host reaction development, and on the contrary stimulated it in patients with NUC. The assay of nonspecific esterase in lymphocytes showed that the least activity was noted in T+G and "O" cells in nonspecific ulcerative colitis.     

DNase I inhibitions in tumors of different metastasizing capacities: a possible index of invasiveness

Tumor pairs, selected on the basis of their different capacities to metastasize in vivo (SP73/AS and ASML from the rat, Eb/ESb from the mouse), have been assayed for their membrane associated actin through the DNase inhibition assay. It is found that, provided inhibitions per cell are corrected for the influence of gross heterogeneities in size distributions, the more metastatic tumor cells have significantly higher DNase I inhibitions than their less invasive counterparts. This observation, which extends our previous study of normal recirculating lymphocytes, is rationalized by postulating a participation of these actin pools to a property critical for both normal recirculation and metastatic spreading, arguments are presented which favor cell surface deformability as a possible candidate.     

Cellular immunity in the mouse. I. In vitro lymphocyte reactivity

The mixed lymphocyte culture (MLC) and antigen-mediated proliferative response represent important correlates to the in vivo phenomena of allograft rejection and delayed hypersensitivity. This study defines an in vitro model to measure mouse lymphocyte responsiveness to allogeneic cells, antigen (tuberculoprotein), and nonspecific mitogens. Results describe optimal cells concentration, time and conditions of culture. Optimal conditions include the use of high cell concentration, flat-bottomed vials, RPMI-1640 medium, and fresh human serum. Peripheral blood lymphocytes demonstrated greater proliferation than lymph node lymphocytes, which in turn demonstrated greater activity than splenic lymphocytes. Significant proliferation occurred in serum-free media, dialyzed against fresh serum and supplemented with hydrocortisone and carrier protein. The MLC response in the mouse appears dependent on multiple subpopulations of cells and on soluble substances produced by them.     

Stimulation of B lymphocytes through surface Ig receptors induces LFA-1 and ICAM-1-dependent adhesion.

Engagement of the surface Ig receptor with anti-IgM antibodies stimulates murine B lymphocytes to markedly increase their expression of the cell adhesion molecules ICAM-1 and LFA-1. Stimulated B cells display increased homotypic adhesiveness and form spontaneous heterotypic conjugates with T lymphocytes. This latter T-B cell interaction is further enhanced if T cells have been previously activated with phorbol esters. In all cases, the formation of cell-cell conjugates is dependent on LFA-1-ICAM-1-mediated interactions as assessed in mAb blocking experiments. B lymphocytes stimulated with anti-IgM display a marked increase in binding to ICAM-1-transfected L cells. This cell-cell interaction is inhibited by anti-LFA-1 mAb binding to the B lymphocyte. Together, these results demonstrate that there is an induction of both ICAM-1 and LFA-1 on stimulated B cells and a corresponding increase in the adhesiveness of these cells. These findings suggest that Ag binding to the surface Ig receptor could prepare a B lymphocyte for subsequent interaction with a T lymphocyte. This provides insight into how efficient T-B collaboration may occur between very infrequent Ag-specific lymphocytes.     

Nonspecific and antigen-specific adhesiveness of circulating lymphocytes in dysentery patients undergoing combined therapy using thymalin and indomethacin

Nonspecific adhesiveness of lymphocytes to polyacrylonitrile fiber and the antigen-specific adhesiveness of T-lymphocytes to Shigella flexneri pellicular immunosorbent have been studied in dysentery patients. Short courses of treatment with indomethacin, but not with thymalin (the preparation of thymic hormones), used for immunomodulation, have accelerated the normalization of nonspecific lymphocyte adhesiveness during regression of the disease, while indomethacin, in contrast to thymalin, inhibits antigen-specific T-lymphocyte adhesiveness which increases with the development of immune response.     

A cytophotometric and flow cytofluorometric approach to the differentiation of T lymphocytes in the thymus

Summary By cytophotometric and flow cytofluorometric DNA and protein determinations two main proliferating subpopulations of thymus lymphocytes with a different percentage of cells in the S phase could be distinguished. One subpopulation had a very low protein content, was cortisone sensitive and located in the cortex. Cells with comparable low protein contents were not found amongst lymphocytes of the peripheral blood. The other lymphocyte subpopulation had a higher protein content, was cortisone resistant and situated in the cortex around a group of epithelial cells and in the medulla. The protein content of these thymus lymphocytes appeared to be comparable to that of the peripheral blood lymphocytes. On the basis of the protein content per cell, it is possible to identify and isolate the more often described major subpopulation of cortisone sensitive thymus lymphocytes remaining and dying in the thymus, and the minor cortisone resistant subpopulation of thymus lymphocytes which is the source of the peripheral T lymphocyte.     

Increased frequency of micronuclei in B and T8 lymphocytes from smokers

The frequency of micronuclei was measured in peripheral B lymphocytes and some T lymphocyte subpopulations from 5 medium-tar cigarette smokers, and 5 non-smokers with no regular exposure to tobacco smoke. The peripheral lymphocytes were stimulated in vitro with phytohemagglutinin and B lymphocytes and the various T lymphocyte subsets were classified by a recently developed MAC (Morphology, Antibody, Chromosomes) method which allows the immunologic identification of different cell lineages. An increased frequency of micronuclei was observed in B and especially in the suppressor/cytotoxic T8 lymphocytes from smokers, as compared with non-smoker values. In non-smoker cultures, no differences in the frequency of micronuclei were observed among the different T lymphocyte subsets. In these cultures, B cells tended to have a higher frequency of micronuclei than did T cells. The proportions of B cells and the various T subpopulations among mitotic and interphasic lymphocytes from smokers and non-smokers were also determined. The proportions of B cells and T cell subsets among all mitotic lymphocytes were similar in smokers and non-smokers. Contrarily, a significant decrease in the proportion of T8 lymphocytes among all interphasic lymphocytes was observed in cultures derived from smokers.     

Basement membrane and its components on lymphocyte adhesion, migration, and proliferation.

During inflammation and recirculation, lymphocytes migrate into tissues by traversing the capillary endothelium, a process known as extravasation. After crossing the endothelial cells, lymphocytes come into contact with the basement membrane, which is a specialized layer of extracellular matrix containing predominantly laminin, collagen type IV, entactin, and heparan sulfate proteoglycans. In tissue invasion by inflammatory cells and metastatic tumor cells, the basement membrane serves as a substratum for cell adhesion and migration. However, the role of basement membrane in lymphocyte extravasation remains unclear. In this study, we investigated the effect of basement membrane on lymphocyte adhesion, migration, and proliferation, using matrigel as a model for basement membrane. We observed that matrigel promotes both lymphocyte adhesion and migration, with entactin primarily responsible for promoting adhesion and laminin for promoting migration. In addition, activation of lymphocytes by anti-CD3 enhances their adhesion and migration on matrigel-coated substratum. We also observed that matrigel inhibits the proliferation of lymphocytes stimulated by Con A. Furthermore, we demonstrated that laminin is the matrigel component responsible for inhibiting lymphocyte proliferation. However, matrigel has no effect on the proliferation of lymphocytes stimulated by LPS. These results suggest that matrigel has different effects on lymphocyte subpopulations. In agreement with the results on proliferation, matrigel also inhibits the production of IL-2 by Con A-stimulated lymphocytes.     

Antibody-dependent cellular cytotoxicity effector cells lack Ia antigens.

Surface immunoglobulin (sIg)-positive and sIg-negative subpopulations of macrophage-depleted murine splenic lymphocytes were obtained by Sephadex anti-Fab immunoabsorbent fractionation. These lymphocyte subpopulations were analyzed for the presence of Thy 1 and Ia alloantigens and also for Fc receptors by fluorescence microscopy. Concurrently, these lymphocyte subpopulations were studied for effector cell activity in antibody-dependent cellular cytotoxicity (ADCC). Effector cells mediating ADCC were contained in the sIg-negative lymphocyte subpopulation and sIg-positive lymphocytes did not mediate cytotoxicity. The majority of sIg-positive lymphocytes were found to bear Ia antigens and Fc receptors, and these cell surface structures were associated in that treatment of these cells with anti-Ia sera inhibited binding of complexed immunoglobulin to Fc receptors. In contrast, most sIg-negative, Thy 1-negative lymphocytes lacked Ia Antigens, and the Fc receptors detected on such cells were not blocked by anti-Ia sera. In addition, a small subpopulation of sIg-negative, Ia antigen-positive, Fc receptor-positive lymphocytes was found. Elimination of this subpopulation of Ia antigen-positive cells from sIg-negative lymphocytes, by treatment with anti-Ia serum and complement, did not diminish ADCC effector cell activity in the resultant cell population when compared with untreated sIg-negative lymphocytes. Thus, in murine spleen, nonphagocytic mononuclear cells that lack both sIg and Ia antigens were shown to mediate ADCC.     

A lymphocyte cell surface molecule that is antigenically related to actin

When viable murine lymphocytes are incubated sequentially with a saturating amount of affinity-purified, rabbit anti-actin and highly conjugated FITC-goat anti-rabbit Ig, about 52% of mesenteric lymph node (MLN) lymphocytes and 36% of thymocytes exhibit a faint, but sharply punctate surface fluorescence. Cell surface actin (CSA) can be distinguished from staining of cytoplasmic actin in permeable cells, which are identified by their uptake of ethidium bromide. Staining of actin in ethidium bromide-permeable cells is 10-fold more intense than staining of actin on ethidium bromide-impermeable cells and is seen as uniformly fluorescent rings or crescents at the periphery of the cell and as dimmer, diffuse fluorescence centrally. Binding of rabbit anti-actin and goat anti-rabbit Ig to the lymphocyte cell surface is not mediated by Fc receptors; F(ab')2 fragments of these antibodies detect the same number of positive cells as do the intact molecules, and affinity-purified anti-KLH does not bind significantly. The cell surface stain, measured by flow cytometry or fluorescence microscopy, can be absorbed by pretreatment of the anti-actin with immobilized actin but not with IgG-Sepharose. Double-label experiments show that about 70% of the non-B cells and 30% of the MLN B cells bear detectable CSA. Although we have not ascertained the origin of CSA, we find that the number and brightness of cells exhibiting CSA cannot be increased by preincubating the cells with exogenous native skeletal muscle actin or with supernatant from dissociated MLN, indicating that there are no free binding sites for exogenous actin. The findings imply that either there is a developmentally expressed binding site(s) for actin, or that at various stages of development lymphocytes express a protein antigenically related to actin on their surface.     

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.     

Characterization of tumor-associated lymphocytes in a series of mouse mammary tumor lines with differing biological properties

Tumor-associated lymphocytes were isolated by isokinetic gradient separation from five related mouse mammary tumor lines with different immunological and growth characteristics. Although considerable variation in recovery rates was seen from experiment to experiment, the five tumor types were found to have reproducible and characteristic patterns of T lymphocyte subpopulations, as detected by cytotoxicity assay using monoclonal antisera to Thy-1, Lyt-1, and Lyt-2 antigens. Tumors of line 168, which are weakly immunogenic at best, had the lowest numbers of recovered ALS+, Thy1+ lymphocytes (12% and 9%, respectively), in contrast to immunogenic lines (mean 38% and 26%, respectively). Line 68H tumors, which grow after prolonged latency periods and also produce tumor cell variants in vivo, were unique in that the numbers of recovered Lyt 1+ lymphocytes exceeded the number of Lyt 2+ lymphocytes, whereas these two T cell subpopulations were either equal or Lyt 2+ cells predominated in the other faster growing, non-variant-producing tumors. No differences in T lymphocyte distribution were associated with the presence or absence of metastatic behavior. These results indicate that distinctive lymphocyte infiltrates may be characteristic of tumors with distinct biological differences.     

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.     

Size-dependent B lymphocyte subpopulations: relationship of cell volume to surface phenotype, cell cycle, proliferative response, and requirements for antibody production to TNP-Ficoll and TNP-BA

Murine splenic B lymphocytes were separated into size-dependent subpopulations by using counterflow centrifugation. Spleen cells were rigorously depleted of T lymphocytes to yield a population of cells that were greater than 90% surface immunoglobulin (Ig)-positive and that had a mean cell volume of 136.6 +/- 3.3 microns. From this population, five fractions of cells were obtained with mean cell volumes that ranged from 115.8 +/- 3.7 microns in fraction 1 to 168.0 +/- 6 microns in fraction 5. The cells in these five subpopulations were characterized by analysis on a fluorescence-activated cell sorter after staining with acridine orange to evaluate RNA and DNA content, and with fluorescein-conjugated anti-mu, anti-delta, and anti-Ia antibodies to evaluate their surface membrane phenotypes. DNA analysis revealed that virtually all of the cells in fractions 1 to 4 had 2 N DNA. Between 7 and 21% of fraction 5 cells were either in S-phase or contained 4 N DNA. In contrast, RNA content increased through the fractions, suggesting a transition from G0 to G1 in the subpopulations with increasing B cell size. As another measure of cell activation seen with increasing cell size, we observed a progressive increase in the expression of surface Ia and a decrease in the expression of surface IgD. In the absence of in vitro stimulation, the larger cells showed significantly higher levels of thymidine incorporation. When polyclonal B cell activators such as LPS or anti-Ig antibody were added, peak proliferative responses were similar in all of the fractions, but the time necessary to achieve a maximal response was shorter for the larger-sized cell subpopulations than it was for the smaller-sized cell subpopulations. Unprimed, size-dependent B lymphocyte subpopulations exhibited spontaneous or "background" antibody formation that occurred primarily in the subpopulations containing the largest cells. T cell factors present in EL4 supernatant enhanced the efficiency of in vitro differentiation of these same subpopulations. When cultured in the absence of T cell help, the thymus-independent type 1 (TI-1) antigen TNP-Brucella abortus (TNP-BA) or the thymus-independent type 2 (TI-2) antigen TNP-Ficoll induced the largest anti-TNP plaque-forming cell (PFC) responses in the fractions containing intermediate-sized cells, suggesting that in vitro, antigen-specific responses came primarily from B cells that have been influenced in vivo to leave their small resting state. The subpopulations containing the smallest size B cells required the presence of both a TI antigen and EL4 supernatant for efficient differentiation.(ABSTRACT TRUNCATED AT 400 WORDS)     

Suppression of in vitro CML generation by alloactivated lymphocytes: analysis of antigen-nonspecific suppressive mechanisms

We have investigated the in vitro phenomena associated with antigen-nonspecific suppression of mixed lymphocyte culture (MLC) responses by allocativated lymphocytes. Using an experimental system that we described in a previous communication, we observed that a) the degree of suppressive activity generated by allocativation correlates directly with the intensity of proliferation observed during induction of suppressive activity, b) suppressive activity segregates exclusively with proliferating (lymphoblast) subpopulations of alloactivated lymphocytes, c) when suppressive cells are included in MLC, subsequent [3H]thymidine incorporation is enhanced and accelerated, rather than impaired, and d) a considerable proportion of the cells recovered from suppressed MLC appear to be the progeny of the suppressive population, and not the progeny of the MLC responder population. These data suggest that antigen-nonspecific suppression mediated by alloactivated lymphocytes has two related components: 1) cytokine preemption by suppressive (alloactivated) lymphocytes, and 2) MLC responder cell dilution by the progeny of suppressive lymphocytes. These data are consistent with the hypothesis that the antigen-nonspecific suppressive activity of alloactivated lymphocytes can reflect the coincidental ability of activated T cells to recognize and respond to mitogenic lymphokines in vitro. The data further explain why antigen-nonspecific suppression is difficult to reverse by addition of exogenous lymphokines to suppressed MLC.     

A cytophotometric and flow cytofluorometric approach to the differentiation of T lymphocytes in the thymus.

By cytophotometric and flow cytofluorometric DNA and protein determinations two main proliferating subpopulations of thymus lymphocytes with a different percentage of cells in the S phase could be distinguished. One subpopulation had a very low protein content, was cortisone sensitive and located in the cortex. Cells with comparable low protein contents were not found amongst lymphocytes of the peripheral blood. The other lymphocyte subpopulation had a higher protein content, was cortisone resistant and situated in the cortex around a group of epithelial cells and in the medulla. The protein content of these thymus lymphocytes appeared to be comparable to that of the peripheral blood lymphocytes. On the basis of the protein content per cell, it is possible to identify and isolate the more often described major subpopulation of cortisone sensitive thymus lymphocytes remaining and dying in the thymus, and the minor cortisone resistant subpopulation of thymus lymphocytes which is the source of the peripheral T lymphocyte.     

Lymphocyte populations of non-scleronodular Hodgkin's disease subtypes in different stages of lymphocyte depletion. An immunophenotypic and quantitative study

Twenty-one cases of non-scleronodular Hodgkin's disease with variable lymphocyte contents were studied immunophenotypically and quantitatively to analyse the distribution of different lymphocyte populations and to determine whether selective loss of lymphocyte subpopulations accompanies overall lymphocyte depletion. In Hodgkin's tissue B-cells were scanty and unevenly distributed in samples with both many and few lymphocytes. Several large B, LN1-positive (possibly activated) cells were observed in a few cases. CD3-positive T-lymphocytes predominated in all cases; the same cells were also UCHL1-positive, thus expressing characteristics of mature T-memory cells. CD4-positive lymphocytes were usually more numerous than CD8-positive lymphocytes, but quantitative evaluation of the latter showed that they did not decrease in proportion to any diminution of the whole lymphocyte population. This finding suggests that in the process of lymphocyte depletion more CD4-positive lymphocytes than CD8-positive lymphocytes are lost, and this might account for the impairment of cell-mediated immunity in Hodgkin's disease.     

A ground-based model to study the effects of weightlessness on lymphocytes

The mitogenic response of human lymphocytes was found to be markedly reduced in weightlessness conditions as compared to normal gravity. One possible explanation is that due to the non-existent sedimentation in space the lymphocytes could not adhere and spread on a substratum. Thus, we investigated the effect of substratum adhesiveness on lymphocyte responsiveness by reducing and blocking cell adhesion with poly-HEMA in a simple on-ground system. Lymphocyte adhesiveness was assessed by measuring the proportion of non-adhesive, slightly, and strongly adhesive 51Cr-radiolabelled cells on uncoated and poly-HEMA coated plastic. The amount of cell spreading on surfaces with varying adhesiveness was determined by measuring the area of cells. Cells grown on medium and thick poly-HEMA films were rounded in shape. By contrast, on tissue culture plastic, they showed clear signs of spreading. The mitogenic response of lymphocytes grown on thick poly-HEMA films was reduced by up to 68% of the control (tissue culture plastic). Interferon-gamma production was virtually nil when the cells were grown on the least adhesive substratum. These results show that activated lymphocytes need to anchor and spread prior to achieving an optimal proliferation response. We conclude that decreased lymphocyte adhesion could contribute to the depressed in vitro lymphocyte responsiveness found in the microgravity conditions of space flight.     

Glucocorticoid receptors in subpopulations of human lymphocytes defined by monoclonal antibodies

Glucocorticoid receptors (GR) were investigated in subpopulations of lymphocytes identified by monoclonal antibodies. Purified T (OKT3+) and non-T lymphocyte subpopulations were isolated from human peripheral blood using Degalan bead columns coated with rabbit anti-human IgG. Purified subpopulations of OKT4+ and OKT8+ lymphocytes were obtained by coating the nonadherent population (T cells) from the first column with OKT4+ or OKT8+ and pouring it into a second Degalan column, coated with goat anti-mouse IgG. GR content and affinity were analyzed by a whole cell assay with [3H]dexamethasone as tracer. The numbers of GR in lymphocyte subpopulations (OKT3+ cells, non-T cells, OKT4+, and OKT8+ cells) were nearly equal. It is concluded that the differential effects of glucocorticoids on the circulatory kinetics of OKT4+ and OKT8+ cells probably are not related to differences in glucocorticoid receptors of these T-cell subpopulations.