Separation methods for lymphocyte populations

Antigen-specific electrophoretic cell separation for immunological investigations

Preincubation of human blood lymphocytes with cell surface antigen specific antibodies under non-capping conditions reduces the electrophoretic mobility of the corresponding lymphocyte subpopulation. Antigen-positive and antigen-negative cells can be separated by free flow electrophoresis with high yield, purity and viability. The use of fluorescence-labelled second antibodies augments the induced decrease in net surface charge density, and allows rapid detection of antigen-positive cells in the fractions of electrophoresis. Carrier-free cell electrophoresis of human peripheral blood lymphocytes after reaction with anti-IgM-antibody or the monoclonal antibodies OKT4 or OKT8, and sandwich staining with tetrarhodamine isothiocyanate-labelled anti-IgG resulted in the large-scale separation of high pure human B and T lymphocyte subpopulations. Their functional integrity was shown in assays of lymphocyte transformation and of antigen-specific induction and regulation of antibody synthesis in vitro. These separate lymphocyte subpopulations are useful tools for immunological investigations. While, for instance, the effects of drugs on human lymphocytes are obscured by coincident changes in cell composition of the peripheral blood tested that do not by themselves reflect whole body immunocompetence, the cell separation and in vitro assays at a defined cell number and cell composition allow the recording of quantitative changes in the function of different cell subpopulations. We studied the influence of the anesthetic thiopental on separated human lymphocyte subsets. In both polyclonal lectin stimulation and in vitro antibody production, thiopental exhibited a noncytotoxic suppression of lymphocyte functions. B-Cells, T-helper and T-suppressor cells were equally affected and showed the same dose response.(ABSTRACT TRUNCATED AT 250 WORDS)

Depletion of human lymphocytes from peripheral blood and bone marrow by affinity ligands conjugated to agarose-polyacrolein microsphere beads

Protein-A or goat anti-mouse-Ig (GAMIg) covalently bound to agarose-polyacrolein microsphere beads (APAMB) were employed for the removal of T cells from human peripheral blood leukocytes (PBL) and bone marrow (BM). The cell suspensions were treated with a monoclonal anti-T cell antibody (Leu-1) or monoclonal antilymphocyte antibody (CAMPATH-1) and passed through the conjugated APAMB columns. Cell separation efficacy was determined by assaying the number and function of T cells in the final cell preparation in comparison with a sample of unseparated cells. The number of cells that form rosettes (E-RFC) with sheep red blood cells (SRBC) in a sample of PBL treated with anti-Leu-1 antibodies and subsequently passed once through GAMIg-conjugated APAMB dropped from a range of 41.5-86.0% to a range of 1.6-13.3%. The in vitro response to concanavalin-A (Con-A) dropped to a range of 0.7-27.2% (GAMIg) and a range of 1.2-21.8% (protein-A column) of the response of untreated PBL. Treatment with CAMPATH-1 antibody and passage through a protein-A-conjugated APAMB reduced E-RFC from a range of 55.6-57.4% to a range of 3.2-3.9% and abolished the Con-A induced proliferative responsiveness to background levels. Treatment of BM cells with CAMPATH-1 and passage of the cells through either GAMIg or protein-A conjugated APAMB columns resulted in reduction of E-RFC from a range of 12.4-17.7% to a range of 0-1% and from a range of 17.7-19% to a range of 1.6-3.2%, respectively. Viability of BM precursors, determined by the CFU-GM assay in semisolid medium, was not affected by these cell separation procedures. The data suggest that protein-A or GAMIg-conjugated APAMB columns may be a useful tool for separation of BM cell suspensions into specific cell subsets that can be defined by monoclonal antibodies.

Cell separation: a review

This review summarizes currently available techniques for cell separation. Techniques that exploit differences in physical properties of cells are widely used but have a number of limitations. Those that are based on differences in surface properties may more readily permit reproducible separation of a functionally homogeneous population of cells. Unfortunately very few techniques achieve separation of cells on the basis of differences in their functional characteristics.

Effects of pulsed electric fields on mouse spleen lymphocytes in vitro

The effects of pulsed electric fields on cell membranes were investigated. In vitro exposure of mouse splenocytes to a single high-voltage pulse resulted in an increase in membrane permeability that was dependent on both the electric field strength and the pulse duration. Exposure to a 2 microseconds, 3.0 kV/cm pulse resulted in the induction of a 1.26 V transmembrane potential, and elicited a 50% loss of intracellular K+. These results are in agreement with previous studies of the effects of pulsed electric fields on erythrocytes and microorganisms. The effect of pulsed electric fields on the functional integrity of lymphocytes was investigated by measuring [3H]thymidine incorporation by cells cultured in the presence and absence of various mitogens following exposure to an electrical pulse. No statistically significant effects on the response of mouse spleen lymphocytes to concanavalin A, phytohemagglutinin or lipopolysaccharide were observed following exposure to 2 microseconds electric pulses at amplitudes of up to 3.5 kV/cm. Exposure to a single 10 microseconds pulse of 2.4-3.5 kV/cm produced a statistically significant reduction in the response of lymphocytes to lipopolysaccharide stimulation that was attributed to cell death.

A method for size separation of murine spleen cells using counterflow centrifugation

A method for the rapid separation of murine spleen cells into subpopulations on the basis of their size has been developed using counterflow centrifugation. Upon separation of normal spleen cells with a mean cell volume of 125.5 +/- 6.0, 5 fractions of cells were obtained with mean cell volumes which ranged from 107.8 +/- 3.2 microns3 in fraction 1 to 152.7 +/- 4.9 microns3 in fraction 5. The cells in these 5 fractions were characterized by analysis on a fluorescence activated cell sorter (FACS) after staining with fluorescein conjugated anti-mu, delta, Ia, or Thy 1.2 antibodies, and by assaying for the presence of non-specific esterase activity. Surface Ig+, Ia+ B lymphocytes and Thy 1.2 T lymphocytes were present in all 5 fractions. However, while these T and B lymphocytes accounted for virtually all of the cells in the first 3 fractions, non-T, non-B cells were found in fractions 4 and 5, and represented 30% of the total population in the 5th fraction. Comparison of the intensity of anti-mu, delta or Ia staining of the B cells in fractions 1-5 revealed differences which suggested that B cell size correlated with different activation states of these cells. Increases in the intensity of the staining of T lymphocytes by anti-theta antibodies were also noted in the various fractions. The capacity of the B and T cells in each fraction to proliferate to B or T cell mitogens, respectively, was proportional to their frequency within the fractions. By contrast, the fractions containing larger cells were enriched in cells which proliferated in vitro in the absence of added mitogen. Furthermore, only fractions containing larger cells had the capacity to stimulate allogeneic T cell proliferation in a mixed lymphocyte reaction. Our data suggest that this technique provides a useful method for separating splenocytes on the basis of cell size. Use of this methodology provides a way to correlate cell size with phenotypic surface markers and functional abilities.

Pulmonary immune effector cells in guinea pigs with immune complex disease. I. Changes in T- and B-lymphocyte populations after exposure to antigen

Changes in immunologic effector cell populations in lung tissue, bronchoalveolar spaces, tracheobronchial lymph nodes, spleen, and peripheral blood were evaluated during the course of a pulmonary immune complex disease in guinea pigs. The number of macrophages, lymphocytes, and neutrophils present in each cell population were determined. T and B lymphocytes were identified by E and EAC rosette formation, respectively. An increase in the total number of lymphocytes in tracheobronchial lymph nodes and a greater proportion of B cells in these lymphocyte populations were observed at 12 and 24 hr postchallenge. The total number of macrophages, lymphocytes, and neutrophils recovered from the bronchoalveolar spaces also increased, as did the proportion of lymphocytes and neutrophils. A similar proportional increase of lymphocytes obtained from lung tissue also occurred. The proportion of B cells in the lymphocyte populations of the bronchoalveolar spaces and lung tissue increased to a maximum at 24-48 hr postchallenge. Cell populations from peripheral blood or spleen remained stable, by all parameters examined, during the disease process. Thus, there appears to be a localization of the immune inflammatory response in the lungs during the course of this pulmonary immune complex disease. In addition, this study provides evidence that immune effector cells obtained by bronchial lavage accurately reflect the cellular changes associated with the acute inflammatory response in lung tissue and pulmonary lymph nodes.

Membrane fluorescent probes for the demonstration of lymphocyte population heterogeneity. I T. and B lymphocytes of mice and rats

Non-fixed lymphocytes of rats and mice were stained with the membrane fluorescent probe, 3-methoxybenzanthrone. The probe is capable of binding preferentially with lymphocyte membranes and fluoresces in the green spectral region. Microfluorometry of single cells showed that lymphocytes differ in all lymphoid organs and these may be a 3-10-fold variation in fluorescence intensity. Lymphocytes can be divided into two groups according to fluorescence intensity: "bright" and "dim". The proportions of "bright" and "dim" cells were determined in rats and mice for various lymphoid organs in the normal state, after thymectomy and cyclophosphamide treatment, and also after lymphocyte separation on a nylon wool column. In all cases the proportion of bright lymphocytes corresponded to the B-cell content, and the proportion of dim lymphocytes corresponded to the content of T-cells.

Screening tests for cell-mediated immunodeficiency diseases

As our knowledge of immunology has become more sophisticated we have had to alter our ideas of the etiology of many immune deficiency diseases. Indeed, current concepts now prevalent have led to reclassification of a number of disease entities. In order to keep our diagnostic efforts abreast of the information being generated by the extensive immunology research programs now in progress, the clinical laboratory has been required to offer a new array of sophisticated tests on a relatively routine basis. This article is intended to serve as a brief review of immunobiology and immunodeficiency diseases with an indepth coverage of specialized tests generally available at the large centers. With an understanding of the principles, procedures, and pitfalls of the tests carried out the laboratory scientist is in a better position to assist the clinician in reaching the correct diagnosis. The detailed review is concerned with methods available to separate, classify, and subclassify lymphocytes and thereby allow a categorization of immune deficiency diseases. Toward that end there is a discussion of surface markers, rosetting, mitogenic and antigenic responsiveness as well as lymphokine production. With a view to present day research tests that might eventually find their way into the armamentarium of the clinical laboratory in the future, there is brief discussion of the methods presently used to classify T-cells as helper, suppressor, or effector cells, assays of some of the lymphokines, and measurement of antibody synthesis in cell culture.

Gut mucosal lymphocytes in inflammatory bowel disease: isolation and preliminary functional characterization

We have developed an enzymatic technique for isolating human intestinal mucosal lymphoid cells. This method was found to be superior to mechanical methods in regard to cell yield and survival. It is based on treating mucosa with serum-free solutions containing collagenase and deoxyribonuclease, followed by isolating the lymphoid cells through centrifugation steps involving fetal calf serum and ficoll-hypaque. Exposure of peripheral blood lymphocytes to the components of the enzymatic solution did not appreciably alter their uptake of tritiated thymidine in the presence or absence of mitogens. Application of the method to derive lymphoid cells from Crohn's disease, ulcerative colitis, and normal intestinal mucosa has shown that gut mucosal lymphocytes from inflammatory bowel disease (1) exceed the number of those from normal mucosa by a factor of 3 to 5; (2) show different degrees of tritiated thymidine uptake, spontaneously and in response to mitogens, depending upon the time they are harvested during the dissociation process; (3) are better stimulators than responders in the allogeneic mixed lymphocyte reaction; (4) generate suppressor cell activity comparable to that of peripheral blood lymphocytes; (5) cannot, in contrast to peripheral blood lymphocytes, generate antibody-dependent cell mediated cytotoxicity; and (6) produce an average of 5 times more IgM than equal numbers of peripheral blood lymphocytes.

Immune conservation: a possible consequence of the mechanism of interferon-induced antibody suppression

The effect of interferon preparations on the development of single clones of antibody-forming cells generated against sheep red blood cells in mouse spleen cell cultures has been studied. It was found that the presence of interferon had no effect on either the number or the size of clones which developed early in the in vitro antibody response. At the peak of the response (day 3), a decrease in the number but not in the size of clones was observed in interferon-treated compared to control cultures, while by day 4 both the size and number of clones were significantly decreased. These findings indicate that interferon appears to affect only nonactivated B cell precursors by preventing them from becoming activated and commencing clonal expansion. Early responding precursors, which are in cell cycle, presumably having been previously activated in vivo, are refractory to interferon-induced suppression in vitro. The way in which this immunosuppressive activity of interferon might be of great advantage to an animal as a means of "immune conservation" during viral infections is discussed.