Modulation of T-lymphocyte differentiation antigens: potential relevance for multiple sclerosis

Use of anti-CD3/CD28 mAb coupled magnetic beads permitting subsequent phenotypic analysis of activated human T cells by indirect immunofluorescence

Functional analysis of T lymphocytes requires in vitro stimulation of these cells under experimental conditions that mimic as closely as possible physiological in vivo stimulation and that involve antigen/T cell receptor (TCR)-mediated activation. Because of the low frequency of antigen-specific T cells in human clinical samples, stimulation with a combination of anti-CD3 and anti-CD28 monoclonal antibodies (mAbs) is a preferred method. Interaction of these mAbs with their ligand results in modulation of the mAb-ligand complex from the cell surface. However, as a result of incomplete modulation, CD3/CD28 mAb complexes often remain at the cell surface, thereby precluding subsequent indirect immunofluorescence and flow cytometry analysis using mouse immunoglobulin (Ig)-specific antibodies. This is of importance in situations in which no specific fluorochrome-conjugated mAbs are available, such as in screening procedures of Ig-containing hybridoma culture supernatants. We propose here the use of CD3/CD28 mAbs, linked to magnetic beads allowing standardization of the activation conditions, optimal activation of T cells and complete modulation of antigen-antibody complexes from the cell surface.

Characterization of T-cell clones generated from skin of patients with psoriasis

BACKGROUND

The infiltrating cells in psoriasis include a subpopulation of autoreactive T cells.

OBJECTIVE

The aim of this study was to further characterize skin-infiltrating T lymphocytes in patients with psoriasis.

METHODS

Forty-five T-cell clones were generated from skin biopsy specimens from two patients.

RESULTS

Phenotypic studies on 25 of 45 clones revealed that 19 (76%) of the clones were CD4+, 5 (20%) were CD8+, and 1 (4%) clone was CD4- and CD8-. Twenty-three clones were stained for identification of T-cell receptors. Twenty-two clones expressed alpha/beta T-cell receptors and one clone (CD4-/CD8-) expressed no T-cell receptor. Nineteen clones (42%) were autoreactive with no restriction to class I or class II HLA antigens. By contrast, proliferation of two of the seven clones was inhibited by class I monoclonal antibody, whereas proliferation of four of seven clones was inhibited by class II monoclonal antibody.

CONCLUSION

These data suggest that skin-infiltrating lymphocytes in patients with psoriasis may recognize HLA-associated molecules, perhaps the peptide of the HLA groove. The recognition of the peptide is presumably inhibited when monoclonal antibody is bound to the HLA molecule.

Immunoregulatory properties of T-cell lines derived from the systemic and intrathecal compartments: a phenotypic and functional study

To determine whether immune regulation can differ within the intrathecal and systemic compartments, we compared phenotypic markers and functional properties of in vitro anti-CD3 monoclonal antibody-stimulated, interleukin 2-expanded lymphoid cell lines simultaneously derived from peripheral blood and cerebrospinal fluid of individual donors (n = 9). We found that the proportions of total CD8+ T cells and of the putative CD8+ suppressor effector subset (CD28-) were lower in the cell lines derived from cerebrospinal fluid compared with cultures derived from peripheral blood (p less than 0.025 and p less than 0.005, respectively; paired t test), whereas the total CD4+ T-cell proportion was higher (p less than 0.025). For a donor subgroup with "normal" peripheral blood cell-mediated activated suppressor function (63 +/- 2%), mean suppressor cell function mediated by unfractionated or CD8(+)-enriched cells derived from cerebrospinal fluid was significantly lower (38 +/- 7%; p less than 0.01, paired t test). For a donor subgroup with "low" peripheral blood cell-mediated suppression (-1 +/- 10%), suppression mediated by cerebrospinal fluid cells was also "low" (9 +/- 12%). Our results support the postulate that the immune response may be differentially regulated between the central nervous system and peripheral blood compartments.

Cerebrospinal fluid lymphocyte subpopulations in multiple sclerosis

T3+ (all-T) and T8+ (suppressor/cytotoxic) cells were studied in cerebrospinal fluid (CSF) from 24 patients with multiple sclerosis (MS) and from 24 subjects with various "non-immunological" disease (NID). MS patients were classed as (a) during the acute phase of the 1st episode of the disease, (b) in acute relapse, (c) with chronic progressive disease, (d) with increased or (e) normal CSF IgG content or (f) with neurological impairment (Kurtzke scale) less than or equal to 3 or (g) greater than 3. In MS cases considered as a whole a significant decrease in CSF T3+ cells was found compared to NID patients. When single groups were considered, T3+ cells decrease was significant in classes (b), (d) and (f). Significantly lower percentages of T8+ cells, compared to NID, were found in MS classes (a), (d) and (f).

Multiple sclerosis: activated cells in cerebrospinal fluid in acute exacerbations

Cerebrospinal fluid (CSF) lymphocytes from three young patients undergoing acute exacerbations of multiple sclerosis were studied by flow cytometry. Using a new method that simultaneously measures cell-surface antigens and the cell-cycle phase, we determined that the CSF lymphocytes in these patients were activated. The majority of the activated cells expressed the OKT4 phenotype, while very few expressed the OKT8 phenotype.

Normal T cell subsets and lymphocyte activity in multiple sclerosis

Nine patients with either chronic progressive or relapsing/remitting multiple sclerosis were treated with several courses of lymphopheresis. The lymphocytes obtained by this procedure showed a significantly lower percentage of OKT3+ cells than normal controls at the beginning of therapy. This percentage increased to normal levels after five lymphopheresis treatments and then decreased during the last stages of treatment. Patients had normal levels of OKT4+ and OKT8+ cells compared to controls and these percentages showed no statistically significant changes during the course of treatment. The proliferative response of patient's lymphocytes after stimulation with concanavalin A, PHA and alloantigen was not significantly different from normal controls and these responses were unchanged during the lymphopheresis treatment. Natural killer cell activity was also normal in our patients. The results reported in this study do not suggest a basic T cell abnormality in our patients with multiple sclerosis. Furthermore, the lymphopheresis treatments did not induce any significant change in T cell numbers or functional activity in vitro.

T lymphocyte populations in multiple sclerosis

In 36 patients representing different clinical stages of multiple sclerosis (MS) (9 patients with acute exacerbations; 21 patients in remission; 5 patients with chronic progressive MS) determinations of T lymphocyte populations using monoclonal antibodies against surface antigens (OKT3 (pan T cells), OKT4 (helper T cells), OKT8 (cytotoxic/suppressor T cells] were performed. Compared to the control group (40 healthy individuals) a clear elevation of the T4/T8 ratio was found in acute exacerbations and to a lesser degree in patients with inactive phases of MS. Patients with chronic progressive disease did not show increased T4/T8 ratios. Serial determination of lymphocyte populations after corticosteroid therapy in 10 selected patients revealed no significant changes which could be attributed to this therapeutic modality. Pathogenetic and clinical implications of the shifts in surface antigen expression of T lymphocyte populations mirroring the clinical course of MS are discussed.

Low T8 antigen density on lymphocytes in active multiple sclerosis

The median fluorescence intensity of peripheral blood T8+ (T-suppressor/cytotoxic) cells in patients with active (relapsing or progressive) or stable multiple sclerosis (MS) and in control subjects was determined with a fluorescence-activated cell sorter using an indirect immunofluorescence assay. Median fluorescence intensity was significantly lower in patients with active MS than in controls. No differences in median fluorescence intensity were found between patients with stable MS and controls. Analysis of T8+ cells that had been modulated in vitro with OKT8 indicated that the resultant reduction in the median T8 antigen density per cell resulted in fewer T8+ cells being enumerated when the fluorescence-activated cell sorter was used than when a fluorescence microscope was used. Reduced median T8 antigen density on cells as found in active MS may contribute to the apparent underrepresentation of circulating T-suppressor cells in such patients and may be associated with reduced suppressor cell function.

Mononuclear lymphoid populations infiltrating the microenvironment of primary CNS tumors. Characterization of cell subsets with monoclonal antibodies

Mononuclear cell infiltrates are found to varying degrees in 30% to 60% of primary human central nervous system (CNS) gliomas. To explore the immunological importance of this, six operative glial tumors, eight non-glial tumors, and three normal brain specimens were studied. Utilizing an immunoperoxidase method, the authors examined frozen sections for lymphoid infiltrates expressing suppressor/cytotoxic and helper phenotypes, as identified with the Leu-1,2,3 monoclonal antibodies. Four of six gliomas demonstrated lymphoid infiltrates: three tumors exhibited a predominant suppressor/cytotoxic cell phenotype and the fourth showed mixed staining of suppressor/cytotoxic and helper cell phenotypes. Varying degrees of lymphoid infiltration characterized four out of eight non-glial primary CNS tumors. Two cases exhibited a prevalence of suppressor/cytotoxic phenotype cells, while two cases demonstrated a more heterogeneous pattern of phenotype expression. Normal brain sections revealed little or no evidence of mononuclear infiltrates. The immunobiological significance of these findings is discussed in the context of tumor-host interaction within the CNS.

Indication of a possible role in a demyelinating neuropathy for an antigen shared between myelin and NK cells

In three patients with monoclonal IgM antibodies to myelin-associated glycoprotein and a demyelinating neuropathy, the human monoclonal antibodies and HNK1, a mouse monoclonal antibody against human natural killer cells, reacted with the same region of myelin-associated glycoprotein. In these three patients there was a pronounced decrease in the number of circulating HNK1-positive cells. Taken together, these findings provide evidence that a cross-reactive cell surface antigen may be involved in an autoimmune response directed simultaneously against the nervous system and the immune system.

A serial study of peripheral blood T lymphocyte subsets in relapsing-remitting multiple sclerosis

Twelve patients with relapsing-remitting multiple sclerosis and 3 control subjects were evaluated weekly for six months. Peripheral blood lymphocyte subsets were enumerated using monoclonal antibodies and analysis with a dual-laser fluorescence-activated cell sorter. Results were correlated with clinically assessed disease activity. Fluctuations occurred in the number of T lymphocytes (Leu 1+) and cells with the helper/inducer phenotype (Leu 3a/OKT4+) in both patients and controls. Fluctuations in the number of cells with the suppressor/cytotoxic (Ts/c) cell phenotype (OKT5, OKT8, Leu 2a+) also occurred. Variations in the relative numbers of cells labeled with all three Ts/c monoclonals did occur, but with OKT5 generally labeling fewer cells than OKT8 or anti-Leu 2a. When findings were correlated with disease activity, OKT5 was a more sensitive gauge of disease activity than either OKT8 or anti-Leu 2a. When peripheral blood lymphocyte subsets were correlated with disease activity, the following patterns were observed: a reduction in the number of Ts/c cells without evidence of clinical disease (four episodes), the development of new symptoms suggestive of an acute relapse but without a reduction in the number of Ts/c cells (two episodes), and a reduction in the number of Ts/c cells associated with acute relapse (two episodes). In the two patients with acute relapse and a reduction in the number of Ts/c cells, clinical disease preceded a reduction in the number of Ts/c cells in 1 patient, whereas the two events occurred simultaneously in the other patient. Taken together, these limited results indicate that in some cases a reduction in the number of Ts/c cells may be the result rather than the cause of disease activity and may represent an epiphenomenon.

The influence of disease activity on the number of blood cells of multiple sclerosis patients

The influence of disease activity on blood cell counts was studied in over 100 multiple sclerosis patients examined at regular intervals of 4-8 weeks over an 18-month period. T-lymphocytes were assessed by the cytochemical alpha-naphthyl-acetate-esterase (ANAE) stain in addition to conventional differentials. In all patients as a group as well as in individual patients studied sequentially, an exacerbation was marked by a striking reduction in both the relative and absolute numbers of ANAE-positive cells. Simultaneously, a strong increase in granulocytes and a slight augmentation of ANAE-negative cells occurred. Similar changes related to disease activity in leucocytes and lymphocytes were also detected in conventional blood smears. Fluctuations in the number of blood cells with disease activity persisted under therapy with corticosteroids and to a lesser degree also with azathioprine.

Wheat germ agglutinin decreases expression of the T8 antigen on human peripheral mononuclear cells

We examined dynamics of expression of the human T-suppressor specific antigen, T8, following interaction of peripheral lymphocytes with wheat germ agglutinin (WGA). Cells were incubated at 37 degrees C with or without WGA (15 micrograms/ml) for 18 hrs, washed sequentially with N-acetylglucosamine (to remove bound WGA) and plain medium, then analyzed by flow cytometry for binding of lectins and monoclonal antibodies OKT8(T-suppressor specific) and OKT3 (pan-T specific). WGA pretreatment induced an overall 65% reduction in WGA binding and concomitant 30% reduction in percentage of T8+ cells. Furthermore, residual T8+ cells showed 50% reduction in T8 expression. Taking into account reductions in both percentages of T8+ cells and also antigen densities, WGA reduced T8 expression by greater than 60% overall. By contrast, binding of OKT3 and the lectins, concanavalin A (con A) and Ricinus communis agglutinin (RCA-I), was unaffected by WGA. The decreased T8 expression could not be explained by residual cell bound WGA and was fully reversible within 48 hours of removal of cells from WGA-containing medium. Therefore, WGA caused downregulation of T8 antigen expression. The effect of WGA was time- and concentration-dependent. Downregulation did not occur at 4 degrees C nor in the presence of azide, thereby demonstrating a requirement for cellular metabolism. The data suggest that WGA may bind to the T8 antigen, and they provide the possibility that similar downregulation of T8 by WGA may underlie certain of the in vitro immunoregulatory effects of this lectin.

T-cell subpopulations in the blood and skin of patients with psoriasis

Monoclonal antibodies were used to determine, simultaneously, the proportions of T-cell populations in the peripheral blood and in the skin lesions of fifty-one patients with psoriasis. The results were analysed in relation to the extent, age and clinical type of the skin lesions. In the group of patients with extensive lesions, a significant reduction in the number of total T (TT) and T helper/inducer-cells, (TH), but not in T suppressor/cytotoxic cells (TS) was observed in the peripheral blood. Furthermore, the skin TH/TS ratio was greater in late guttate and in chronic plaque lesions than the corresponding ratio in the blood. These findings suggest that there is an active selective recruitment of TH cells into established psoriatic lesions. In contrast, the TH/TS ratio in early guttate lesions was the same as in the blood, and significantly lower than in the plaque lesions. An additional finding was a decrease of TS, and a corresponding increase of null cells in the blood of patients with chronic plaque psoriasis. These observations provide further evidence for the participation of T cells in the pathogenesis of psoriasis.

Suppressor T-lymphocytes in multiple sclerosis: analysis of patients with acute relapsing and chronic progressive disease

T cell-specific antigens as identified by the anti-Leu 1, anti-Leu 2a, and anti-Leu 3a monoclonal antibodies were quantitated in 31 normal control subjects, 21 adults with spinal cord injury, 58 patients with stable multiple sclerosis, 31 patients with chronic progressive multiple sclerosis, and 15 patients with multiple sclerosis in acute relapse. The only significant deviations from normal values were a slightly low mean T cell (Leu 1-positive) value in patients in acute relapse and a low suppressor T cell (Leu 2a-positive) mean value in patients with chronic progressive multiple sclerosis. We were unable to confirm previous studies using the OK series of monoclonal antibodies that reported low suppressor T cell levels (OKT5 and OKT8 positive) in patients with acute relapses. We suggest that modulation (a spontaneous or induced variability in the expression) of individual cell surface antigens may explain the differences seen between our study and other reported series.