Cytochemical analysis of human peripheral blood lymphocyte subsets defined by monoclonal antibodies

Cytotoxic effector cells of the immune system

The organism contains several types of cytotoxic cells which are able to lyse host and foreign cells. Cytotoxic T-lymphocytes (CTL) appear to play the most important role among the killer cells but other lymphatic cells, such as natural killer (NK) cells and lymphokine-activated killer (LAK) cells as well as macrophages are also highly effective in the lysis of appropriate targets. The various cytotoxic effector cells differ distinctly concerning origin, phenotype, morphology and target cell specificity, but they bear the common feature that they destroy the target cells in a contact-dependent non-phagocytotic process. CTL are characterized by typical lysosomal granules and by the expression of a characteristic pattern of surface molecules. They recognize specific antigens which are presented in context with molecules of class I major histocompatibility complex (MHC). NK cells, on the other hand, kill the appropriate targets without prior immunisation and without requiring recognition of MHC molecules at the target cells. They also bear a typical pattern of surface markers which differ in several aspects from that of CTL. Human NK cells are further characterized by peculiar cytoplasmic granules with parallel tubular arrays which are not present in other cytotoxic cells. LAK cells constitute an additional, only recently described, killer cell population which arise from lymphatic cells in the presence of interleukin-2. They appear to represent a functional unique cytotoxic effector cell system with an exceptionally wide target cell spectrum including normal and malignant cells of different origin. LAK cells, however, show a profound heterogeneity concerning the expression of phenotype surface markers and it is not yet clear whether they are a unique cell line. By electron microscopy they display peculiar intranuclear inclusion bodies which may be associated with prolonged stimulation by interleukin-2. CTL, NK and LAK cells appear to possess similar mechanisms for cytolysis including secretion of pore-forming proteins, serine proteases and other proteins. Furthermore, they are able to trigger the cleavage of DNA in the target cell nucleus by a hitherto unknown pathway. Macrophages differ substantially from other cytotoxic effector cells concerning morphology, phenotype, kinetic of activation and target cell spectrum. They perform a variety of functions whereby contact-dependent target cell lysis represents only one of their properties. After target cell binding they release over 20 different molecules such as interleukin-1 and tumor necrosis-factor-alpha as mediators for cytolysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Double phenotyping of immunoregulatory T cell subsets in patients with allergic asthma

In order to determine whether the dissection of helper/inducer (CD4+) and suppressor/cytotoxic (CD8+) lymphocyte subsets with Leu 8 reagent would reveal any differences between allergic asthma patients and non-atopic controls, we compared in both groups the 'true helper' T cell subset (Leu 8- CD4+), responsible for the major helper effect, and one of the suppressor T cell subpopulations (Leu 8- CD8+). Peripheral blood mononuclear cells from sixty-nine individuals, including nineteen extrinsic asthmatics, fifteen intrinsic asthmatics, seventeen patients with chronic obstructive lung disease and eighteen healthy controls, were comparatively analysed. Although total CD4+ cells and total CD8+ cells were similar for all groups, we found in the extrinsic asthma patients group a significant increase in the number of 'true helper' T cell sublineage (Leu 8- CD4+) and of suppressor cells expressing Leu 8- CD8+ phenotype. Such imbalances may be implicated in the pathogenesis of atopic asthma.

T-cell chronic lymphocytic leukemia with a helper/inducer membrane phenotype: a distinct clinicopathologic subtype with a poor prognosis

T-cell chronic lymphocytic leukemia (T-CLL) accounts for about 2% of the various types of CLL and can be subtyped into helper/inducer (h/i) and cytotoxic/suppressor (c/s) cell membrane phenotypes. Seven patients with CLL were shown to have T-CLL with a h/i cell membrane phenotype; four with monoclonal antibody reagents and three by demonstration of the E-rosette receptor and focal acid alpha naphthyl acetate esterase activity. The clinical courses, treatment responses, and laboratory findings of these seven patients were reviewed to determine the prognosis and unique clinicopathologic features of this subtype. Two patients presented with skin rashes, and five were diagnosed during evaluation for other medical problems. Initially, four patients had splenomegaly and two had lymphadenopathy, but none of the patients had hepatomegaly. Morphologic examination revealed uniform, small lymphocytes in three patients, and the lymphocytes had nuclear indentations in four patients. Sera from the three patients tested were negative for antibody to the human T-cell leukemia/lymphoma virus I. Peripheral blood mononuclear cells from one patient showed normal interleukin-2 production and lacked antibody-dependent cell-mediated cellular cytotoxicity and natural killer activity. Cytogenetic analysis was done on one patient, revealing an abnormal clone with several chromosomal abnormalities, including an X;14 translocation with a break point at 14q11. All patients required chemotherapy, and all died a median of 21 months from the time of diagnosis. The findings in these patients, in addition to those in 31 patients described in the literature, indicate that h/i T-CLL is associated with a poor prognosis and has distinct clinical and pathologic features that separate it from c/s T-CLL, adult T-cell leukemia/lymphoma, the cutaneous T-cell lymphomas, and B-CLL.

Activity of acid phosphatase in resting and mitogen-stimulated human peripheral blood lymphocytes

Activity of acid phosphatase was found to be higher in T than in non-T cells of human peripheral blood lymphocytes. The T cell mitogen PHA induced an increase in the magnitude of acid phosphatase activity, while the B cell mitogen LPS was not able to produce any effect on acid phosphatase activity. Acid phosphatase activity in lymphocytes correlated with their spontaneous proliferative activity.

beta-D-N-acetylglucosaminidase, a new cytochemical marker of human lymphocyte subpopulations

beta-D-N-acetylglucosaminidase staining characteristics of rosetted or non-rosetted normal and malignant lymphoid cells were compared with those observed after nonspecific esterase and acid phosphatase staining. With the three cytochemical techniques a similar staining pattern was observed in T cells (E-rosettes), their subpopulations T mu and T gamma, B cells and the non-T, non-B cells, as well as in the T cell populations defined with the monoclonal antibodies OKT3,4 and 8. T mu cells mostly displayed a "dot-like" reaction, T gamma and the non-T, non-B cells a "fine to heavy granular" reaction, while most B cells were negative. OKT4 and OKT8 positive lymphocytes showed for the larger part a dot-like staining pattern, however, the frequency of cells with a granular pattern was distinctly higher in the OKT8, than in the OKT4 positive cells. E(+)mIg(-) and E(-)mIg(-) A.L.L. blasts stained either with a dot-like or granular pattern or failed to react when stained cytochemically for beta-D-N-acetylglucosaminidase, nonspecific esterase and acid phosphatase activity. Only in a few instances a discrepancy was observed between the types of staining for esterase and acid phosphatase on one hand and those for beta-D-N-acetylglucosaminidase on the other.

Age-related changes of activity of acid phosphatase in PHA-stimulated lymphocytes

Peripheral blood lymphocytes of 70-year-old individuals as well as spleen cells of 18-month-old Balb/c mice were characterized by diminished activity of acid phosphatase in relation to the activity of that enzyme in cells from young subjects. Simultaneously performed histochemical tests revealed that aging process in both species examined was accompanied by a reduction of the number of cells, disclosing the activity of acid phosphatase. Age-related differences with regard to the level of acid phosphatase became more pronounced after stimulation of cells with PHA. The decrease of acid phosphatase activity during aging is discussed in relation to the function of lymphocytes.

Failure to distinguish ultrastructurally between T4+ (helper) and T8+ (suppressor/cytotoxic) T-cell subsets

Human peripheral T-cell subpopulations revealed by monoclonal antibodies by means of a rosetting method were isolated by micromanipulation and submitted to electron microscopic analysis. The T3+ subset (total T cells) displayed a high degree of heterogeneity, including multiple transitional forms, from cells with a high nuclear to cytoplasmic ratio and rare organelles to cells with a low nuclear to cytoplasmic ratio and a complex system of cytoplasmic organelles. T4+ (inducer/helper) and T8+ (suppressor/cytotoxic) cell subpopulations were shown to have no evident distinguishing characteristics. They both displayed the same morphological variation mentioned for T3+ lymphocytes. On morphometric analysis, these two cell subsets were very similar, with only slight differences for cell surface roughness, volume of mitochondria, extent of nuclear indentation, and surface area of the rough endoplasmic reticulum. The significance of these minor morphological differences is discussed.

Differential effect of the serine protease inhibitor phenyl methyl sulfonyl fluoride on cytochemically detectable esterases in human leucocytes and platelets

Esterases of human leucocytes and platelets were studied by cytochemical methods. The aim of the study was to clarify the cellular distribution and possible nature of esterases types differing in their substrate specificity and/or their inhibitor sensitivity. 3 substrates (alpha-naphthyl acetate: ANA; naphthol AS-D chloroacetate: NASDCA; and N-acetyl DL-alanine alpha-naphthyl ester: NACALA) were used and the effects of 2 inhibitors (sodium fluoride and the serine protease inhibitor phenyl methyl sulfonyl fluoride: PMSF) were evaluated. 4 enzyme types were described: Type I, present in granulocytes, was detected using NASDCA and NACALA and was resistant to fluoride but sensitive to PMSF. Other types were detected using ANA as substrate. Type II, present in monocytes, was inhibited by both fluoride and PMSF. Type III, present in platelets and plasma cells, was inhibited by fluoride but resistant to PMSF. Type IV, present in lymphocytes, was resistant to both fluoride and PMSF. The specific aims and possible areas for application of these results are discussed.

Distribution of acid alpha-naphthyl acetate esterase among human T lymphocyte subsets

Human T lymphocyte subsets, identified by means of OKT3, 4 and 8 monoclonal antibodies, were isolated by a fluorescence activated cell sorter (FACS IV) and analyzed for distribution of alpha-naphthyl acetate esterase (ANAE) activity. As compared to OKT8+ lymphocytes a higher proportion of OKT4+ lymphocytes was ANAE-positive exhibiting a spot or dot-like pattern in the cytoplasm. OKT8 and 4 positive subsets showed a similar ANAE distribution in diffuse granular form. Although OKT4 and OKT8 populations presented a different ANAE dot-like reactivity, this marker did not allow as clear a distinction between them as that reported for TG and TM lymphocytes.

Cytochemical analysis of acid hydrolases expression during phorbol diester (TPA)-driven differentiation of B-chronic lymphocytic leukaemia cells in vitro

Four acid hydrolases, acid phosphatase (AP), alpha-naphthyl acetate acid esterase (ANAE), beta-glucuronidase (BG) and N-acetyl-beta-glucosaminidase (NABG) were determined cytochemically in B-chronic lymphocytic leukaemia (B-CLL) cells exposed in vitro to the tumor promoter 12-0-tetradecanoyl phorbol 13 acetate (TPA). TPA, which has been previously shown to induce B-CLL cells to mature towards plasmacytoid cells, results in the progressive expression of the enzymes tested in the cytoplasm of malignant cells, in particular AP and ANAE. Furthermore, the sensitivity to inhibitors and the pattern of reactivity of ANAE provide evidence for an enzyme subtype normally restricted to plasma cells. Thus, acid hydrolases--some of which showing plasma cell type of activity--are expressed during B-CLL cells differentiation induced in vitro. These results confirm the value of cytochemistry in subtyping B-cell malignancies.