Major Lymphocyte Subpopulations Research Articles

Histometric study of the localisation of lymphocyte subsets and accessory cells in human Mantoux reactions.

Intradermal injection of purified protein derivative produced typical delayed type hypersensitivity reactions in five healthy human subjects. The major subpopulations of lymphocytes and certain accessory cells were located in frozen sections of biopsies of the lesions with monoclonal antibodies and immunohistochemical staining. The densities (expressed as number/unit area for comparison) of the different types of cells were counted at various microanatomical locations in the tissue. The inflammatory cells were concentrated in narrow zones, initially (24 h) only surrounding small blood vessels but later (48-96 h) also around sweat ducts. Lymphocytes were the predominant cell type at these sites with T4 and T8 cells randomly intermixed at a ratio similar to that in the mononuclear cell fraction of the peripheral blood samples removed at the time of biopsy. There was also a scanty diffuse infiltrate in the intervening dermis, but here the T4:T8 ratio was significantly lower than that in the peripheral blood or perivascular cuffs. There was considerable intersubject variation in the relative preponderance of T8 cells in the diffuse infiltrate. The results suggest that there is no subset selection in the initial emigration of lymphocytes through vascular endothelium in the delayed hypersensitivity reaction, but that the subsets behave differently during the subsequent migration through the tissues. It remains to be determined whether the extent to which T8 cells migrate more rapidly than T4 cells through the tissues may influence the reaction at the site of entry of organisms or antigens into the body by altering the balance of the immunoregulatory lymphocyte subsets. This may underlie some of the differences in susceptibility to infection between subjects and determine the type of granuloma that develops in a particular patient.

Surface properties of lymphocyte subpopulations in autoimmune NZB/NZW F 1 hybrid mice: Alterations correlated with the immunodeficiency of aging

Partitioning in a two-polymer aqueous phase system was used to probe the surface properties of lymphoid cell subpopulations in aged male NZB/NZW F 1 hybrid (B/W) mice, an important model of autoimmunity, immunodeficiency, and lymphoid malignancy. Spleen cells were fractionated by countercurrent distribution (CCD, a multiple-step extraction procedure) in a charged dextran-polyethylene glycol system. CCD of spleen cells from young, clinically normal male B/W mice yielded several broad distribution patterns which frequently had two or more peaks. Analysis of differentiation antigens and functional properties of cells from different parts of the distribution revealed a subfractionation of the three major lymphocyte subpopulations. B lymphocytes had a low partition coefficient ( K); T cells had an intermediate K and null cells had the highest K. To examine the partitioning behavior of T lymphocytes, spleen cells which were nonadherent to nylon wool columns were subjected to CCD. Nonadherent cells from young B/W mice consistently gave a single peak with high K. Aged mice (18 months) usually had nonadherent cells with a predominantly low K. In some experiments a systematic increase in the number of these cells could be demonstrated with increasing mouse age. An analysis of the adherence and partitioning behavior of lymphocyte subpopulations revealed no change in the adherence properties or proportions of B lymphocytes in aged mice. The large proportion of cells having a low partition coefficient in the nonadherent spleen cell population of old mice appears to be due to an increase in the number of null cells and in a decrease in the K of some T lymphocytes.

Volume regulation by human lymphocytes. Identification of differences between the two major lymphocyte subpopulations.

Following exposure to hypotonic media, human peripheral blood lymphocytes swell initially but restore their isotonic volume within minutes. In contrast, tonsillar lymphocytes demonstrate a similar initial phase of swelling but fail to restore their isotonic volume. We have studied the ionic basis for this second or regulatory volume decrease (RVD) phase using lymphocytes from peripheral blood, tonsil, and thymus. RVD was characterized by 86Rb efflux and a decrease in K+ content. The increase in K+ permeability in response to hypotonic challenge was characteristic for T lymphocytes obtained from peripheral blood, tonsil, or thymus. B lymphocytes showed only a modest increase in K+ permeability and consequently little RVD. The data confirm that the response of peripheral blood and tonsillar lymphocytes to a hypotonic environment can be accounted for by differences in the proportions of T and B cells, and the differential behaviour of B and T lymphocytes is based on differences in membrane permeability to K+ upon swelling.

Cyclic AMP-dependent protein kinase content of murine T and B lymphocytes

Murine splenic lymphocytes have been separated by non-activating procedures into enriched T and B cell populations. Cyclic AMP-dependent protein kinase (cAPK) activity has been measured in those separated cell types by histone phosphorylation. As in other tissues, lymphocyte cAPK activity was found to be predominantly a soluble enzyme. By an analysis of cyclic AMP (cAMP) activation of enzyme activity it was shown that: (1) the basal activities were indistinguishable between these major lymphocyte subpopulations, (2) the K a values for cAMP activation were identical for the two cell types (24 nM cAMP), and (3) the V max for enzyme activity was higher in T (5.47 pmole/min/10 6 cells) than in B (3.58 pmole/min/10 6 cells) cells. DEAE-cellulose chromatography experiments with mixed and enriched splenic lymphocyte populations extended and amplified this quantitative difference between T and B cells.

Selective migration of murine lymphocytes and lymphoblast populations and the role of endothelial cell recognition.

We have examined the organ specificity of migration of three major subpopulations of mature small lymphocytes in the mouse — B cells, the Ly-2- and Lyt-2+ T cells. It is shown that difference in the distribution of these lymphocyte classes between Peyer’s patches (PP’s) and peripheral lymph nodes (PN’s) are determined by selective recognition of endothelial determinants associated with high endothelial venules (HEV) in these organs. HEV are specialized venules that mediate lymphocyte exit from the blood into lymph nodes and Peyer’s patches. In addition, we report preliminary studies of the HEV-recognition specificity of gut-derived (mesenteric node) immunoblasts.KeywordsLymphoid OrganMesenteric NodeDistribution IndexHigh Endothelial VenuleSelective RecognitionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

An Lyt differentiated thymocyte subpopulation detected by flow microfluorometry

DATA on the T-cell antigens, Lyt 1, 2, 3 (refs 1, 2), relating to functional T-cell subsets, suggest that some peripheral T cells express restricted Lyt phenotypes, that is, Lyt 1+23− or Lyt 1−23+ (ref. 3). Evidence has been presented showing that two major subpopulations of lymphocytes, Lyt 1+ T cells and Lyt 23+ T cells, are committed to particular lines of functional differentiation in the immune response before encountering exogenous antigen in peripheral lymphoid tissue4,5. It has been suggested that the two major subpopulations representing T-cell help (Lyt 1+) and T-cell cytotoxicity or suppression (Lyt 23+) arise in the periphery from peripheral Lyt 123+ cells6. Recent studies have concluded that as stem cells mature in the thymus, the thymic epithelium is important in determining which H–2 specificities the maturing T cells are able to recognise as self7. Previous cytotoxicity data have been interpreted as indicating that Lyt 1, 2, 3 antigens are expressed on each of most if not all, mouse thymocytes; that is, that most thymocytes are Lyt 123+ (refs 1–4, 8–10). However, the data presented here suggest that the commitment to differentiation of the Lyt 1+ or the Lyt 123+ phenotype, and thus presumably the relevant functional differentiation occurs before cell migration from the thymus. Using flow microfluorometry (FMF) and anti-Lyt antisera, we demonstrate a normal thymocyte subpopulation which is not expressing Lyt 2 or Lyt 3 antigens (Lyt 1+23−). This subpopulation represents a significant constant proportion (10%) of normal thymocytes which is markedly increased following in vivo cortisone treatment. The data also show that Lyt 1 expression, rather than being decreased on cortisone-resistant thymocytes (CRT), as would have been predicted from previous cytotoxicity data2,8, is expressed in increased amounts on CRT.

Alterations in immune responsiveness in acute measles and chronic post-measles chest disease.

Immune responses in 24 children with acute measles (AM) were compared with those in 20 children who had chronic pulmonary complications (CPMC) following measles. The immuno-suppressive effects of acute measles were extensive: total white cells were reduced and this reduction was accounted for entirely by lymphopenia which was equally expressed among the major lymphocyte sub-populations studied; the function of 'T' cells, assessed by radio-isotope incorporation into phytohaemagglutin (PHA) transformed lymphocytes and delayed skin hypersensitivity (DHR) to dinitrochlorobenzene (DNCB), was depressed. Serum IgA was reduced in AM patients. In contrast there was a relative sparing of the measured indices of immunity in patients with chronic post-measles chest disease, with the major defect being an impaired DHR to DNCB. There were minor alterations of complement components in both groups of patients.

Fractionation of Human Blood Lymphocytes on Helix pomatia A Haemagglutinin Coupled to Sepharose Beads

Treatment of human blood lymphocytes with neuraminidase has previously been shown to uncover receptors for the A haemagglutinin of the snail Helix pomatia (HP). Neuraminidase-treated lymphocytes were now fractionated on columns charged with large Sepharose particles to which HP had been coupled covalently. HP-receptor negative (HP-) lymphocytes passed the columns while HP-receptor positive (HP+) lymphocytes were retained. The latter cells were eluted by addition of the competitive hapten N-acetyl-D-galactosamine (D-GalNAc). The total yield of cells recovered after fractional was 60-80% Surface marker studies indicated that there was no selective loss of any of the major lymphocyte subpopulations. The fraction that passed the columns (fraction I) consisted of approximately 10% of all lymphocytes. It contained approximately 1% HP+cells and approximately 3% of all lymphocytes forming rosettes which sheep erythrocytes (E+ cells) present before fractionation. 50-55% of the lymphocytes in this fraction had surface-bound immunoglobulin (SIg+ cells) and complement receptors (EAC+ cells). Of the SIg+ cells, approximately 60% were true B cells while the remaining 40% had IgG adsorbed to their surface. The majority of the B cells were recovered in this fraction. The lymphocytes of this fraction responded poorly to T-cell mitogen but had an enhanced K-cell activity to chicken erythrocytes. Elution of the cells retained on the column with 0.1 mg/ml D-GalNAc gave a fraction II, consisting of approximately 15% of all lymphocytes. This fraction had a mixed composition. The majority of the cells (approximately 45%) were recovered by subsequent elution with 1.0 mg/ml D-GalNAc. This fraction III was strongly enriched with HP+ and E+ cells (T cells). About 10% of the HP+ cells in this fraction were SIg+. However, on the majority of these cells this surface-bound immunoglobulin was probably externally absorbed IgG. These HP+-SIg" cells were also EAC+ and had Fc receptors, as shown by rosette formation with IgG-coated bovine erythrocytes. The lymphocytes of fraction III responded most strongly to T-cell mitogen while their K-cell activity was weak.

T and B lymphocyte subpopulations

The two major subpopulations of lymphocytes, T cells (thymus-dependent lymphocytes) and B cells (bursal equivalent or thymus-independent lymphocytes) have multiple roles in the immune system. In general, T cells are the functioning cells in the cellular immune system (delayed hypersensitivity, graft rejection, graft-versus hostreaction); and B cells, the precursors of plasma cells which form specific antibodies, are the functioning cells in the antibody immune system. It is now well recognized, however, that these cell types and immune systems usually do not function independently, but interact with one another in multiple ways and also with other, cells such as macrophages. For example, T cells may increase or suppress the production of antibodies by the B cell system, and macrophages may increase or suppress the response of T and B cells to antigens.

Cellular composition of the mouse thymus: Developmental changes and the effect of hydrocortisone

The cellular composition of the mouse thymus has been analysed at different ages and in different strains by using size distribution analysis in combination with preparative cell electrophoresis and bovine serum albumin (BSA) gradient centrifugation. It was possible to distinguish three major subpopulations of small lymphocytes: cell type I is small, dense and electrophoretically slow, cell type II is intermediate by all three parameters, and cell type III has the largest volume, lowest buoyant density and highest electrophoretic mobility. Cell type III was enriched in animals treated with cyclophosphamide and was practically the only cell type found in the thymus of hydrocortisone-treated mice. The data thus show that the increase of the average size of thymus cells after hydrocortisone treatment reported previously is due to a shift in relative proportions of distinct cell types with different size rather than due to a drug-induced enlargement of individual cells. The larger cell type III resides probably in the thymic medulla and carries graft-versus-host (G.v.H.) reactivity as well as other typical T cell functions. Possible functions of the smaller, probably cortical, cell types are discussed. Newborn mice were found to contain only cell types II and III, 4-week-old CBA contained I, II, and III, and adult mice were found to contain only cell types I and III. The two-dimensional distribution patterns (“finger prints”) in respect to size and electrophoretic mobility appeared to be typical for the three cell types irrespective of the age or strain of the mice tested. These physical parameters, therefore, provided relatively constant markers for the identification and characterization of distinct cellular subpopulations in the thymus. Each of these subpopulations is probably in itself heterogenous in respect to antigen specificity. It is proposed to call lymphocytes with different antigen specificity but identical physical characteristics “isotypic lymphocytes.”

Hypothesis: HOMING OF LYMPHOCYTES TO NON-LYMPHOID TISSUES

Two major subpopulations of lymphocytes, thymus dependent (T) and bursa equivalent (B) are now recognised. In spleen, lymph-nodes, and other secondary lymphoid organs these subpopulations occupy separate anatomical compartments' to which circulating T and B lymphocytes "home" appropriately by a process which has been called "ecotaxis". From the behaviour of extranodal lymphoid tumours in man it is suggested that small numbers of circulating lymphocytes may normally home on quite sharply defined areas of the body not usually regarded as secondary lymphoid organs, and that this may help to explain the curious distribution of various pathological lesions characterised by lymphoid infiltration. A similar principle may also apply to "lymphoid" cells other than lymphocytes.