T and B lymphocytes in myasthenia gravis.

Peripheral blood lymphocytes from seventeen non-thymectomized and nine thymectomized patients with myasthenia gravis (MG) and thirteen healthy controls were examined for the presence of surface markers characteristic of T and B lymphocytes by rosette formation with sheep red blood cells (SRBC). T cells were identified by their capacity to spontaneously form rosettes with SRBCs. The percentage of B lymphocytes was determined by the erythrocyte antibody complement (EAC) rosette-forming test. The EAC complex was prepared with either whole rabbit anti-SRBC serum or with the IgM fraction of rabbit anti-SRBC serum. The two kind of erythrocyte complement rosette-forming cells (EAC-RFC) are designated erythrocyte-haemolysin-complement RFC (EA(H)C-RFC), and erythrocyte-IgM-complement RFC (EA(M)C-RFC). The percentage of total lymphocytes and T cells was not altered in MG patients. The percentage of 'active' T cells, which have been considered to be more actively involved in cellular immunity, was also similar in MG patients and controls. A significant increase in EA(H)C-RFC occurred in both thymectomized and non-thymectomized MG patients, while in B cells detected by EA(M)C-RFC no alterations were found. The increase in EA(H)C-RFC in lymphocytes from MG patients may be due to an increase in the 19S antibody-forming B lymphocytes or to an increase in T cells which have Fc receptors on their surface.     

T and B lymphocytes in multiple sclerosis.

The percentage and total number of E and EAC rosettes, as indicators of T and B lymphocytes respectively, were studied in the blood of subjects with multiple sclerosis (MS) and normals. MS patients in acute exacerbation were found to have a decrease in E rosettes and an increase in EAC rosettes. The relationship of these findings to the pathogenesis of MS is unclear; several possible pathogenetic implications are considered.     

Blastogenic factors: production by T and B lymphocytes. Effect on T and B cells.

The aim of the present report is to identify the cells responsible for the in vitro production of blastogenic factor and to evaluate the effect of blastogenic factor on T and B lymphocytes. Human T lymphocytes were purified by a nylon wool column filtration method and B-cell-enriched populations were purified by sedimentation of E rosettes on Ficoll-Hypaque. The results were summarized as follows: Both T cells and B cells can produce blastogenic factor. However, blastogenic factor produced by T cells differed in some respects from blastogenic factor produced by B cells. (a) Blastogenic factor produced in unmixed B-cell cultures stimulated both B cells and T cells to proliferate, whereas blastogenic factor produced in unmixed T-cell cultures stimulated only B cells. (b) The production of T-cell blastogenic factor was accelerated when stimulated by allogeneic cells. In contrast, the blastogenic activity of supernatants from mixed cultures of B cells was not different from that of supernatants from unmixed cultures. The significance of these findings for mixed leucocyte reaction is discussed.     

Immunoregulation in the common marmoset, Calithrix jaccus: functional properties of T and B lymphocytes and their response to human interleukins 2 and 4.

Non-human primates have been used to study immune function to a much lesser extent than readily available strains of inbred rodents. Nevertheless, in situations where it might be desirable, but impossible, to study human immune responses in vivo, lower primates could provide an acceptable alternative. In order to extent the knowledge of T- and B-lymphocyte function in lower primates, the common marmoset Callithrix jaccus was used as an experimental model. The functional similarities between this species and humans at the level of T-B co-operation in the antibody response were examined, and xenoreactive T-lymphocyte clones were obtained from marmoset spleen cells using Epstein-Barr virus (EBV)-transformed human B cells as stimulators. These clones could act as helper cells when co-cultured with human B lymphocytes, inducing the secretion of both IgM and IgG. Lymphokine production by mitogen-stimulated marmoset T-cell clones was also examined. Interleukins (IL) 2 and 4 activities were detected in clone supernatants using bioassays and interferon-gamma (IFN-gamma) was detected using a solid-phase ELISA system. However, SDS-PAGE analysis of biosynthetically labelled marmoset and human T-cell clone supernatant proteins revealed major differences between the soluble T-cell products of the two species. The proliferative responses of marmoset T and B cells to recombinant human IL-2 and IL-4 were also examined. Stimulation of [3H]thymidine uptake was detected in both T cell- and anti-IgM-stimulated B-cell cultures with both of the lymphokines. These results suggests that the key components of the antibody response are functionally conserved between lower primates and man and that the common marmoset may be useful as an in vivo model of immune function, particularly with regard to the role of interleukins such as IL-2 and IL-4.     

T and B lymphocytes in AIDS. Morphological aspects

This paper presents scanning electron microscopic features of T and B Lymphocytes in patients affected with AIDS and ARC and compares these results with others obtained in patients showing an immunodeficiencey associated with therapy for oncological diseases and in normal healthy donors. The SEM observations showed some surface alterations of the lymphocytes consisting in protrusions, buddings and characteristic "bowl-shaped" cavities particularly evident on the lymphocytes' surface of end stage patients suffering from AIDS. Similar aspects were not found in the other groups including the healthy donors. These lymphocyte surface alterations might likely correspond to the first sign of cell disfunction and therefore represent an early marker of this complex disease.     

T and B lymphocytes in pregnancy

Summary The proportion of human peripheral B- and T-lymphocytes of pregnant women was studied by immunofluorescence and rosette tests. No significant difference between pregnant women and controls was found in the absolute number of circulating T-cells. A slight increase in the absolute number of B-cells was observed in pregnancy. The percentage of total RFC was the same in pregnant women and in controls whereas the percentage of stable RFC and PHA induced RFC decreased in pregnancy. The conclusion of the results was drawn that the depression of maternal immunity may depend on other factors than the decreased proliferation of T-cells.     

T and B lymphocytes in the ontogenetic development of man.

Cord blood lymphocytes of premature and mature fetuses and peripheral blood of infants and adults were studied by rosette techniques and membrane immunofluorescence. Percentage of lymphocytes carrying surface immunoglobulins, receptors for complement and receptors for uncoated sheep erythrocytes or receptors for Fc IgG was determined. T lymphocyte receptors were found to appear later in ontogeny than the receptors typical of B lymphocytes. Receptors for Fc IgG were the earliest to appear: already in premature fetuses the percentage of lymphocytes resembled the one seen in healthy adults. However, the absolute number of T cells increased during development of fetuses and infants and slightly decreased in adults. On the other hand, the absolute number of B lymphocytes were highest in mature fetuses and decreased in subsequent age groups. In the course of human ontogeny a progressive increase was found in lymphocytes carrying full sets of T or B lymphocyte receptors, paralleled by a corresponding decrease in mean values of "null" lymphocytes free of detectable receptors.     

Antigen presentation by B lymphocytes to CD4+ T lymphocytes in vivo: importance for B lymphocyte and T lymphocyte activation.

B lymphocytes, like macrophages and dendritic cells, can present antigen to CD4+ T cells. Antigen presentation by B cells is essential for the generation of an in vivo T cell dependent antibody response, and repeated antigen presentation by B cells to T cells is necessary to induce B cell clonal expansion. Presentation of antigen by resting B cells to unprimed T cells tolerizes T cells, while anti-IgD antibody activates B cells and allows B cell antigen presentation that productively activates T cells. However, activation is not all that is required for B cells to productively present antigen to T cells.     

The radiosensitivity of T and B lymphocytes in mice.

The radiosensitivity of T and B lymphocytes in spleens of specific pathogen-free C3Hf/HeMs male mice was studied by the direct and indirect immunofluorescence technique. It was found that the radiobiological parameters characterizing the survival curve of Bpsi lymphocytes were DO = 200 R and n = 1-00. The T lymphocytes, on the other hand, were shown to consist of two distinct subpopulations with respect to their radiosensitivity. The radiobiological parameters of the radiosensitive fraction of T lymphocytes were Dq = 185 R, DO =195 R and n = 2-50. The DO value of the radioresistant T lymphocyte subpopulation was practically unmeasurable. It was estimated that approximately 8 per cent of the T lymphocytes present in the spleen of normal C3Hf mice belonged to this radioresistant subpopulation.     

T and B lymphocytes in patients with pulmonary tuberculosis.

Counts of T and B lymphocytes were made in the peripheral blood from patients with active and inactive pulmonary tuberculosis and in healthy subjects. In patients with active pulmonary tuberculosis the numbers of T cells were significantly lower than in the controls. After treatment for two months, if the patient's condition improved the percentage of T cells returned to nearly normal levels. If the patient failed to improve, the numbers of T cells remained low. The mechanism of these phenomena is discussed.     

T and B lymphocytes in pituitary dwarf Snell-Bagg mice.

The lymphocyte composition of the thymus and spleen from weaned (4 month old) hypopituitary dwarf Snell-Bagg mice were compared to those of their phenotypically normal littermates and of hormone (somatotropic hormone plus thyroxine)-treated individuals. Detection of cells bearing receptors for peanut agglutinin, physical analysis and measurement of in vitro reactivities to phytohaemagglutinin and concanavae intra-thymic lymphocyte population of dwarf mice. Examination of spleen-cell suspensions demonstrated a slightly higher frequency of T lymphocytes (Thy 1-2+ alpha-Naphthyl esterase+, high electrophoretic mobility) and lower frequency of B lymphocytes (surface immunoglobulin+, low electrophoretic mobility) in dwarf mice than in control mice. The degree of splenocyte responsiveness to T- and B-cell mitogens, however was similar in the two mouse types. High mobility (T) splenic cells were found to exhibit a smaller modal volume in dwarf mice (110 micron3) than in control mice (122 micron3) but this difference was not corrected by hormone administration. More pronounced were the quantitative differences between the spleens of hormone-deficient and normal mice. Thus, when expressed as a function of body weight, the numbers of splenic T and B lymphocytes in untreated dwarf mice were about half the corresponding values in hormone-reconstituted or normal littermates. These data suggested that in adult life, developmental hormones exert little direct effect on the thymus lymphocytes but influence the size of the pool of both peripheral T and B lymphocytes.     

The peripheral T and B lymphocytes in uremic patients.

By employing the rosette technique the peripheral T and B lymphocytes were determined in 24 patients with terminal renal failure treated by diet and 17 subjects treated by program of repeated hemodialysis. The decreased percentage of B-cells was found in both groups of patients in comparison with the control group. The more distinct decrease of B-cells was observed in patients treated by hemodialysis in comparison with undialized patients but the difference was statistically nonsignificant. The degree of immunity disturbance in chronic renal failure does not depend on dialysis but on the duration of the renal insufficiency.     

Development of peripheral B and T lymphocytes in piglets.

The percentage of B and T lymphocytes in the peripheral blood of piglets during their first 35 days of life was estimated by means of the immunofluorescence-labelled anti-L chains sera and the spontaneous E-rosette techniques. The mean values obtained for adult pigs PBL were 23.8 +/- 10.2% of B and 38.0 +/- 8.4% of T lymphocytes. The piglets showed a linear increase for the B lymphocytes starting from a mean value of 4% observed for the newborns. The trend of the T lymphocytes was represented by a bimodal curve. It starts for newborns at 3% and shows a change in shape by the 10th day. It is suggested that the piglets have adult levels of B and T lymphocytes by the time of weaning.     

T and B lymphocytes in patients with enteric fever.

Estimation of T and B lymphocytes was done in 50 patients of enteric fever, 50 duration matched non enteric fever patients and 50 normal healthy individuals. The difference in both early and late rosette forming T lymphocytes was found to be statistically significant in enteric versus non-enteric patients. Significant difference was also observed in enteric versus normal individuals in case of late rosette forming T lymphocytes.     

T and B lymphocytes in South American pemphigus foliaceus.

T and B lymphocytes were quantified in peripheral blood of thirty patients with South American pemphigus foliaceus according to their ability to form rosettes with sheep erythrocytes (E) or sheep erythrocytes sensitized with antibody an complement (EAC). When compared with the counts obtained from thirty normal subjects, a decrease was found in the total T-lymphocyte count (32-33+/-7-7 versus 46-7+/-8-7) and in the T functional lymphocyte count as detected by the active rosette test. The mean percentage of B lymphocytes within the total number of lymphocytes was not significantly different from that of normal subjects (24-0 +/- 8-2 versus 25-3+/-8-0). Lymph node sections from three pemphigus patients examined for E or EAC adherence showed depletion of T cells in the paracortical areas. The low percentage of E cells in the peripheral blood and the depletion of E cells in paracortical areas of lymph nodes from patients with South American pemphigus foliaceus may reflect an impaired cellular immunity.     

Changes in T and B blood lymphocytes after splenectomy.

The blood lymphocytes of 37 splenectomised patients were analysed by means of T and B lymphocyte surface markers. Sixteen patients had had a splenectomy for non-haematological and 21 for haematological reasons. The results show that 15 had normal numbers of T and B cells; decreased T cells were found in two patients, raised B cells in seven, raised T and B cells in eight, and raised T cells in five patients. Increased numbers of 'null' cells were observed in some patients, especially in those with raised B cells. Follow-up studies indicate that raised levels of T and B cells can be established by one to three months post-splenectomy and may persist, although in some patients the cells fall to normal levels. The lymphocyte proliferative response to phytohaemagglutinin and Concanavalin A in vitro was normal in eight out of nine patients with raised T cells and was depressed in one patient, possibly due to an intrinsic cell defect.