Sustained B-lymphocyte immunodeficiency attributed to phenytoin therapy.
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Adolescent↗
Biomedical subjects
R E Rocklin
Publications and source records attributed to R E Rocklin.
Generation of suppressor cells in atopic patients during immunotherapy that modulate IgE synthesis.
We prospectively studied the effect of ragweed immunotherapy on the generation of suppressor T cells that modulate total and antiragweed IgE production in five patients with seasonal allergic rhinitis. Suppressor T cell depletion was accomplished by treating mononuclear cells (MNCs) with the monoclonal antibody Leu 2b followed by the addition of complement. Treated and untreated MNCs were obtained before and during (6 to 24 months) immunotherapy and were cultured at 1 X 10(6) cells per milliliter for 7 days in RPM1-1640 containing 10% fetal calf serum. In order to determine the effect of ragweed antigen on IgE production, untreated or Leu 2b-depleted MNCs were incubated with short ragweed extract (SRW) (1.0 to 10 micrograms/ml) for 20 hours, washed three times, and incubated for a further 6 days. The cell-free supernatants from each were harvested and assayed for total IgE by use of a modified PRIST assay. To determine specific IgE, a modified RAST procedure was used. Total or antiragweed IgE production was calculated by subtracting preformed IgE from the total or specific IgE content in the supernatant. Depletion of Leu 2-positive cells did not affect total IgE production before immunotherapy. In contrast, a statistically significant increase was observed in total IgE 6 months (p less than 0.05) and 13 months (p = 0.005) after immunotherapy. Specific antiragweed IgE production at these times was also enhanced, but this increase did not reach statistical significance. Before immunotherapy was begun, preincubation of MNCs with SRW did not change the amount of total IgE produced.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Histamine modulation of lymphocyte biology: membrane receptors, signal transduction, and functions.
Until recently, histamine has been considered only in the context of its being the major mediator of immediate-type hypersensitivity responses. However, subsequent investigations have demonstrated an additional role for histamine as a regulator of both cellular and humoral immune responses. In this review, we will analyze critically histamine modulation of lymphocyte biology by examining the methods employed to identify cell membrane histamine receptors, the mechanisms of signal transduction following histamine-receptor interaction, and the effects of histamine on lymphocyte function.
Animals↗
Leukocyte inhibitory factor (LIF) potentiates neutrophil responses to formyl-methionyl-leucyl-phenylalanine.
The ability of purified (80,000-fold) human leukocyte inhibitory factor (LIF) to modulate several formyl-methionyl-leucyl-phenylalanine (f-met-leu-phe)-induced neutrophil functions was evaluated. Although not affecting directed migration itself, at low concentrations (1/2 to 2 U/ml), LIF was demonstrated to potentiate chemotaxis induced by f-met-leu-phe (40.3% +/- 8.1) and to reduce the concentration of f-met-leu-phe necessary for maximal chemotaxis (10(-8) to 10(-9) M). Similarly, LIF did not directly induce the respiratory burst, but potentiated both superoxide generation (151.6% +/- 77) and hydrogen peroxide production (54.9% +/- 15.5) in the presence of f-met-leu-phe (10(-7) M). LIF was also shown to induce degranulation of neutrophil-specific granules in a dose-dependent manner. Neutrophil-specific granules have been shown to contain an intracellular pool of receptors for f-met-leu-phe, and on degranulation provide the surface membrane with a fresh source of receptors. Our data suggested that LIF potentiation of neutrophil stimulation by f-met-leu-phe might be mediated, at least in part, by increasing the number of available membrane receptors as a result of its ability to induce degranulation. Radioligand receptor analysis using f-met-leu-[3H] phe was performed, and LIF was shown to mediate an increase in receptors for f-met-leu-phe from an average of 18,600 on untreated cells to 27,000 after pretreatment with LIF. This increase in receptors could "sensitize" the neutrophils for f-met-leu-phe and possibly explain the potentiation of neutrophil stimulation observed in the presence of the ligand. LIF was also found to have a more generalized effect on the transduction of neutrophil activation stimuli, mediating a 35.8% increase in superoxide production after exposure to calcium ionophore. The data do not permit a determination as to whether the increase in receptor number is responsible for the potentiation of f-met-leu-phe-mediated function, or whether this occurs secondary to the more generalized effect on neutrophil stimulation transduction.
Chemotaxis, Leukocyte↗
Reduced prostaglandin E2 (PGE2) receptors on atopic T lymphocytes.
We have recently demonstrated that atopic T lymphocytes have decreased sensitivity to prostaglandin E2 (PGE2). In order to determine whether this decreased sensitivity was reflected at the receptor level, we have employed a radioligand binding assay utilizing [3H]PGE2. We have demonstrated a single specific reversible binding site for [3H]PGE2 on normal T cells (N = 10) with a mean KD (+/-SD) of 32.2 (+/-25.0) nM, a binding capacity of 20.2 (+/-13.0) pM, and a mean of 1004 (+/-118) receptors per cell. Atopic T cells (N = 10) were also found to have a single specific binding site for [3H]PGE2 with a mean KD of 24.9 (+/-17.8) nM, a binding capacity of 7.1 (+/-10.1) pM, and a mean of 372 (+/-61) receptors per cell. These radioligand binding studies were correlated with functional studies in the same subjects. Phytohemagglutinin-stimulated protein synthesis ([3H]leucine uptake) was suppressed in a dose-dependent fashion by PGE2 (10(-6)-10(-12) M). The maximal effect of PGE2 on normal T cells was 10(-6) M PGE2 with an IC50 of 10(-12) M. Atopic T cells responded quantitatively less than normal T cells to PGE2. Further, the maximum suppression of protein synthesis by PGE2 occurred at 10(-6) M with an IC50 of 10(-10) to 10(-11) M. These studies suggest that part of the decreased sensitivity of atopic T cells to PGE2 may result from a reduction in PGE2 binding sites.
Depression, Chemical↗
Histamine type I (H1) receptor radioligand binding studies on normal T cell subsets, B cells, and monocytes.
We have documented a single, specific binding site for [3H]pyrilamine on normal human T helper, T suppressor, B cells, and monocytes. The binding of the radioligand to its receptor is reversible with cold H1 antagonist, saturates at 40 to 60 nM, and binding equilibrium is achieved in 2 to 4 min. Using a computer program (Ligand), we calculated the dissociation constants, binding capacities, and numbers of receptors per cell for each of the different cell types. Monocytes were found to have the highest affinity (mean KD +/- SD; 3.8 +/- 4.8 nM) for [3H]pyrilamine, followed by T helper cells (KD = 5.0 +/- 6.6 nM), B cells (KD = 14.2 +/- 2.0 nM), and T suppressor cells (KD = 44.6 +/- 49.4 nM). T suppressor cells were found to express the higher number of H1 receptors per cell (35,697 +/- 15,468), followed by B cells (10,732 +/- 9060), T helper cells (6838 +/- 8167), and monocytes (5589 +/- 2266). The kinetics of binding for this radioligand was carried out in resting and mitogen-stimulated T cells over a 48-hr period. We found that the binding affinity for [3H]pyrilamine increased over the 48-hr period, whereas the number of receptors per T cell was essentially unchanged. In contrast, T cells stimulated with Con A or PHA were shown to have a greater than fourfold increase in the number of receptors per cell, whereas the binding affinity for [3H]pyrilamine decreased over the 48-hr period. Preincubation of T cells with unlabeled histamine before carrying out the radioligand binding assay resulted in a decrease in the binding affinity of the receptors to [3H]pyrilamine, but the number of receptors per cell did not change significantly. Although the function of H1 receptors on T cells, B cells, and monocytes has not been completely defined, this receptor has the potential of playing an important role in modulating the immune response.
B-Lymphocytes↗
Penicillin reactions. Desensitize or discontinue?
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Aged↗
Altered arachidonic acid content in polymorphonuclear and mononuclear cells from patients with allergic rhinitis and/or asthma.
We previously have found that monocytes from patients with allergic rhinitis and/or asthma produce less PGE2 than cells from normal subjects in response to a histamine-induced lymphokine. In order to investigate this observation further, we measured the fatty acid content in the total phospholipids derived from the plasma, red cells, buffy coat cells, neutrophils, monocytes and lymphocytes of 27 allergic patients and 21 normal controls. There were no substantial differences between atopics and normals in the fatty acid analyses carried out for plasma and red cells. However, linoleic acid (18:2n-6) levels were elevated significantly in the buffy coat fraction, while arachidonic acid (20:4n-6) levels were reduced. Measurement of fatty acid levels after fractionation of the buffy coat population into neutrophils and monocytes yielded similar elevations in 18:2n-6 and reduced 20:4n-6. In contrast, lymphocytes appeared to have the reverse pattern, i.e., significantly reduced 18:2n-6 and elevated 20:4n-6 levels. These data suggest that atopic leukocytes may have altered essential fatty acid metabolism.
Adolescent↗
Phenotypic and functional evaluation of suppressor cells in normal pregnancy and in chronic aborters.
To evaluate the potential role of immunoregulatory cells modulating the maternal immunologic response during pregnancy, we carried out phenotypic and functional studies in patients with normal obstetrical histories during each trimester and in patients with chronic idiopathic spontaneous abortions. Using monoclonal antibodies (Ortho), total numbers of T cells (T3+) and T4+ cells progressively increased during pregnancy (compared to nonpregnant controls) and then declined in the third trimester. Increased percentages of T8+, T10+, and Ia+ cells were found in the third trimester. The relative decline in numbers of T4+ cells, with increased numbers of T8+ cells, led to a significantly reduced T4/T8 ratio in the third trimester. Histamine receptors on T cells were quantitated by an immunofluorescent technique. Significantly reduced numbers of H1-type receptors were noted during the second trimester of pregnancy and this was associated with a decreased H1/H2 ratio. Functionally, histamine-induced suppression was measured in a lymphocyte proliferation assay. Patients in the first and second trimester of pregnancy had greater histamine-induced suppression of phytohemagglutinin (PHA)-stimulated proliferation at high concentrations of histamine (10(-3) to 10(-7)) but less suppression at the lower concentrations (10(-9) to 10(-11) M), compared to nonpregnant controls. In contrast, patients studied in the third trimester failed to respond to any concentration of histamine. MLC-induced suppressor activity was generated by incubating the maternal cells with either paternal or third-party mononuclear cells for 2 or 6 days and assaying the cell-free supernatant for its suppressive effects on PHA-stimulated proliferation. Maternal responses to paternal cells did not result in significant suppression in 2-day supernatants during any trimester but by 6 days the suppressive activity was equivalent to non-pregnant controls in patients during the first and second trimester. Maternal responses to third party cells was greater during the second trimester than either the first or third trimesters in both 2- and 6-day supernatants. Patients with histories of chronic idiopathic spontaneous abortions, who were not pregnant at the time of study, exhibited normal numbers of T-cell subsets and T4/T8 ratios. Numbers of both H1 and H2 receptor bearing T cells were proportionally reduced, resulting in a normal H1/H2 ratio. Despite having decreased numbers of H1 and H2 receptor bearing cells, histamine-induced suppression of PHA-stimulated proliferation was comparable to nonpregnant controls over the concentration range (10(-3) to 10(-11) M) employed.(ABSTRACT TRUNCATED AT 400 WORDS)
Abortion, Habitual↗
In vitro anti-mitochondrial antibody synthesis in patients with primary biliary cirrhosis.
Suppressor cell function was studied in 31 patients with primary biliary cirrhosis. Blood mononuclear cells were activated in vitro with suboptimal or optimal concentrations of concanavalin A and suppression of mitogen-induced proliferation or synthesis of anti-mitochondrial antibodies was measured. At suboptimal concentrations of concanavalin A, mean (+/- SE) suppression of proliferation by patients' cells was significantly less than 14 controls (18.7 +/- 5% vs 34.3 +/- 5%; P less than 0.005). The degree of suppressor activity correlated with the clinical disease, i.e., suppression was greater in patients with early than advanced disease. Spontaneous anti-mitochondrial antibody synthesis was not detected in cultures of mononuclear cells from normal subjects nor from patients with negative serum antibody, nor could it be induced by pokeweed mitogen in either group. In contrast, spontaneous anti-mitochondrial antibody synthesis was detected in cultures of 18/23 patients with positive serum antibody and was significantly augmented by pokeweed in 12/18. Anti-mitochondrial antibody synthesis was augmented by 48% (+/- 19) in response to pokeweed and concanavalin A-induced suppression higher (39.4 +/- 7%) in patients with low titer antibody compared to 1.6% (+/- 8) pokeweed augmentation and 5.5 +/- 3% concanavalin A-induced suppression in patients with high titer antibody. These results suggest that some patients with primary biliary cirrhosis have an immunoregulatory defect which expresses itself in part as an inability to regulate autoantibody synthesis.
Antibody Formation↗
Inhibition of neutrophil superoxide production by fanetizole.
The effects on neutrophil function of the new immunomodulatory agent fanetizole mesylate were studied. Fanetizole did not affect random or stimulated migration, phagocytosis, or degranulation by normal human neutrophils. Production of superoxide in response to the chemotactic factor formyl-methionyl-leucyl-phenylalanine (f-Met-Leu-Phe) was markedly inhibited (41.3 +/- 3.9%) by 250 microM fanetizole. This inhibition was not due to scavenging of superoxide by fanetizole, as there was no impairment of superoxide detection in a cell-free xanthine-xanthine oxidase system. Inhibition was dose dependent (no effect seen with 1 or 10 microM fanetizole) and stimulus specific (no impairment of superoxide production in response to phorbol myristate acetate). Washing the cells after fanetizole treatment partially restored their superoxide response to f-Met-Leu-Phe. Suppression of neutrophil production of toxic oxygen metabolites may partially explain the antiarthritic effect of fanetizole, and study of such selective inhibitors may be useful in probing the contribution of neutrophils to inflammatory tissue damage.
Adult↗
Physiological studies with human leukocyte inhibitory factor.
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Antibody-Dependent Cell Cytotoxicity↗
Human lymphocyte-eosinophil interactions. I. Modulation of phytohemagglutinin-induced lymphocyte proliferation by eosinophils.
Do eosinophils modulate lymphocyte function? This question was studied by examining the effect of purified eosinophils (eos) on lectin-induced human lymphocyte proliferation. Intact resting or zymosan-stimulated eos or their extracts were cocultured with phytohemagglutinin-stimulated mononuclear cells in vitro and [3H]thymidine uptake was measured at 72 hr. Zymosan-stimulated eos consistently suppressed (up to 90%) the lectin-induced proliferative response by a noncytotoxic mechanism. Freeze-thaw extracts from zymosan-stimulated eos also significantly suppressed lymphocyte proliferation to a similar degree. The amount of suppression was directly proportional to the number of eos or the amount of extract added to the lymphocyte cultures. Intact resting eos and their extracts occasionally exhibited suppressive effects (up to 40%) on lymphocyte proliferation; this suppression, however, was always less than that of activated eos or their extracts. Eos pretreated with the protein synthesis inhibitor, pactamycin, exhibited significantly less suppressive activity, suggesting that a protein was responsible in part for the reduction in proliferation. The addition of superoxide dismutase or catalase to the eos-mononuclear cell cocultures did not reduce the amount of suppression observed, thus making it unlikely that active oxygen products were involved in the mechanism of suppression. Heating extracts from stimulated eos to 80 degrees C for 30 min resulted in partial loss of suppressive activity while extensive dialysis of the extracts had no effect. The studies reported here provide evidence that a nondialyzable and heat sensitive factor(s) produced by stimulated eos may exert feedback inhibition of lymphocyte function.
Catalase↗
Abnormal regulation of in vitro IgE synthesis by T cells obtained from patients with atopic dermatitis.
The regulatory influence of atopic eczema and non-atopic T cells on spontaneous IgE synthesis by eczema B cells was examined. Eczema B cells were cocultured with either autologous or allogeneic T cells in RPMI 1640 with 10% fetal calf serum at 0.75 X 10(6) cells/ml (B/T = 0.5) and supernatant IgE was measured by a modified PRIST assay. Net IgE synthesis was obtained by subtracting preformed IgE (+ cycloheximide at Day 0) from total IgE in 7-day supernatants. T cells were either untreated, heat-killed, exposed to 2000 rad, or depleted of helper/suppressor T cells by "panning" with monoclonal antibodies (Leu 3a and Leu 2a). Atopic eczema B cells spontaneously synthesized IgE when cultured alone. No significant suppression of net IgE synthesis occurred when atopic eczema T cells were cocultured with autologous B cells. In allogeneic recombinations, non-atopic T cells significantly suppressed net IgE synthesis by atopic eczema B cells (mean suppression = 59%; P less than 0.05). This suppression was abrogated if allogeneic control T cells were heat-killed, irradiated, or depleted of Leu 2a+ suppressor cells. In order to exclude an "allogeneic effect" as the sole mechanism to explain the suppression of IgE synthesis observed by coculturing non-atopic T cells with eczema B cells, the latter were recombined with either T cells from HLA-DR and mixed lymphocyte culture-matched sibling or autologous T cells. Greater suppression of net IgE synthesis was seen in the presence of histoidentical non-atopic T cells than in the presence of autologous eczema T cells, indicating that the latter have a partial defect in their suppressor function. This apparent "defect" in immunoregulatory function may be overcome by in vitro activation of atopic eczema T cells by concanavalin A.
Adolescent↗
Effect of dexamethasone on de novo IgE synthesis by human blood lymphocytes.
The effect of dexamethasone (DM) on de novo in vitro total IgE synthesis by blood mononuclear cells (MNC) was studied in atopic patients with eczema and in nonatopic control subjects. Unfractionated blood MNC were cultured at 1 X 10(6) cells per milliliter for 7 days in RPMI 1640 with 10% fetal calf serum with or without decreasing concentrations of DM (10(-7) to 10(-11). Net IgE synthesis was calculated by subtracting preformed (+ cycloheximide at day 0) from total IgE in 7-day supernatants. Supernatant IgE was measured by use of a modified PRIST assay. A significant increase in net IgE synthesis occurred in the presence of DM in 11 of 11 atopic patients with eczema (mean percent increase = 68%; p less than 0.05) and five of five atopic patients without eczema (mean percent increase = 53%; p 0.05) but not in seven of seven nonatopic controls. This increase in de novo IgE synthesis could not be explained by a significant change in cell viability. In five of five experiments, a mean increase of 78% was still noted when DM was added to atopic blood MNCs depleted of T cells by sheep red blood cell rosetting. The addition of 10(-9)M of DM to eczema B+ T cell recombinations enriched for suppressor cells (depleted of Leu 3a+ helper T cells) resulted in a loss of suppressor-T cell activity and maximal augmentation of IgE synthesis. Enhancement of IgE synthesis was also noted when DM was added to eczema B+ T cell recombinations enriched for helper T cells (depleted of suppressor Leu 2a+ T cells).(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Increased blastogenic responses to worm antigen and loss of adherent suppressor cell activity after treatment for human infection with Schistosoma mansoni.
Fifteen Egyptian subjects infected with Schistosoma mansoni were evaluated parasitologically, clinically, and immunologically; treated with praziquantel; and reevaluated nine months later. Fecal egg counts were 97% lower after therapy; seven subjects no longer excreted eggs, as determined by Kato thick smears. Optimal [3H]thymidine incorporation induced by soluble adult worm antigenic preparation (SWAP) in peripheral blood mononuclear cells (PBMCs) increased significantly, from 4,041 +/- 434 (mean change in cpm +/- SE) before treatment to 11,232 +/- 3,414 after treatment (P less than .0005). The relation between dose of antigen and response also shifted; the SWAP concentration producing optimal responses was 30.0 micrograms/ml before and 1.0 microgram/ml after therapy. Before treatment, depletion of adherent cells from PBMCs in six subjects resulted in enhancement of responses to SWAP from 5,575 +/- 1,210 to 14,719 +/- 8,190 (P less than .025). However, in these same individuals after treatment, PBMC and nonadherent lymphocyte responses were similar (22,917 +/- 6,505 and 21,239 +/- 6,122). These studies indicate loss of activity of adherent suppressor cells after treatment of chronic infection with S. mansoni. Waning of cellular regulatory mechanisms as the parasite load decreases may contribute to restoration of blastogenic responses.
Adolescent↗
Variability in the intradermal and in vitro lymphocyte responses to PPD in patients receiving isoniazid chemoprophylaxis.
Much attention has been focused on problems related to the interpretation of the tuberculin (Tb) skin test in terms of the "booster" phenomenon observed with repeated skin testing. However, relatively little attention has been given to the problem of the interpretation of repeat Tb skin tests in patients who have been given isoniazid (INH) chemoprophylaxis. Sixteen female hospital workers who were receiving INH for asymptomatic recent conversion of their Tb skin test, and 1 male physician under treatment with INH and rifampin for active tuberculosis as a result of a patient exposure, were studied over a 1-yr period. Intradermal skin tests with 5 tuberculin units purified protein derivative (PPD) and assessment of in vitro lymphocyte proliferation and production of leukocyte inhibitory factor on exposure to PPD were performed on 4 occasions at 3-month intervals-3 during therapy and 1 after completion of therapy. Four of 10 patients tested on all occasions showed at least 1 negative Tb skin test. In 2 of 4, the reversions were not stable. Considerable variability was observed between results of skin tests and in vitro lymphocyte responses, and no one in vitro lymphocyte response to PPD was adequate to identify the presence of delayed hypersensitivity to PPD. On the basis of these data, it is concluded that the presence of a single negative PPD skin test during or shortly after the completion of INH chemoprophylaxis does not constitute sufficient evidence to conclude that a patient has had a stable skin test reversion. Confirmation of the loss of tuberculin reactivity requires the in vitro assessment of lymphocyte responses to PPD both in terms of proliferation and the production of a lymphokine(s).
Cross Infection↗
Decreased sensitivity of atopic mononuclear cells to prostaglandin E2 (PGE2) and prostaglandin D2 (PGD2).
The effect of PGE2 and PGD2 on several lymphocyte functions in vitro was evaluated in nonatopic and atopic subjects. Both PGE2 and PGD2 inhibited phytohemagglutinin-induced protein synthesis ([3H] leucine uptake) by nonatopic mononuclear cells and T cells in a dose-dependent manner (10(-6) to 10(-12) M). Protein synthesis by atopic mononuclear cells was not significantly suppressed by the above concentration of PGE2. Although PGD2 effectively suppressed protein synthesis by atopic mononuclear cells and T cells at 10(-6) M, lower concentrations were ineffective. Kinetic studies revealed significant differences in the suppressive effects of PGE2 and PGD2 on atopic and nonatopic mononuclear cells at 24 and 48 h, but not at 72 or 96 hr. Protein synthesis by T helper-enriched populations (suppressor cell depletion by anti-Leu-2b + complement) obtained from nonatopics was significantly reduced by PGE2 and PGD2, suggesting that these mediators may be directly inhibiting the responding population. By contrast, protein synthesis by T suppressor-enriched populations (helper cell depletion by OKT4 + complement) obtained from nonatopics was enhanced by PGE2 and PGD2, suggesting that the PG were activating these cells. Atopic T helper and T suppressor cells exhibited decreased responsiveness to PGE2 and PGD2 compared with nonatopic cells. PGE2 and PGD2 inhibited the phytohemagglutinin-stimulated proliferative response ([3H]thymidine uptake) by both atopic and nonatopic mononuclear cells in a dose-dependent manner and to the same extent. However, although PGE2 and PGD2 generated functional suppressor activity (when using a coculture technique) in nonatopic mononuclear cells, these mediators failed to activate atopic suppressor cells. These results suggest that reduced responses by atopic T cells to signals provided by PGE2 and PGD2 are not solely restricted to suppressor cell function, and could indicate an impaired ability to regulate immune and/or inflammatory reactions.
DNA↗