Anti-idiotypic activity against anti-myeloperoxidase antibodies in pooled human immunoglobulin

We investigated the ability of six different pooled human immunoglobulin (PHIG) preparations to inhibit the binding of anti-myeloperoxidase (MPO) antibodies to MPO. All six PHIG preparations inhibited the binding of anti-MPO antibodies from six sera to MPO in a concentration-dependent manner in the concentration range 0.016-10 mg/ml. There was considerable variation in the ability of each PHIG preparation to inhibit the binding of anti-MPO antibody in a given serum. Further differences were seen in the ability of a given PHIG to inhibit anti-MPO binding in different sera. F(ab')2 fragments from two PHIG preparations also inhibited in a concentration-dependent manner anti-MPO binding to MPO in all six sera in the concentration range 0.002-2.65 mg/ml, with a maximum inhibition of 42%. Little inhibition was seen with F(ab')2 of normal human IgG from individual donors (1.8-12.2% at the maximum concentration of 2 mg/ml). F(ab')2 fragments from three anti-MPO containing sera and two affinity-purified anti-MPO antibodies were eluted by affinity chromatography from Sepharose-bound PHIG F(ab')2 and showed anti-MPO antibody activity. We have shown that PHIG and F(ab')2 fragments of PHIG inhibit anti-MPO binding to MPO, and further that F(ab')2 fragments of PHIG bind to F(ab')2 fragments of anti-MPO antibodies. These observations indicate binding between the variable regions of PHIG and the antigen binding site of anti-MPO antibodies, and are consistent with an anti-idiotypic reaction. The variability seen in the inhibitory effect of the different PHIG preparations in anti-MPO-positive sera implies differences in their anti-idiotype content, while the variability of the inhibitory effect of a particular PHIG preparation between different sera suggests heterogeneity in the idiotypic repertoire of anti-MPO antibodies. Such variations in the inhibitory effect of different PHIG preparations on antibody binding may be an important determinant of their therapeutic effect.     

Differential suppression of dialysis patients' lymphocyte IFN-gamma production by glucocorticoids and cyclosporine

IFN-gamma is a potent pro-inflammatory cytokine involved in the immunologic rejection of transplanted organs. Having previously demonstrated differential suppressive effects of methylprednisolone (MP), prednisolone (P) and cyclosporine (CsA) on dialysis patients' lymphocyte proliferative responses to phytohaemagglutinin (PHA), we studied the effects of these drugs on dialysis patients' lymphocyte IFN-gamma production during mitogenic and allogeneic (MLR) stimulation. The mean +/- SEM 50% inhibitory concentration (ng/ml) on cell proliferation was significantly lower for MP than P in PHA-stimulated haemodialysis (HD) patients' (35 +/- 7 vs 152 +/- 25, P < 0.001) and peritoneal dialysis (PD) patients' (35 +/- 11 vs 134 +/- 33, P = 0.001) cultures and in HD patients' MLR cultures (15 +/- 3 vs 48 +/- 9, P < 0.001). The mean +/- SEM fractional responses (PHA or MLR + drug/PHA or MLR) in culture supernatant IFN-gamma concentrations were significantly lower with 10(-7) M concentrations of MP than P in HD (0.19 +/- 0.05 vs 0.31 +/- 0.06, P = 0.01) and PD (0.30 +/- 0.11 vs 0.46 +/- 0.11, P < 0.05) PHA cultures and in HD MLR cultures (0.15 +/- 0.04 vs 0.28 +/- 0.07, P = 0.01). CsA (400 ng/ml) alone not only caused less than 50% inhibition of IFN-gamma production in 15/27 HD PHA, 6/14 PD PHA and 4/13 HD MLR cultures, but actually stimulated it in 9 HD and 5 PD PHA cultures. The results suggest that: (1) MP has greater immunosuppressive potential than P for renal transplant recipients; (2) the stimulation of IFN-gamma by CsA in some patients could be harmful in patients with initial allograft dysfunction; and (3) pre-transplant in-vitro assessment of recipients' PBMC responsiveness to glucocorticoids and CsA may help individualize the post-transplant immunosuppressive regimen.     

Accurate measurement of intrinsic positive end-expiratory pressure: how to detect and correct for expiratory muscle activity

The basic amino acid L-lysine was administered to mice in an attempt to circumvent unwanted renal accumulation of 67Cu-labelled F(ab')2 fragments derived from the anti-NCAM IgG1, SEN7 and anti-CEA IgG1 monoclonal antibody (MAb)35. In control experiments, significant renal uptake of both 67Cu-labelled F(ab')2 fragments was observed, radiolabel being primarily localised to proximal tubules in the renal cortex. Following optimised L-lysine dosing protocols, renal uptake of 67Cu-MAb35 F(ab')2 was inhibited by up to 42%. Surprisingly, little inhibition (< 10%) of 67Cu-SEN7 F(ab')2 uptake was observed. Experiments to investigate this differential inhibition indicated that inhibition of MAb35 F(ab')2 uptake was relatively short-lived (approx. 6 hr), whilst no apparent differences were found in blood clearance rates between either 67Cu-F(ab')2 fragment. L-lysine administration caused a significant diuresis with high levels of intact 67Cu-labelled SEN7 and MAb35 F(ab')2 appearing in the urine, possibly due to blockade of renal uptake and lysine-induced increases in glomerular membrane permeability. Iso-electric focusing studies failed to identify any charge differences between the 67Cu-labelled F(ab')2 fragments, although a cathodal migration of all 67Cu-labelled samples, presumably due to the net positive charge conferred by addition of 67Cu2+ ions, was observed. Our results demonstrate that in addition to net charge, other unidentified characteristics may influence renal accumulation of radiometal-labelled F(ab')2 fragments and their inhibition by L-lysine.     

Specificity of Fcgamma receptors in human malignant tissue and normal lymphoreticular tissue

The specificity of the Fcgamma receptors in normal spleen and liver and in malignant tissues was studied using hemadsorption to cryostat sections. Indicator cells (EA) were sheep erythrocytes (E) sensitized with rabbit IgG antibody (A). The binding of EA to sections of normal and malignant tissues was inhibited by pooled IgG of human, rabbit, and guinea pig origin and by human IgG1, and IgG3, and IgG4 myeloma proteins. Heat-aggregated IgG inhibited the binding to sections of liver and some malignant tissues more effectively than monomeric IgG. The Fc fragments of IgG were also inhibitory, but not the F(ab')2, Fab', and Facb fragments. The inhibition obtained increased with decreasing amounts of A used for sensitization of E. The inhibitory activity of IgG was abolished after partial reduction and alkylation. No inhibition was obtained with IgG2, IgM, IgA, or albumin. E sensitized with Facb or F(ab')2 fragments of A did not bind to normal or malignant tissues. The specificity of the Fc receptors in normal spleen and liver and in malignant tissues is apparently very similar.     

Different effects of methylxanthines on central serotonergic postsynaptic neurons in a mouse behavioral model

We have used genetic engineering to obtain secretion of anti-human CD5 antibody fragments from Escherichia coli for conjugation to the 30-kDa form of ricin A chain (RTA30). This was accomplished by introducing stop codons at two positions in the hinge region of the human IgG1 gene so that coexpression of the truncated heavy-chain genes (Fd') with a light chain would result in Fab' and/or F(ab')2 proteins containing either one or two interheavy-chain cysteines. An Fd' gene encoding both interheavy-chain cysteines yielded a mixture of F(ab')2 and Fab', which could be separated by size-exclusion chromatography. An Fd' gene encoding only one interheavy-chain cysteine yielded primarily Fab'. Purified F(ab')2 protein was equivalent to unlabeled chimeric IgG in competing for binding of IgG with CD5 antigen, while the molar concentration of the monovalent Fab' required for 50% binding inhibition was 4- to 5-fold higher than IgG. An immunoconjugate was prepared with Fab' by direct coupling to the unique free cysteine on RTA30. The bivalent F(ab')2 was conjugated to RTA30 after derivatization with the crosslinking agent 5-methyl-2-iminothiolane. These immunoconjugates efficiently killed a CD5+ T-cell line and human peripheral blood T cells.     

Human transfer factor: effects on lymphocyte transformation

Transfer factor preparations from 57 different donors have been compared for effects on mitogen- and antigen-induced lymphocyte transformation. Nine of the preparations were mitogenic when added to cultured lymphocytes although the magnitude of this activity was relatively low. The majority of the preparations (48/57) did not affect PHA-induced lymphocyte transformation although augmentation (6 of 57) and suppression (3 of 57) was observed with some. In addition we observed that most of the preparations tested suppressed ConA stimulation and augmented the PWM response. When selected preparations were evaluated on antigen-responsive cells, there was a correlation between the magnitude of antigen responsiveness and the magnitude of TF augmentation of antigen-induced lymphocyte transformation (p less than 0.005). Cultures that were not responsive to antigen (KLH-negative or BUdR-treated) could not be stimulated by TF from immune donors and antigen. These data suggest that TF preparations contain either stimulatory or inhibitory components and that TF is not capable of activating naive lymphocytes to undergo transformation in response to antigen.     

Analysis of cytokine and specific antibody profiles in hydatid patients with primary infection and relapse of disease

We studied in vitro cytokine production by peripheral blood mononuclear cells (PBMC) from patients with primary and recurrent hydatid disease when cells were incubated with mitogen (PHA) and antigen from hydatid cyst fluid (HCFAg); levels of specific IgE, IgG4 and eosinophil counts were also measured in sera. When specifically stimulated, PBMC from patients produced higher levels of IL-2 (P < 0.02), IFN-gamma (P < 0.0028) and IL-5 (P < 0.01) than those from uninfected donors, whereas IL-10 levels were comparable. Notably, IL-5 was also produced in higher levels (P < 0.01) by PBMC from patients when incubated with PHA. The IL-5:IFN-gamma ratio was significantly greater (P < 0.02) when measured in response to specific stimulation than it was for PHA-stimulated cultures. These cytokine data suggest a bias towards a Th2-response which is in agreement with the high levels of IgG4 and IgE observed. The polarized response appears to be related to clinical status, as differences between patients with primary infection and those with relapse of disease were demonstrated, with significantly higher levels of IgE (P < 0.003), IgG4 (P < 0.04) titres and eosinophil counts (P < 0.04) in the latter; in addition a tendency to an increased production of IL-5 buy lower IFN-gamma was also observed in this group. These results merit further study as they are suggestive of a putative role of Th2-like responses in susceptibility to reinfection by E. granulosus.     

Characterization of the human immunoglobulin G Fc-binding activity in Prevotella intermedia

Many pathogenic bacteria possess cell surface receptors which can bind immunoglobulins via the Fc portion. The aim of this study was to characterize the human immunoglobulin G (IgG) Fc-binding activity of Prevotella intermedia, a suspected etiologic agent of adult chronic periodontitis. The Fc-binding activity of P. intermedia on whole cells and on extracellular vesicles was demonstrated. Incubation of P. intermedia cells in the presence of Zwittergent 3-14 allowed complete solubilization of the Fc receptor from the cell surface. This cell envelope extract was thus used to characterize the Fc-binding activity. A microtiter plate assay using alkaline phosphatase-labeled Fc fragments showed that preincubation of the cell envelope extract with human IgG, human IgG Fc fragments, or human serum completely inhibited the Fc-binding activity. Partial inhibition was obtained with human IgG F(ab')2 fragments, whereas no inhibition occurred following preincubation with human IgA, carbohydrates, and selected proteins. Preincubation of the cell envelope extract with IgG from a variety of animals demonstrated that rabbit, mouse, rat, goat, and sheep IgG did not inhibit Fc-binding activity, whereas cow, pig, and dog IgG partially inhibited Fc-binding activity. A strong inhibition comparable to that obtained with human IgG was noted with monkey IgG. The Fc receptor of P. intermedia is thus different from the six types previously reported in other nonoral bacteria. Polyacrylamide gel electrophoresis and Western blotting (immunoblotting) analysis of the cell envelope extract revealed a major band with a molecular mass of approximately 65 kDa which reacted with peroxidase-labeled human IgG Fe fragments. Transmission electron microscopy showed a uniform distribution of the Fc receptor on the bacterial surface, as revealed by gold labeling. The Fc-binding activity demonstrated in this study may act as an additional virulence factor for P. intermedia by reducing IgG reactions with the bacterial cell.     

Passive sensitization of human airways induces myogenic contractile responses in vitro

We assessed effects of passive sensitization on human bronchial smooth muscle (BSM) response to mechanical stretching in vitro. Bronchial rings were sham (control) or passively sensitized overnight by using sera from donors demonstrating sensitivity to Dermatophagoides farinae and having immunoglobulin E (IgE) concentrations of 2,600 +/- 200 U/ml. Tissues were fixed isometrically to force transducers to measure responses to electrical field stimulation (EFS) and quick stretch (QS). The myogenic response to QS was normalized to the maximal response to EFS (%EFS). The myogenic response of sensitized BSM was 47.9 +/- 10.9 %EFS to a QS of approximately 6.5% optimal length (Lo); sham-sensitized tissues had a myogenic response of 13.5 +/- 6.4 %EFS (P = 0.012 vs. passively sensitized). A QS of approximately 13% Lo in sensitized BSM caused a response of 82.8 +/- 20.9 %EFS; sham-sensitized tissues developed a response of 38.2 +/- 17.3 %EFS (P = 0.004). BSM incubated with serum from nonallergic donors did not demonstrate increased QS response (4.6 +/- 1.4 %EFS, P = not significant vs. tissue exposed to atopic sera). However, tissues incubated in sera from nonatopic donors supplemented with hapten-specific chimeric IgE (JW8) demonstrated augmented myogenic response to QS of approximately 6.5% Lo (21.9 +/- 6.2 %EFS, P = 0. 027 vs. nonatopic sera alone). We demonstrate that passive sensitization of human BSM preparations causes induction and augmentation of myogenic contractions to QS; this hyperresponsiveness corresponds to the IgE concentration in sensitizing sera.     

Effect of pentachlorophenol on immune function

The organochlorine compound, pentachlorophenol, was evaluated for effects on immune system function in male Fisher 344 rats. Pentachlorophenol was prepared in an olive oil vehicle and was administered by oral gavage twice weekly for 28 days at a dose of 2.0 mg/kg per treatment. Exposure to pentachlorophenol increased body weight gains (P=0.024) during the treatment period. Liver (P=0.034) and kidney (P=0.012) body weight ratios were also increased. Pentachlorophenol exposure enhanced T-lymphocyte blastogenesis induced by concanavalin A (Con A)(P=0.0001) and phytohemagglutinin (PHA)(P=0.048) evaluated using stimulation indices. Corresponding B-lymphocyte blastogenesis induced by lipopolysaccharide/dextran (LPS/dex)(P=0.0034) was also enhanced by pentachlorophenol exposure. Pentachlorophenol suppressed the antibody response against sheep red blood cells (SRBCs) by 39% when the response was expressed per viable spleen cell (P=0.006). This suppression was not evident when the response was expressed per spleen (P=0.22), suggesting that a compensatory mechanism or extramedullary splenic hemopoiesis was occurring minimizing the overall impact on humoral immunity. The enhanced B- and T-lymphocyte blastogenesis may also reflect compensatory or hemopoietic activity. Pentachlorophenol exposure had no effect on peritoneal macrophage phagocytosis (P=0.31) or lymphocyte cell surface antigen expression. The observed alterations in lymphocyte blastogenesis and humoral immunity subsequent to pentachlorophenol exposure do not appear to be associated with phagocytosis or lymphocyte cell surface antigen expression.     

T cell responses in coinfection with Onchocerca volvulus and the human immunodeficiency virus type 1

Onchocerca volvulus and the human immunodeficiency virus (HIV) are two immunocompromising infectious agents of major public health concern in Uganda. To examine the effect of coinfection with O. volvulus and HIV on cellular immune responses, lymphocyte proliferative responses and cytokine production of peripheral blood mononuclear cells (PBMC) from persons infected with O. volvulus with and without HIV type 1 infection were compared. Proliferation of PBMC to PHA and tuberculin (PPD) in coinfection was less (P = 0.08, P < 0.01) than in O. volvulus infection. O. volvulus extract stimulated lymphocyte proliferation in microfilaria-negative and HIV-negative O. volvulus infection while only an inconspicuous response was observed in microfilaria-negative coinfection. After stimulation of PBMC with PPD, the production of interferon-gamma (IFN-gamma), interleukin (IL)-4 and IL-5-demonstrated in O. volvulus infection-were reduced in coinfection with HIV (P < 0.01). While both groups failed to produce IFN-gamma in response to O. volvulus extract, only O. volvulus infected persons generated pronounced IL-5 and low IL-4 levels (0.01 > P = 0.02). The cellular immune responses in coinfection suggested an HIV-related lack of specific reactivity to O. volvulus antigen and impairment of IL-4 and IL-5 production in addition to the lack of IFN-gamma response on antigenic stimulation.     

In vitro suppression of the normal mitogenic T lymphocyte response by steady state sickle cell disease sera

This study is part of a long term evaluation of sickle cell disease (SCD) as a paradigm for immunosuppression. Serum was obtained from 43 SCD patients during the steady (healthy) state. Peripheral blood mononuclear cells (PBMC), separated by density gradient were obtained from 8 normal healthy donors. PBMC were utilized in assays directly or as a source for obtaining, total T (CD3) and helper T (CD4) cell populations separated by specific T cell columns. Standard in vitro phytohemagglutinin (PHA) stimulation of lymphocyte cultures was done with culture media containing 10% SCD serum, as compared to normal pooled O, Rh+ (O+) serum. Mitogenic responses were expressed as mean counts per minute (cpm) and stimulation index of triplicate cultures. Results revealed PHA responses were positive in all experiments when a standard stimulation index of 10 or greater was used as a test parameter for comparison. Positive results were demonstrated in 43/43 (100%) of triplicate cultures regardless of serum type in all experiments. Conversely, by using mean cpm as the test criterion, suppression of PHA response was shown in SCD serum supplemented cells as follow; 36/43 (84%) of PBMC, 35/43 (81%) of CD3 and 37/43 (86%) of CD4 cultures. The degree of suppression ranged from > 10% to 98% in individual experiments, as compared to O+ serum. Inhibitors of normal T lymphocyte in vitro PHA response appear to be present in a significant percentage of SCD sera even during the healthy state of disease. Type 2 cytokines which suppress cell mediated immunity would seem to be the most likely inhibitory agents.     

Lymphocytes produce IL-1beta in response to Fcgamma receptor cross-linking: effects on parenchymal cell IL-8 release

Neutrophils mediate tissue injury in response to immune complexes, although the factors that induce their recruitment are incompletely understood. We have reported that lymphocytes may be important regulators of monocyte and macrophage IL-8 release in the presence of immobilized IgG. Since tissue parenchymal cells are important local producers of IL-8 but are not directly stimulated by FcgammaR cross-linking, we hypothesized that lymphocytes may also regulate parenchymal IL-8 release. Supernatants from lymphocytes incubated on immobilized IgG induced primary human fibroblasts and human mesangial cells to produce IL-8 (17 +/- 3.5 and 44 +/- 8 ng/ml, respectively). Fibroblast and mesangial cell IL-8 mRNA levels were similarly increased by the conditioned lymphocyte supernatant. Immobilized anti-human FcgammaRIII, but not FcgammaRI or FcgammaRII Abs, could stimulate this IL-8-inducing activity in lymphocytes, suggesting that FcgammaRIII-bearing lymphocytes were responsible. Supernatants from lymphocytes incubated on immobilized IgG contained 2.2 +/- 0.8 ng/ml of IL-1beta, while enriched monocyte preparations from the same donors incubated on immobilized IgG released only 0.1 +/- 0.04 ng/ml of IL-1beta (p = 0.05). Consistent with the identification of IL-1beta as the lymphocyte factor, fibroblast or mesangial cell IL-8 release induced by the IgG-stimulated lymphocyte supernatants was inhibited by 1) the combination of IL-1R antagonist and soluble type II IL-1R, 2) an IL-1-converting enzyme inhibitor, or 3) anti-IL-1beta but not preimmune Abs. These data suggest that targeted deposits of IgG can stimulate FcgammaRIII-bearing lymphocytes to produce IL-1beta, which induces parenchymal cell IL-8 release.     

Carbohydrate supplementation and the lymphocyte proliferative response to long endurance running

This randomized, double-blind, placebo-controlled study examined the influence of 6% carbohydrate ingestion on hormonal and lymphocyte proliferative responses (5 total samples over 9 hours) to 2.5 h of high-intensity running by 30 experienced marathon runners. The T-cell response differed between groups, with the placebo group exhibiting a greater increase immediately post-run and greater decrease at 3 h of recovery. No group differences were observed for Con A-, PHA-, or PWM-induced lymphocyte proliferation. However, when PHA was adjusted per T-cell, group differences were observed, highlighted by a decrease in the placebo group immediately post-run. Glucose and cortisol responses differed between groups, with glucose lower and cortisol higher in the placebo group immediately post-run. Post-run glucose correlated negatively with postrun cortisol (r=-0.670, P< 0.001) and epinephrine (r=-0.540, P=0.002). Post-run cortisol also correlated negatively with total lymphocytes and T-cells at 1.5 hours (r=-0.429, P=0.018 and r=-0.424, P=0.019, respectively) and 3 hours (r=-0.566, P=0.001 and r=-0.523, P=0.003, respectively) of recovery. The pre- to post-run change in glucose correlated to the same changes in PHA/T-cell (r=0.456, P=0.011). The data support an interactive effect of carbohydrate ingestion on plasma glucose and cortisol. The data support an interactive effect of carbohydrate ingestion on plasma glucose and cortisol, T-cell trafficking, and cell-adjusted PHA-induced lymphocyte proliferation following long endurance running.     

The antigen-binding domain of a human IgG-anti-F(ab')2 autoantibody

Recent studies revealed an immunoregulatory role of natural IgG-anti-F(ab')2 antibodies in both healthy individuals and patients with certain diseases. The implication of anti-F(ab')2 antibodies in the pathogenesis of diseases prompted us to study the gene segment structure of their antigen-binding domains and their binding characteristics. cDNA was prepared from the lymphocytes of a patient with a high IgG-anti-F(ab')2 serum titer. Variable heavy and light gene segments were amplified by PCR and inserted into a phagemid surface expression vector. Single-chain antibodies displayed on the phage surface were screened for binding to F(ab')2 fragments. The subsequent analysis of 95 single clones demonstrated that they all bound specifically to F(ab')2. Sequence analyses of 12 clones showed that 11 were identical and 1 contained a silent point mutation in the heavy chain and three amino acid exchanges in the light chain. The heavy chains belonged to the V(H)3 and the light chains to the V(kappa)2 gene family. The 11 identical light-chain genes were completely homologous to a germ-line sequence (DPK-15). Binding assays showed that the single-chain antibodies bind to F(ab')2, but not to Fab, Fc, or intact IgG. This binding pattern was confirmed by surface plasmon resonance studies, which revealed a relatively high affinity (Ka = 2.8 x 10(7) M(-1)). The strong binding capacity was further demonstrated by competitive inhibition of the serum anti-IgG antibody's interaction with antigen. The present study defines for the first time to our knowledge the gene segment structure of the antigen-binding domain of two human IgG-anti-F(ab')2 autoantibody clones and describes the binding kinetics of the purified monomeric fragments.     

Experimental seizure-induced brain damage: electrophysiological, metabolic and pathological correlation

We have studied IL-6 gene expression and production by in vitro stimulated peripheral blood mononuclear cells (PBMC) isolated from common variable immunodeficiency (CVI) patients. A strong hybridization signal for the IL-6 probe was observed in mRNA extracted from phytohaemagglutinin (PHA)- and PHA/phorbol myristate acetate (PMA)-stimulated PBMC from most of 12 CVI patients analysed. IL-6 production by PHA-stimulated PBMC from 28 CVI patients was evaluated in ELISA and found to be significantly (P < 0.0001) higher than in normal controls. IL-6 production, however, did not correlate with the lymphocyte populations examined, nor with the absolute number of monocytes. We have also showed that IL-6 was able to increase IgM secretion by several Epstein-Barr virus (EBV)-transformed cell lines derived from both normal donors and CVI patients, but it failed to modify substantially the amounts of IgM and IgG produced in vitro by PBMC derived from CVI patients and activated with pokeweed mitogen (PWM) or anti-IgM. Our data indicate that IL-6 gene expression and production is increased in CVI, but CVI cells do not respond to IL-6 with increased production of immunoglobulin.     

In vitro effects of the pyrethroid S-bioallethrin on lymphocytes and basophils from atopic and nonatopic subjects

Synthetic pyrethroids are increasingly used as insecticides and marketed as having relatively low human toxicity. The aim of this study was to examine the in vitro effects of the synthetic pyrethroid S-bioallethrin on human blood lymphocytes and basophils in atopic individuals and nonatopic control subjects. S-bioallethrin caused inhibition of lymphocyte proliferation after a 72-h culture period in a concentration-dependent manner. The inhibition of the lymphocyte proliferation by S-bioallethrin at the concentration 6.5 microM correlated well with the total serum IgE values (r = -0.89, P < 0.001). Samples from atopic subjects were more sensitive to this inhibition than those from nonatopic volunteers. The regulatory interleukin-4/interferon-gamma (JL-4/IFN-gamma) balance showed a significant difference between atopic and nonatopic subjects after a short-term culture period (24 h) in the presence of the same concentration range of S-bioallethrin (P < 0.001). Additionally, IFN-gamma secretion was consistently lower in cells from the atopic donors. Furthermore, S-bioallethrin induced histamine release from human basophils in a concentration-dependent manner. Although the effect was small compared to histamine liberators such as N-formyl-Met-Leu-Phe and anti-IgE, the response to S-bioallethrin was significantly different in atopic donors from nonatopic (P = 0.0431). These findings are the first demonstration of the immunotoxicologic properties of the synthetic pyrethroid S-bioallethrin by this combined in vitro approach with human lymphocytes and basophils. Further studies will investigate the responses of lymphocytes from patients who are sensitive to these agents.     

Influence of the specific T cell response on seroconversion after measles vaccination in autologous bone marrow transplant patients

Six patients who were seronegative to measles after autologous bone marrow transplantation (ABMT) were vaccinated with a live attenuated measles vaccine. The specific T helper cell response was studied by measuring lymphocyte proliferation induced by measles antigen and B cell response by measles specific IgG by ELISA. Blood samples were drawn before, at 1-3 months, and at 1 year after vaccination. It was found that a pre-existing T cell response correlated with an impaired B cell response 1 year after vaccination (r = 0.83, P = 0.04), whereas no correlation was found between IgG titers before vaccination and IgG titer increase, or T cell response after vaccination. Furthermore, there was a transient negative correlation between the T cell response at 1-3 months after vaccination and the T cell response before vaccination (r = -0.90, P = 0.04) that became positive at 1 year after vaccination (r = 0.90, P = 0.02). In conclusion, in patients seronegative to measles who were revaccinated with measles vaccine after ABMT, a pre-existing T cell response correlated with an impaired B cell response, while pre-existing low-level IgG antibodies had no significant influence on the IgG titer rise. A sustained T cell response to measles antigen before vaccination may thus be one possible explanation for measles vaccine failure in ABMT patients.     

Lasers in pediatric surgery

OBJECTIVE: To characterize immunologic specificity and possible antiidiotype activity of IgG anti-F(ab')2 in normal subjects as well as in patients with active and inactive systemic lupus erythematosus (SLE). METHODS: IgG anti-F(ab')2 and anti-double-stranded DNA (anti-dsDNA) were affinity isolated from immunoadsorption columns of F(ab')2 and dsDNA linked to Sepharose 4B. Affinity-purified IgG anti-F(ab')2 (APAF) and affinity-isolated IgG anti-dsDNA (APAD) were tested by enzyme-linked immunosorbent assay (ELISA) for other cross-reacting specificities including anti-Sm, anti-Sm/RNP, and anti- Crithidia binding. Anti-DNA specificity of APAF and APAD was assayed by S1 nuclease treatment of heat-denatured DNA. Rabbit antiidiotypic antisera were prepared by immunization with APAF and APAD from normal subjects and SLE patients and absorption with insolubilized human Cohn fraction II (Fr II). VL and VH regions of 5 monoclonal IgM antibodies with anti-F(ab')2/anti-DNA specificity generated by Epstein-Barr virus B cell stimulation were sequenced by polymerase chain reaction and characterized for VH and VL subgroup. APAF and APAD were also examined by high-resolution electron microscopy for possible ring forms indicative of antiidiotypic V-region interactions. RESULTS: APAF from normal subjects, representing 0.08-0.18% of serum IgG, showed striking relative concentrations of both anti-F(ab')2 and anti-DNA, as well as anti-Sm and anti-Sm/RNP ELISA reactivity. Both APAF and APAD reacting with F(ab')2 or dsDNA on the ELISA plate could be cross-inhibited by F(ab')2 or DNA in solution. Anti-DNA reactivity in normal APAF and APAD was much more sensitive to S1 nuclease treatment than similar fractions from SLE patients. Neither APAF nor APAD from controls produced positive antinuclear immunofluorescence or positive Crithidia staining, whereas these were strongly positive using SLE APAF and APAD. Absorbed rabbit antisera against normal or SLE APAF and APAD showed strong ELISA reactivity against both APAF and APAD, but no residual reactivity with normal Fr II. VL and VH sequencing of monoclonal human IgM antibodies showing both anti-F(ab')2 and anti-DNA reactivity showed relative VH3, V kappa 1 or VH1, V kappa 3 restriction. No evidence of ring forms or V-region "kissing" dimers was obtained when normal or SLE APAD or APAF was examined by high-resolution electron microscopy. CONCLUSION: IgG anti-F(ab')2 in both normal subjects and SLE patients represents a polyreactive Ig subfraction with concomitant anti-DNA, anti-Sm, and anti-Sm/RNP specificities. Anti-DNA reactivity in SLE is qualitatively different from that in normal APAD and APAF since normal APAD and APAF anti-DNA is much more sensitive to S1 nuclease digestion of denatured dsDNA. APAF and APAD share distinct V-region antigens which may be related to prominent VH3 or VH1 antigenic components. No evidence for in vivo complexing of anti-DNA and anti-F(ab')2 as ring forms or antiidiotype-IgG complexes was observed during ultrastructural studies. In both normal individuals and SLE patients, APAF may represent a small polyreactive IgG subfraction which also contains antinuclear and anti-DNA specificities.     

Inhibitory serum factor of lymphoproliferative response to allogeneic cells in pregnancy

INTRODUCTION: An inhibitory serum factor of mixed lymphocyte culture (MLC) has been associated with successful pregnancy after lymphocyte transfusion in women with unexplained recurrent spontaneous abortions (RSA). OBJECTIVE: Investigate whether the inhibitory serum factor of MLC is essential for a successful pregnancy. METHOD: Sera from 33 healthy pregnant women and from 40 women with RSA were assessed by a one-way MLC in which the woman's lymphocytes were stimulated with her partner's lymphocytes or with third party lymphocytes. RESULTS: An inhibitory serum effect (inhibition > 50% as compared to normal serum) was detected in 45% of the pregnant women who had at least 1 previous parity, in 8% of the primigravidea, in 29% of those with one abortion and in 58% of those with more than one abortion. CONCLUSION: MLC inhibitory serum factor does not seem to be an essential factor for pregnancy development. Therefore, it should not be considered as a parameter for the assessment of RSA patients.