Citations

Abstract A double-antibody radioimmunoassay (RIA) was developed to measure the protein comprising the human eosinophil Charcot-Leyden crystal (CLC). Critical requirements in the development of this assay were the production of large quantities of pure CLC, the solubilization of CLC at neutral pH, and an assessment of the purity of the CLC protein. CLC were prepared from eosinophil-rich leukocyte suspensions by homogenization of cells in hypotonic-buffered saline. Centrifuged eosinophil extracts formed CLC spontaneously at 4°C, but the yield of crystals was significantly augmented by slow freezing of extracts to −20°C and thawing. Lyophilization of crystals was required to obtain material soluble at neutral pH. Soluble CLC protein produced 3 dense bands on polyacrylamide gel electrophoresis (PAGE) at pH 8.9, and these bands gave reactions of identity in immunodiffusion analyses with rabbit anti-CLC antibody. PAGE in 1% sodium dodecyl sulfate revealed a single protein band of 13,000 daltons. Isoelectric focusing of soluble CLC protein yielded 2 major and 4 minor bands with pI’s between 5.7 and 5.1, indicating the slightly acidic nature of the CLC protein. In the RIA, CLC levels were measured by inhibition of the binding of 131I-CLC reacted with specific rabbit anti-CLC antibody. Burro anti-rabbit IgG was used as the second antibody to precipitate immune complexes. The maximum precipitability of 1 ng 131I-CLC by antibody was 97%; the RIA was sensitive to 0.25 ng. CLC protein is immunologically distinct from human eosinophil major basic protein as determined by RIA and Ouchterlony analysis. Serum levels of CLC for 10 normal healthy subjects averaged 37 ± 4.7 ng/ml compared with 8507 ± 2494 ng/ml for 10 patients with diseases associated with a peripheral blood eosinophilia greater than 30%. The RIA for CLC protein provides us with a tool to investigate the biological function(s) of this protein and the role of eosinophils in certain disease states.

Abstract We previously found that sera of patients immunized with ragweed pollen extract contained a factor that interfered with the binding of IgE antibodies to solid-phase allergens in the radioallergosorbent test (RAST). We now describe an assay, RAST interference, to measure this factor, and we present evidence that the factor is IgG blocking antibody. Sera from immunized allergic patients were heated at 56 degrees C for 4 hr to destroy heat-labile Fc determinants on IgE and were tested for their ability to prevent binding of additional IgE antibody to solid-phase allergens in the RAST. Eight of 10 sera from allergic immunized patients gave RAST interference dose-response curves that did not differ from the arbitrary standard. The factor causing interference showed specificity for the immunizing antigen, was heat-stable, eluted from Sephadex G-200 in the 7S peak, was present only in sera of immunized patients, and rose after initiation of immunization. These results indicated that RAST interference can be used to measure IgG blocking antibodies with the same reagents employed for the measurement of IgE antibodies, provided the antiserum to IgE is specific for the heat-labile FC determinants on IgE.

Abstract Eosinophilia is a common sequela of treatment in patients infected with the parasitic helminth Wuchereria bancrofti. We investigated the relationship between peripheral blood eosinophil levels and serum levels of eosinophil granule major basic protein (MBP) and Charcot-Leyden crystal (CLC) protein in 37 patients with Bancroft’s filariasis who were treated with diethylcarbamazine (DEC). Before treatment with DEC, eosinophil levels and serum levels of CLC protein, but not MBP, were found to be significantly elevated in both filariasis patients and an uninfected endemic control population. After treatment, patients with microfilaremia developed an initial eosinopenia followed by significant increases in their eosinophil levels and serum levels of both MBP and CLC protein, which peaked 1 to 2 wk after initiating treatment. Before treatment, eosinophil levels and serum levels of MBP and CLC protein were unrelated to the number of microfilariae in circulation, but after treatment, the degree of eosinophilia and the elevations in serum MBP and CLC protein were significantly correlated with the patients’ microfilarial worm burdens before treatment. In microfilaremic patients on DEC therapy, there was a statistically significant increase in serum MBP levels concomitant with the initial decrease in eosinophil levels observed on day 1 of therapy in these patients. Patients with filariasis (elephantiasis, hydrocoeles, or filarial fevers) but without microfilaremia, as well as an uninfected endemic control population, showed no change in their eosinophil levels or serum MBP or CLC protein levels during an identical course of DEC therapy. The eosinophilic response resulting from DEC therapy of patients with microfilaremia provides a unique opportunity to study the relationship between eosinophilia, eosinophil function, and possibly eosinophilopoiesis as reflected by the synthesis and/or release of eosinophil proteins in humans exposed to a quantifiable antigenic stimulus.

Abstract The discovery of immunoglobulin E (IgE) (1) has contributed significantly to the understanding of hypersensitivity reactions mediated by reaginic antibody (2) and has led to the development of new diagnostic procedures in the field of allergology (3, 4). Recent studies have demonstrated the production of IgE protein by peripheral blood lymphocytes in vitro and have examined the kinetics and pharmacologic control of IgE biosynthesis (5, 6). The purpose of this communication is to describe our observation of in vitro production of IgE protein and antigen-specific IgE antibodies by peripheral blood mononuclear cells obtained from atopic and nonatopic individuals. A modification of the lymphocyte culture method of Waldmann et al. (7) was used in our studies. Blood, 60 ml, was obtained from 11 patients, eight of whom are atopic (geometric mean serum IgE, 247 ng/ml; range 61 to 1079) and three of whom are nonatopic (geometric mean serum IgE, 96 ng/ml; range 73 to 143).

Abstract A double antibody radioimmunoassay (RIA) was developed to measure IgD in serum and secretions. One IgD myeloma protein was used as radiolabeled antigen and standard with antiserum to a second IgD myeloma protein. The IgD standard and normal sera yielded parallel inhibition curves in the RIA and inhibition was produced by IgD and not by any of the other immunoglobulins. The assay had a lower limit of sensitivity of 0.01 International Unit (I.U.)/ml and modifications increased the sensitivity to 0.0008 I.U./ml. Measurable IgD levels were found in all 112 normal adult sera assayed (geometric mean 13.0 I.U./ml, arithmetic mean 30.1 I.U./ml, median 14.8 I.U./ml, range 0.10 to 202 I.U./ml, 95% of values between 0.19 and 156 I.U./ml. The distribution of IgD in the 112 normal sera appeared trimodal with modes at approximately 0.25 I.U./ml, 5 I.U./ml, and 35 I.U./ml. IgD was measurable in nasal and bronchial washes and human milk, but could not be detected in parotid fluid.

Abstract We compared the quantities and avidities of IgE and IgG antibodies from three phospholipase-A (PLA) sensitive patients during honeybee venom immunotherapy. IgG antibody was purified by affinity chromatography through a Sepharose anti-IgE Column followed by ionexchange chromatography on DEAE Sephadex. IgE antibody was obtained by elution from the Sepharose anti-IgE column with 4 M guanidinium HCl and by passage of the eluate over Sepharose anti-IgG. Absolute amounts of IgE and IgG antibody to PLA were determined by immunoabsorption and radioimmunoprecipitation, respectively. IgE antibody to PLA accounted for 25.1% to 28.7% (X̄ = 27.0%) of the total IgE protein; IgG antibody accounted for 0.073% to 0.210% (X̄ = 0.130%) of the total IgG protein. The relative avidities of IgE and IgG antibodies were assessed by the ability of equimolar amounts to bind radioiodinated PLA. In two patients, avidities of IgE and IgG antibody for PLA were comparble, whereas in the third, IgG antibody bound PLA more avidly than IgE antibody. The valence of IgE antibody was greater than 1.9, assuming that PLA behaved as a univalent ligand in extreme antigen excess. IgG antibody was able to inhibit binding of IgE antibody in the PLA radioallergosorbent test (RAST) from 10% to 40% at a molar excess of 10- to 1000-fold. The results indicate that: 1) IgE antibody to PLA accounts for a high percentage of total IgE protein; 2) the avidities of IgE and IgG antibodies are similar (two of three patients); 3) the valence of IgE antibody approaches two; and (4) IgG antibody can interfere with the measurement of IgE antibody in the PLA RAST.

Summary The eosinophil major basic protein (MBP) damages cells including those from organs whose dysfunction is associated with eosinophil infiltration. Concentrations of MBP in the toxic range were found in sputa from asthmatics, in pleural fluid and in sera. These findings suggest the hypothesis that the eosinophil produces damage to cells in disease.

Abstract Although the eosinophil has been recognized as a distinctive cell type for almost 100 years, the major functions of these cells remain unknown. As an approach to defining these functions we have treated guinea pigs with rabbit antiserum to eosinophils (AES) in an attempt to ablate these cells from tissues. Rabbits were immunized thrice with purified eosinophils and the antisera were absorbed with peripheral blood cells from guinea pigs made eosinopenic with methyprednisolone to remove antibodies reactive with serum proteins and erythrocytes. The resulting sera reacted strongly with eosinophils in cytotoxicity tests and had weak or no reactivity with neutrophils. However, absorption of AES with purified neutrophils removed anti-eosinophil activity. Intraperitoneal injection of potent AES into guinea pigs resulted in complete absence of eosinophils from the peripheral blood and from the peritoneal cavity with only transient or no reduction in circulating neutrophils. Eosinophils were also reduced in bone marrow, spleen, and intestine. The ability of neutrophils to absorb AES activity in spite of weak reactivity in cytotoxicity tests may reflect a quantitative difference in antigenic determinants between eosinophils and neutrophils.

Abstract An anti-γM serum which distinguishes between 19SγM and a low-molecularweight γM from human serum (γMs-N) was prepared by immunizing a goat with normal human γM in Freund's complete adjuvant; it was absorbed with γG and hypogammaglobulinemic serum and was specific for γM. The reactivity of this antiserum was examined with 19SγM, with the γM monomer produced by reduction and alkylation (γMs-RA), and with the γM monomer prepared by reduction alone (γMs-R). In agar double diffusion the 19SγM band spurred over the bands formed by γMs-RA and γMs-R whereas the bands formed by γM monomers fused. Mixtures of 19SγM and γMs-RA formed concentric zones of precipitation in radial immunodiffusion and produced two bands in agar double diffusion. By quantitative precipitin analysis, with 19SγM the antiserum contained 30 µg Ab N/0.1 ml serum and with γMs-RA, 19 µg Ab N/0.1 ml. After absorption at equivalence with γMs-RA the antiserum still precipitated with 19SγM and Fc-γM but did not precipitate with Fab-γM. The precipitin reaction between 19SγM and the anti-γM serum absorbed with γMs-RA was inhibited by three γM subunits (γMs-RA, γMs-R, and γMs-N). Thus, the antiserum is reactive with an antigenic determinant on the Fc portion of the µ chain present on both 19SγM and the γM subunits. The difference in the reactivity of the antiserum with 19SγM and the γM subunits may be related to the number of specific antigenic determinants on these molecules.

Summary A naturally occurring low molecular weight γM protein (γMN) was isolated from the serum of a patient with type I dysgammaglobulinemia by preparative electrophoresis and gel filtration. This protein was compared to the macroglobulin (γM19) isolated from the patient’s serum and to the γM subunit (γMS) prepared by reduction and alkylation of γM19. The results indicate that γMN and γMS are similar in size and have the same antigenic determinants. These observations support the concept that the γMN is a naturally occurring subunit of γM19 and is very similar to γMS, γM19, γMN and γMS were also prepared from the patient’s serum after tetanus immunization and were found to bind radiolabeled tetanus toxoid. Most, but not all, controls did not show nonspecific binding of tetanus toxoid. These results suggest but do not conclusively establish the capacity of these γM proteins to bind antigen specifically.