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R D Soltis

Publications and source records attributed to R D Soltis.

At least 19 recordsLinked to original sources
PubMed1986

Further characterization of the in vitro tumoricidal activity of staphylococcal protein A.

Treatment of plasma or serum from leukemic patients with solid phase staphylococcal Protein A induced leukemic blast cell lysis in vitro, but this effect was relatively independent of the amount of immunoglobulin G (IgG) removed. Samples with approximately equal cytotoxic activity contained markedly different IgG levels, while samples with similar IgG levels had a wide range of tumoricidal activity. Assays of plasma samples collected during a perfusion of one plasma volume through a Protein A-Sepharose column indicated that the duration of the procedure had a greater effect on cytotoxic activity than did the amount of IgG removed. Neither added leukemic nor normal IgG significantly improved blast cell viability in treated serum. Cytotoxic activity was not dialyzable and concentrated in the Mr less than 100,000 fraction of samples separated by filtration. Treated cytotoxic serum samples did not have important Clq binding activity. These results suggest that the in vitro tumoricidal activity of solid phase Protein A is probably due to a toxic substance added to serum during immunoadsorption rather than to its immunoadsorptive capacity.

Antigen-Antibody Complex↗
PubMed1985

Systemic complications of inflammatory bowel disease.

Radiologic assessment of the sacroiliac joints should be part of every inflammatory bowel disease patient's workup; ankylosing spondylitis is 10 to 20 times more common in ulcerative colitis patients than in normal persons. Iritis, which occurs in 10 to 20% of ulcerative colitis patients, often precedes bowel symptoms. It may be necessary to use long-term, low-dose steroid therapy to control frequently recurring iritis.

Aged↗
PubMed1984

Acute oligoarthritis associated with Clostridium difficile pseudomembranous colitis.

The abrupt onset of a sterile inflammatory oligoarthritis developed in a patient with active Clostridium difficile pseudomembranous colitis. The arthritis affected a hip and a knee. Leukocyte counts of synovial fluid obtained from the patient's left hip and knee were elevated. He was haplotyped as HLA-B27 antigen-positive. The colitis and arthritis promptly abated after treatment with oral vancomycin hydrochloride. Three other cases of arthritis associated with antibiotic-induced colitis were reviewed. It seems as if treatment of the colitis leads to resolution of the arthritis.

Adult↗
PubMed1983

The effect of serum immunoglobulin concentration on immune complex detection by polyethylene glycol.

The addition of 4% polyethylene glycol (PEG) to serum and quantitation of immunoglobulins in the dissolved precipitate has been advocated as a simple, reliable method for detecting circulating immune complexes. Because pathological sera, which often yield positive results in this assay, may contain increased concentrations of immunoglobulins compared to normal control sera, we have determined the relationship between total serum immunoglobulin concentration and the quantity of immunoglobulins precipitated by 4% PEG. When IgG was added to normal serum, the quantity and percentage of IgG in the precipitate was directly proportional to total serum IgG concentration. This concentration-dependent precipitation appeared to be unrelated to the presence of aggregates in the IgG preparation, the serum concentration of albumin, or interactions with serum complement. With normal serum, concentrated to yield a wide range of endogenous immunoglobulin concentrations, the percentage of IgG, IgM and IgA in the PEG precipitates was likewise directly proportional to the total serum concentration of these immunoglobulins. In view of these findings, this method is likely to give false-positive results in pathological sera containing increased immunoglobulin concentrations and is probably invalid as a means for detecting circulating immune complexes. However, with a final concentration of 2% PEG, successful discrimination between aggregated immunoglobulin and monomeric IgG may be achieved.

Antigen-Antibody Complex↗
PubMed1982

Cholinergic stimulation of immunoglobulin A secretion in rat intestine.

This study was undertaken to assess a possible role for cholinergic agents in the regulation of intestinal immunoglobulin A secretion. Intestinal loops, constructed in anesthetized rats, were perfused with phosphate buffered normal saline. Immunoglobulin A concentrations were measured by radioimmunoassay. When compared with the effect of normal saline in the same rats, intravenous injection of pilocarpine, 10 mg/kg, increased immunoglobulin A concentrations in perfusates from ileal loops (p less than 0.001). Qualitatively similar results were obtained with muscarine and bethanechol, from jejunal and colonic loops, and from unanesthetized rats. Immunoglobulin A concentrations increased four- to eightfold during maximal cholinergic stimulation. Atropine, 250 micrograms intravenously, completely blocked the effect of pilocarpine on immunoglobulin A secretion (p less than 0.005), and also inhibited basal intestinal immunoglobulin A secretion for 40 min after injection. As determined on 10%-40% sucrose density gradients, much of the immunoglobulin A secreted after cholinergic stimulation sedimented in the 11S range. These data indicate that intestinal secretion of immunoglobulin A is stimulated by the muscarinic effect of cholinergic agonists, and suggest that basal secretion of immunoglobulin A may be influenced by the parasympathetic nervous system.

Anesthesia, General↗
PubMed1982

125I-C1q binding activity of soluble antigen-antibody complexes formed in vitro.

The ability of the 125I-C1q binding test to detect soluble antigen-antibody complexes formed in vitro was tested with two antigen-antibody systems. Using tetanus toxoid:anti-toxoid complexes, all of the increased 125I-C1q binding activity was due to soluble immunoglobulin aggregates present in the unheated tetanus immune globulin. Using BSA:anti-BSA complexes, maximum 125I-C1q binding activity was present in the soluble supernatants from the equivalence zone. No immune complexes were present in these supernatants and the increased activity appeared to be due to alterations in endogenous C1 during the formation of large, insoluble immune complexes. The 125I-C1q binding test readily detected large, insoluble BSA:anti-BSA complexes but may not detect small, soluble complexes which have been suggested to be important in disease pathogenesis.

Antigen-Antibody Complex↗
PubMed1982

Studies on the nature of intermolecular bonding in antigen-antibody complexes.

The formation and dissociation of BSA:anti-BSA complexes was studied under two dissociating conditions: (i) low pH, which disrupts Coulombic bonds, and (ii) low surface tension, which disrupts van der Waals bonds. Soluble complexes formed in marked (thirty-two times) antigen excess were almost totally dissociated at low pH. By contrast, complexes formed near equivalence or in the zone of antibody excess, while becoming smaller, were not dissociated at low pH. Lowering surface tension at neutral pH likewise resulted in smaller complexes but not in dissociation of antigen from antibody. Dissociation of complexes formed near equivalence or in antibody excess was achieved by simultaneously lowering pH and surface tension. These data suggest that complexes formed in marked antigen excess involve predominantly Coulombic bonding while complexes formed at other antigen:antibody ratios involve both Coulombic and van der Waals bonding.

Antigen-Antibody Complex↗
PubMed1982

Dissociation of IgG aggregates at low pH.

Previous studies have reported that antigen-antibody complexes dissociate at low pH while IgG aggregates do not, and it has been suggested that dissociation of high molecular weight IgG in serum at low pH supports the presence of circulating antigen-antibody complexes. Our studies confirm the observation that heat-aggregated IgG does not dissociate at low pH. By contrast, non-thermal IgG aggregates, formed in isolated IgG preparations or in hypoalbuminemic serum and which may also form in vivo, are almost totally dissociated at low pH. Consequently dissociation of high molecular weight IgG in serum at low pH does not distinguish antigen-antibody complexes from IgG aggregates.

Centrifugation, Density Gradient↗
PubMed1982

Spontaneous aggregation of native immunoglobulins in hypoalbuminemic serum.

We have previously demonstrated that isolated IgG, when added to buffer or serum, undergoes aggregation during incubation at 37 degrees C. The addition of albumin inhibits aggregation. The present studies were designed to determine whether endogenous immunoglobulins in normal serum, present in low-normal concentration, would likewise aggregate in the presence of hypoalbuminemia. Albumin was removed from normal serum by absorption with Affi-gel Blue. Following incubation at 37 degrees C, high molecular weight IgG, IgM and IgA were detectable by density gradient ultracentrifugation. Reconstituting the samples with albumin prior to incubation prevented the formation of immunoglobulin aggregates. These data suggest that immunoglobulin aggregation might also occur in vivo in a variety of pathological conditions associated with hypoalbuminemia and/or hypergammaglobulinemia and might be incorrectly assumed to represent antigen-antibody complexes.

Antigen-Antibody Complex↗
PubMed1979

Evidence against the presence of circulating immune complexes in chronic inflammatory bowel disease.

Several investigators have reported the presence of circulating immune complexes in serum from patients with Crohn's disease and chronic ulcerative colitis. Because previous assays employed conditions which might have caused immunoglobulin aggregates to form in vitro, thus falsely suggesting the presence of immune complexes in vivo, we tested inflammatory bowel disease sera for immune complexes using four assays designed to minimize in vitro immunoglobulin aggregation. In three assays immune complexes were not detectable, while in a fourth, the Clq precipitin test, positive reactions occurred. These precipitin reactions did not have characteristics of immune complexes. Our data suggest that circulating immune complexes are either not present in patients with inflammatory bowel disease or that they occur infrequently or in low concentration.

Antigen-Antibody Complex↗
PubMed1979

Studies on the nature of heat-labile anti-complementary activity in normal human serum.

Heat-labile anti-complementary activity (ACA) appears in normal human serum during storage or heating as endogenous haemolytic activity disappears. Following gel filtration of unheated serum, two peaks of heat-labile ACA are present. The ACA of both whole and fractionated serum has previously been attributed to the presence of heat-labile immunoglobulin aggregates or immune complexes. Our data demonstrate that the heavy peak of ACA obtained by gel filtration does not bind to 125I-C1q or to Raji cells, and that its effect is abolished to C1INH, suggesting that it represents C1 rather than immunoglobulin aggregates or immune complexes. The lighter peak of ACA in fractionated serum has the functional characteristics of C1s and free C1s is demonstrable in fractions containing this activity. The ACA of whole serum likewise has functional characteristics of C1. The anti-complementary effect of C1 on guinea-pig complement would not be evident in the complement fixation assay until most endogenous haemolytic activity in human serum has been inactivated, either by heat or by storage. C1INH only partially inhibits this ACA in serum or in solutions containing isolated C1 in high concentrations. These observations indicate that heat-labile ACA in whole or fractionated sera is due to the presence of C1 and C1s and that this activity cannot be taken as evidence for the presence of immune complexes.

Agammaglobulinemia↗
PubMed1979

The effect of heat inactivation of serum on aggregation of immunoglobulins.

Heating serum at 56 degrees is used to inactivate complement in several immunological assays. During heating, both heat-labile and heat-stable anticomplementary activity (ACA) develop. While heat-labile ACA can be completely inactivated, heat-stable ACA increases progressively with continued heating. Heat-stable ACA develops in deaggregated IgG and in normal, but not in hypogammaglobulinaemic, human and porcine serum heated at 56 degrees suggesting that this ACA is due to formation of immunoglobulin aggregates. These aggregates would produce false-positive tests for immune complexes and could inhibit a variety of cell-mediated reactions in assays which incorporate heat-inactivated serum. Other temperatures were tested to determine whether endogenous haemolytic activity could be destroyed without forming immunoglobulin aggregates. At 53 degrees both endogenous haemolytic activity and heat-labile ACA were inactivated and formation of heat-stable ACA in normal serum was minimal. ACA, however, could be induced in deaggregated IgG at 53 degrees. Moreover, the degree of heat-induced aggregation of IgG in vitro at either temperature was directly proportional to IgG concentrations and inversely related to albumin concentrations. Thus, pathological sera with these protein alterations might form more aggregates during heating than normal sera. These data suggest the following: (1) heat inactivation of complement at 53 degrees for 90 min is preferable to the traditional 56 degrees; (2) in any assay where immunoglobulin aggregates might interfere, normal serum may be an inadequate control and correlations will need to be made between serum IgG and albumin concentrations and the results obtained in these assays.

Adult↗