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J E Volanakis

Publications and source records attributed to J E Volanakis.

At least 127 records · Page 7Linked to original sources
PubMed1982

CRP-associated determinant expressed by human monocytes.

Reports of a large number of biological activities of the acute phase reactant C-reactive protein (CRP) (1,2) and its association with a variety of blood borne cells (3,4), led us to a study of the expression of CRP by human peripheral blood cells (PBL) using two kinds of CRP-reactive monoclonal antibodies. We had previously described a reaction of CRP with a monoclonal antiidiotype antibody to a murine phosphocholine (PCh) binding myeloma protein (5). Of another group of monoclonal antibodies obtained by immunizing mice with human CRP, three were shown to react with human CRP in a Ca++-dependent manner while a fourth reacted with CRP independently of calcium and binding of this antibody was also not blocked with PCh (6). Initial experiments showed that one of these site specific antibodies also reacted with a proportion of normal human peripheral blood cells. We then showed that this subpopulation included 100% of human monocytes suggesting that a CRP-like determinant exists on the surface of human monocytes but not on other lymphoid or NK cells or granulocyte populations.

Animals↗
PubMed1982

Complement-induced solubilization of C-reactive protein-pneumococcal C-polysaccharide precipitates: evidence for covalent binding of complement proteins to C-reactive protein and to pneumococcal C-polysaccharide.

Insoluble precipitates between C-reactive protein and pneumococcal C-polysaccharide were solubilized by fresh but not heat-inactivated human serum. Solubilization was dependent on the C-reactive protein to C-polysaccharide ratio and the serum concentration and proceeded optimally at 37 degrees C. On 12 to 30% sucrose density gradients solubilized complexes sedimented as a broad peak between the 7S region and the bottom of the tube. In C2-deficient human serum, solubilization was delayed by 30 min and then proceeded at a slow rate. Immunoprecipitation experiments indicated that C3, C4, C5, and to a lesser extent C1q were deposited on solubilized complexes. After dissociating solubilized complexes with EDTA, a considerable percentage of C-polysaccharide coprecipitated with C3, C4, and C5, whereas C-reactive protein coprecipitated with only C3. SDS-PAGE analysis of solubilized precipitates indicated the formation of covalent complexes between fragments of C3 and both C-polysaccharide and C-reactive protein.

C-Reactive Protein↗
PubMed1981

Cross-reactivity between C-reactive protein and idiotypic determinants on A phosphocholine-binding murine myeloma protein.

Binding of human 125I-C-reactive protein (CRP) to sheep erythrocytes sensitized with pneumococcal C polysaccharide (E-PnC) was found to be Ca++ dependent and inhibitable by phosphocholine, CRP, and HOPC 8. Binding of 125I-HOPC 8 to EPnC was Ca++ -independent but could also be inhibited by phosphocholine, CRP, and HOPC 8. Thus, CRP and HOPC 8, despite a differential Ca++ requirement, share a common binding specificity for phosphocholine. A monoclonal anti-idiotypic antibody (MAB), GB4-10, prepared in A/J mice immunized with BALB/c HOPC 8 inhibited the binding of both 125I-CRP and 125I-HOPC 8 to E-PnC. In addition, both proteins bound to GB4-10 immobilized on polysterene tubes. Interestingly, binding of 125I-CRP to GB4-10 required Ca++. Similar results were also obtained with another MAB (AB1-2) prepared similarly to GB4-10, whereas neither protein bound to a control MAB (EB3-7) against an alpha1 leads to 3 dextran-binding myeloma protein, J558. Binding of 125I-HOPC 8 to GB4-10 could be inhibited by HOPC 8, keyhole limpet hemocyanin-phosphocholine but not phosphocholine but not phosphocholine, and in the presence of Ca++ by CRP. These data indicate that CRP bears antigenic determinants cross-reacting with certain idiotypic determinants on HOPC 8. They also suggest that Ca++ acts as an allosteric effector, perhaps stabilizing the phosphocholine-binding site of CRP.

Animals↗
PubMed1981

Glomerular disease in two patients with urticaria-cutaneous vasculitis and hypocomplementemia.

We assessed the clinical, serologic, and renal abnormalities of two patients with the syndrome of hypocomplementemia, vasculitis, and urticaria. Both patients presented with recurrent urticaria and were found subsequently to have glomerulonephritis. Both manifested depletion of the early complement (C) components, and their Cl inhibitor levels were normal. Circulating immune complexes were detected by two of three assays in both patients. One patient had a high titer of Sm antibodies. The detectable immune complexes were of high molecular weight, and were more suggestive of classical lupus erythematosus than the low molecular weight (7S) Clq precipitins which characterize some cases of hypocomplementemia-vasculitis-urticaria syndrome. Biopsy of the skin lesions in both patients revealed leukocytoclastic vasculitis with immunoglobulin and C deposits at the dermal-epidermal junction. Renal biopsy specimens showed segmental or diffuse proliferative mesangial glomerulonephritis. The results suggest that patients with this syndrome do not conform to a discrete entity but rather exhibit a spectrum of diseases ranging from systemic lupus erythematosus to the syndrome of urticaria, hypocomplementemia, and low molecular weight Clq precipitins.

Adult↗
PubMed1981

Interaction of C-reactive protein with artificial phosphatidylcholine bilayers and complement.

We have examined the interaction of C-reactive protein (CRP) with model membranes and complement. Binding of CRP to multilamellar liposomes or unilamellar vesicles of egg-phosphatidylcholine required the presence of lysophosphatide in the bilayer. The binding was Ca++-dependent, could be inhibited by phosphocholine, and resulted in activation of the classical complement pathway. A weak interaction between CRP and agarose was observed, which was also CA++-dependent and could be inhibited by phosphocholine and galactose. In addition, incorporation of galactocyl cerebroside in phosphatidylcholine:lysophosphatidylcholine liposomes enhanced the binding of CRP. Binding constants of 1.9 X 10(-5) M and 7.1 X 10(-5) M were calculated for liposomes containing and lacking the glycolipid, respectively. Furthermore, CRP bound to galactocyl cerebroside-containing liposomes bound approximately twice as much C1q as the same amount of CRP bound to liposomes lacking the glycolipid. We conclude that: 1) An alteration of the normal organization of phosphatidylcholine bilayers is necessary for binding of CRP. 2) The presence of galactosyl residues on the surface of the bilayer enhances the binding of CRP, perhaps through interaction with a putative secondary binding site on the protein.

Animals↗
PubMed1981

Circulating immune complexes in carcinoma of the pancreas.

Circulating immune complexes were detected by the Clq binding assay in 45% of patients with pancreatic carcinoma. 75% of patients with primary biliary cirrhosis and 60% of patients with sclerosing cholangitis. The immune complexes present in most sera from these three groups were not reactive in the Raji cell radioimmune assay or monoclonal rheumatoid factor radioimmunoassay for soluble immune complexes. Thus, it was not possible to differentiate among these diseases on the basis of circulating immune complexes.

Adult↗
PubMed1980

Partial amino acid sequence of human factor D:homology with serine proteases.

Human factor D purified to homogeneity by a modified procedure was subjected to NH2-terminal amino acid sequence analysis by using a modified automated Beckman sequencer. We identified 48 of the first 57 NH2-terminal amino acids in a single sequencer run, using microgram quantities of factor D. The deduced amino acid sequence represents approximately 25% of the primary structure of factor D. This extended NH2-terminal amino acid sequence of factor D was compared to that of other trypsin-related serine proteases. By visual inspection, strong homologies (33--50% identity) were observed with all the serine proteases included in the comparison. Interestingly, factor D showed a higher degree of homology to serine proteases of pancreatic origin than to those of serum origin.

Amino Acid Sequence↗
PubMed1980

Immune complexes and other laboratory features of pleural effusions: a comparison of rheumatoid arthritis, systemic lupus erythematosus, and other diseases.

We have evaluated the clinical usefulness of certain diagnostic tests in consecutive patients with pleural effusions, including 12 who had rheumatoid arthritis, nine who had systemic lupus erythematosus, and 39 who had other diseases. Effusions from patients with rheumatoid arthritis and systemic lupus erythematosus differed with respect to glucose level, lactic dehydrogenase activity, and pH. Complement levels differentiated rheumatoid from control effusions but did not segregate rheumatoid from systemic lupus erythematosus. Immune complexes were detected in all the rheumatoid pleural fluids by radioassays using monoclonal rheumatoid factor, C1q, and Raji cells. In most of the fluids, these complexes were reactive in all three assay systems and their levels higher than those found in paired serum samples. In effusions from patients with systemic lupus erythematosus, however, immune complexes were detected mainly by the Raji cell radioimmunoassay, and levels by all three assays were similar to those of paired serum samples.

Adult↗
PubMed1979

Interaction of C-reactive protein with artificial phosphatidylcholine bilayers.

C-Reactive protein (CRP), the most characteristic of the 'acute phase proteins' (ref. 1) is thought to participate in the mediation and/or modulation of acute inflammatory processes, but its exact function is unknown. CRP has a Ca2+-dependent binding specificity for phosphorylcholine, the polar head group of two widely distributed lipids, lecithin (phosphatidylcholine, PC) and sphingomyelin (SM). A number of observations suggest that at least some of the biological activities of CRP depend on its interaction with phospholipids of cell membranes. In addition, interaction of CRP with PC- and SM-containing lipid dispersions and with PC-containing liposomes can activate the complement system. We report here that binding of CRP to model membranes of PC requires the incorporation into the bilayer of lysophosphatidylcholine (LPC). Thus, a disturbance of the molecular organisation of the bilayer appears to be necessary for binding of CRP. These findings provide a possible biochemical explanation for binding of CRP to damaged but not intact cell membranes and might be relevant to its biological function.

Binding Sites↗
PubMed1979

Immune complexes in rheumatoid arthritis sera and synovial fluids: a comparison of three methods.

Sera and synovial fluids from 88 patients with rheumatoid arthritis were examined for circulating immune complexes by three assays: monoclonal rheumatoid factor radioimmunoassay, C1q binding assay, and Raji cell radioassay. Paired samples were available for 82 patients. Immune complexes were detected with high frequency in the synovial fluid by each assay (75% by the monoclonal rheumatoid factor radioimmunoassay, 95% by the C1q binding assay, and 61% by the Raji cell readioassay). In rheumatoid arthritis sera, immune complexes were detected with high frequency by the C1q binding assay (85%) and the monoclonal rheumatoid factor radioimmunoassay (70%) but infrequently by the Raji cell radioassay (26%). The presence of immune complexes in serum was most frequently accompanied by the presence of complexes in fluid, regardless of the method of detection; moreover, the levels of immune complexes in synovial fluid were generally higher than in paired serum. Further, the levels of immune complexes as measured by the C1q binding assay correlated with certain parameters of clinical activity, while the monoclonal rheumatoid factor radioimmunoassay and Raji cell radioassay correlated with extraarticular features (excluding nodules) of rheumatoid arthritis.

Antigen-Antibody Complex↗
PubMed1979

Circulating immune complexes in mixed connective tissue disease.

Circulating immune complexes were measured by three assays (monoclonal rheumatoid factor radioimmunoassay, C1q-binding assay, Raji cell radioassay) in sera from patients with mixed connective tissue disease. Evidence for circulating immune complexes was found by at least one method in 94% of sera. The highest frequency of positive results was noted by the Raji cell radioassay (88%). However, a significant number of patients also had immune complexes measured by the C1q-binding assay (50%) and monoclonal rheumatoid factor radioimmunoassay (45%). Further, the levels of immune complexes are measured by the Raji cell radioassay, and to a lesser extent the C1q-binding assay, correlated with disease activity and represent a potentially useful clinical tool. The pattern of reactivity in mixed connective tissue disease sera differed from rheumatoid arthritis, scleroderma, and polymyositis. This suggests that a spectrum of immune complexes is found in these rheumatic diseases and supports the concept that mixed connective tissue disease is distinct from these diseases.

Antibodies, Antinuclear↗
PubMed1978

A search for antigen-antibody complexes in pre-eclampsia: further evidence against immunologic pathogenesis.

Circulating immune (antigen-antibody) complexes have been proposed as possible important in the pathogenesis of pre-eclampsia. Thirty-four serum samples from pre-eclamptic women were examined for the presence of antigen-antibody complexes by the C1q binding and Raji cell assays. Slightly abnormal C1q binding occurred in two serum samples, while all Raji cell determinations were found to be in the normal range for a healthy, nonpregnant population. It is concluded that circulating immune complexes do not occur regularly in pre-eclampsia.

Antigen-Antibody Complex↗