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J M Kilpatrick

Publications and source records attributed to J M Kilpatrick.

30 records · Page 2Linked to original sources
PubMed1985

Opsonic properties of C-reactive protein. Stimulation by phorbol myristate acetate enables human neutrophils to phagocytize C-reactive protein-coated cells.

We examined phagocytosis of sheep erythrocytes passively sensitized with pneumococcal C-polysaccharide (E-PnC) and of E-PnC coated with C-reactive protein (E-PnC-CRP) by human polymorphonuclear leukocytes (PMN). PMN isolated from blood of normal individuals failed to ingest either E-PnC or E-PnC-CRP; however, after stimulation with 12-O-tetradecanoylphorbol-13-acetate (PMA; 2 ng/ml), PMN ingested E-PnC-CRP efficiently with a mean phagocytic index (PI) of 99.5 +/- 4.8 (mean +/- SD, n = 11), and E-PnC to a lesser extent with a mean PI of 33.2 +/- 11.7 (mean +/- SD, n = 11). PMN that had adhered to PnC-coated glass and that were stimulated with PMA attached but did not ingest E-PnC-CRP. In contrast, PMN plated on E-PnC-CRP-coated glass and stimulated with PMA did not attach or ingest E-PnC-CRP. These data indicate that PMN can be induced to phagocytize PnC-CRP and that both PnC and CRP are required for ingestion. They also suggest that specific receptors for these ligands are expressed by stimulated PMN. Neither attachment nor phagocytosis of E coated with rabbit anti-E IgG (E-IgG) was affected by plating PMN on PnC or PnC-CRP. On the other hand, both phagocytosis and ingestion of E-PnC-CRP as well as E-IgG was blocked by plating PMA-stimulated PMN on immune complexes containing rabbit IgG. Inhibition experiments with the use of 3G8, a monoclonal antibody to the Fc gamma receptor of PMN, and human monomeric IgG1 demonstrated that attachment of E-PnC-CRP is mediated by receptors other than the Fc gamma receptors. These combined results indicated a nonreciprocal association between the putative CRP receptors and the Fc gamma receptors of stimulated PMN, resulting in the clearance of both types of receptors from the apical surface of PMN by antigen-immobilized rabbit IgG.

Animals↗
PubMed1985

Solid-phase enzymoimmunoassay of antitetanus toxoid antibodies.

A solid-phase enzymoimmunoassay (EIA) for antitetanus toxoid antibodies has been developed using activated agarose beads as the solid phase to which tetanus toxoid was covalently attached. The resulting EIA proved to be remarkably free of interference due to nonspecific absorption of reactants to the solid phase. The lower limit of detection for the assay was 0.008 U/ml of antibody. Reproducibility studies showed a satisfactory degree of consistency with coefficients of variation of 4.8% (within run) and 6.6% (run-to-run). This assay has been applied successfully to the evaluation of the humoral response to tetanus toxoid in both normal and immunocompromised individuals and it has sufficient sensitivity to determine serum levels of antitetanus antibody above the accepted protective limit of 0.01 U/ml.

Adolescent↗
PubMed1985

Validation of the PEG-IgG screening test for soluble immune complexes by longitudinal studies in experimental acute serum sickness.

A wide variety of tests for the detection of circulating immune complexes (IC) has been proposed by different authors, but there is very little to no information concerning the performance of IC screening assays in samples known to contain in vivo-formed IC. The purpose of our investigation was to compare the behavior of a non-specific assay, the PEG-IgG screening test for IC, with an antigen-specific assay in serum samples sequentially obtained from rabbits to which we induced acute serum sickness. Five animals were used in the study; we were able to detect an increase of IC constituted by the heterologous antigen (human serum albumin) and corresponding antibodies in all, and in 4 animals the results of the PEG-IgG assay closely correlated with the results of the antigen-specific assay (rho values between 0.975 and 1.00). The 4 animals in which IC showed a definite peak by both assays developed proteinuria and IC deposits at the glomerular level, while the animal that failed to develop IC detectable by the PEG-IgG test remained normal throughout the study. These results demonstrate the ability of the PEG-IgG test to detect in vivo-formed IC and suggest that the IC detected by this test have pathogenic potential.

Acute Disease↗
PubMed1983

Localization of the phosphocholine-binding sites on C-reactive protein by immunoelectron microscopy.

C-reactive protein (CRP) was reacted with monoclonal IgG antibody or Fab antibody fragments directed against the phosphocholine- (PC) binding site or a second unrelated site. The resulting immune complexes were viewed by a negative stain immunoelectron microscopy technique. Monoclonal anti-PC-binding site antibody bound to a single epitope on each of the five CRP subunits. The orientation of the PC-binding sites was determined to be slightly medial to one of the planar faces (A-face) of the molecule. The second monoclonal antibody, which was not PC-binding site related, bound to epitopes (one per CRP subunit) that were located slightly lateral to the other planar face (B-face) of the CRP molecule, i.e., opposite of the PC-binding site. Thus, the PC-binding site and the non-PC-binding site are oriented nearly perpendicular but on opposite sides with respect to the plane of the CRP molecule. The functional significance of this configuration is discussed.

Animals↗
PubMed1983

Statistical analysis of five immune complex screening assays: patterns of detection in patients with rheumatoid arthritis, systemic lupus erythematosus, infectious endocarditis, and diabetes mellitus.

A comparative study of four nonspecific screening techniques (direct nephelometry, PEG-C4, PEG-IgG, and radiolabeled Clq binding) for immune complexes (IC) and of a technique specific for the detection of insulin-anti-insulin IC was undertaken in four groups of patients with diagnosis of infectious endocarditis, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and diabetes. The highest frequency of positive results was given by the PEG-IgG test in RA, the Clq-binding test in SLE, the insulin-anti-insulin IC screening test in diabetes, and the PEG-IgG and Clq-binding tests in infectious endocarditis. Of the four nonspecific tests, the PEG-C4 assay appeared to be the least discriminative, since it failed to show significant differences between any group of patients and the group of controls. Direct nephelometry, PEG-IgG, and radiolabeled Clq binding gave consistently higher results in RA than in other diseases, and in this disease the rates of agreement between these tests were highly significant. Significant agreements between the rates of positivity of Clq binding and PEG-IgG tests were seen in all groups of patients studied. Spearman's analysis of rank showed the best correlations among tests based on similar principles (ie, PEG precipitation), and also a strong correlation between Clq binding and the PEG-IgG test in RA. The PEG-IgG test appears to be a reliable IC screening test for general use with the advantage of not involving radioisotopes. In regard to antigen-specific tests, although their specificity and sensitivity may be high, their results may show no correlation with nonspecific screening tests nor with the presence or absence of clinical or laboratory abnormalities suggestive of IC deposition, as exemplified by the insulin-anti-insulin IC screening test in diabetic patients.

Antigen-Antibody Complex↗
PubMed1982

Demonstration of calcium-induced conformational change(s) in C-reactive protein by using monoclonal antibodies.

Three out of four anti-C-reactive protein monoclonal antibodies [HB3-2, (micro, k)], EA4-1 (gamma 2a, k) and FB2-1 (gamma 1, k) bind to C-reactive protein in the presence of 2.5 mM Ca2+ but not in the presence of 1.0 mM EDTA, indicating that the conformation of the antigenic determinant(s) recognized by these three antibodies is dependent upon Ca2+. This Ca2+-dependent binding can be inhibited by 1.0 mM phosphocholine, indicating that this antigenic determinant is at or near the phosphocholine-binding site of C-reactive protein. The binding of the fourth monoclonal antibody [HD2-4 (gamma 2-k)] is independent of the presence of Ca2+ and is not inhibited by phosphocholine. HB3-2 (micro, k) recognizes an antigenic determinant on the structurally related proteins, rabbit CRP and serum amyloid P.

Antibodies, Monoclonal↗
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

Development of a single numerical expression for the results of multiple screening tests for immune complexes in diabetic patients: use in statistical comparison of clinically and biochemically defined patient populations.

A series of 88 diabetic patients were studied for the presence of soluble immune complexes, proteinuria, microangiopathy, and diabetic complications. Results of the five different assays for immune complexes were analyzed individually, and four combinations of the individual results (i.e. four different immune complex "scores") were also analyzed. The only assay which consistently discriminated between the different patient groups was the PEG-IgG test, in which a ratio between the amount of IgG precipitated with 3% PEG 6000 and the serum concentration of IgG is determined. In contrast, all four of the immune complex "scores" detected significant differences between patients with and without the clinical or biochemical parameter in question. One combination, designated as the "weighted and corrected IC score", gave a particularly high probability of detecting differences between groups. These results indicate that proper compilation of the results of a battery of immune complex screening assays can provide definite advantages over the results of individual tests for the investigation of correlations between the presence of soluble immune complexes and the course and pathology of various diseases.

Analysis of Variance↗
PubMed1981

Plasma factors and platelet aggregation in diabetes mellitus.

Plasma fron some diabetic patients, particularly those with advanced retinopathy and nephropathy, will potentiate ADP-induced platelet aggregation. Partial purification of plasma from a diabetic patient with nephropathy has yielded a fraction with this activity. A linea dose response curve relating plasma factor (6.25-50 ng protein) and platelet aggregation or ATP release at 4 minutes after adding ADP has been found. The effect is blocked by exposure of platelets to aspirin, prostaglandin or eicosapentaenoic acid. Soluble immune complexes are found in many diabetics and are known to be platelet-active. We have isolated immune complexes from sera of six diabetics and have shown enhancement of the second phase of platelet aggregation and of ATP release by these immune complexes from platelets sensitized to ADP. We conclude that plasma proteins from diabetics may accentuate ADP-induced platelet aggregation and ATP release, possibly by acting through prostaglandin pathways. Immune complexes appear to be one group of plasma proteins with such platelet active behavior. Further studies are indicated to characterize these plasma factors and to assess their in vivo significance regarding platelet function and vascular disease in diabetes mellitus.

Antigen-Antibody Complex↗
PubMedDate not supplied

The role of circulating immune complexes in the pathogenesis of diabetes mellitus.

We have studied soluble immune complexes (IC) in the sera of both insulin-dependent and non-insulin-dependent diabetics by a variety of non-specific techniques and also by a method that detects specifically insulin-anti-insulin IC. Our screening studies, detailed in the first section of this work, showed that insulin-anti-insulin IC appear not to be the only type of IC present in diabetics. Non-specific screening tests gave practically identical percentages of positive results in insulin-dependent and non-insulin-dependent diabetics. However, the agreement between different screening tests was poor. We propose the use of 'IC scores' (numerical expressions of the general trend of several screening tests performed with one given serum sample) for the statistical analysis of correlations between the presence of soluble IC and clinical evidence of diabetic microangiopathy. As expected, the use of 'scores' minimized false positive or negatives and considerably enhanced statistical correlations between levels of IC and proteinuria, nephropathy, retinopathy, peripheral neuropathy, and peripheral vasculopathy. The second section of this report describes our isolation studies, which provided definitive proof for the existence of soluble insulin-anti-insulin IC and allowed us to carry out the first successful studies of the biological properties of soluble IC purified from the sera of diabetic patients, as detailed in the third section of this report. Such IC-induced platelet aggregation and activation which in vivo could lead to the development of microvascular lesions could explain, at least in part, the abnormalities in platelet function seen in diabetics. Although the precise mechanisms by which soluble IC could induce pathological damage in diabetics have not been totally clarified, we have obtained sufficient evidence to prove that antigen-antibody complexes exist in diabetics, are associated with higher frequencies of complications, and have the capacity to interact with cells in a potentially pathogenic fashion.

Antigen-Antibody Complex↗