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T McNally

Publications and source records attributed to T McNally.

At least 19 recordsLinked to original sources
PubMed2003

Eosinophil activation and preschool viral wheeze.

BACKGROUND: A study was undertaken to ascertain whether systemic eosinophil activation is associated with preschool viral wheeze (PVW). METHODS: Urinary eosinophil protein X (uEPX) and serum total IgE (IgE) levels were measured in children admitted to hospital with PVW, and uEPX was measured 6 weeks after discharge. Two years after admission, current wheeze in children aged > or =5 years was determined by questionnaire. Controls were recruited from children undergoing elective surgery (normal controls) and from those with skin prick test reactivity to foods (atopic controls). RESULTS: There was no difference in uEPX levels between normal controls (n=15) and atopic controls (n=8). uEPX levels were increased in children with acute PVW (n=84; p<0.001 v normal controls, p<0.01 v atopic controls) and fell on convalescence (n=20, 95% CI -217 to -31 microg/mmol creatinine, p<0.05). In children with acute PVW there was no association between uEPX and serum IgE levels or markers of clinical severity. Respiratory questionnaires were returned for 25/55 eligible children. There was no difference in uEPX level during acute PVW when stratified by "current wheeze" (n=18) or "no wheeze" (n=7) 2 years later. CONCLUSIONS: Systemic eosinophil activation is associated with PVW but is not associated with serum IgE, clinical severity, or persistence of wheeze into the early school age period.

Child, Preschool↗
PubMed2001

Regulation of P-selectin binding to the neutrophil P-selectin counter-receptor P-selectin glycoprotein ligand-1 by neutrophil elastase and cathepsin G.

In the inflammatory response, leukocyte rolling before adhesion and transmigration through the blood vessel wall is mediated by specific cell surface adhesion receptors. Neutrophil rolling involves the interaction of P-selectin expressed on activated endothelium and its counter-receptor on neutrophils, P-selectin glycoprotein ligand-1 (PSGL-1). Here, it is reported that P-selectin binding to neutrophils is lost under conditions that cause the release of proteinases from neutrophil primary granules. Treatment of neutrophils with the purified neutrophil granule proteinases, cathepsin G and elastase, rapidly abolished their capacity to bind P-selectin. This inactivation corresponded to loss of the N-terminal domain of PSGL-1, as assessed by Western blot analysis. A loss of intact PSGL-1 protein from the surfaces of neutrophils after the induction of degranulation was also detected by Western blot analysis. Cathepsin G initially cleaved near the PSGL-1 N-terminus, whereas neutrophil elastase predominantly cleaved at a more C-terminal site within the protein mucin core. Consistent with this, cathepsin G cleaved a synthetic peptide based on the PSGL-1 N-terminus between Tyr-7/Leu-8. Under conditions producing neutrophil degranulation in incubations containing mixtures of platelets and neutrophils, the loss of PSGL-1, but not P-selectin, from platelet-neutrophil lysates was detected. Cathepsin G- or neutrophil elastase-mediated PSGL-1 proteolysis may constitute a potential autocrine mechanism for down-regulation of neutrophil adhesion to P-selectin.

Amino Acid Sequence↗
PubMed2000

Molecular characterization of human SUR2-containing K(ATP) channels.

The distribution of human sulfonylurea receptor-2 (SUR2)-containing K(ATP) channels was investigated using reverse transcriptase-polymerase chain reaction (RT-PCR). mRNA for SUR2B was detected in a variety of tissues including brain, skeletal, cardiac and smooth muscle, whereas SUR2A message was restricted to cardiac and skeletal muscle. An additional splice variant of SUR2 that lacked exon 17 was also identified by RT-PCR in tissues expressing both SUR2A and SUR2B or SUR2B alone. Quantification of RNA for SUR2 exon 17+ and SUR2 exon 17- splice variants using real-time Taqman PCR indicated differential levels of expression in brain, kidney, skeletal muscle, heart and small intestine. Interestingly, the SUR2 exon 17+ variant is the major species expressed in all tissues examined in this study. Each of the SUR2 splice variants transiently expressed with the inward rectifier Kir 6.2 formed functional K(ATP) channels in HEK 293 cells as assessed either by changes in DiBAC(4)(3) fluorescence responses or glyburide-sensitive whole cell currents. Collectively, our findings demonstrate that various SUR2 splice variants have distinct expression patterns and can form functional K(ATP) channels.

ATP-Binding Cassette Transporters↗
PubMed2000

Structure and function of the von Willebrand factor A1 domain: analysis with monoclonal antibodies reveals distinct binding sites involved in recognition of the platelet membrane glycoprotein Ib-IX-V complex and ristocetin-dependent activation.

Binding of the adhesive glycoprotein, von Willebrand factor (vWf), to the platelet membrane glycoprotein (GP) Ib-IX-V complex initiates platelet adhesion and aggregation at high shear stress in hemostasis and thrombosis. In this study, the GP Ib-IX-V binding site within the vWf A1 domain was analyzed using a panel of murine monoclonal antibodies raised against a 39/34-kd vWf fragment (Leu-480/Val-481-Gly-718) encompassing the A1 domain. One antibody, 6G1, strongly inhibited ristocetin-dependent vWf binding to platelets, but had no effect on botrocetin- or jaracetin-dependent binding, or asialo-vWf-dependent platelet aggregation. The 6G1 epitope was mapped to Glu-700-Asp-709, confirming the importance of this region for modulation of vWf by ristocetin. Like ristocetin, 6G1 activated the vWf A1 domain, because it enhanced binding of the 39/34-kd fragment to platelets. In contrast, 5D2 and CR1 completely inhibited asialo-vWf-induced platelet aggregation and ristocetin-induced vWf binding to GP Ib-IX-V. However, only 5D2 blocked botrocetin- and jaracetin-induced vWf binding to platelets and binding of vWf to botrocetin- and jaracetin-coated beads. Epitopes for 5D2 and CR1 were conformationally dependent, but not congruent. Other antibodies mapped to epitopes within the A1 domain (CR2 and CR15, Leu-494-Leu-512; CR2, Phe-536-Ala-554; CR3, Arg-578-Glu-596; CR11 and CR15, Ala-564-Ser-582) were not functional, identifying regions of the vWf A1 domain not directly involved in vWf-GP Ib-IX-V interaction. The combined results provide evidence that the proline-rich sequence Glu-700-Asp-709 constitutes a regulatory site for ristocetin, and that ristocetin and botrocetin induce, at least in part, separate receptor-recognition sites on vWf. (Blood. 2000;95:164-172)

Amino Acid Sequence↗
PubMed2000

In vitro biomechanical evaluation of the double loop suture for flexor tendon repair.

Fifty-one fresh frozen human anatomic specimen flexor superficialis and profundus tendons that had been transected completely were repaired using the double loop, the single loop, and the modified Kessler techniques, and the resistances to mechanical distraction at 1, 2, and 3 mm and the ultimate load to failure were compared. The mechanical distraction at 1, 2, and 3 mm created nearly identical gaps at the tendon repair sites. There was no significant difference among the three repair techniques to resisting distraction at 1 and 2 mm. However, the double loop technique presented a mean resistance force of 22.0 N to distraction at 3 mm and 45.8 N in load to failure, which was significantly greater than the single loop (18.8 N at 3 mm distraction and 31.5 N failure load) and the modified Kessler (19.0 N at 3 mm distraction and 26.0 N failure load). This suggests the double loop technique may be superior to the single loop and the modified Kessler techniques in resisting gap in the range of forces generated in the early rehabilitation protocol.

Biomechanical Phenomena↗
PubMed1998

Binding of purified 14-3-3 zeta signaling protein to discrete amino acid sequences within the cytoplasmic domain of the platelet membrane glycoprotein Ib-IX-V complex.

The glycoprotein (GP) Ib-IX-V complex constitutively expressed on the platelet plasma membrane mediates initial adhesion of circulating platelets to vessel wall matrix at high shear, and shear-induced platelet aggregation. In both cases, this involves binding of GP Ib-IX-V to the adhesive glycoprotein, von Willebrand Factor (vWF). vWF binding to GP Ib-IX-V rapidly induces platelet activation, leading to cytoskeletal rearrangement, shape change, and secretion that enables alphaIIbbeta3 integrin (GP IIb-IIIa)-dependent platelet aggregation. All these events are critical in (patho)physiological thrombus formation. The recent discovery that the signaling protein, 14-3-3 zeta, copurifies with the GP Ib-IX complex (minus GP V) [Du, X., Harris, S. J., Tetaz, T. J., Ginsberg, M. H., & Berndt, M. C. (1994) J. Biol. Chem. 269, 18287-18290] indicated a potential mechanism for vWF-dependent signaling. The aim of the present study was to identify discrete amino acid sequences that bind 14-3-3 zeta within the cytoplasmic domain of the receptor. As an initial screening assay, overlapping synthetic peptides based on the cytoplasmic domains of GP Ibalpha (100 residues), GP Ibbeta (34 residues), GP IX (5 residues), and GP V (16 residues) were immobilized and assessed for the ability to bind purified 14-3-3 zeta. The C-terminal sequence GHSL of GP Ibalpha was identified as one 14-3-3 zeta interactive sequence, consistent with previous results [Du, X., Fox, J. E., & Pei, S. (1996) J. Biol. Chem. 271, 7362-7367]. Binding of 125I-labeled 14-3-3 zeta to GHSL-containing peptides was inhibitable by unlabeled 14-3-3 zeta and by anti-14-3-3 zeta IgG. Ala-walking through the GHSL sequence suggested all residues were necessary for optimal binding. In addition, 14-3-3 zeta bound with lower affinity to a peptide based on the central region of the GP Ibalpha cytoplasmic domain (Arg-557-Gly-575), whereas peptide sequences within the cytoplasmic domains of GP Ibbeta (Arg-160-Arg-175) and GP V (Lys-529-Gly-544) bound 14-3-3 zeta with comparable affinity to the GHSL-containing peptide. Soluble GHSL-containing peptides, GP Ibbeta- and GP V-based peptides semidissociated 14-3-3 zeta from GP Ib-IX-V or GP Ib-IX in platelet extracts as analyzed by immunoprecipitation, suggesting these sequences, at least partially, mediate the GP Ib-IX-V-14-3-3 zeta interaction in cells. Further, phosphorylation of the GP Ibbeta peptide at a site corresponding to a protein kinase A phosphorylation site (Ser-166) enhanced the affinity of 14-3-3 zeta binding by approximately 8-fold, suggesting phosphorylation as a potential mechanism for regulating 14-3-3 zeta association with the GP Ib-IX-V complex.

14-3-3 Proteins↗
PubMed1997

Cloning and expression of the adenosine kinase gene from rat and human tissues.

Adenosine kinase is ubiquitous in eukaryotes and is a key enzyme in the regulation of the intracellular levels of adenosine, an important physiological effector of many cells and tissues. In this paper we report the cloning of cDNAs encoding adenosine kinase from both rat and human tissues. Two distinct forms of adenosine kinase mRNA were identified in human tissues. Sequence variation between the two forms is restricted to the extreme 5'-end of the adenosine kinase mRNA, including a portion of the coding region, and is consistent with differential splicing of a single transcriptional product. We have expressed both forms in E. coli and produced soluble active enzyme which catalyzes the phosphorylation of adenosine with high specific activity in vitro and is susceptible to known adenosine kinase inhibitors.

Adenosine Kinase↗
PubMed1997

The production, binding characteristics and sequence analysis of four human IgG monoclonal antiphospholipid antibodies.

Antiphospholid antibodies (APL) have a notable association with recurrent miscarriages, arterial and venous thrombosis and thrombocytopenia. Analysis of the potential pathogenic effects of such human antibodies has been hampered by the considerable difficulty in producing IgG as opposed to IgM monoclonal immunoglobulins. We have developed four human monoclonal IgG APL (LJ1, AH2, DA3 and UK4) by fusing the peripheral blood lymphocytes of three patients with SLE with a mouse human heteromyeloma cell line, CB-F7. These antibodies bind to a variety of anionic phospholipids, two (LJ1 and AH2) bind total histones but none binds to ssDNA or dsDNA. Binding to beta 2 GPI is non-specific. UK4 alone demonstrates lupus anticoagulant activity. All four have lambda light chains, two are IgG1 (AH2 and UK4) and two are IgG3 (LJ1 and DA3). These APL utilize VH genes present in the fetally restricted repertoire and multiple somatic mutations in the CDR suggest an antigen-driven process. In contrast, there is no restriction in V lambda gene usage and only one lambda chain is extensively mutated. Two clonally related hybridomas were isolated from a single patients. This supports the theory that clonal expansion is the mechanism whereby antigen selects high affinity mutations.

Amino Acid Sequence↗
PubMed1997

Interactions between HIV and hepatitis B virus in homosexual men: effects on the natural history of infection.

OBJECTIVES: Hepatitis B virus (HBV) and HIV infections share risk-factors; therefore coinfection is common. Interactions have been reported but controlled studies have been limited. Our objective was to study the effect of HIV infection on the natural history of chronic HBV infection and the reverse effect of the HBV carrier state on HIV infection. DESIGN: Prospective observational cohort study. SETTING: Open-access outpatient HIV/genitourinary medicine clinic at a Central London hospital. PATIENTS: Total of 152 untreated homosexual male HBV carriers and 212 HBV surface antigen-negative controls (41.4 and 70.3% HIV-seropositive, respectively). OUTCOME MEASURES: The rate of loss of serum HBV e antigen (HBeAg) and its reappearance in HIV-infected and HIV-uninfected HBV carriers; serum HBV DNA levels measured by dot-blot hybridization assay), HBV DNA polymerase activity and liver transaminase activities, the progression of HIV infection to symptomatic disease or AIDS in HIV-infected compared with HBV-HIV coinfected patients. RESULTS: In HIV-infected HBV carriers, serum HBV DNA polymerase activity was higher, alanine aminotransferase was lower and loss of serum HBeAg (mean follow-up, 2.8 years) occurred at a lower rate when compared with HIV-uninfected HBV carriers (estimated relative hazard, 0.39; 95% confidence interval, 0.161-0.942) Concomitant chronic HBV infection had no detectable effect on the rate of progression of HIV disease after correction for lead-time bias. CONCLUSION: This study strengthens the evidence for a significant effect of HIV infection on the natural history of chronic HBV infection, which by prolonging the period of infectivity could have an important impact on the epidemiology of HBV infection in regions, or patient groups, with high HIV seroprevalence. There was no evidence of an important effect of HBV carriage on HIV disease progression.

AIDS-Related Opportunistic Infections↗
PubMed1996

Effects of systematic variation of the minimal Escherichia coli met consensus operator site: in vivo and in vitro met repressor binding.

We have produced a set of sequence variants based upon the idealized, minimal Escherichia coli met operator in which each position within the basic recognition unit, the 8 bp met box (dAGACGTCT), has been changed to all other possible sequences containing single symmetrical base substitutions. The effects of these sequence variations have been assayed in vivo by monitoring the production of beta-galactosidase from a standard promoter regulated by the operator variants, and in vitro by gel-retardation assay. The two sets of data are consistent and correlate well with expectations based on the three-dimensional structure of the holorepressor bound to a minimal idealized operator and the results of in vitro evolution experiments. Comparison with two natural operators, metA and metC, suggests that in vivo, with non-consensus operators, the repressor binds to at least four consecutive met boxes.

Bacterial Proteins↗
PubMed1996

beta 2 glycoprotein-I inhibits factor XII activation on triglyceride rich lipoproteins: the effect of antibodies from plasma of patients with antiphospholipid syndrome.

It is now well recognised that antiphospholipid antibodies are associated with thrombosis and recurrent fetal loss. Some antiphospholipid antibodies (aPAs) have been shown to require a cofactor, beta 2 glycoprotein-I (beta 2 GPI), for binding to phospholipids, and recently beta 2 GPI has been identified as the antigenic target for some aPAs. beta 2 GPI possesses in vitro anticoagulant properties and modulation of beta 2 GPI function may therefore result in altered haemostatic regulation. In the present study, the influence of plasma derived aPAs and beta 2 GPI on factor XII activation on the surface of very low density lipoprotein (VLDL) was investigated. Factor XIIa generation was dependent on lipoprotein lipase treatment of VLDL and beta 2 GPI inhibited the factor XIIa generation in a concentration dependent manner. No consistent effects on factor XIIa generation were demonstrated with the IgG fractions from patients with aPAs. Inhibition of the beta 2 GPI activity was demonstrated by some antibodies, and study with cardiolipin affinity purified antibody indicated that antibody concentration is critical. These results suggest that perturbation of beta 2 GPI function may contribute to the pathogenic mechanism for thrombosis in some patients with aPAs.

Adult↗
PubMed1995

A subunit interface mutant of yeast pyruvate kinase requires the allosteric activator fructose 1,6-bisphosphate for activity.

A variant form of yeast pyruvate kinase (EC 2.7.1.40) with Ser-384 mutated to proline has been engineered in order to study the allosteric properties of this enzyme. Both the mutant and wild-type enzymes were overexpressed in a strain of yeast in which the genomic copy of the pyruvate kinase gene had been disrupted by an insertion of the Ura3 gene. Both enzymes were purified to homogeneity and their kinetic properties characterized. The wild-type enzyme displays sigmoid kinetics with respect to phosphoenolpyruvate (PEP) concentration, and is activated by the allosteric effect fructose 1,6-bisphosphate with concomitant reduction in co-operativity. In contrast, the mutant was found to be dependent on the presence of the effector for catalytic activity and was inactive in its absence. The fully activated mutant enzyme had a kcat. 1.6 times greater than that of the wild-type enzyme. The mutation introduced into the enzyme is in an intersubunit contact which is known to be critical for the allosteric properties of the enzyme, and is far removed from the active site. The major effect of the mutation seems to be to stabilize the low-affinity T state of the apoenzyme, although kcat. is also affected. The S0.5 for PEP and S0.5 for ADP of the wild-type enzyme were 0.22 +/- 0.004 and 0.15 +/- 0.01 mM respectively (means +/- S.E.M.). In the activated mutant enzyme, these kinetic parameters increased to 0.67 +/- 0.03 and 0.43 +/- 0.03 mM respectively. The cooperativity between ADP-binding sites was altered in the mutant enzyme, with the Hill coefficient (h) for ADP increasing to 1.65 +/- 0.07 in the presence of the effector, compared with a value of 0.01 +/- 0.07 for the wild-type enzyme under the same conditions. CD spectroscopy revealed the secondary structure of the mutant enzyme to be little different from that of the wild-type enzyme, indicating that the two enzymes have similar secondary structures in solution. Precise tertiary and quaternary structures such as intersubunit and interdomain interactions may be modified. An improved purification procedure has been devised that allows large quantities of enzyme to be rapidly prepared.

Allosteric Regulation↗
PubMed1995

Antiphospholipid antibodies and beta 2-glycoprotein-I in 500 women with recurrent miscarriage: results of a comprehensive screening approach.

Five hundred consecutive women (median age 33 years; range 19-45) with a history of recurrent miscarriage (median 4; range 3-16) were screened for the presence of antiphospholipid antibodies (APA)-lupus anticoagulant (LA) and/or anticardiolipin antibodies (ACA). The prevalence of persistently positive tests for LA was 9.6% and for immunoglobulin G (IgG) and immunoglobulin M (IgM) ACA was 3.3 and 2.2% respectively. Only seven women (1.4%) were LA and ACA positive. Repeat testing, after an interval of at least 8 weeks, demonstrated that only 65.7% of LA positive, 36.6% IgG ACA positive and 36.0% IgM ACA positive women on initial testing had a second positive test result. The dilute Russell's viper venom time detected the LA significantly more often than either the activated partial thromboplastin time or the kaolin clotting time (P < 0.001). There was no difference in the gestation of previous miscarriages between APA positive and APA negative women. There was no difference in the plasma beta 2-glycoprotein-I concentrations between APA positive and APA negative women with miscarriages and normal women. All women with a history of recurrent miscarriage should be tested for the presence of both LA and ACA. A second confirmatory test should be performed in those with an initial positive test result.

Abortion, Habitual↗
PubMed1995

Increased levels of beta 2 glycoprotein-I antigen and beta 2 glycoprotein-I binding antibodies are associated with a history of thromboembolic complications in patients with SLE and primary antiphospholipid syndrome.

beta 2 Glycoprotein-I (beta 2GPI), a plasma component with in vitro anticoagulant properties, has been identified as a cofactor for the binding of some antiphospholipid antibodies (aPAs). In order to determine whether beta 2GPI changes were associated with the thromboembolic complications of aPAs, we measured beta 2GPI antigen (beta 2GPI:Ag), beta 2GPI aPA cofactor activity (beta 2GPI:Cof) and antibodies to beta 2GPI (alpha beta 2GPI) in 44 systemic lupus erythematosus (SLE) patients, of whom 19 had evidence of aPAs (SLE-aPA+) and 17 patients with primary antiphospholipid syndrome (PaPS). beta 2GPI:Ag levels were significantly increased in SLE-aPA+ patients and PaPS patients compared with SLE-aPA- patients and normal healthy controls. The ratio of beta 2GPI:Cof/Ag was significantly reduced in SLE-aPA+ patients compared with SLE-aPA- patients, indicating functional modification of beta 2GPI in SLE-aPA+ patients. Eighty per cent of patients with anticardiolipin (aCL) IgG also had alpha beta 2GPI, and 13% patients with no detectable aCL IgG had alpha beta 2GPI. Increased beta 2GPI:Ag and alpha beta 2GPI were associated with a clinical history of thrombosis or recurrent fetal loss. The results of these investigations suggest that beta 2GPI may play a role in the pathogenic mechanism of thrombosis associated with aPAs.

Adult↗
PubMed1995

Elevated levels of beta 2 glycoprotein-I (beta 2 GPI) in antiphospholipid antibody syndrome are due to increased amounts of beta 2 GPI in association with other plasma constituents.

beta 2 glycoprotein-I (beta 2 GPI) is a 50 kDa plasma protein which associates with a number of anionic plasma constituents and has been identified as a cofactor for the binding of some antiphospholipid antibodies (aPAs). beta 2 GPI antigen levels are increased in some patients with aPAs. In order to examine the distribution of beta 2 GPI in these patients, we developed a method for measurement of free beta 2 GPI. Forty-three patients with SLE, of whom 18 had laboratory evidence of aPAs, and 22 normal healthy subjects were studied. Plasma was filtered by centrifugation at 650 x g through a 100 kDa filter in order to allow separation of free and complexed beta 2 GPI, and beta 2 GPI levels were measured in the starting plasma and filtrate by a standardized ELISA. Total beta 2 GPI levels of the SLE aPA positive patients (253.3 mg/l) were significantly increased compared with the SLE aPA negative patients and normal controls (188.0, P < 0.001 and 194.9 mg/l, P < 0.01, respectively), but there were no significant differences between free beta 2 GPI levels of these groups (20.8, 24.0 and 20.5 mg/l, respectively). These results suggest that levels of complexed beta 2 GPI are increased in patients with aPAs, perhaps as a result of immune complex formation, or altered binding to other plasma constituents.

Adult↗
PubMed1995

The use of an anti-beta 2-glycoprotein-I assay for discrimination between anticardiolipin antibodies associated with infection and increased risk of thrombosis.

Antiphospholipid antibodies (aPAs), occurring in association with infection, are not generally associated with an increased risk of thrombosis. Anticardiolipin antibodies (aCL) from patients with infection, unlike those from patients with SLE, do not have the beta 2GPI cofactor requirements. Antibodies to beta 2GPI (alpha beta 2GPI) are more closely associated with a previous history of thrombosis than aCL in patients with SLE. In the present study we have investigated the reactivity of the alpha beta 2GPI assay for aPAs associated with infection. Serum from 114 patients with infections including syphilis (n = 11), tuberculosis (n = 63) and Klebsiella (n = 42) were assayed for alpha beta 2GPI and aCL antibodies. The incidence of aCL in serum of patients with tuberculosis. Klebsiella infection and syphilis was 6.0%, 5.0% and 64.0%, respectively, but all patients were negative for alpha beta 2GPI. These results indicate that the alpha beta 2GPI assay is negative in patients with transiently positive aCL assays associated with infection.

Adult↗
PubMed1995

Phospholipid binding specificities and idiotype expression of hybridoma derived monoclonal autoantibodies from splenic cells of patients with systemic lupus erythematosus.

OBJECTIVE: To analyse the phospholipid binding specificity, functional characteristics and idiotype expression of human hybridoma derived monoclonal autoantibodies (MAb) derived from the spleens of two patients with active systemic lupus erythematosus (SLE). METHODS: The IgM MAbs binding to phospholipids were generated from spleen cells of two patients (RSP and RT) with active SLE and their specificity of binding to neutral phospholipids (phosphatidyl ethanolamine, phosphatidyl choline, platelet activating factor, sphingomyelin) and negatively charged phospholipids (phosphatidyl glycerol, phosphatidyl serine, phosphatidic acid, phosphatidyl inositol and cardiolipin (CL)) analysed. Binding specificity of cross reactive antibodies (those binding to CL and DNA) was confirmed by fluid phase inhibition assays. Lupus anticoagulant activity and beta 2-glycoprotein-1 (beta 2 GP-1) requirement for the antigen binding of these MAbs were detected using the modified dilute Russell's viper venom test and modified anti-CL enzyme linked immunosorbent assay (ELISA), respectively. Expression of idiotypes (Id) Id RT-84 and Id H3 was analysed using rabbit polyclonal and murine monoclonal anti-idiotype reagents, respectively. RESULTS: Twelve clones from the patient RSP and eight clones from patient RT were reactive with phospholipids. Marked differences in phospholipid binding of these MAbs were noted, varying from truly polyreactive (RT-72 bound to most phospholipids tested) to monospecific (RT-84 bound only to CL). Furthermore, MAbs RT-84, RT-129, and RSP-57 had lupus anticoagulant activity and required beta 2 GP-1 for CL binding. It was found that 75% of phospholipid binding antibodies from RT clones expressed RT-84 Id, but none from RSP clones did so, and that Id H3 was expressed only by the RT-83 antibody. CONCLUSION: These results show that human anti-phospholipid MAbs are heterogeneous with respect to phospholipid binding, functional characteristics, and Id expression.

Adolescent↗