Rat C3 Conversion by Rat Anti‐2,4, Dinitrophenyl (DNP) Hapten IgA Immune Precipitates

Rits, M.; Kints, Jp.; Bazin, Hervé; Vaerman, Jp.

doi:10.1111/j.1365-3083.1987.tb02201.x

Cited by 23 publications

(13 citation statements)

References 30 publications

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“…This reaction occurs via the alternative pathway (AP) [46] .Very recently, Schneiderman et al [47] described 2 different rabbit-mouse chimeric transfectomas of the IgA isotype directed against dansyl hapten. Those IgA antibodies also activate C via the AP Which pathway of C activation was involved in our present in vivo studies is a matter of further investigation, but in vitro studies have shown involvement of the AP [24,25]. Although immune precipitates of aIgA induced some C4 consumption in vitro [25], recent in vivo studies with d g A , dIgA and pIgA could not demonstrate deposition of C4 on IgA in vivo (manuscript in preparation).…”

Section: Discussionmentioning

confidence: 68%

Complement enhances the clearance of large‐sized soluble IgA aggregates in rats

et al. 1991

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In the present study the involvement of the complement system (C) in the clearance of soluble IgA aggregates in the rat was studied. Monoclonal monomeric IgA (mIgA) antibody (which does not activate C) or aggregated polymeric IgA (aIgA; which activates C) were administered intravenously to phosphate-buffered saline-treated and complement-depleted [Cobra venom factor (CVF)-treated] rats and assessed for clearance from the circulation. In control rats, mIgA was cleared in a biphasic fashion with a first half-life (T1/2) of 29.5 +/- 14.2 min and a second T1/2 of 230 +/- 176 min. No differences were observed in clearance of mIgA in CVF-treated rats as compared to PBS-treated rats. In PBS-treated rats, aIgA with a size between 20 S and 150 S disappeared very rapidly from the circulation with a first T1/2 of 1.1 +/- 0.4 min and a second T1/2 of 23.2 +/- 11.3 min. In CVF-treated rats the clearance of aIgA was significantly delayed as compared to that in control rats, namely with a first T1/2 of 7.3 +/- 2.6 min and a second T1/2 of 64.2 +/- 19.4 min. Immunohistochemical studies of the liver (which is the main site of clearance of aIgA) revealed that Kupffer cells (KC) are mainly responsible for the uptake of aIgA. Furthermore, in PBS-treated rats aIgA deposition was accompanied by C3 deposition in the KC. In CVF-treated rats, the percentage of KC containing aIgA was significantly lower during the first 16 min after aIgA administration as compared to PBS treated rats. In addition no detectable C3 was found in KC of CVF-treated rats. These results indicate that KC play an important role in the clearance of large molecular weight IgA in rats and that C facilitates the clearance of these complexes from the circulation.

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Section: Discussionmentioning

confidence: 68%

Complement enhances the clearance of large‐sized soluble IgA aggregates in rats

et al. 1991

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“…Rat C3, C4 and C5 were titrated by specific hemolytic assays using EA (SRBC coated with a subagglutinating amount of rabbit IgG anti-sheep RBC) and C3DHS, C4DGPS and CSDHS, respectively [18,19,331.…”

Section: Complement Titrations 3 Resultsmentioning

confidence: 99%

“…We have reported previously that IgA IC prepared with DNPs RSA and MC rat IgA anti-DNP are able to elicit rat C3 conversion [19] and are solubilized by rat C via the AP [20]. The present studies were designed to investigate the capacities of rat MC m-, d-and p-IgA to activate the C system.…”

Section: Discussionmentioning

confidence: 98%

“…Rat or mouse Mc Ab against DNP were isolated as described [18][19][20]281. Briefly, ascites containing rat (LO-DNP-65) rat dimeric (d)-and polymeric (p)-IgA (LO-DNP-45), rat monomeric (m)-IgA (LO-DNP-67) or mouse IgA (MOPC-315) were absorbed to DNP-lysine Sepharose and eluted from this immunosorbent with 0.1 M dinitrophenol, pH 7.4.…”

Section: Purification Of Rat and Mouse Ab To Dnpmentioning

confidence: 99%

“…Briefly, ascites containing rat (LO-DNP-65) rat dimeric (d)-and polymeric (p)-IgA (LO-DNP-45), rat monomeric (m)-IgA (LO-DNP-67) or mouse IgA (MOPC-315) were absorbed to DNP-lysine Sepharose and eluted from this immunosorbent with 0.1 M dinitrophenol, pH 7.4. After removal of free DNP by chromatography on Dowex AGl-X8 (Bio-Rad, Richmond, CA), the IgA Ab were further purified by gel filtration on Ultrogel AcA 22 (LKB, Bromma, Sweden) to yield m-, d-and p-IgA [18, 191. Residual polyclonal IgG was removed from the m-IgA fraction by absorptions to concanavalin A Sepharose (Pharmacia) [19]. Finally all the IgA preparations were tested by agarose gel electrophoresis and immunoelectrophoresis for their purity and stored as aliqutos at -7O"C.Rat MC m-IgA was labeled with '*'I by the lactoperoxidase method [29] to obtain a specific activity of 0.18 yCUpg = 6.66 kBq/pg.…”

Section: Purification Of Rat and Mouse Ab To Dnpmentioning

confidence: 99%

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Activation of rat complement by soluble and insoluble rat IgA immune complexes

Rits¹,

Hiemstra

Bazin

et al. 1988

Eur J Immunol

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The ability of rat monoclonal IgA, specific for 2,4-dinitrophenyl (DNA), to activate the complement (C) system of the rat was investigated using aggregated IgA or IgA immune complexes (IC). IgA was coated onto a solid phase, and tested for its capacity to bind C3 upon incubation at 37 degrees C in normal rat serum (NRS) in the presence of Mg-EGTA. Binding of C3 was observed dependent on the dose of dimeric (d-), polymeric (p-) and secretory IgA tested. In contrast, little C3 fixation was observed in this system with monomeric (m-) rat IgA or with mouse m- and d-IgA (MOPC315). Soluble and insoluble rat IgA IC were prepared using dinitrophenylated rat serum albumin (DNP8RSA) as antigen (Ag), and assessed for C activation. It was shown that insoluble IC (immune precipitates; IP) containing m-, d- or pIgA of rat origin activate the alternative pathway of rat C, as demonstrated by their capacity to induce C consumption in NRS in the presence of Mg-EGTA. When p- and m-IgA IP were compared for their capacity to activate C, it was found that p-IgA activated C four times as efficiently as m-IgA IP (at 2 mg/ml). Soluble rat IgA IC were prepared in an excess of DNP8RSA, fractionated by gel filtration on Sepharose 6B, and analyzed for C activation and antibody (Ab)/Ag ratio. In contrast to m-IgA IP, soluble m-IgA did not activate C. On the other hand soluble d-IgA IC activated C dependent on their concentration and size: at a concentration of 0.1 mg/ml high-molecular weight d-IgA IC with a high Ab/Ag ratio were four times as efficient as low-molecular weight IC with a low Ab/Ag ratio, and twice as efficient as IP prepared at equivalence. To demonstrate the induction by IgA of the assembly of the terminal membrane attack complex, trinitrophenyl (TNP)-conjugated rat red blood cells (TNP-RRBC) coated with d- or p-IgA were shown to be lysed in NRS in the presence of Mg-EGTA. No lysis of m-IgA-coated TNP-RRBC was observed. The results in this study demonstrate that both soluble and insoluble rat IgA IC activate the alternative pathway of homologous rat C. Alternative pathway activation by soluble rate IgA IC is dependent on the size of the IC. The degree of polymerization of the IgA Ab itself also influences C activation.

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Anti‐inflammatory activity of human IgA antibodies and their Fabα fragments: inhibition of IgG‐mediated complement activation

1989

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The interaction of human IgA antibodies with the classical pathway of complement activation was investigated in a homologous human system, by means of two IgA1 and three IgG1 myeloma proteins having antibody activity against a defined antigen, staphylococcal alpha-toxin. In a solid-phase antigen-dependent C3b-binding ELISA system, the monoclonal IgG antibodies were previously shown to activate the classical complement pathway synergistically, resembling polyclonal IgG antibodies, whereas IgA antibodies were unable to activate complement by either pathway. In the present study, IgA antibodies were found to inhibit significantly the activation of complement initiated by antigen-bound polyclonal or mixed monoclonal IgG antibodies, in relation to the amount of IgA antibodies applied and bound to antigen. IgA1 myeloma proteins devoid of antigen-binding activity were without effect. Inhibition was independent of the ability of the IgA antibodies to compete against the IgG antibodies in binding to antigen, and was demonstrable with physiological concentrations of antibodies. Similar results were obtained with polyclonal serum IgA having antigen-binding activity. However, the binding of C1q to antigen-complexed IgG was inhibited only by a monoclonal IgA antibody that could compete against one of the three monoclonal IgG antibodies that bound C1q synergistically. This observation implied that at least two mechanisms were involved in the inhibition of C3b fixation. Fab alpha fragments of monoclonal IgA antibodies, obtained by cleavage with IgA1 protease from Haemophilus influenzae type b, were found to have a similar inhibitory effect on C3b fixation to the intact IgA1 antibodies. This observation supports the hypothesis that IgA1 proteases contribute to the invasive pathogenicity of certain mucosal bacteria, by cleaving secretory IgA1 antibodies to antigen-binding Fab alpha fragments, which are not only defective in mucosal defense properties, but which also protect the organisms from other immune effector systems, such as complement activation.

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Rat C3 Conversion by Rat Anti‐2,4, Dinitrophenyl (DNP) Hapten IgA Immune Precipitates

Cited by 23 publications

References 30 publications

Complement enhances the clearance of large‐sized soluble IgA aggregates in rats

Complement enhances the clearance of large‐sized soluble IgA aggregates in rats

Activation of rat complement by soluble and insoluble rat IgA immune complexes

Anti‐inflammatory activity of human IgA antibodies and their Fabα fragments: inhibition of IgG‐mediated complement activation

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