European Journal of Immunology

doi: 10.1002/eji.1830181201pmid: N/A

Rits, Michel; Hiemstra, Pieter S.; Bazin, Hervé; Van Es, Leendert A.; Vaerman, Jean‐Pierre; Daha, Mohamed R.

doi: 10.1002/eji.1830181202pmid: 3220102

The ability of rat monoclonal IgA, specific for 2,4‐dinitrophenyl (DNP), 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°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)‐conjugugated 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.

Rees, Ann; Scoging, Anne; Mehlert, Angela; Young, Douglas B.; Ivanyi, Juraj

doi: 10.1002/eji.1830181203pmid: 3146508

Human CD8 T lymphocyte clones (TLC) were generated from the pleural effusion of patients with tuberculosis using a protocol that required, in addition to antigen, co‐culture of purifed CD8+ T cells, accessory cells, interleukin 2 (IL2) and anti‐CD3‐Sepharose. The TLC obtained were stimulated by mycobacterial soluble extracts in an IL2‐dependent and MHC class I‐restricted manner. When antigen‐responsive TLC were screened with extracts from the recombinant mycobacterial library they were found to respond to either the Y3125 (100‐kDa) or the Y3111 (71‐kDa) λgt11 clones. Polyacrylamide gel immunoblot analysis demonstrated that the CD8 TLC responded to fractions with the molecular mass range 27–45 kDa in the Y3125 lysogen and 60–90 kDa in the mycobacterial soluble extract. The specificity of TLC reactive with the Y3111 clone was confirmed using the 71‐kDa antigen purified from the same lysogen. These TLC recognized sequences common to the 71‐kDa protein derived from mycobacteria, E. coli or a human cell line. Studies of three TLC using antigen‐presenting cells of known genetic haplotype indicated that stimulation with both the Y3125 and the 71‐kDa antigens were restricted by determinants encoded by HLA‐B8.

Ouaissi, Ali; Cornette, Jocelyne; And, Phillipe Velge; Capron, Andre

doi: 10.1002/eji.1830181204pmid: 3146509

This report presents evidence that human acetylcholinesterase (AChE; acetylcholine hydrolase, EC 3.1.1.7) exhibits immunological cross‐reactivity with the protozoan parasite Trypanosoma cruzi. The immunological probes used indicate that the cross‐reactive determinant is an oligosaccharidic epitope. Antibodies to AChE were detected in a high proportion of T. cruzi‐infected patients sera and during the experimental infection of BALB/c mice. Moreover, anti‐idiotypic antibodies against an anti‐AChE rabbit antibody or a monoclonal antibody to a parasite surface antigen of 80–85 kDa were detected in sera of patients presenting the chronic cardiac form of the disease. The antibodies were less frequently found in sera from individuals with asymptomatic chronic infection. Our data may provide a biochemical basis for denervation hypersensitivity in Chagas' disease. In addition, it may support the notion of an idiotype‐anti‐idiotype regulation of conducting tissue damage during the course of T. cruzi infection.

Martinez‐A., Carlos; Bandeira, Antonio; Toribio, Maria Luisa; Coutinho, António; Marcos, Miguel Angel; Pereira, Pablo

doi: 10.1002/eji.1830181205pmid: 2975596

Helper T cells directed to B cell surface determinants activate their “targets” into polyclonal antibody production in vitro and in vivo, but B cells which bind to epitopes on the helper cell surface are preferentially induced. Furthermore, “anti‐helper” B cell activation also occurs by “back‐stimulation”, that is even when the responding B lymphocytes are not specific targets for the inducing helper cells, as long as these are simultaneously activated by appropriate interactions with presenting cells. In our experimental systems, this is the only condition where “bystander” activation can be recorded. These findings suggest mechanisms of auto‐antibody production associated with unrelated helper cell activity in vivo.

Dariavach, Piona; Mattéi, Marie‐Geneviève; Golstein, Pierre; Lefranc, Marie‐Paule

doi: 10.1002/eji.1830181206pmid: 3220103

The mouse CTLA‐4 gene has been shown to code for an activated lymphocyte‐associated sequence belonging to the Ig gene superfamily. We now report on the molecular cloning and study of the human corresponding gene isolated from a genomic library and designated Hu‐CTLA‐4. The Hu‐CTLA‐4 gene exists as a single copy per human haploid genome and maps to band q33 of chromosome 2. It comprises 3 exons notwithstanding the leader sequence. The first exon encodes a V‐like domain of 116 amino acids, the second one a hydrophobic putative transmembrane region of 37 amino acids and the third one a 34 amino acid putative cytoplasmic domain. Whereas the overall homology between the human and murine CTLA‐4 proteins is 76%, there is, remarkably, a complete identity of their cytoplasmic domains. This complete interspecies conservation comes in support of an important role for this domain in CTLA‐4 function.

Jones, Barry; Carding, Simon; Kyes, Susan; Mjolsness, Shelley; Janeway, Charles; Hayday, Adrian

doi: 10.1002/eji.1830181207pmid: 2851446

Northern analysis, hybridization in situ and cDNA sequence analysis have been used to demonstrate that the induction of T cell γ‐gene expression is a general occurrence when primary splenic T cells of adult mice are cultured in short‐term mixed lymphocyte reactions (MLR). Splenic T cells from nine strains of mice examined in eleven different MLR all showed significant induction of γ‐RNA, even when the primary T cell response was to only a three amino acid mismatch in a major histocompatibility complex class I antigen. In MLR examined in detail, the expression is highly enriched for in CD3+ “double‐negative” T cells (lacking both CD4 and CD8 expression). A cDNA sequence analysis, constituting the first such analysis of any size of γ‐gene transcripts from circulating, peripheral cells of adult mice, revealed transcription to be frequently of productively rearranged genes. These genes display extensive junctional diversity.

Michel, Frédérique; Hoffenbach, Angès; Lanlade‐Demoyen, Pierre; Guy, Bruno; Girard, Marc; Lecocq, Jean‐Pierre; Wain‐Hobson, Simon; Kieny, Marie‐Paule; Plata, Fernando

doi: 10.1002/eji.1830181208pmid: 2905993

Kane, Kevin P.; Goldstein, Steven A. N.; Mescher, Matthew F.

doi: 10.1002/eji.1830181209pmid: 3265386

Based largely on antibody blocking studies, a number of surface “accessory” molecules on effector cytolytic T lymphocytes (CTL) have been implicated as having a role in mediating CTL binding and lysis of target cells, possibly via binding to ligands on the target cell surface. Despite this, cloned allogeneic CTL were able to specifically bind cell‐size, artificial membranes (pseudocytes) bearing only class I alloantigen. This binding triggered CTL degranulation, as measured by serine esterase release. Thus, class I alloantigen alone is both a necessary and sufficient ligand for specific binding and effective transmembrane signaling to occur.

Zöller, Margot

doi: 10.1002/eji.1830181210pmid: 3265387

Prenatal treatment with a reactive hapten may be well suited for analyzing the establishment of self tolerance because the hapten binds ubiquitously to proteins and cells and persists for a long period in the developing organism. Based on this consideration, pregnant BALB/c mice were treated with 2,4,6‐trinitrobenzenesulfonic acid (TNBS), searching for differences in 2,4,6‐trinitrophenyl (TNP) responsiveness in their offspring as compared to litters of untreated mice. The frequency of TNP‐specific T‐independent B cells of litters from TNBS‐treated mothers was very low at birth and remained below 10% of controls until the age of 42 days. On the contrary, in 8‐day‐old prenatally TNBS‐treated litters, the frequency of TNP‐specific T‐dependent B cells was higher than in controls. Expansion of TNP‐specific B cells after antigenic stimulation of control mice started at the age of 3–4 weeks and expansion rates increased with age, while in prenatally TNBS‐treated mice, significant expansion rates were seen at the age of 2 weeks only. Yet, after restimulation with TNP‐lipopolysaccharide or with a TNP‐anti‐TNP conjugate, but not after restimulation with TNP‐ovalbumin, similar numbers of plaque‐forming cells (PFC) were observed with spleen cells of prenatally untreated and TNBS‐treated mice, the latter revealing an exceptional predominance of IgG PFC. Thus, TNP‐specific B cells were not deleted, but prenatal TNBS treatment resulted in an altered compositon of TNP‐specific B cell subpopulations, their regulation differing qualitatively from the one observed in prenatally untreated mice.