Monoclonal antibodies to the acetylcholine receptor by a normally functioning auto-anti-idiotypic mechanism

Recently we described a procedure for preparing antibodies to the acetylcholine receptor (AChR) based on immunoglobulin idiotypes and on the hypothesis that, regardless of functional differences, macromolecules of the same specificity will show structural homologies in their binding sites. Antibodies were prepared in rabbits to a structurally constrained agonist of AChR, trans-3,3'-bis[alpha-(trimethylammonio)methyl]azobenzene bromide (BisQ). These antibodies mimicked the binding specificity of AChR in its activated state--agonists were bound with affinities that were in accord with their biological activities and antagonists were bound poorly. Rabbits were then immunized with a specifically purified preparation of anti-BisQ to elicit a population of antibodies specific for the binding sites of anti-BisQ. A portion of the anti-idiotypic antibodies produced in the second set of rabbits cross-reacted with determinants on AChR preparations from Torpedo californica, Electrophorus electricus and rat muscle. Moreover, several of the rabbits showed signs of experimental myasthenia gravis, in which circulating AChR antibodies are typically found. To devise a more direct route to monoclonal anti-receptor antibodies we based our strategy on acceptance of the concept of the anti-idiotypic network theory of Jerne. According to this theory, injection of an antigen elicits, in addition to antibodies to the antigen, other populations that include anti-idiotypic antibodies directed at the combining sites of the antigen-specific antibodies. If the antigen-specific antibodies recognize a ligand of a receptor, then the anti-idiotypic antibodies should bind receptor. Thus, when a mouse is immunized with a bovine serum albumin conjugate of BisQ (BisQ-BSA), it should be possible to expand populations of spleen cells that secrete antibodies which bind anti-BisQ and AChR, in addition to populations specific for BisQ. Fusion of the spleen cells with an appropriate myeloma line should yield monoclonal anti-AChR antibodies. Here we report the success of this approach and its implications.     

Effect of sodium butyrate on the interferon sensitivity of normal or cells transformed by murine sarcoma virus]

Sodium butyrate enhances the sensitivity of MSV transformed murine cells to interferon, but does not influence the response of normal cells. Sodium butyrate might act in transformed cells by restoring the different elements of the cytoskeletal system.     

High incidence area of cattle cancer with a possible interaction between an environmental carcinogen and a papilloma virus.

Cattle in upland areas of Scotland and northern England are substantially more prone to alimentary cancer than those of the immediately neighbouring lowlands, and epidemiological evidence implicates a combination of papilloma virus and bracken in the aetiology of the disease. Here Professor Jarrett outlines the circumstantial case against these agents and discusses its implications.     

Increased membrane-bound polyribosome fraction in the brains of rats with hereditary diabetes insipidus

Summary Rats homozygous for hypothalamic diabetes insipidus were found to have a significantly higher concentration of membrane-bound polyribosomes thant their heterozygous littermates. There was no difference in the concentration of free polyribosomes.     

Demonstration of exocytosis in the sinus gland of Astacus Leptodactylus (Nordmann) under the influence of serotonin injections]

Following a serotonin injection, a rise of exocytosis in the sinus gland of the crayfish Astacus leptodactylus is observed together with an increase of the glucose level in the hemolymph. The phenomenon of exocytosis reaches a peak between 2 and 4 h after injection, wheras the highest glucose level in the hemolymph appears between 4 and 6 h after the same injection.     

Characterisation of deletions which affect the expression of fetal globin genes in man.

Deletions in the DNA of individuals with hereditary persistence of fetal haemoglobin (HPFH) and 8 beta-thalassaemia have been mapped as a means of identifying regulatory sequences involved in the switch from fetal to adult globin gene expression. The end points of these deletions have been precisely located with respect to restriction endonuclease cleavage sites within and surrounding the gamma-, delta- and beta-globin genes in normal human DNA and the deletion maps were used to obtain definitive evidence for the physical linkage of the fetal and adult beta-like globin genes in the order 5'Ggamma-Agamma-delta-beta 3'. Correlation of haematological data and the location of deletions in two cases of HPFH and one case of deltabeta-thalassaemia suggest that a region of DNA located near the 5'-end of the delta-globin gene may be involved in the suppression in cis of gamma-globin gene expression in adults. The interpretation of a second case of deltabeta-thalassaemia is complicated by the fact that the deletion removes the Agamma-gene in addition to the region near the 5'-end of the delta-globin gene.     

Avian sarcoma virus-transforming protein, pp60src shows protein kinase activity specific for tyrosine

The protein responsible for malignant transformation by avian sarcoma viruses (ASVs) has been identified as a phosphoprotein of molecular weight 60,000 designated pp60src (refs 1--4). It has been suggested that this protein has a functional role in cellular transformation involving the phosphorylation of cellular proteins, for it was discovered that specific immunoprecipitates from ASV-transformed cells that contain pp60src catalysed the transfer of phosphate from [gamma-32P]ATP to the heavy chain of rabbit immunoglobulin. Additional studies involving the cell-free synthesis of the ASV src protein further demonstrated that the presence of the src polypeptide correlated with that presence of a phosphotransferase activity. Our studies, involving the biochemical purification of this protein, have demonstrated that the ASV-transforming gene product, pp60src, is itself a protein kinase. We have purified the pp60src protein approximately 5,000-fold using either conventional ion-exchange chromatography or immunoaffinity chromatography. The resultant partially purified preparations contain a cyclic AMP-independent protein kinase activity. We report here that the soluble phosphotransferase activity of partially purified pp60src results in the phosphorylation of exclusively tyrosine residues in a variety of proteins that serve as substrates.     

Sclerotization and coloration of the insect cuticle

Summary Evidence indicating linkage between the processes of cuticle hardening and coloration are reviewed. Data and observations for the mutants black and ebony inDrosophila melanogaster are used to construct a possible model for the relationship between these developmental events.     

A genetic study of intergradation betweenMytilus edulis andMytilus galloprovincialis

Summary A study of geographic variation at 2 diagnostic allozyme loci in the musselsMytilus edulis andM. galloprovincialis reveals considerable spatial variation, both in allele frequencies and in the extent of intergradation.This work was supported in part by grant GR3/2452 from the NERC. We thank M. Hunt, A. Dunn and M. Newton for technical assistance and the many people who gave advice or helped in the collection of specimens.