Recombinant dissection of myosin heavy chain of Toxocara canis shows strong clustering of antigenic regions

Myosins from nematode parasites elicit strong humoral and cellular immune responses and have been investigated as vaccine candidates. In this study we cloned and sequenced a cDNA coding for myosin heavy chain from Toxocara canis, a nematode parasite of canids which may also infect humans and cause various unspecific symptoms. To determine the major antigenic regions the myosin heavy chain was systematically dissected into ten overlapping recombinant fusion polypeptides which were purified by metal chelate chromatography. Single fragments were then tested for their IgG reactivity in sera from toxocarosis patients and healthy probands. Two regions, one region at the mid to carboxy-terminal end of the head domain and one region in the rod domain, were identified as major antigens, which in combination were positive with 86% of the sera. The other domains were less reactive. This shows that the patients' IgG reactivity was not directed evenly against all parts of the molecule, but was rather clustered in few regions.     

Precipitable immune complexes in healthy homosexual men, acquired immune deficiency syndrome and the related lymphadenopathy syndrome.

Increased levels of 3% PEG precipitable circulating immune complexes (CIC) were found in healthy homosexual men, in homosexual patients with the acquired immune deficiency syndrome (AIDS), and in the AIDS related lymphadenopathy syndrome (LAS). The degree of CIC elevation increases from healthy homosexual men to LAS and AIDS. Patients suffering from AIDS associated with opportunistic infections had a more pronounced increase in CIC than patients with AIDS associated Kaposi's sarcoma. In LAS and AIDS the amount of CIC correlated with the degree of inversion of the T4/T8 lymphocyte ratio, whereas in healthy homosexual men with increased levels of CIC the T4/T8 ratio was not significantly altered. Laser nephelometric partial components analysis revealed that these complexes were of a complement poor subtype with low component levels of C4, C1q and C3c. IgM and IgG were found to be the major components. It is suggested that these CIC might represent a marker of the total antigenic burden of the immune system. Possibly, they are of prognostic and monitoring value for clinical handling of patients at risk for AIDS.     

Identification and characterization of a new variant of Shiga toxin 1 in Escherichia coli ONT:H19 of bovine origin

A new variant of Shiga toxin 1 (Stx1), designated Stx1d, which deviates considerably more than any other known variant from Stx1 encoded by phage 933J, was identified in an Escherichia coli strain, ONT:H19, isolated from bovine feces. The complete stx(1) gene of this strain was amplified and sequenced. Nucleotide sequence homology with stx(1) from phage 933J was only 91%, resulting in the substitution of 20 amino acids in the A subunit and 7 amino acids in the B subunit of the protein. Cell culture supernatant of this strain, which was negative for stx(2) by PCR testing, was cytotoxic to Vero cells and gave positive results in two commercial enzyme-linked immunosorbent assays for Stx. PCR primers were constructed for the specific detection of the new variant. The findings of this study suggest that Stx1 is not as conserved as thought before and that there might be more variants which cannot be detected by commonly used PCR methods.     

Equalization of asymmetries of tonus in the optomotor system of rabbits

Summary Turning a rabbit on a turn-table for a few degrees induces compensatory eye-movements and results in an asymmetry of tonus in the optomotor system. If the visual input is discontinued (darkness), this asymmetry decays and the eyes drift back to the mid-position within 12–18 sec. The equalization of such asymmetries of tonus under normal conditions and under curare is described. Tonus asymmetries induced by tilting the animals about the longitudinal axis are neither compensated under visual, nor under non-visual, conditions. Recordings were taken from oculomotor neurons, and changes of their firing frequencies were used as a measure for eye movements.A preliminary report was given at the spring meeting of the German Physiological Society 1973.Supported by the Deutsche Forschungsgemeinschaft, SFB 33.     

The immune response to heterologous red cells in mice: II. Antibody formation to red cells from species taxonomically related to sheep or mouse

An attempt was made to establish the relative immunogenicity of various heterologous erythrocytes in the mouse. The immune response to multispecies red cells was examined by zone centrifugation of the antibodies, and by studying cross-reactivity between the varioys erythrocytes, time-course of haemagglutinin formation, and finally, antigen dose—antibody response relationships. As compared to sheep erythrocytes, goat erythrocytes were found to have a greatly reduced agglutinability, which merely simulated a reduced immunogenicity. However, erythrocytes from gerbil and hamster proved to be genuinely weaker antigens in the mouse. For alkylating agents, anti-metabolites and anti-mitotic compounds the drug-sensitivity of the immune response to cells of different antigenicity was not altered.     

Multilocus haplotype analyses reveal association between 5 novel IL-15 polymorphisms and asthma

BACKGROUND: IL-15 is a T(H)1-related cytokine that is involved in the inflammatory response in various infectious and autoimmune diseases. IL-15 has recently been shown to be upregulated in T-cell-mediated inflammatory disorders. The observations suggest a potential role for this cytokine in a variety of pathologic conditions, including T(H)1-mediated and T(H)2-mediated inflammatory diseases. OBJECTIVE: In this study, we searched for single nucleotide polymorphisms in the whole IL-15 gene and investigated their association with inflammatory and/or atopic phenotypes. METHODS: The screening for single nucleotide polymorphisms was performed by single-strand conformation polymorphism analysis. Genotyping of the identified polymorphisms was performed by restriction fragment length polymorphism. Genotypic association analysis used the Armitage trend test. Haplotype frequency estimation and subsequent testing for differences between cases and controls were performed by using the programs FASTEHPLUS and FAMHAP. RESULTS: We identified 5 novel noncoding nucleotide sequence variants, all of which were typed in our asthmatic, our atopic, and our control population. According to the Armitage trend test, none of the 5 polymorphisms is associated with the phenotype bronchial asthma or atopy. However, multilocus haplotype analysis based on simulations to find out whether the haplotype frequencies differed between cases and controls by using the program FAMHAP yielded a P value of 6.1 x 10(-5) in the asthmatic versus the control population, which is highly significant. Furthermore, we obtained a nominally significant result of P=.0232 for the atopic versus the control population by using FAMHAP. CONCLUSION: These results strongly underscore previous findings that suggest a potential role of this cytokine in allergic diseases.     

Syntheses and ESR spectra of radicals produced in the thermal decomposition of tetraarylsuccinonitriles

Tetraarylsuccinonitriles 2a – e were synthesized via oxidative dimerization of diarylacetonitriles 1a – e in basic media. The thermal decomposition of 2 results in two identical cyanodiarylmethyl radicals 3 . Both ¹H and ¹³C NMR analyses of 1a – e and 2a – e and ESR spectra of 3a – e are presented and discussed. The results of ESR measurements provide a plausible explanation for the different reactivity of cyanodiarylmethyl radicals 3a – e in free radical polymerization.     

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Isolation and immunoelectronmicroscopical characterization ofTheileria annulata macroschizonts

Theileria annulata macroschizonts were isolated from bovine lymphoblastoid cells grown in cell culture. To release the parasites, the cells were homogenized under hypotonic conditions. Intact host lymphocyte nuclei were lysed and the resulting chromatin precipitate was degraded by DNase. Host cell fragments were removed by ion-exchange chromatography. As revealed by electron microscopy, the preparations were free of intact host lymphocytes, lymphocyte nuclei and organelles. Antisera raised in rabbits against purified macroschizonts showed a specific reaction with the intracellular parasite in the indirect immunofluorescence test and in immuno-electron microscopy.