T2 lipopolysaccharide antigen of Salmonella: genetic determination of T2 and properties of the T2, T2,S, and T2,SR Forms.

The T2 antigenic form of Salmonella bareilly was examined. The absence of O specificity in this strain was shown to be due to its nonfunctional rfb genes; when the rfb gene cluster was replaced by the rfb cluster derived from smooth donor strains, T2,S and T2,SR recombinants were produced that expressed both T2 and either 0-6,7 or 0-4,12 specificity, depending on O antigen of the donor strain. The T2, T2,S, and T2,SR forms were all unstable on culture and segregated T2-negative forms (R, S, and SR, respectively) at a high rate. In all these respects the T2 antigen closely resembled the other T-form antigen, T1. The genes responsible for the T2 antigen, rfu, were not close to rfb, but their precise location and relation to rft (which determines T1 antigen) could not be discovered because of the instability to the T2 form and low recombination frequency in the necessary interspecies crosses.     

Characterization of an automated radioimmunoassay for T4, T3, T3 U, and FTI

The performance characteristics of assays is reported for thyroxine (T4), triiodothyronine (T3), and T3-uptake (T3U) using the GAMMAFLOTM Automated Assay System. A comparison of calculated free thyroxine index (FTI) values is also presented. This automated radioimmunoassay (RIA) system utilizes a combination of continuous-flow methodology and chromatographic separation techniques. The T4 assay studied had a standard curve range of 1.5 to 24.0 microgram per dl. The intra- and inter-assay precisions were 4.3 and 5.3 percent CV, respectively, for a T4 concentration of 10.0 microgram per dl. The T3 assay had a standard curve range of 50 to 1000 ng per dl, the corresponding precisions were 7.3 and 7.1 percent CV, respectively, for a concentration of 213 ng per dl. The automated serum T4 and T3 results correlated (r = 0.966 and 0.864) with a manual radioimmunoassay procedure. Intra-assay and inter-assay precisions for a mid-range normal 30.1 percent T3U value were 6.2 percent and 4.9 percent CV, respectively. Reference range comparison of FTI by both automated and manual results correlated for 47 out of 51 (95 percent) patients compared. It is concluded that this automated system appears to offer a viable alternative to T4, T3, and T3U manual RIA techniques in terms of operational simplicity, analytical performance, and sample through-put flexibility.     

On T cell development,T cell signals,T cell specificity and sensitivity,and the autoimmunity facilitated by lymphopenia

We propose a framework to explain how T cells achieve specificity and sensitivity, how the affinity of the TcR peptide/MHC interaction controls positive and negative thymic selection and mature T cell survival, and whether antigen-dependent activation and inactivation takes place. Two distinct types of signalling can lead to mature T cell multiplication. One requires the TcR to recognize with a certain affinity an antigen-derived peptide, an agonist peptide, bound to an MHC molecule. The other, the tonic signal, leads to naïve T cell survival and modest proliferation if the T cell successfully competes for endogenous, self-peptide/MHC ligands, involving lower affinity TCR/ligand interactions. Many suggest lymphopenia contributes to autoimmunity by increasing the strength of TcR-tonic signalling, and so activation of anti-self T cells. We suggest T cell activation requires antigen-mediated cooperation between T cells. Increased tonic signalling under lymphopenic conditions facilitates T cell proliferation and so antigen-dependent cooperation and activation of anti-self T cells.     

Comparative expression of T9, T10, and Ia antigens on activated human T cell subsets

In the present study, the expression of three surface molecules T9, T10, and Ia, which are found on activated T lymphocytes, was examined utilizing monoclonal antibodies and indirect immunofluorescence. These antigens were shown to appear on T lymphocytes in a defined temporal sequence which was dependent on the specific triggering stimulus. Moreover, when T cells were fractionated into individual subsets of T4+ inducer and T8+ cytotoxic/suppressor lymphocytes, the expression of all three molecules was restricted to the T4+ subset following soluble antigen stimulation. By contrast, both subsets expressed these surface determinants following mitogen or alloantigen stimulation. The above results suggest that there may be successive stages in the T cell activation process associated with the appearance of unique cell surface antigens and further support the view that various triggering stimuli activate T cell populations differently.     

Electron microscope heteroduplex study of sequence relations of T2, T4, and T6 bacteriophage DNAs

The regions of sequence homology and nonhomology between the DNA molecules of bacteriophages T2, T4, and T6 have been mapped by the electron microscope heteroduplex method. The heteroduplexes show characteristic reproducible patterns of substitution and deletion loops. The heteroduplex maps have been oriented with respect to the T4 genetic map by observing the positions of several T4 rII deletion loops and a lysozyme deletion loop relative to the heteroduplex patterns. All heteroduplexes show more than 85% homology. Some of the loop patterns in $\text{T}\text{2}\text{T}\text{4}$ heteroduplexes are similar to those in $\text{T}\text{4}\text{T}\text{6}$.We find that the rII, the lysozyme and ac genes, the D region, and gene 52 are homologous in T2, T4, and T6. Genes 43 and 47 are probably homologous between T2 and T4. The region of greatest homology is that bearing the late genes. The host range region, which comprises a part of gene 37 and all of gene 38, is heterologous in T2, T4, and T6. The remainder of gene 37 is partially homologous in the $\text{T}\text{2}\text{T}\text{4}$ heteroduplex (Beckendorf et al. 1972), but it is heterologous in $\text{T}\text{4}\text{T}\text{6}$ and in $\text{T}\text{2}\text{T}\text{6}$. Some of the tRNA genes are homologous, and some are not. The internal protein genes in general seem to be nonhomologous.Most of the regions of homology and nonhomology are gene size or larger. There is no evidence for many partially homologous sequences. This is the expected situation for phages which undergo genetic recombination.The molecular lengths of the T-even DNA's are the same within experimental error; the ratio of this molecular length to that of λ DNA is 3.63 ± 0.06, corresponding to a molecular length of 170 kilobase pairs (kb). This suggests that the molecular weight of the nonglucosylated T-even DNAs, carrying hydroxymethylcytosine, is 112 ± 4 × 10⁶ daltons.Circular duplexes with single-stranded tails are observed by denaturation and renaturation of any one of the T-even DNAs because of its circular permutation and terminal repetition. The observed lengths of the circular duplexes indicate that the genome sizes are 166 ± 2 kb (T4), 164 ± 2 kb (T6), and 160 ± 2 kb (T2). Thus, T2 has a smaller genome than T4 and T6. The mean lengths of the terminal repetitions are 3.3 ± 1 kb (T4 and T6) and 9 ± 2 kb (T2). These differences in length of the terminal repetitions are consistent with the observed differences in genome size. The variability in length of the terminal repetition in any one phage is consistent with the interpretation that there is a variability of about 1% of the full molecular length in the amount of DNA packaged by the head-full mechanism.     

Workshop T: Novel Strategies for Vaccination and Immunotherapy, Abstract T1 bis T32

T. 1 Bioartificial immune support in an animal model of sepsisT. 2 Prevention of experimental herpetic stromal keratitis by topical cytokine plasmid-mediated immune modulationT. 3 Protection against leishmaniasis after vaccination with dendritic cells pulsed ex vivo with recombinant parasite antigensT. 4 MHC class I downregulation on HUVEC cells: An experimental approach for artificial vascular graft seedingT. 5 Oligodeoxynucleotides containing CpG motifs induce low levels of TNF-α in human B lymphocytes: Possible adjuvants for Th1 responsesT. 6 Complement activation by recombinant adenovirusesT. 7 Cure of Burkitt's lymphoma by T cells, CD3×CD19 tandem diabody, and CD28 costimulationT. 8 Prevention of experimental autoimmune enzephalomyelitis by a rationally designed synthetic RT1.Dⁿ nonapeptide ligandT. 9 Rebuilding the T cell compartment from the periphery with a mitogenic CD28-specific mAbT. 10 In utero DNA vaccination induces neonatal mucosal immunity and immune memoryT. 11 Induction of an intralesional Th2 phenotype and regression of psoriasis during interleukin-4 therapy in humansT. 12 Impact of chemokine receptor expression on the migration of antigen pulsed dendritic cellsT. 13 Induction of tumor-specific CTL using RNA transfected dendritic cellsT. 14 CD4⁺ T cells engrafted with a recombinant immunoreceptor efficiently lyse target cells in a MHC antigen- and FAS-independent fashionT. 15 Comparison of the immunomodulating effects of lipopeptide and saponin adjuvants in orally immunized miceT. 16 Blockade of CD40L during activation of the autoaggressive response prevents type 1 diabetes by inducing novel CD11c⁺DX5⁺ regulatory cellsT. 17 Anti-CD4 may differentially regulate the delayed-type hypersensitivity responseT. 18 Induction of specific anti-tetanus toxoid antibody responses after Haemophilus b conjugate vaccine (tetanus toxoid conjugate) ActHIBT. 19 Human anti-idiotypic antibodies cloned by phage display from a neuroblastoma patient as possible tumor vaccines against GD2 expressing tumorsT. 20 The combination poly-L-arginine/CpG-ODN acts as potent immunostimulatorT. 21 Lipopeptides as adjuvants for bacterial and viral vaccines: Studies on their molecular mode of actionT. 22 Analysis of immunodominant regions of the human CD4 molecule using a panel of anti-CD4 mAbsT. 23 Characterization of the antigen-specific CD4 T cell response to DNA vaccination and immunomodulation by co-immunization with cytokine genesT. 24 Crosspresentation of human shared tumor antigen by dendritic cells: Dual function of HSP70 as chaperone for tumor-derived T cell epitopes and cytokine for dendritic cell maturationT. 25 Attenuated Toxoplasma gondii ts-4 mutants engineered to express the Leishmania antigen KMP-11 elicit a specific immune response in BALB/c miceT. 26 A rapid highly efficient non-viral gene transfer method for unstimulated primary human blood cellsT. 27 Universal method for attaching diabodies to the surface of tumor cells for the enhancement of cellular vaccinesT. 28 Membrane-anchored recombinant anti-phOx single-chain antibodies for customized cellular tumor vaccinesT. 29 In vitro induction of a bladder cancer-specific T cell response by mRNA-transfected dendritic cellsT. 30 Gene delivery by attenuated Salmonella typhimurium: Comparing the efficacy of helper versus cytotoxic T cell priming in tumor vaccinationT. 31 Effect of renal cell carcinoma cells expressing GM-CSF and designer cytokine on tumor infiltrating antigen presenting cellsT. 32 A recombinant anti-CD5/human pancreatic ribonuclease immunotoxin for the therapy of B cell chronic lymphocytic leukemia: Evaluation in a preclinical model     

Growth of Porphyromonas gingivalis, Treponema denticola, T. pectinovorum, T. socranskii, and T. vincentii in a chemically defined medium.

A chemically defined medium, OMIZ (Oral Microbiology and Immunology, Zürich)-W1 was developed. Medium OMIZ-W1 supports the long-term proliferation of a wide range of oral anaerobes, including representative strains of four Treponema species and Porphyromonas gingivalis. High concentrations of ascorbic acid and ammonium ions proved to be important for the growth of these organisms. T. denticola CD-1 grew in the absence of polyamines and long-chain fatty acids, T. pectinovorum and T. socranskii required polyamines, whereas T. vincentii depended on both polyamines and lecithin for growth. Specific requirements for purines and/or pyrimidines were detected, and these requirements could be used to distinguish Haemophilus-Actinobacillus group organisms. Some strains of P. gingivalis grew without vitamin K, while others were not satisfied by menadione but required its precursor 1,4-dihydroxy-2-naphthoic acid. Protoporphyrin IX or hemin equally satisfied the porphyrin requirements of P. gingivalis and Bacteroides forsythus, whereas ferrous sulfate was more efficiently used as a source of iron than was hemin. The cellular cohesiveness of P. gingivalis increased with high concentrations of hemin in the growth medium. Prevotella intermedia, B. forsythus, and several strains of P. gingivalis were more fastidious and required a protein or serum supplement to grow in medium OMIZ-W1.     

Accurate,precise, simultaneous myocardial T1 and T2 mapping using a radial sequence with inversion recovery and T2 preparation

We propose a simultaneous myocardial T1 and T2 mapping technique using a radial sequence with inversion recovery and T2 preparation, which achieves high accuracy and precision, with T1 and T2 reproducibility similar to the Modified Look‐Locker Inversion recovery (MOLLI) sequence and the conventional bright blood T2 mapping technique, respectively. The sequence was developed by incorporating gold angle radial fast low angle shot (FLASH) readout combined with an inversion pulse and T2prep pulses. The extended Bloch equation simulation with slice profile correction (BLESSPC) algorithm was proposed to reconstruct T1 and T2 maps at the same time in a few seconds, while maintaining good T1 and T2 estimation accuracy. Accuracy and precision were compared among the proposed technique, MOLLI and conventional T2 mapping techniques using phantom studies, 10 healthy volunteers and three patients. In phantom studies, the proposed technique was more accurate than MOLLI (P < 0.05) while achieving similar precision (P = 0.3) in T1 estimation, and was more accurate (P < 0.05) and precise (P < 0.001) than conventional T2 mapping (two‐parameter fitting) in T2 estimation. In vivo, the proposed technique achieved significantly higher T1 values (P < 0.001) and similar reproducibility (P = 0.3) compared with MOLLI, with significantly lower T2 values (P < 0.001) and similar reproducibility (P = 0.6) compared with the conventional T2 mapping technique. Thus, the proposed radial T1‐T2 mapping technique allows for accurate, precise, simultaneous myocardial T1 and T2 mapping in an 11‐heartbeat single breath‐hold acquisition.     

Dopamine and T cells: dopamine receptors and potent effects on T cells,dopamine production in T cells,and abnormalities in the dopaminergic system in T cells in autoimmune,neurological and psychiatric diseases

Dopamine, a principal neurotransmitter, deserves upgrading to ‘NeuroImmunotransmitter’ thanks to its multiple, direct and powerful effects on most/all immune cells. Dopamine by itself is a potent activator of resting effector T cells (Teffs), via two independent ways: direct Teffs activation, and indirect Teffs activation by suppression of regulatory T cells (Tregs). The review covers the following findings: (i) T cells express functional dopamine receptors (DRs) D1R‐D5R, but their level and function are dynamic and context‐sensitive, (ii) DR membranal protein levels do not necessarily correlate with DR mRNA levels, (iii) different T cell types/subtypes have different DR levels and composition and different responses to dopamine, (iv) autoimmune and pro‐inflammatory T cells and T cell leukaemia/lymphoma also express functional DRs, (v) dopamine (~10^?8M) activates resting/naive Teffs (CD8⁺>>>CD4⁺), (vi) dopamine affects Th1/Th2/Th17 differentiation, (vii) dopamine inhibits already activated Teffs (i.e. T  cells that have been already activated by either antigen, mitogen, anti‐CD3 antibodies cytokines or other molecules), (viii) dopamine inhibits activated Tregs in an autocrine/paracrine manner. Thus, dopamine ‘suppresses the suppressors’ and releases the inhibition they exert on Teffs, (ix) dopamine affects intracellular signalling molecules and cascades in T cells (e.g. ERK, Lck, Fyn, NF‐κB, KLF2), (x) T cells produce dopamine (Tregs>>>Teffs), can release dopamine, mainly after activation (by antigen, mitogen, anti‐CD3 antibodies, PKC activators or other), uptake extracellular dopamine, and most probably need dopamine, (xi) dopamine is important for antigen‐specific interactions between T cells and dendritic cells, (xii) in few autoimmune diseases (e.g. multiple sclerosis/SLE/rheumatoid arthritis), and neurological/psychiatric diseases (e.g. Parkinson disease, Alzheimer's disease, Schizophrenia and Tourette), patient's T cells seem to have abnormal DRs expression and/or responses to dopamine or production of dopamine, (xiii) drugs that affect the dopaminergic system have potent effects on T cells (e.g. dopamine=Intropin, L‐dopa, bromocriptine, haloperidol, quinpirole, reserpine, pergolide, ecopipam, pimozide, amantadine, tetrabenazine, nomifensine, butaclamol). Dopamine‐induced activation of resting Teffs and suppression of Tregs seem beneficial for health and may also be used for immunotherapy of cancer and infectious diseases. Independently, suppression of DRs in autoimmune and pro‐inflammatory T cells, and also in cancerous T cells, may be advantageous. The review is relevant to Immunologists, Neurologists, Neuroimmunologists, Hematologists, Psychiatrists, Psychologists and Pharmacologists.     

A biochemical comparison of the related bacteriophages T7, phiI, phiII, W31, H, and T3

The female-specific coliphages T7, T3, φI, φII, W31, and phage H have been compared by several biochemical techniques. The DNA base-sequence homologies have been determined by examining the appropriate heteroduplexes in the electron microscope. The patterns of RNA and protein syntheses have been investigated by electrophoreses of the radioactively labeled material on polyacrylamide gels. Phages φI, φII, W31, and H are clearly closely related to T7 and more distantly related to T3.     

A comparative study of the proteolytic enzymes of Trypanosoma brucei, T. equiperdum, T. evansi, T. vivax, Leishmania tarentolae and Crithidia fasciculata

Four types of proteolytic activity were detected in the bloodstream form of each of the four Trypanosoma species: (i) HPAase, active on hide powder azure and detected on polyacrylamide gels containing denatured haemoglobin; (ii) AZCase, active on azocasein; (iii) type 1, active on the chromogenic peptide N-benzoyl-L-prolyl-L-phenylalanyl-L-arginine p-nitroanilide in the presence of dithiothreitol, and (iv) type 2, active against several nitroanilide derivatives in the absence of dithiothreitol. Studies of the pH optimum, dithiothreitol requirement and inhibitor sensitivities of the proteolytic activities suggested that: (a) HPAase and type 1 activities could be due to the same enzymes, probably a family of cysteine proteinases; (b) AZCase had some characteristics of a cysteine proteinase, but was not identical to HPAase, and (c) type 2 activity could be due to a serine proteinase. Procyclic T. brucei contained relatively low cysteine proteinase activities (HPAase, AZCase and type 1) but high type 2 activity. Their proteolytic enzymes thus were apparently more similar to those in Crithidia fasciculata and Leishmania tarentolae promastigotes than those in T. brucei bloodstream forms.