Reciprocal Reactivity Research Articles

CD4 +CD25 + regulatory T cells in HIV infection

The immune system faces the difficult task of discerning between foreign, potentially pathogen-derived antigens and self-antigens. Several mechanisms, including deletion of self-reactive T cells in the thymus, have been shown to contribute to the acceptance of self-antigens and the reciprocal reactivity to foreign antigens. Over the last decade it has become increasingly clear that CD4 +CD25 + T Reg cells are crucial for maintenance of T cell tolerance to self-antigens in the periphery, and to avoid development of autoimmune disorders. Recently, evidence has also emerged that demonstrates that CD4 +CD25 + T Reg cells can also suppress T cell responses to foreign pathogens, including viruses such as HIV. In this article we review the current knowledge and potential role of CD4 +CD25 + T Reg cells in HIV infection.

One‐step functionalization of an ethylene/propylene random copolymer with two different reactive groups

AbstractThe efficiency of a macromolecular compatibilizer for reactive blending is strongly dependent on its potentiality of producing a grafted or block copolymer during processing. For the preparation of such a compatibilizer, the grafting of two different reactive groups onto the backbones of ethylene/propylene copolymer macromolecules was performed. The ethylene/propylene (70/30) copolymer was then processed in a Brabender mixer at 190°C in the presence of a mixture of maleic anhydride and diethylmaleate with either dicumyl peroxide or di‐tert‐butyl peroxide as an initiator. The experiments clearly showed that the two functionalities, 2‐diethyl succinate and 2‐succinic anhydride, could be grafted in one step. The effect of the feed composition demonstrated that the two monomers influenced the reciprocal reactivity and the resulting product. A detailed Fourier transform infrared analysis of the grafted macromolecules was performed, and the respective amounts of ester and anhydride derived groups were detected by deconvolution of the vibrational bands in the carbonyl spectral region. The validity of the process on an industrial scale was tested by the successful performance of the reaction in a twin‐screw extruder. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 14–23, 2003

Dephosphorylation of the phosphoprotein P(II) in Synechococcus PCC 7942: identification of an ATP and 2-oxoglutarate-regulated phosphatase activity.

The phosphorylation state of the putative signal transduction protein P(II) from the cyanobacterium Synechococcus sp. strain PCC 7942 depends on the cellular state of nitrogen and carbon assimilation. In this study, dephosphorylation of phosphorylated P(II) protein (P[II]-P) was investigated both in vivo and in vitro. The in vivo studies implied that P(II)-P dephosphorylation is regulated by inhibitory metabolites involved in the glutamine synthetase-glutamate synthase pathway of ammonium assimilation. An in vitro assay for P(II)-P dephosphorylation was established that revealed a Mg2+-dependent P(II)-P phosphatase activity. P(II)-P phosphatase and P(II) kinase activities could be separated biochemically. A partially purified P(II)-P phosphatase preparation also catalysed the dephosphorylation of phosphoserine/phosphothreonine residues on other proteins in a Mg2+-dependent manner. However, only dephosphorylation of P(II)-P was regulated by synergistic inhibition by ATP and 2-oxoglutarate. As the same metabolites stimulate the P(II) kinase activity, it appears that the phosphorylation state of P(II) is determined by ATP and 2-oxoglutarate-dependent reciprocal reactivity of P(II) towards its phosphatase and kinase.

Variation with composition of the intrinsic sensitivity of halogen-substituted styrene copolymers to electron-beam radiation

In the polymer literature (Handbook of Polymer Science and Technology, ed. N. P. Cheremisinoff, Marcel Dekker, New York, 1989, vol. 1, p. 307) a simple equation has been derived to estimate the lithographic sensitivity of a copolymer of known composition and molecular weight from the constituent homopolymer values. Sensitivity has often been equated with the reactivity parameter DgMw where Dg is the gel dose and Mw the weight-average molecular weight of the polymer. This report demonstrates that the use of the reciprocal reactivity (DgMw)–1 leads to a clearer interpretation of the lithographic results and that furthermore, the conclusions drawn from earlier analyses neglect the consequences of co-operative action between differing monomer units within copolymers.

Characterization of human peripheral lymphocytes expressing the CD3-gamma/delta complex with anti-receptor monoclonal antibodies.

Three mAb, anti-Ti gamma A, anti-TCR delta 1, and anti-delta TCS1, have been developed against the CD3-associated gamma/delta molecular complex. One of this antibody anti-Ti gamma A is specific for an epitope encoded by the V9 gamma-gene. The two others react with the delta-chain but their fine epitopic specificity has not been characterized previously. In the present study, we have compared the surface expression of these three antigenic determinants on 27 cloned and 5 polyclonal CD3+ TCR gamma/delta + cell lines derived from human peripheral blood of 13 distinct individuals. It was found that all CD3+ TCR alpha/beta- clones and polyclonal cell lines tested were recognized by anti-TCR delta 1. In contrast, only a fraction of both clones and cell lines reacted with either anti-Ti gamma A or anti-delta TCS1 mAb. In fact reactivity of the latter reagents was found to be mutually exclusive on the cell panel. Northern blot analysis of RNA extracted from a series representative clones showed a positive correlation between the surface expression of the delta TCS1 epitope and the transcription of the V-delta gene isolated from the IDP2 cell line. These data support the view that anti-TCR delta 1 can be used to positively define the entire TCR gamma/delta+ fraction. Moreover, the reciprocal reactivity of anti-delta TCS1 and anti-Ti gamma A on cultured cell lines suggests that these reagents should delineate in human peripheral blood distinct, essentially non-overlapping, subsets. Taken together, the present results indicate that the complementary use of these three antibodies will be helpful to further characterize the TCR gamma/delta + peripheral lymphocyte fraction.

Role of the H-2 complex in the induction of T cell tolerance to self minor histocompatibility antigens.

The present study has utilized cytotoxic T lymphocyte (CTL) responses specific for minor histocompatibility (minor H) antigens as an experimental approach to determining whether recognition of self MHC determinants is involved in the induction of T cell tolerance to self antigens. It was observed that C3H.SW splenic T cells from C3H.SW leads to B10 X B10.BR radiation bone marrow chimeras contained CTL precursors (pCTL) reactive against self C3H minor H antigens + H-2k but were tolerant to self C3H minor H antigens + H-2b. Precursor CTL with the reciprocal reactivity pattern were observed for C3H leads to B10 X B10.BR chimeras. In addition, it was observed that C3H.SW thymocytes from C3H.SW leads to B10 X B10.BR chimeras could generate minor H-specific CTL responses and were reactive against self C3H minor H antigens + H-2k, but were tolerant to self C3H minor H antigens + H-2b. Thus, the present study demonstrates that for peripheral and intrathymic T cell populations at least a component of T cell tolerance to self antigens is restricted by products of the MHC.

The polypeptides of canine distemper virus: Synthesis in infected cells and relatedness to the polypeptides of other morbilliviruses

The biochemical and immunological properties of the polypeptides of canine distemper virus (CDV), their synthesis and processing in infected cells, and their relatedness to the polypeptides of other morbilliviruses have been studied. CDV virions contain six major polypeptides which are analogous to those of measles virus (MV). These polypeptides with their estimated molecular weights ( m r) are: L (200,000); H (76,000); P (66,000); NP (58,000); F (62,000), which consists of two disulfide-linked polypeptides, F 1 (40,000) and F 2 (23,000); and M (34,000). The H, F 1, and F 2 polypeptides of CDV are glycosylated; the presence of carbohydrate on F 1 is in contrast to its absence on the F 1 of MV. The CDV F 2 has a larger apparent M r than the MV F 2 (23,000 vs 12,000). The NP and P polypeptides of CDV are phosphorylated, and in pulse-chase experiments in CDV-labe;ed cells the P polypeptide was rapidly lost. In addition to the structural polypeptides, a putative nonstructural protein, NS ( M r ∼ 18,000), was found in CDV-infected cells. The polypeptide also turned over rapidly in pulse-chase experiments. The immunological relatedness of the polypeptides of MV and CDV and of two other morbilliviruses, rinderpest (RV) and a bovine encephalitis virus (107) was shown by immuno-precipitation of the viral polypeptides from CDV- and MV-infected cells with antisera against each of the four viruses. The only failure to exhibit reciprocal reactivity between CDV and MV was found with the H polypeptides, where only a one-way cross was found, i.e., MV antiserum precipitated all of the CDV polypeptides, whereas CDV antiserum precipitated all of the MV polypeptides except H. RV antiserum resembled that of MV; it precipitated all of the polypeptides of both MV and CDV, whereas 107 antiserum, like that of CDV, precipitated all of the CDV polypeptides and all of the MV polypeptides except H. These results indicate that these four morbilliviruses with different host ranges are antigenically closely related, with MV apparently more closely related to RV, and CDV to 107 virus. In spite of their antigenic similarities, the individual polypeptides of CDV and MV could be easily distinguished by peptide mapping. Some similarities were found in the internal polypeptides P, NP, and M, but very little in the surface glycoproteins, H and F 1.

The effects of reciprocal reactivity on positively and negatively valenced self-rated behaviors

Reactivity refers to behavioral changes that occur in a target behavior when some assessment procedure is used to record that behavior (Webb. Campbell. Schwanz and Sechrest, 1966). One example of these reactive effects is the change in response frequency that occurs when individuals are asked to self-record their own behavior. Several studies have demonstrated that self-recorded behaviors will increase or decrease in frequency (Ciminero. Nelson and Lipinski. 1977). Kanfer (1970) speculated that the direction of this reactive behavior change is related to the social norms or valence of the response. Thus, appropriate or positively valenced behaviors are likely to increase when they are self-monitored whereas inappropriate or negatively valenced behaviors would be more likely to decrease (e.g. Broden. Hall and Mitts. 1971). Cavior and Marabotto (1976) directly examined the effects of behavior valence on the direction of change due to self-monitoring. They used heterosexual dyads to compare the effects of various monitoring procedures on behaviors that were selected by subjects as having one of three valences: High social desirability, neutral social desirability, or low social desirability. They found that the valence of a target behavior was important in determining the direction of change: positive verbal behaviors increased whereas negative verbal behaviors decreased during the dyadic interactions. Reactive effects other than those found in self-monitoring have also received some attention. In an examination of the parameters of reactivity Ciminero. Graham and Jackson (1977) studied a phenomenon they labelled reciprocal reactivity. This term describes the behavior changes that occur in individuals who are asked to record the behavior of others. Ciminero et al. reported four single-case designs in which parameters of reciprocal reactivity were examined in female dyads. In the first three experiments, various motor responses (e.g. leg-kicking, head-nodding, or face-touching) decreased in subjects when they were asked to monitor those behaviors in their partners. The fourth experiment showed that self-monitoring resulted in greater decreases in response rate than did the reciprocal reactivity. As with self-monitoring, the valence of the target behavior may have an important influence on the direction of the behavior change due to reciprocal reactivity. Since the valence of behaviors targeted in the study by C iminero et al. (1977) were not specifically evaluated the effects of valence could not be established. Therefore, the present study was designed to replicate the effects of reciprocal reactivity and to examine the influence of the valence of the target behaviors.

Reciprocal reactivity: Response-specific changes in independent observers

Recording another person's behavior within a dyadic interaction of femalecollege students changed the behavior of the member of the dyad who served as the observer . This phenomenon, labeled “reciprocal reactivity”, was investigated in four separate single-case experiments. Experiment 1 demonstrated that the observer's response rate changed systematically whenever she was instructed to record the other subject's behavior, and Experiments 2 and 3 demonstrated that the reactive effects were limited to the particular response being recorded. All three experiments found that the reactive effects dissipated as soon as the observation was discontinued. In Experiment 4, reciprocal reactivity was found to be weaker than the reactive effects of self-observation.

Exact solution of the reactor kinetics equations for linear, exponential, or reciprocal reactivity dependence on time

Les équations générales de la dynamique des réacteurs nucléaires à basse puissance sont intégrées au moyen d'intégrales du type de Laplace pour les trois cas de variation linéaire, exponentielle ou réciproque (1/t) de la réactivité. Dans les premier et deuxième cas, la solution exacte peut être écrite respectivement sous la forme de fonction généralisée du cylindre parabolique et de fonction G de Meijer. Lorsque l'effet des neutrons retardés est représenté par un seul groupe équivalent, la solution peut être exprimée dans les trois cas au moyen de la fonction confluente hypergéométrique.