A Role of Suppressor of Cytokine Signaling 3 (SOCS3/CIS3/SSI3) in CD28-mediated Interleukin 2 Production

Suppressor of cytokine signaling (SOCS)3 has been characterized as a negative feedback regulator in cytokine-mediated Janus kinase signal transducer and activator of transcription signaling. However, this study shows that T cells from transgenic mice expressing SOCS3 exhibit a significant reduction in interleukin (IL)-2 production induced by T cell receptor cross-linking when T cells are costimulated with CD28. Decreased protein expression in SOCS3+/− mice enhanced CD28-mediated IL-2 production, clearly indicating the correlation between expression level of SOCS3 and IL-2 production ability. The SOCS3 protein interacted with phosphorylated CD28 through its SH2 domain but not the kinase inhibitory region. In addition, a point mutation in the SOCS3 SH2 domain attenuated the inhibition of CD28 function in IL-2 promoter activation. Committed T helper (Th)2 cells exclusively expressed SOCS3 and production of Th2 cytokines, such as IL-4 and IL-5, was much less dependent on CD28 costimulation compared with interferon γ and IL-2 production in Th1 cells. Consistent with this notion, the expression level of SOCS3 in early T cell activation influenced the ability of IL-2 production induced by CD28 costimulation. Therefore, the SOCS3 may play an alternative role in prohibiting excessive progression of CD28-mediated IL-2 production

Mite-antigen Stimulates MAL Expression in Peripheral Blood T Cells of Mite-sensitive Subjects

ABSTRACTBackgroundDifferential gene expression in CD3+ T cells from allergic patients stimulated with allergen will provide important information on the responses of T cells.MethodsAfter stimulation of peripheral blood mononuclear cells (PBMCs) with mite extracts, levels of gene transcription were examined in CD3+ T cells from allergic patients.ResultsStimulation of PBMCs from mite specific IgE positive subjects resulted in specific upregulation of MAL transcription levels that was mediated by IL-4 secretion. The MAL protein in IL-4 stimulated primary T cells preferentially localized in glycolipid-enriched membrane (GEM) microdomains. When MAL was exogenously expressed in primary T cells, CD3ζ was concomitantly enriched, along with the expression of MAL, in GEM microdomains.ConclusionsGEMs are important for the formation and stabilization of TCR signaling complexes. Therefore, MAL may play a role in the formation of GEMs in activated T cells and the high expression of MAL may contribute to Th2 immune response

Plasma progesterone profiles in Beagle bitches with and without the whelping experience

The aim of this study was to investigate differences between the progesterone profiles of Beagle bitches with (multiparous) and without (nulliparous) the whelping experience and to examine whether the selection of bitches by progesterone analyses before the programmed mating improved the whelping rates. In the first experiment, the progesterone profiles of nulliparous and multiparous bitches were evaluated from Days 1 to 13 (onset of prooestrus = Day 0). The mean duration of the elevation in progesterone levels (> 2 ng/mL) after the onset of prooestrus tended to be approximately 1 day shorter in nulliparous bitches (7.7 days) than in multiparous bitches (8.5 days). In the second experiment, progesterone analyses in the bitches were carried out once on Days 4, 5 or 6. Bitches with progesterone levels of > 10 ng/mL were excluded from mating because it was unclear when the progesterone levels reached > 10 ng/mL considering the optimal date for mating. No significant differences were observed in the percentages of bitches excluded from mating and in the whelping rates of the mated bitches between the groups, irrespective of the day of progesterone analysis and the type of bitch. In conclusion, the initial elevation of progesterone levels was of shorter duration in nulliparous bitches. The selection of bitches by the measurement of progesterone levels once before mating was not effective for the programmed mating

IL-7/STAT5 cytokine signaling pathway is essential but insufficient for maintenance of naive CD4 T cell survival in peripheral lymphoid organs

Abstract Constitutive expression of suppressors of cytokine signaling (SOCS)1 in T lineage in vivo attenuated cytokine signaling and resulted in a dramatic reduction in the number of naive CD44lowCD62Lhigh CD4 T cells in the spleen. After adoptive transfer of thymocytes from SOCS1 transgenic mice into normal recipients, naive CD4 T cells rapidly disappeared from the spleen within 1 wk. Likewise, T cell-specific deletion of STAT5a/b in vivo resulted in a similar phenotype characterized by loss of naive CD4 T cells. Thus, STAT5-mediated signaling is crucial for promoting naive T cell survival. However, forced expression of constitutively active STAT5 failed to rescue CD4 T cells in SOCS1 transgenic mice, implying that STAT5 activation is necessary but not sufficient for naive CD4 T cell survival. Although blockade of the IL-7R, a SOCS1 target, resulted in clear inhibition of naive T cell survival, the effect occurred 3 wk after anti-IL-7R Ab treatment, but not at earlier time points. These results suggest that IL-7-mediated STAT5 activation is essential for long-term survival of naive CD4 cells after export from thymus, and that another SOCS1-sensitive cytokine is critical for short-term naive T cell survival.</jats:p