SummaryInterleukin 10 (IL-10) and viral Ibl0 (v-IL-10) strongly reduced antigen-specific proliferation of human T cells and CD4 + T cell clones when monocytes were used as antigen-presenting cells. In contrast, IL-10 and v-Ibl0 did not affect the proliferative responses to antigens presented by autologous Epstein-Barr virus-lymphoblastoid cell line (EBV-LCL). Inhibition of antigen-specific T cell responses was associated with downregulation of constitutive, as well as interferon 3'-or Ib4-induced, class II MHC expression on monocytes by IL-10 and v-Ibl0, resulting in the reduction in antigen-presenting capacity of these ceUs. In contrast, IL-10 and v-Ibl0 had no effect on class II major histocompatibility complex (MHC) expression on EBV-LCL. The reduced antigenpresenting capacity of monocytes correlated with a decreased capacity to mobilize intracellular Ca 2 + in the responder T cell clones. The diminished antigen-presenting capacities of monocytes were not due to inhibitory effects of II.-10 and v-Ibl0 on antigen processing, since the proliferative T cell responses to antigenic peptides, which did not require processing, were equaUy well inhibited. Furthermore, the inhibitory effects of Ibl0 and v-IL-10 on antigen-specific proliferative T cell responses could not be neutralized by exogenous Ib2 or Ib4. Although IL-10 and v-IL-10 suppressed IL-lc~, IL-1B, tumor necrosis factor ot (TNF-c~), and IL-6 production by monocytes, it was excluded that these cytokines played a role in antigen-specific T cell proliferation, since normal antigenspecific responses were observed in the presence of neutralizing anti-Ibl, -IL-6, and -TNF-tx mAbs. Furthermore, addition of saturating concentrations of IL-lot, IL-I~, IL-6, and TNF-o~ to the cultures had no effect on the reduced proliferative T cell responses in the presence of Ibl0, or v-Ibl0. Collectively, our data indicate that IL-10 and v-IL-10 can completely prevent antigen-specific T cell proliferation by inhibition of the antigen-presenting capacity of monocytes through downregulation of class II MHC antigens on monocytes.

Moving beyond the historical and theoretical traditions that have defined teacher education in TESOL over the last quarter century, in this introductory piece we argue for a reconceptualization of the knowledge-base of ESOL teacher education. Essential to this reconceptualization is the premise that the institutional forms and processes of teacher education frame how the profession responds to the basic sociocultural processes of learning to teach. As such, our teacher education practices constitute our professional self-definition. We argue that the core of the new knowledge-base must focus on the activity of teaching itself; it should center on the teacher who does it, the contexts in which it is done, and the pedagogy by which it is done. Moreover, this knowledge-base should include forms of knowledge representation that document teacher learning within the social, cultural, and institutional contexts in which it occurs. Finally, we believe the knowledge-base of language teacher education needs to account for the teacher as a learner of teaching, the social context of schools and schooling within which teacher-learning and teaching occur, and the activities of both language teaching and language learning. This tripartite framework calls for a broader epistemological view of ESOL teacher education, one that accounts for teaching as it is learned and as it is practiced; we argue that it will ultimately redefine how we as teacher educators create professionals in TESOL.

Although the overall mission of second language (L2) teacher education has remained relatively constant, that is, to prepare L2 teachers to do the work of this profession, the field's understanding of that workof who teaches English, who learns English and why, of the sociopolitical and socioeconomic contexts in which English is taught, and of the varieties of English that are being taught and used around the worldhas changed dramatically over the past 40 years. This article examines the epistemological underpinnings of a more general sociocultural turn in the human sciences and the impact that this turn has had on the field's understanding of how L2 teachers learn to do their work. Four interrelated challenges that have come to the forefront as a result of this turn are discussed: (a) theory/practice versus praxis, (b) the legitimacy of teachers' ways of knowing, (c) redrawing the boundaries of professional development, and (d) "located" L2 teacher education. In addressing these challenges, the intellectual tools of inquiry are positioned as critical if L2 teacher education is to sustain a teaching force of transformative intellectuals who can navigate their professional worlds in ways that enable them to create educationally sound, contextually appropriate, and socially equitable learning opportunities for the students they teach.

We have demonstrated the existence of human cytokine synthesis inhibitory factor (CSIF) [interleukin 10 (IL-10)]. cDNA clones encoding human IL-10 (hIL-10) were isolated from a tetanus toxin-specific human T-cell clone. Like mouse IL-10, hIL-10 exhibits strong DNA and amino acid sequence homology to an open reading frame in the EpsteinBarr virus, BCRFI. hIL-lO and the BCRFI product inhibit cytokine synthesis by activated human peripheral blood mononuclear cells and by a mouse Thl clone. Both hIL-10 and mouse IL-1O sustain the viability of a mouse mast cell line in culture, but BCRFI lacks comparable activity in this assay, suggesting that BCRFI may have conserved only a subset of hIL-10 activities.

No abstract