Cytotoxic T lymphocytes (CTL) are important for the recognition and lysis of virally infected cells, but their effectiveness can be limited by viral immune evasion mechanisms. We investigated the immunophenotype and function of human CD8 T cells raised in response to herpes simplex virus (HSV). The expanded population contained cells of an activated and mature phenotype, as determined by the expressions of CD25, CD45RO, CD57, CD95 and HLA-DR. Cultured cells also expressed CD45RA. These cells lysed autologous and allogeneic HSV-infected lymphoblastoid cell line (LCL) targets via a non-major histocompatibility complex (MHC) restricted recognition pathway. Inhibition assays showed the mechanism of cytotoxicity to be calcium-dependent, granule exocytosis pathway, rather than the internal disintegration pathway. Cold target competition assays indicated that a common CTL population contributed to the recognition of autologous and allogeneic-infected targets. These effectors showed recognition of infected targets which was distinct from that of K562 cells. Non-MHC restricted lysis-associated molecule 2B4 (CD244) was upregulated on culturing and made a significant contribution to lysis of FcgR-bearing targets in a redirected killing assay. These findings suggest that CTL can recognize virally infected cells through a combination of non-MHC restricted mechanisms and may result in more efficient lysis than classical CD8 T cells.
Natural killer cell (NKC) cytotoxicity and antibody-dependent cellular cytotoxicity (ADCC) represent the ability of human leukocyte effector cells to destroy target cells in the absence and presence of antibody, respectively. Since these immune systems play a pivotal role in the body's primary lines of defense against a variety of pathogens including herpes simplex virus (HSV), a study was undertaken to evaluate the influence of pregnancy on these systems. Eleven uncomplicated gravidas were followed serially through each trimester and compared to 11 nonpregnant female controls. Mononuclear cells were acquired by Ficoll-Hypaque centrifugation of heparinized blood. Chang liver cells infected with HSV-I were utilized as target cells in a 51Cr release assay. Mean NKC values in the pregnant patients were uniformly lower than in the controls. No similar decreases in ADCC activity were observed in a comparison between the two study populations. These data support previous observations suggesting that pregnancy represents a relatively immunocompromised state. Differences apparently exist between NKC and ADCC effector cell populations with regard to the influence of pregnancy. Although these physiologic alterations in immunoregulation may help support the fetoplacental allograph, detrimental conditions may exist regarding susceptibility to various pathogens such as HSV.
In this article, we examine three literacy autobiographies written by pre-service teachers. Narratives are seen as not just stories relating a set of facts, but rather a means by which individuals interpret their experience. Literacy autobiographies are a reflective and interpretive account of one's development as a literate being. Using the tools of narrative analysis, we (a) examine these stories to understand the processes of literacy development through the experiences of learners' storied lives; (b) seek to understand the impact that teachers' literacy journeys have on their view of literacy and literacy education; and (c) explore what these literacy autobiographies reveal about the contributions of teacher reflection to pre-service teacher education. Our analysis points to the importance of personal relationships in the development of literacy, providing the context within which literacy practices give meaning to the literacy events active in the narrators' lives. We also note a persistent view of traditional forms of literacy in contrast to pre-service teachers' involvement in multiliteracies, and argue that this gap needs to be addressed in order to prepare teachers for the twenty-first century classroom. We also consider how reflection can be a more intentional aspect of pre-service teacher education to enhance pedagogy and learning.
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