ABSTRACT
We addressed the question whether it is possible to lower the threshold for naive T cells to respond to antigens. Purified adult and cord blood derived CD4+ CD45RA+ naive T cells were incubated in the presence of various cytokines for two days ("primed T cells"), after which the cytokines were removed by extensive washing. Primed and unprimed cells were activated with solid phase-coupled anti-CD3 and soluble anti-CD28 monoclonal antibodies (MoAb). Naive T cells, primed with interleukin(IL)-7 proliferated more vigorously than unprimed cells. Primed cells required 6 h for antigenic stimulation, whereas unprimed cells required 20 h. The priming also shifted the threshold of naive T cells in order to stimulate the antigen concentration to a lower level. The addition of IL-10 almost completely abrogated the enhancing effect of IL-7 on naive T cells. Other cytokines (IL-1, IL-2, IL-6, IL-12, interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha had less effect on the cell proliferation. However, priming of naive T cells with IL-7 had no impact on the proliferation to allogeneic immature or mature dendritic cells (DC). We conclude that the antigen-independent activation of naive T cells with IL-7 prior to antigen stimulation sensitizes cells, and may be of help in trying to stimulate immune responses against weak antigens. This approach, however, does not enhance proliferative responses stimulated by DC.
Subject(s)
CD4-Positive T-Lymphocytes/immunology , Interleukin-7/pharmacology , Adult , Antibodies, Monoclonal/pharmacology , CD28 Antigens/metabolism , CD3 Complex/metabolism , Cytokines/pharmacology , Humans , In Vitro Techniques , Infant, Newborn , Interleukin-10/pharmacology , Lymphocyte Activation , Receptors, Antigen, T-Cell/metabolismABSTRACT
The relationship between simultaneous and successive processing and their assumed underlying neuro-anatomical structures was examined. According to the model of Das, Kirby, and Jarman (1975, 1979) simultaneous processing, occurs mainly in the posterior parts of the brain (parieto-occipital areas) and successive processing in anterior regions of the brain (fronto-temporal areas). The theory of lateralized hemispheric specialization suggests differences in processing due to right-left hemispheric differences. A battery of measures was factor-analyzed and simultaneous and successive factors identified in 106 brain-damaged adults and a control group. The brain damaged group was divided into four subgroups, left and right anterior and left and right posterior groups. The two-way ANOVA revealed no interactions (laterality x anterior/posterior), but instead two main effects for laterality on simultaneous verbal (p<.01) and successive (p<.05) processing and one weak (p<. 10) main effect for anterior/posterior divisions of simultaneous nonverbal processing. It was concluded that the results partially supported both assumed neuropsychological models of processing.
