Further Characterization of an Interleukin-2-1Ike Cytokine Produced by Xenopus Laevis T Lymphocytes

A T-cell growth factor (TCGF) is produced by antigen- or mitogen-stimulated T lymphocytes from the South African clawed frog Xenopus laevis. This study further defines the physical and biological properties of this cytokine and demonstrates that TCGF is biochemically similar to mammalian interleukin-2 (IL-2). Biologically active TCGF eluted from SDS-PAGE displays a M_r of 16 kD and lectin-affinity chromatography indicates that the three-dimensionmal configuration of carbohydrates on TCGF and human IL-2 is similar. Secretion of TCGF is detectable 1 day after stimulation of splenocytes with the T-cell mitogen phytohemagglutinin (PHA) and peaks following 2 to 3 days of stimulation. Finally, despite the biological and physical similarities between Xenopus TCGF and mammalian IL-2, anti-human IL-2 monoclonal antibodies do not recognize Xenopus TCGF.     

Delayed antiretroviral therapy in HIV-infected individuals leads to irreversible depletion of skin- and mucosa-resident memory T cells

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Interleukin-21 is a T-helper cytokine that regulates humoral immunity and cell-mediated anti-tumour responses

Cytokines and their receptors represent key targets for therapeutic intervention. Ligands are being used to supplement cell numbers that become depleted as a result of disease (organ failure, infection) or subsequent disease treatments (i.e. chemotherapy). Conversely, the inhibition of target cell binding by cytokines is an established strategy for abrogating pathologic cellular activities common to many immunological diseases. Considerable effort in biomedical research is being focused on the cytokine families that play a dominant role in regulating immunity and then prioritizing each member for its therapeutic potential. Currently, the interleukin-2 (IL-2) family of cytokines is widely recognized for its central involvement in controlling lymphocyte function and is the most explored for medical utility. Collectively, these proteins (or their antagonists) are either marketed drugs or have received advanced testing for an impressive array of indications including cancer, infectious disease, transplantation, inflammation and allergic asthma. Here we review the current understanding of IL-21, the most recent member of this cytokine family to be discovered. As will be discussed, IL-21 shares many of the same attributes as its relatives in that it has broad immunoregulatory activity and can modulate both humoral and cell-mediated responses. Its ability to stimulate durable anti-tumour responses in mice defines one therapeutic indication that merits clinical development.     

Immunoglobulin leakiness in scid mice with CD4(+) T-cell-induced chronic colitis

Inflammatory bowel disease in scid mice is initiated by transplantation of CD4(+) T-cells from immunocompetent syngenic donor mice. As the disease progresses, immunoglobulin (Ig)-containing cells appear in the gut lamina propria, suggesting that locally accumulating Ig may play a role in disease development. In the present work we have investigated the relationship between disease progression and patterns or levels of Ig isotypes in the feces of scid mice suffering from an ongoing colitis. The data clearly showed that the severity or progression of the disease did not influence the levels of IgA, IgG1, IgG2a, IgG2b, and IgG3, whereas the level of fecal IgM increased during the course of colitis. The presence of the serum protein alpha-1-antitrypsin in fecal extracts from diseased mice suggests that some of the fecal Ig has leaked through the inflamed epithelial membrane into the gut lumen. Finally, Ig-containing cells were observed in mesenteric lymph nodes and in the spleen, suggesting that the fecal Ig is produced both systemically and locally in the gut wall. In conclusion, the present results demonstrate that the level of IgM increases as colitis progresses. Also, the five remaining major Ig isotypes are increased in the gut lumen of scid mice with colitis, but the individual Ig types vary randomly during the course of the disease. Thus, it is unlikely that immunoglobulins are involved in the immunopathogenesis of this model of colitis.     

On-line respiratory artefact removal via adaptive FIR filters in rheopneumographic measurement

Impedance rheopneumography is a simple non-invasive technique that can reflect the vascular condition in the human pulmonary circulatory system. However, the much larger and almost in-banding respiratory artefact present has greatly restricted its usefulness to only respiratory patients of a less severe type, in view of the existing practice of requiring the subject to stop breathing momentarily during measurement. Conventional fixed or adaptive filtering cannot satisfactorily remove the artefact in view of the non-time stationary characteristic of the latter. In the paper, a fast adaptive FIR filter design method, which is based on the filter coefficient look-up table (CLT) concept, is presented as a solution. The CLT is constructed with the coefficients indexed to the cut-off frequency to separate the two components of the plethysmogram. An on-line fast Fourier transform is calculated to track the cut-off frequency. This filter can adaptively change its coefficients, not only for different subjects, but also for the same subject during long-term monitoring. Results show that this filter design is capable of providing an almost respiratory artefact-free signal for a majority of patients. The high speed of implementation also renders it a possibility for real-time monitoring applications.     

Prevalence of antibody to current influenza virus strains in adolescents

During the Spring of 1986, 118 pupils aged 15-18 years were surveyed for the presence of humoral antibodies to five influenza strains. Prevalence of humoral immunity (HI) antibodies and immunity was found to be related to the year of the strain's emergence and to length of circulation time in the community. A high percentage of the adolescents were not immune to one or more of the tested strains. More than 40% of the studied group were not immune to the old A strains A/Philipines 2/82 (H3N2) and A/Chile 1/83 (H1N1), nearly 70% were not immune to the two B strains (B/USSR 100/83 and B/Ann Arbor 1/86), and almost the entire group (96%) was unprotected against the recent strain A/Singapore 6/86. Only one pupil was immune to all five strains; 35.6%, 22.2%, 17.8%, and 9.2% were immune to one, two, three, or four of the strains, respectively; and 14.4% were not immune to even one strain.     

新型微波热疗机研制及其临床应用

重点对新型电脑微波热疗机的构成、测温控温方案进行了研究。采用自适应广义预测控制算法对热疗温度进行控制，解决了因更换不同辐射器导致对象特性变化使控制性能降低的问题，从而得到了满意的疗效。文中介绍了该仪器关键的硬件、软件设计，基本的特点和临床应用     

天然免疫与获得性免疫的进化关系

免疫有天然免疫和获得性免疫两种类型,它们有不同的机制和起源.天然免疫可识别某些"非己”细胞或分子并加以清除;获得性免疫则对分子抗原表位进行识别,按抗原提呈细胞等有无协同信号(发育阶段/类型)而有所区别.两者有不同的生物学起源与意义;天然免疫源于防御入侵者的需求,获得性免疫则源于系统及个体自身发育中调节细胞发育的需求.两者嫁接性混合进化形成了复杂的可识别"自己/非己”的免疫系统,并留下了神奇的机制.     

Co-expression of CD8α in CD4+ T cell receptor αβ+ T cells migrating into the murine small intestine epithelial layer

We investigated the surface phenotype of CD3⁺CD4⁺ T cell receptor (TCR) αβ⁺ T cells repopulating the intestinal lymphoid tissues of C.B-17 scidlscid (severe-combined immunodeficient; scid) (H-2^d, L^d+) mice. CD4⁺ CD8^? T cells were cell sorter-purified from various secondary and tertiary lymphoid organs of congenic C.B-17 +/+ (H-2^d, L^d+) or semi-syngeneic dm2 (H-2^d, L^d?) immunocompetent donor mice. After transfer of 10⁵ cells into young scid mice, a mucosa-homing, memory CD44^hi CD45RB^lo CD4⁺ T cell population was selectively engrafted. Large numbers of single-positive (SP) CD3⁺ CD2⁺ CD28⁺ CD4⁺ CD^8? T cells that expressed the α₄ integrin chain CD49d were found in the spleen, the mesenteric lymph nodes, the peritoneal cavity and the gut lamina propria of transplanted scid mice. Unexpectedly, large populations of donor-type doublepositive (DP) CD4⁺ CD8α⁺ CD8β^? T cells with high expression of the CD3/TCR complex appeared in the epithelial layer of the small intestine of transplanted scid mice. In contrast to SP CD4⁺ T cells, the intraepithelial DP T cells showed low expression of the CD2 and the CD28 co-stimulator molecules, and of the α₄ integrin chain CD49d, but expressed high levels of the α_IEL integrin chain CD103. The TCR-Vβ repertoire of DP but not SP intraepithelial CD4⁺ T cells was biased towards usage of the Vβ6 and Vβ8 viable domains. Highly purified populations of SP and DP CD4⁺ T cell populations from the small intestine epithelial layer of transplanted scid mice had different abilities to repopulate secondary scid recipient mice: SP CD4⁺ T cells repopulated various lymphoid tissues of the immunodeficient host, while intraepithelial DP CD4⁺ T cells did not. Hence, a subset of CD3⁺ CD4⁺ TCRαβ⁺ T cells apparently undergoes striking phenotypic changes when it enters the microenvironment of the small intestine epithelial layer.     

Immunity and depression: Insomnia,Retardation, and reduction of natural killer cell activity

Depressed patients show a reduction of natural killer (NK) cell activity which may be associated with specific depressive symptoms. The present study demonstrated that sleep disturbance and retardation, but not other depressive symptoms, were negatively correlated with NK activity in 38 depressed patients. Specific behavioral changes in depression such as sleep disturbance and retardation were found to predict 16% of the variance of cytotoxicity levels in depression.