Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Cell image analysis of lymphocytes from (1) control and (2) killed coccidioides immitis arthrospore immunized guinea pigs was performed. Lymphocytes from peripheral blood and lymph nodes were obtained two and tree weeks after immunization from each group of animals. Histograms from peripheral lymphocytes taken at two weeks from immunized animals showed no significant difference from those of the control animals. A significant difference, however, was seen in the conturs of the histograms of the cells taken at three weeks from four of six immunized animals. These histograms extended into the higher optical density range when compared to histograms of control animals. Smaller nuclear areas were also found in the majority of three week peripheral cells. In material from the nodes of immunized animals two weeks after immunization, the ratio of densely staining to lightly staining cells reverses from 3:1 to .7:1. Samples taken from nodes three weeks after immunization show no such differences in their cellular composition between control and immunized animals.

The Bar-Or laboratory recently reported that human B cells from normal subjects can produce either pro-inflammatory (TNF-alpha; LT) or regulatory (IL-10) effector cytokines depending on their context of activation. It was of interest to investigate the change in B cell cytokine profiles from normal subjects when activated in the context of a Th1 pro-inflammatory environment or a Th2 anti-inflammatory environment. It was found that the B cell regulatory network of effector cytokines from normal subjects is significantly modulated depending on the local cytokine milieu. In addition, it was of interest to study how MS patients' B cell cytokine network would respond in a Th1 pro-inflammatory and a Th2 anti-inflammatory context. It was found that MS patients' B cell cytokine network was dysregulated compared to B cell responses from normal subjects. The findings define a novel regulatory network involving human B cells from normal subjects and point to a newly discovered abnormality in MS patients' B cells.

No description available.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.

Thesis (M.Med.Sc.)--University of Hong Kong, 2003. / Includes bibliographical references (leaves 57-59). Also available in print.

The effect of sera from patients with metastatic breast cancer on the response of normal lymphocytes to phytohaemagglutinin (PHA) was studied. A preliminary experiment indicated that dialysis of sera against tissue culture medium RPMI-1640 revealed differences between patient and control sera which were not apparent using undialysed sera. The ability of a dialysed serum sample to support the PHA response of normal lymphocytes, as measured by 3H-thymidine incorporation, was called the serum support of lymphocyte stimulation (SSLS). Sera having an SSLS value less than 30% of the control mean in the same experiment were called inhibitory sera. Dialysed sera from a proportion of patients with metastatic breast cancer on various treatments were found to inhibit the response of normal lymphocytes to PHA compared with control sera. This effect was not due to cytotoxicity of the inhibitory sera. The SSLS of inhibitory sera remained lower than that of most controls when experimental conditions such as concentration of reagents and duration of incubation were varied. The ability of undialysed sera to support a mixed lymphocyte reaction was significantly correlated with the SSLS of the same sera when dialysed. The presence of inhibitory sera was apparently related mainly to treatment. In the earlier (Phase 1) experiments, treatment with chemotherapy or oestrogens was associated with inhibitory sera, whereas treatment with androgens or corticosteroids was associated with sera which supported PHA stimulation well. In later (Phase 2) experiments, there was a higher proportion of persons with inhibitory sera among patients receiving one or both of the newer hormonal agents, Tamoxifen and Aminoglutethimide, than among controls or untreated patients. In the phase 1 experiment, advanced disease and disease of long duration appeared to be associated with inhibitory sera, but these associations were not confirmed in Phase 2. Higher patient age in both phases and greater tumour differentiation in Phase 1 were associated with inhibitory sera, but in Phase 1, the presence of inhibitory sera was unrelated to prognosis. Prognosis and tumour differentiation were not studied in Phase 2. Lymphocytes from breast, cancer patients responded to PHA significantly less well than did control lymphocytes. However, there was no correlation between the PHA response of patients' lymphocytes and the SSLS of sera from the same patients. A low molecular weight (10,000 dalton) inhibitory substance appeared to be present in a pool of two very inhibitory patients' sera in much greater concentration than in control sera. However, no similar substance could be demonstrated in other less inhibitory sera. Measurement of several serum proteins revealed a borderline significant negative linear relationship between the serum concentration of ai-antitrypsin and the logarithm of the SSLS. Variability in the concentration of ai-antitrypsin could account for less than 10% of the variability in log SSLS. Thus, apparently more than one substance is involved in determining SSLS. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Multiple Sclerosis (MS) is a chronic inflammatory and demyelinating disease of the central nervous system. The etiology of MS is unknown but many researchers believe that it is autoimmune mediated. This study investigated naive CD4+ and naive CD8+ T-cell homeostasis in patients with Primary Progressive Multiple Sclerosis and Relapsing Remitting Multiple Sclerosis. The naive T-cell compartment involves a balance between thymic production of naive T-cells, homeostatic proliferation and the delivery of death and survival signals. Naive T-cell production was quantified by measuring signal joint T-cell receptor excision circles (sj-TRECs); episomal byproducts formed during V(D)J T-cell receptor rearrangement. / Homeostatic proliferation was quantified by flow cytometry analysis of % expression of CD31 and Ki-67. CD31 is a marker found on CD4+ recent thymic emigrants (RTE) but not on naive T-cells that have undergone homeostatic proliferation. CD31 can be used as a marker of the proliferation history of naive CD4+ T-cells. Ki-67 is a nuclear and nucleolar antigen found in actively cycling cells. It can be used as a marker of cell proliferation at the moment of isolation. Cell survival was measured by quantifying plasma IL-7 levels and by measuring Bcl-2 expressions. IL-7 plays an important role in maintaining and restoring peripheral naive T-cell homeostasis. It stimulates naive T-cell proliferation and prevents the reduction of Bcl-2, an antiapoptotic protein. / In this study, PPMS patients had significantly reduced naive CD4 + T-cell sj-TRECs compared to healthy controls (p = 0.0007) and compared to RRMS patients (p = 0.0010). RRMS patients had fewer sj-TRECs than healthy controls but this difference was not significant (p = 0.4652). Similarly, in PPMS, naive CD4+ T-cells had significantly lower CD31 expression than healthy controls (p = 0.0017) and RRMS patients (p = 0.0032). This finding indicates increased homeostatic proliferation in naive CD4 + T-cells in PPMS, most probably a response to decreased thymic export as marked by the decreased naive CD4+ T-cell sj-TRECs. % CD31 expression in naive CD4+ T-cells did not differ significantly in RRMS compared to healthy controls (p = 0.7455) which is consistent with their naive CD4+ sj-TREC levels. / Naive CD8+ T-cell sj-TRECs were significantly reduced in PPMS patients compared to healthy controls (p = 0.0212) but not compared to RRMS patients (p = 0.2379). RRMS patients had fewer naive CD8 + T-cell sj-TRECs compared to healthy controls but this difference was not significant (p = 0.1517). PPMS patients expressed increased Bcl-2 levels in their naive CD8+ T-cells. This finding indicates upregulation of survival signals, most probably a consequence of reduced thymic export of naive CD8+ T-cells. / The data from this study indicate that PPMS is different from RRMS in their naive CD4+ T-cell sj-TRECs and naive CD4 + T-cell % CD31 expression but is similar to RRMS in their naive CD8+ T-cell sj-TRECs. This study concludes, therefore, that both PPMS and RRMS patients have altered naive T-cell homeostasis.

No description available.

A sepse é a Síndrome da Resposta Inflamatória Sistêmica decorrente de uma infecção por gram positivos/negativos, fungos ou vírus. É caracterizada por alta liberação de mediadores inflamatórios podendo levar à morte. As células B-1 são encontradas em cavidades peritoneal e pleural de camundongos e sua origem e função ainda não são completamente conhecidas. Apresentam marcadores de superfície de linhagem mielóide e linfóide e migram para focos inflamatórios comportando-se como macrófagos. Objetivo: investigar o papel da célula B-1 na resposta inflamatória após estímulo com lipopolissacáride (LPS) in vitro e in vivo. Métodos: TNF-, IL-6, IL-10 (ELISA) e nitrito (Griess) foram dosados em sobrenadante de cultura celular (106 cel./ml). As células em cultura receberam por 24h de estímulo com 10 g/mL de LPS de Escherichia coli (026:B6 Sigma®). Foram realizados os seguintes grupos cultura de célula B-1 (Balb/c), cultura de macrófagos de linhagem (RAW 264.7) coculturas (macrófagos de linhagem RAW 264.7 e células B-1 (Balb/c, C57BL/6 e C57BL/6 IL-10 -/-), e células peritoneais de camundongos Balb/c e Balb/Xid (imunodeficiente em célula B-1) A endotoxemia foi induzida com injeção de LPS 15 mg/kg (i.p.) em camundongos Balb/c e Balb/Xid. Foram quantificados, TNF-, IL-6, IL-10 e nitrito em soro, pulmão e intestino dos animais após 1,5, 4 e 6 horas após a injeção de LPS. Ensaios de inoculação de células B-1 (Balb/c) em camundongos Balb/Xid foram realizados, e curva de sobrevida foi analisada após indução de endotoxemia. Resultados: Após o estímulo com LPS, células B-1 produziram IL-10 e a presença destas células em cocultura com macrófago promoveu a diminuição na produção de TNF-, IL-6, Nitrito e aumento de IL-10. Contudo, célula B-1 (IL-10 -/-) em cocultura com macrófagos, não inibem a produção de mediadores pro inflamatórios. Análise com macrófagos peritoneais de camundongo Balb/Xid e Balb/c após estímulo com LPS em cultura mostrou reprodução do fenômeno encontrado com os experimentos com cultura de célula imortalizada, isto é, maior produção de TNF-, IL-6 e NO em Balb/Xid (B-1 deficiente). Os estudos in vivo mostraram 60% de mortalidade em camundongo Balb/Xid comparando com Balb/c (0%) após 16 horas de injeção de LPS. Nos animais Balb/Xid encontramos padrão pro inflamatório exacerbado com maiores concentrações de TNF-, IL-6 e menores concentrações de IL-10 no plasma e tecidos quando comparamos com Balb/c. Conclusões: Nossos dados mostraram que a presença de células B-1 promoveram diminuição de mediadores pro inflamatórios e aumento de IL-10 em coculturas com macrófagos e que a modulação da resposta inflamatória pode ser devida a secreção de IL-10 pela célula B-1. Este padrão de resposta pro inflamatória se repete in vivo e é a possível causadora da maior taxa de mortalidade em camundongos da linhagem Balb/Xid. / Sepsis syndrome is caused by inappropriate immune activation due to bacteria and bacterial components released during infection. This syndrome is the leading cause of death in intensive care units. Specialized B-lymphocytes located in the peritoneal and pleural cavities are known as B-1 cells. These cells produce IgM and IL-10, both of which are potent regulators of cell-mediated immunity. It has been suggested that B-1 cells modulate the systemic inflammatory response in sepsis. In this study, we conducted in vitro and in vivo experiments in order to investigate a putative role of B-1 cells in a murine model of LPS-induced sepsis. Macrophages and B-1 cells were studied in monocultures and in co-cultures. The B-1 cells produced the anti-inflammatory cytokine IL-10 in response to LPS. In the B-1 cell-macrophage co-cultures, production of proinflammatory mediators (TNF-, IL-6 and nitrite) was lower than in the macrophage monocultures, whereas that of IL-10 was higher in the co-cultures. Co-culture of B-1 IL-10/ cells and macrophages did not reduce the production of the proinflammatory mediators (TNF-, IL-6 and nitrite). After LPS injection, the mortality rate was higher among Balb/Xid mice, which are B-1 cell deficient, than among wild-type mice (65.0% vs. 0.0%). The Balb/Xid mice also presented a proinflammatory profile of TNF-, IL-6 and nitrite, as well as lower levels of IL-10. In the early phase of LPS stimulation, B-1 cells modulate the macrophage inflammatory response, and the main molecular pathway of that modulation is based on IL-10-mediated intracellular signaling.