Comparison of interferon-γ-, interleukin (IL)-17- and IL-22-expressing CD4 T cells, IL-22-expressing granulocytes and proinflammatory cytokines during latent and active tuberculosis infection.

In this study, we investigated the role and expression of T helper type 17 (Th17) cells and Th17 cytokines in human tuberculosis. We show that the basal proportion of interferon (IFN)-γ-, interleukin (IL)-17- and IL-22-expressing CD4(+) T cells and IL-22-expressing granulocytes in peripheral blood were significantly lower in latently infected healthy individuals and active tuberculosis patients compared to healthy controls. In contrast, CD4(+) T cells expressing IL-17, IL-22 and IFN-γ were increased significantly following mycobacterial antigens stimulation in both latent and actively infected patients. Interestingly, proinflammatory IFN-γ and tumour necrosis factor (TNF)-α were increased following antigen stimulation in latent infection. Similarly, IL-1ß, IL-4, IL-8, IL-22 and TNF-α were increased in the serum of latently infected individuals, whereas IL-6 and TNF-α were increased significantly in actively infected patients. Overall, we observed differential induction of IL-17-, IL-22- and IFN-γ-expressing CD4(+) T cells, IL-22-expressing granulocytes and proinflammatory cytokines in circulation and following antigenic stimulation in latent and active tuberculosis.

ß-Catenin and NF-κB co-activation triggered by TLR3 stimulation facilitates stem cell-like phenotypes in breast cancer.

Cancer stem cells (CSCs) are responsible for tumor initiation and progression. Toll-like receptors (TLRs) are highly expressed in cancer cells and associated with poor prognosis. However, a linkage between CSCs and TLRs is unclear, and potential intervention strategies to prevent TLR stimulation-induced CSC formation and underlying mechanisms are lacking. Here, we demonstrate that stimulation of toll-like receptor 3 (TLR3) promotes breast cancer cells toward a CSC phenotype in vitro and in vivo. Importantly, conventional NF-κB signaling pathway is not exclusively responsible for TLR3 activation-enriched CSCs. Intriguingly, simultaneous activation of both ß-catenin and NF-κB signaling pathways, but neither alone, is required for the enhanced CSC phenotypes. We have further identified a small molecule cardamonin that can concurrently inhibit ß-catenin and NF-κB signals. Cardamonin is capable of effectively abolishing TLR3 activation-enhanced CSC phenotypes in vitro and successfully controlling TLR3 stimulation-induced tumor growth in human breast cancer xenografts. These findings may provide a foundation for developing new strategies to prevent the induction of CSCs during cancer therapies.

A quick, easy and inexpensive method for the isolation of human peripheral blood monocytes.

A commercial monocyte isolation technique based on the OptiPrep density-gradient medium was up-scaled with respect to sample and reagent volumes. The results of 7 isolations are reported in which the average purity ranged from 87.9 to 96.4%. In all but the initial isolation, monocytes were defined as CD15+ dim CD4+ dim as assessed by flow cytometric analysis; in the first isolation, monocytes were defined by the traditional CD14+ CD4+ dim combination. The mean yield (the number of isolated monocytes relative to the number present in the buffy coat) of all isolations was 26.1%, with the individual yields ranging from 10.8 to 41.4%. The mean number of isolated monocytes per experiment was 3.6 x 10(6) monocytes for those isolations performed using 14 ml of buffy coat/OptiPrep mixture (n = 4). The isolated cells were viable (> 95%) and were not activated, according to HLA-DR expression. This technique is a convenient, tast (less than 2 h), relatively simple, and inexpensive alternative to traditional monocyte isolation techniques. The up-scaled version of this method also results in significantly higher numbers of monocytes per isolation than some traditional techniques. Furthermore, this is the first literature report of the use of the OptiPrep density-gradient medium for the isolation of monocytes.

Detection of surface and cytoplasmic CD4 on blood monocytes from normal and HIV-1 infected individuals.

CD4 on blood monocytes is generally regarded as being found on a subset of blood monocytes. However, our results show that all monocytes are CD4+ but the number of molecules per cell is lower than T cells. We have performed immunofluorescent (flow cytometry, microscopy) analysis of monocytes from normal donors and HIV-1-infected patients using anti-CD4 (Leu-3a) and the monocyte-specific marker anti-CD14 (Leu-M3) monoclonal antibodies. Specifically: (1) 91% of monocytes from normal individuals show dual positivity for CD14 and CD4 (n = 14) as measured by flow cytometry; (2) 76% of monocytes expressed surface bound CD4 and CD14 when an enhanced two colour immunofluorescence microscopic technique was employed; (3) all CD14+ monocytes stained with an intensity of 3+(-)4+ for cytoplasmic CD4. Few monocytes were CD14- and CD4+. Cell surface CD4 expression was blocked with unconjugated anti-CD4 prior to staining; (4) the staining intensity for cytoplasmic CD4 in T cells was negligible; (5) CD4 expression on monocytes obtained from patients was as observed with normal individuals. The conclusion drawn is that all monocytes are CD4+ and the CD4 expression in monocytes is mainly cytoplasmic. Thus, all monocytes are potentially infectable with HIV-1.

Mechanism of gammadelta T cell-induced human oligodendrocyte cytotoxicity: relevance to multiple sclerosis.

Gammadelta T cells may contribute to the pathogenesis of Multiple Sclerosis (MS) via cytotoxicity directed at the myelin-oligodendrocyte unit. We have previously demonstrated that peripheral blood-derived gammadelta T cells lyse fresh human oligodendrocytes in vitro. The present work extends these observations to gammadelta T cells derived from both peripheral blood (PBL) and cerebrospinal fluid (CSF) of MS and non-MS neurological disease controls and addresses the mechanism of cellular cytotoxicity. We found that MS patients contained increased proportions of Vdelta1+ gammadelta T cells in both CSF and PBL samples compared to other neurological disease (OND) controls. Although gammadelta T cells from all patients were cytotoxic towards Daudi, RPMI 8226, U937, Jurkat, oligodendroglioma and fresh human oligodendrocyte targets, OND-derived, Vdelta2+ rich, populations derived from the CSF exhibited greater cytotoxicity towards cell lines (Daudi, RPMI 8226) known to express high levels of heat shock proteins (hsp). To clarify the mechanism(s) of cytotoxicity used by gammadelta T cells, we first showed that cell-target contact was necessary by the use of physical barriers (transwells), which reduced target cell lysis by at least 75%. The use of Ca2+-free media reduced lysis by up to 50%, but fully blocking gammadelta T cell Perforin release and function by either Ca2+ chelation (Mg2EGTA) or the H+-ATPase inhibitor Concanamycin-A (CMA), completely abrogated the lysis of Fas-/hsp60high expressing targets (Daudi, U937). However, additional treatment with Brefeldin A was required for the complete inhibition of gammadelta T cell mediated killing of Fas+ expressing Jurkat targets and fresh human brain-derived oligodendrocytes. Inhibition of granzyme activity by an isocoumarin compound reduced cytolysis only slightly. The use of either Brefeldin A or an anti-Fas antibody alone did not significantly affect lysis. These findings suggest that in MS, gammadelta T cells may utilize either the Fas-mediated or Perforin-based cell cytotoxicity pathways in exerting oligodendrocyte damage, though the Perforin pathway is predominant.

Safe use of the CXCR4 inhibitor ALX40-4C in humans.

ALX40-4C is a small peptide inhibitor of the chemokine receptor CXCR4 that can inhibit X4 strains of HIV-1. Prior to the discovery of chemokine receptors as the HIV coreceptors, ALX40-4C was used in phase I/II clinical trials to evaluate its therapeutic potential against HIV-1, making ALX40-4C the first anticoreceptor inhibitor to be tested in humans against HIV-1. Patients in the highest dose groups achieved ALX40-4C levels above the effective concentration of the drug for nearly the entire 1-month treatment period. ALX40-4C was well tolerated by 39 of 40 asymptomatic HIV-infected patients, despite the critical role of CXCR4 in normal development and hematopoiesis. No significant or consistent reductions in viral load were observed, but only 12 of the enrolled patients harbored virus types that used CXCR4. We also found that ALX40-4C interacts with the second extracellular loop of CXCR4 and inhibits infection exclusively by blocking direct virus-CXCR4 interactions.

Effect of IL-2 and indomethacin on the activation of suppressor cells induced by tetanus toxoid.

Experiments were performed to delineate the mechanism by which tetanus toxoid (TT) suppresses the immune response. A CD4+ cell has been shown to suppress the PHA response (18). TT suppresses the phytohemagglutinin (PHA) blastogenic response and pokeweed mitogen (PWM) induction of IgM and IgG in a dose-dependent fashion. The suppression is partially reversed by indomethacin or interleukin-2. The tumor necrosis factor had no effect. TT induced the suppression within 36 h and the immunosuppressive activity induced could downregulate the response of fresh syngeneic cultures of peripheral blood leucocytes. We conclude that TT can induce nonspecific suppressor cells that can dampen mitogen responses which has important implications in the development and usage of vaccines.

Cellular interactions in the generation of bovine Con A-suppressor cells and in the mitogenic proliferative response.

Previously we have shown that macrophages acted as accessory cells for the induction of bovine suppressor cells with concanavalin A (Con A) and in mitogen induced lymphocyte proliferation. In exploration of possible mechanisms for the lymphocyte-macrophage interaction, it was found that the requirement for macrophages could not be substituted for with 2-mercaptoethanol. Furthermore, direct contact between lymphocytes and macrophages was necessary for optimal generation of suppressor cells. However, de novo protein synthesis by macrophages or lymphocytes apparently was not essential for the induction of Con A suppressor cells. For generation of suppressor cells, Con A had to be present in a soluble form during the entire induction period, as mitogen "pulsing" of either lymphocytes or macrophages prior to cocultivation did not lead to generation of suppressor activity.

Characterization of the bovine secondary in vitro antibody response.

In the present report, the bovine secondary in vitro antibody response to keyhole limpet hemocyanin is described. The induction of anti-KLH antibody was not dependent upon the presence of mitogen but was antigen specific (KLH vs ovalbumin). Furthermore, this response was dependent upon cell density (10(6) per well), antigen dose (1 to 10(-5) ug/culture) and time in culture (5 days). The antibody produced was specific for KLH as measured in several binding assays. An unresponsive state was detected with high concentrations of KLH (more than 10 ug per culture) which was not due to the formation of immune complexes but to the inactivation of B and/or T cells. The induction of the antibody response was dependent on the presence of macrophages (syngeneic or allogeneic) and their presence could not be replaced with 2-mercaptoethanol.

The effects of activated complement on myocardial performance in vitro.

Activated complement has been implicated in the dysfunction of several organ systems, but can it directly affect the myocardium? This possibility was studied using human right atrial trabeculae contracting isometrically "in vitro" in four solutions: Tyrode's (T), autologous arterial blood (B), plasma (P) and denaturated plasma (DP). Complement was activated by the addition of Zymosan while vehicle alone was used as control. Complement activation occurred in the blood and plasma solutions, as assessed by a significant drop in CH50 (p less than 0.05), while there was no detectable complement activity in either T or DP. Myocardial functional integrity was assessed by the change in contractile parameters with time. Subsequent resting forces, relative developed forces (DF), and rates of decay of DF were similar between muscles contracting in the four solutions. We conclude that activated complement has no direct effect on myocardial performance.

Occurrence of Legionella in groundwater: an ecological study.

The natural habitat of Legionella is the water environment. Little is known about their presence in groundwater in spite of the fact that many millions around the globe regularly rely on groundwaters. This pilot study was aimed at evaluating the occurrence of Legionella in groundwater samples (water and biofilms) collected from various sites. Water and biofilm samples from selected groundwater sources were examined for Legionella using culture media (selective and non-selective) and a semi-nested PCR assay. Innovative approaches such as immunomagnetic separation (IMS) in combination with cultivation and flow cytometry were also evaluated. The findings available thus far show that (a) Legionella could be readily recovered from groundwater samples by cultivation even though their numbers showed considerable variations, (b) surprisingly, the PCR methodology was not yet as sensitive as cultivation and (c) flow cytometry was not directly applicable on natural samples because of debris and the high number of heterotrophic associated microflora from which some members were likely to cross-react with the monoclonal antibody used for separation procedures (IMS).

Filter selection for five color flow cytometric analysis with a single laser.

Flow cytometry has evolved from single- and two-color analysis to the current use of 11-16 colors. The relatively bright excitation spectra of most fluorochromes have made color compensation a challenge especially when performed manually. We describe how by choosing filters with narrower bandwidths results in the color compensation values between FITC, PE, PE-TxR (ECD), PE-Cy5, and PE-Cy7 that range from 0 % to 50% depending on the combination of fluorochromes. Peripheral blood mononuclear cells were stained with alpha-CD4-FITC, alpha-CD27-PE, alpha-CD62L-ECD, alpha-CD45RA-PE-Cy5 and alpha-CD3-PE-Cy7. The samples were acquired on a MO Flo. The initial (first) and second filter sets for our experiments consisted of 530/30 or 519/20 for FITC, 580/30 or 575/20for PE, 630/30 or 630/22 for PE-TxR (ECD), 670/30 or 675/20 for PE-Cy5 and 740LP or 780/40 for PE-Cy7. Nonstained cells were used to adjust the threshold values of detection for each photo multiplier tube (PMT) for each filter set. The mean fluorescent intensity (MFI) of each fluorochrome was not reduced to any great extent by either filter set. However, the compensation value between PE and PE-TxR (ECD) with the first filter selection ranged from 84% to 89% and with the second set of filters it was 25-36%. In addition, the compensation between PE-TxR (ECD) and PE-Cy5 were reduced to 30.2% from 44.2% with the second filter set. The reduction of filter bandwidths that results in minimizing spectral overlaps without lost of signal provides a method by which discrimination of signals between PE containing fluorochromes can be achieved.

Induction of the in vitro anti-HBs response by hepatitis B surface antigen.

The production in vitro of antibody to hepatitis B surface antigen by peripheral blood mononuclear cells of healthy volunteers was studied after each of the three doses of hepatitis B vaccine. An in vitro hepatitis B surface antigen antibody response was successfully induced in 12% of the specimens taken over a 7 month period. The response to this antigen was induced in additional samples if cells had been treated previously with anti-CD4 and complement or anti-CD8 and complement prior to culture initiation. The addition of interleukin 2 could also induce the formation of antibodies to hepatitis B surface antigen. The results suggest that the antibody response to hepatitis B surface antigen is complex and varies depending on the individual and time of sampling.

Monoclonal antibodies (Mabs) in head and neck cancer.

The development of monoclonal antibodies (Mabs) represents a major contribution of immunology to the study of head and neck cancer. The interest of the otolaryngologist in this new field is quite recent, but our knowledge of cancer and other immunoproliferative disorders will exponentially expand with the characterization of tumor-associated antigens of squamous cell carcinomas. The author reviews briefly the technique for producing monoclonal antibodies and presents an overview of the application of Mabs to clinical medicine, oncology and, more specifically, head and neck cancer. Very few contributions have been made in head and neck cancer, but the field of Mabs will significantly alter our diagnostic and therapeutic armamentarium.

Bovine monocytes and macrophages: an accessory role in suppressor-cell generation by Con A and in lectin-induced proliferation.

Non-specific suppressor-cell activity was generated in bovine peripheral-blood leucocytes by treatment with various concentrations of concanavalin A. The activity was expressed against syngeneic and allogeneic responder cells. The involvement of the macrophage-monocyte was found to be necessary for the induction of suppressor cells. After depletion of monocytes from peripheral-blood leucocytes, by sequential plastic adherence and passage through Sephadex G-10 columns, the inducible suppressor activity was significantly reduced or completely abolished. Reconstitution with monocytes resulted in renewed activity in a dose-dependent manner. Histocompatibility identity of macrophages and non-adherent cells was not required since allogeneic macrophages reconstituted the response of non-adherent cells to a degree comparable to syngeneic cells. Alveolar macrophages were shown to be even more efficient as accessory cells for suppressor-cell induction than peripheral-blood monocytes.

Nonspecific suppressive effect of bovine herpesvirus type 1 on bovine leukocyte functions.

The effect of bovine herpesvirus type 1 on the specific and nonspecific immune response of calves was examined. Animals with or without prior aerosol exposure to Pasteurella haemolytica serotype A1 were aerosol challenged with 10(8) PFU of virus. Blood and serum samples were taken before and after virus challenge for determining cell-mediated, humoral, and neutrophil responses. A significant depression of the blastogenic responses to phytohemagglutinin, P. haemolytica, and Pasteurella multocida and of neutrophil chemotactic response was observed 4 to 7 days after challenge. However, the antibacterial activity of neutrophils was not significantly affected by virus exposure. Anti-bovine herpesvirus type 1 antibody responses were detected 11 days postchallenge. A significant elevation of the anti-P. haemolytica antibody response (day 0 versus day +11) was detected in animals previously exposed to P. haemolytica.

The role of CD4+ lymphocytes in the activation of non-specific suppressor cells by antigen.

Tetanus toxoid (TT) and hepatitis B surface antigen (HBsAg) can suppress lectin-induced responses. The suppression induced by TT is dose-dependent and can also down-regulate the induction of a blastogenic response by anti-CD3 and anti-CD4 monoclonals. In addition, TT can dampen the blastogenic response induced by phytohaemagglutinin (PHA) and anti-CD3. The cellular mechanism involved in the turning off of the blastogenic response was investigated by transferring cells treated for 5 days with TT to freshly obtained syngeneic cells and stimulation with PHA. The response of cultures that had received TT-treated cells was significantly lower than of those that had received cells treated with medium only. The removal of CD4+ cells at the induction phase of the suppression reversed the suppression, whereas the elimination of most CD8+ cells had no effect. We propose that CD4+ cells together with monocytes can dampen the specific and non-specific blastogenic responses.

Phytohemagglutinin mitogenic response of normal individuals vaccinated with hepatitis B vaccine.

The phytohemagglutinin (PHA) blastogenic response of normal healthy individuals was studied before and after vaccination with hepatitis B surface antigen. The PHA response was suppressed 2 d after the first dose of vaccine but was not affected by the second and the third doses of vaccine. The suppressed PHA blastogenic response on day 7 was not enhanced by the addition of interleukin-2 or indomethacin even though an increase in cell number expressing CD25 was observed. The removal of CD4+ or CD8+ cells enhanced the PHA response but only on days 2 or 4 and not at other sampling times, which suggests that the suppression is mediated by CD4+ or CD8+ cells. The addition of interleukin-2 alone or with PHA did not reverse the suppression at any time tested. In vitro induction of suppressor cells was performed and was blocked by the addition of indomethacin at the time of culture initiation.

Humoral and cellular immune responses by normal individuals to hepatitis B surface antigen vaccination.

The kinetics of the cellular and humoral responses of 30 recipients of hepatitis B vaccine were studied. All individuals exerted an HBsAg blastogenic response sometime throughout the study period but the maximum response was detected on day 28 and 56. The removal of CD8+ cells enhanced significantly the HBsAg response at the times tested, whereas treatment with anti-CD4, anti-CD8, C' and anti-CD4+ C' had no effect. Vaccination also led to the depression of phytohaemagglutinin (PHA) blastogenic response. This response was maximally suppressed 4 to 8 days after immunization at least for the primary and secondary responses and 28 days after the third dose of vaccine. The humoral response to HBsAg was detected only after the second dose of vaccine was given. The results suggest that a CD8+ cell controls the magnitude and intensity of the HBsAg blastogenic response, which may help to explain why several investigators had not been able to detect this response in hyperimmunized individuals. Primary immunization with HBsAg does lead to an expansion of B memory since a secondary response anti-HBsAg was observed.

Down regulation of CD4 expression following isolation and culture of human monocytes.

The down regulation of CD4 by cultured monocytes has been observed by our group and by other investigators. Flow cytometric experiments were done to examine which factors might influence this phenomenon. The addition of lipopolysaccharide, granulocyte-macrophage colony-stimulating factor, macrophage colony-stimulating factor, or interleukin-10 to monocyte cultures failed to inhibit the decrease in monocyte CD4 expression routinely observed following overnight culture. The down regulation was an adherence-independent phenomenon and was not influenced by the type of anticoagulant into which the peripheral blood was collected or by the presence or absence of lymphocytes within the cultures. The avoidance of the use of Ficoll-Paque to isolate peripheral blood mononuclear cells did not prevent monocyte CD4 down regulation. Finally, by tagging monocyte CD4 with an anti-CD4 phycoerythrin-conjugated monoclonal antibody prior to culture, we were able to determine that the down regulation observed was the result of the internalization of the molecule. At this time, we conclude that the observed down regulation of monocyte CD4 is probably due to the differentiation of blood monocytes into tissue culture-derived macrophages rather than to some artifact of the isolation procedure.