Search

The MLV-related retrovirus, XMRV, was recently identified and reported to be associated with both prostate cancer and chronic fatigue syndrome. At the National Cancer Institute-Frederick, MD (NCI-Frederick), we developed highly sensitive methods to detect XMRV nucleic acids, antibodies, and replication competent virus. Analysis of XMRV-spiked samples and/or specimens from two pigtail macaques experimentally inoculated with 22Rv1 cell-derived XMRV confirmed the ability of the assays used to detect XMRV RNA and DNA, and culture isolatable virus when present, along with XMRV reactive antibody responses. Using these assays, we did not detect evidence of XMRV in blood samples (N = 134) or prostate specimens (N = 19) from two independent cohorts of patients with prostate cancer. Previous studies detected XMRV in prostate tissues. In the present study, we primarily investigated the levels of XMRV in blood plasma samples collected from patients with prostate cancer. These results demonstrate that while XMRV-related assays developed at the NCI-Frederick can readilymeasure XMRV nucleic acids, antibodies, and replication competent virus, no evidence of XMRV was found in the blood of patients with prostate cancer. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Human Lyme arthritis caused by Borrelia burgdorferi is characterized by an inflammatory infiltrate that consists mainly of neutrophils and T cells. This study was undertaken to evaluate the role of the innate and acquired immune responses elicited by the neutrophil-activating protein A (NapA) of B burgdorferi in patients with Lyme arthritis. METHODS: Serum anti-NapA antibodies were measured in 27 patients with Lyme arthritis and 30 healthy control subjects. The cytokine profile of synovial fluid T cells specific for NapA was investigated in 5 patients with Lyme arthritis. The cytokine profile induced by NapA in neutrophils and monocytes was also investigated. RESULTS: Serum anti-NapA antibodies were found in 48% of the patients with Lyme arthritis but were undetectable in the healthy controls. T cells from the synovial fluid of patients with Lyme arthritis produced interleukin-17 (IL-17) in response to NapA. Moreover, NapA was able to induce the expression of IL-23 in neutrophils and monocytes, as well as the expression of IL-6, IL-1beta, and transforming growth factor beta (TGFbeta) in monocytes, via Toll-like receptor 2. CONCLUSION: These findings indicate that NapA of B burgdorferi is able to drive the expression of IL-6, IL-1beta, IL-23, and TGFbeta by cells of the innate immune system and to elicit a synovial fluid Th17 cell response that might play a crucial role in the pathogenesis of Lyme arthritis [ABSTRACT FROM AUTHOR]

In an accompanying paper (Am J Epidemiol 2002;155:1066–73), the authors describe the design of a large multicenter study being carried out in three West African countries for investigation of the roles of environmental and host-related factors in the development of tuberculosis. In this paper, the authors review some evidence that host genetic factors play a role in susceptibility to tuberculosis. They describe the three components of the study that are designed to investigate the effect of host genetic factors on the development of tuberculosis: case-control and family-based association studies of candidate genes and analysis of affected relative pairs to screen the human genome for areas of linkage to the disease. The authors also address a number of methodological issues that arise, such as the effects of consanguinity, half-siblings, and nonpaternity. Lastly, they review opportunities to assess gene-environment interaction in the framework of the study, in light of current methodological knowledge. Consideration of these issues may be useful in the design of other studies of genetic susceptibility to infectious diseases, particularly those to be carried out in developing countries. [ABSTRACT FROM PUBLISHER]

Host-related and environmental factors for tuberculosis have usually been investigated separately using different study designs. Joint investigation of the genetic, immunologic, and environmental factors at play in susceptibility to tuberculosis represents an innovative goal for obtaining a better understanding of the pathogenesis of the disease. In this paper, the authors describe methods being used to investigate these points in a West African study combining several designs. Patients with newly diagnosed smear-positive cases of tuberculosis are recruited. The effect of host-related factors is assessed by comparing each case with a healthy control from the case's household. The role of environmental factors is estimated by comparing cases with randomly selected community controls. The frequencies of candidate gene variants are compared between cases and community controls, and results are validated through family-based association studies. Members of the households of cases and community controls are being followed prospectively to determine the incidence of “secondary” tuberculosis and to evaluate the influence of geographic and genetic proximity to the index case. This type of design raises important methodological issues that may be useful to consider in studies investigating the natural history of infectious diseases and in attempts to disentangle the effects of environmental and genetic factors in response to infection. [ABSTRACT FROM PUBLISHER]

Spontaneous IgE production in vitro was investigated in 7-day cultures of unfractionated mononuclear cells (MNC) and MNC subpopulations from atopic patients. Depletion of either phagoctytic or adherent cells decreased the amount of IgE detectable in 7-day culture supernatants, but this decrease was due, at least in part, to a loss of cytophilic IgE. Depletion of immunoglobulin-bearing cells (SIg+) reduced significantly but did not abolish the spontaneous IgE production in vitro. On the other hand, depletion of IgM- bearing lymphocytes (SIgM+) which virtually abolished the production of immunoglobulins of the IgM class, did not change significantly the spontaneous production of IgE. Similarly, no change in the spontaneous production of IgE was found when lymphocyte suspensions were depleted of complement receptor-bearing cells (CR+). In contrast. spontaneous IgE product ion was significantly increased by depict ion of T lymphocytes and this increase did not simply reflect the enrichment for IgE-producing cells caused by the fractionation procedure. No significant change in the spontaneous IgE production was found when small numbers of autologous T lymphocytes were added to B cell fractions, whereas the addition of higher concentrations of autologous T cells induced a marked inhibition of the spontaneous IgE production. On the other hand, the addition in culture of pokeweed mitogen (PWM) resulted in a marked reduction of the spontaneous IgE production by B cells, also in the presence of small concentrations autologous T lymphocytes. Normal T cells were consistently effective in inducing a partial inhibition of the spontaneous IgE production by B cells from atopic patients. whereas T cells from a noticeable proportion of atopic patients were not. These data suggest that MNC responsible for the spontaneous IgE production in atopic subjects arc SIgM- and CR-deficient well-differentiated lymphocytes which probably represent the result of an activation which has occurred in vivo. However, this spontaneous IgE production can still be influenced by in vitro manipulation. such as variations in T-B cell ratios or addition of PWM. The results here reported also indicate that normal T cells arc generally more effective than T cells from atopic patients in regulating the activity of spontaneous IgE-producing cells present in the blood of atopic subjects. [ABSTRACT FROM AUTHOR]

Recombinant interleukin-2 (rIL-2) induced highly purified human tonsillar B cells to differentiate into immunoglobulin (Ig)-producing cells in vitro. The B-cell response was not due to rIL-2- contaminating substances, but reflected the activity of IL-2 itself, since it was inhibited by addition to the cultures of anti-TAC monoclonal antibody. The rIL-2-induced B-cell response was apparently not mediated by factors released by residual T cells present in B-cell suspensions at undetectable levels, since supernatants (SN) from unstimulated autologous T cells cultured at concentrations even much higher than those possibly contaminating B-cell suspensions did not induce any detectable Ig production. In addition, the Ig production by B cells cultured with SN prepared from high numbers of autologous T cells stimulated with rIL-2, as well as from allo-activated or mitogen-stimulated T cells, was of the same magnitude as the Ig production resulting from direct addition of rIL-2 concentrations comparable with those present in the supernatants. After centrifugation on Percoll density gradients, most of the tonsillar B cells responsive to rIL-2 were recovered in the lower density cell fraction containing a number of larger activated B cells. Moreover, B-cell enriched suspensions from peripheral blood (PB) (which usually contains a lower number of in vivo activated B cells than tonsil) showed poor or no response to rIL-2 alone, but displayed significant Ig production when rIL-2 was added to the cultures in the presence of Staphylococcus aureus Cowan I (SAC) bacteria. Taken together, these data indicate that IL-2 can directly induce differentiation into Ig-producing cells of in vivo or in vitro activated human B cells. [ABSTRACT FROM AUTHOR]

We have previously demonstrated that a proportion of human T cell clones (TCC) derived from tonsil or peripheral blood (PB) of non-allergic donors, upon triggering with phytohaemagglutinin (PHA) or anti-CD3 monoclonal antibody (MoAb), were able to provide help for IgE synthesis in B cells from both allergic and non-allergic individuals. In this study we show that, upon PHA stimulation, culture supernatants from 10 selected TCC active on IgE synthesis also provided helper activity for IgE, whereas supernatants from unstimulated cultures of the same TCC were ineffective. In contrast, culture supernatants derived from five PHA-stimulated TCC, unable to provide helper function for IgE synthesis, consistently failed to elicit production of IgE. While the induction of IgE synthesis by TCC occurred in B cells from virtually all allergic and non-allergic donors, their soluble factor(s) were found to be able to provide substantial help for IgE production only in B cells from a proportion of donors tested. In addition B cells from non-atopic donors usually appeared to be less responsive than atopic B cells to the activity of such factor(s). In contrast, synthesis of both IgG and IgM was induced in every B cell donor by both TCC and their supernatants. Partial characterization of the factor(s) providing helper function for IgE synthesis in B cells showed that it apparently had a mol. wt between 10 and 50 kD and did not bind to immobilized IgE. Such an activity appeared to be associated with the presence of interleukin 4 (IL-4) in supernatants and it was inhibited by adding both gamma-interferon and anti-human IL-4 antibody in culture. [ABSTRACT FROM AUTHOR]

T lymphocytes from thyroid infiltrate and peripheral blood (PB) of four patients with Hashimoto's thyroiditis (HT) were analysed at clonal level for their ability to secrete interleukin 2 (IL-2) and y-interferon (y-IFN), As controls, T cell clones from PB of four normal donors and from spleen of two trauma victims were used. While no abnormality was found in the capacity lo produce lL-2, the proportion of y-IFN-producing (IFN-P) T cell clones derived from HT infiltrates was significantly higher (p<0-0005) than that of IFN-P clones derived from normal or patient PB. Most of CD4 +and CD8 + IFN-P clones from thyroid infiltrates, as well as a proportion of CD4 + PB-derived clones of patients with HT, released higher amounts of v-IFN than control clones. A relationship could be demonstrated between high y-IFN production and natural killer (NK) activity in T cell clones from thyroid and PB of HT patients. In fact, the percentage of I FN-P clones with NK potential (NK + ) was remarkably higher (p<0.0005) in thyroid infiltrates than in normal spleen or PB. The proportion of IFN-P NK + clones from patient PB was also significantly increased (P<0.02) but, unlike thyroid-derived clones in which the majority of IFN-P NK + clones were CD8 +, most PB-derived IFN-P NK + clones from the same patients expressed the CD4 + phenolype. Almost all thyroid NK + clones could be triggered to produce more y-IFN, while y-IFN synthesis by NK-negative thyroid clones was comparable to that of control clones. In view of the multiple effects ascribed to y-IFN in the cascade of events leading to immune responses, the abnormal potential to y-lFN secretion shown by intrathyroidal T lymphocytes may be of importance in the pathogenesis of autoimmune throiditis. [ABSTRACT FROM AUTHOR]

High proportions of T8+ cells with inverted T4/T8 ratio were found in freshly isolated thyroid lymphocytes from patients with Hashimoto's thyroiditis. In addition, about one third of thyroid infiltrating cells expressed the TAC antigen, whereas in patient peripheral blood (PB) or normal lymphocytes from PB or lymphoid organs the percentage of TAC-positive cells was consistently lower than 10%. Following negative selection with OKT4 or OKT8 monoclonal antibodies and complement, TAC+ T cells were enriched in the T8+ cell population. Thyroid infiltrating T cells from two patients underwent two different cloning procedures. In the first, single T cells were initially activated with phytohaemagglutinin (PHA) and interleukin 2 (IL-2), in the other with recombinant IL-2 (rIL-2) alone. The majority of T cell clones obtained by initial PHA-stimulation (55 - 65%) had the T8+ phenotype, but the frequency of T8+ clones obtained by stimulating T cells with rIL-2 alone was even higher (78 & 71%, respectively). The majority of T8+ clones elicited by PHA (35/37 & 36/38) and all the T8+ clones (36/ 36 & 22/22) obtained from thyroid infiltrates with initial stimulation by rIL-2 displayed cytolytic activity, Most of cytolytic T8+ clones obtained from thyroid infiltrates with both cloning procedures, displayed NK activity against human K562and MOLT-4 target cells, but not against a NK-resistant target, such as Raji cells. These data suggest that in Hashimoto's disease a considerable proportion of thyroid infiltrating T cells are in vivo activated T8+ cytolytic T cells with N K activity, which may be of importance in determining or maintaining the tissue damage of the target gland. [ABSTRACT FROM AUTHOR]

The role of T cells and monocytes, as well as that of cytokines, such as IL-I, IL-2 and IL-6, on the IL-4-dependent in vitro human IgE synthesis was investigated. Recombinant IL-4, IL-4-containing T-cell clone supernatants and different combinations of recombinant cytokines failed to induce highly purified B cells to synthesize IgE. IL-4-dependent IgE synthesis was restored by addition to purified B cells of either untreated or mitomycin C-treated autologous T lymphocytes. Addition to purified B cells of autologous monocytes did not restore the IgE response, but usually it exerted a potentiating effect on the synthesis of IgE induced by IL-4 in the presence of suboptimal concentrations of T cells. The activity of T cells apparently preceded that of IL-4 and required a physical contact with B cells. The presence in culture of IL-2 also appeared to be necessary for the T-cell and IL-4-depeodent IgE synthesis. Even though not essential, IL-6 was able to potentiate IgE synthesis in most experimentS, whereas IL-I did not display any modulatory effect. [ABSTRACT FROM AUTHOR]

The pokeweed mitogen (PWM)-induced immunoglobulin (Ig) production by cultures of peripheral blood mononuclear cells (PBMC) was reduced in healthy haemophiliacs treated with commercial factor VIII (or IX) concentrate, whereas the spontaneous IgG synthesis in vitro was enhanced, PWM-induced Ig production was lower in those who had received greater amounts of concentrate, in those with inverted T4/T8 lymphocyte ratios and in those with antibody to HTLV-III, The spontaneous IgG production in vitro was higher in haemophiliacs who had received larger amounts of concentrate, in those with inverted T4/T8 ratio and in those with antibody anti-HTLV-III. However, some patients with normal T4/T8 ratio and some with HTLV-III antibody also had raised spontaneous IgG production. [ABSTRACT FROM AUTHOR]

The effect of unstimulated T cell culture supernatants (TCS) from patients with atopic dermatitis and high serum IgE levels on the IgE production in vitro by B cell rich suspensions from normal individuals or grass pollen sensitive patients with mild atopy was evaluated. TCS from patients with raised IgE enabled B cell suspensions from normal individuals to produce detectable amounts of IgE and potentiated the spontaneous IgE synthesis in vitro by B cell suspensions from grass sensitive patients. In contrast, the addition of TCS from normal subjects with low serum IgE levels did not increase or even reduced IgE synthesis by B cell cultures. When the same B cell cultures were analysed for their ability to produce IgG or IgM protein, no significant differences were observed. These findings indicate that T lymphocytes from patients with high serum IgE levels can release soluble factor(s) possessing isotype (IgE) specific potentiating activity. [ABSTRACT FROM AUTHOR]

This article focuses on the development and application of in vitro models for the study of human immunogloubinbin E (IgE) synthesis. Several attempts were made to induce reproducible synthesis of measurable IgE concentrations by atopic and normal B cells. A large series of experiments were devoted to studying the helper activity for IgE synthesis exerted by one of these alloreactive clones. The clone was able to induce proliferation of B cells derived from the original donor of the stimulating cells, with the production of all immunoglobulin classes, including IgE.

Peripheral blood lymphocytes (PBL) from 15 of 38 patients with chronic lymphocytic leukaemia (CLL) were capable of forming rosettes with human erythrocytes coated with staphylococcal protein A (SpA-HRBC). PBE from seven patients also showed a marked proliferative response after stimulation with Staphylococcus aureus bacteria strain Cowan I (Cowan Staph). The SpA-rosetting of CLL cells was inhibited by incubation with F(ab')2 fragments of anti-immunoglobulin (Ig) antibodies. In addition, incubation with these fragments inhibited the proliferative response of leukaemic B cells to Cowan Staph. The Cowan-Staph-induced proliferation of CLL cells was also impaired by the addition of normal human IgG and human IgG F(ab')2 fragments to the cultures, whereas non-immune rabbit IgG was not inhibitory. The inhibitory activity of human IgG (ab')2 fragments was retained by a SpA-Sepharose column, and it was found in the material recovered from the same column by acid elution. These data indicate that an interaction between SpA and a structure located in the F(ab')2 region of surface Ig of different classes is responsible for either SpA-binding or the Cowan-Staph-induced proliferative response of PBL from some patients with CLL. [ABSTRACT FROM AUTHOR]