Activation of the respiratory burst in murine phagocytes by certain guanine ribonucleosides modified at the 7 and 8 positions: possible involvement of a pertussis toxin-sensitive G-protein.

The capacity of certain guanine ribonucleosides (modified at the 7 and/or 8 positions) to enhance the respiratory burst of murine peritoneal phagocytes was evaluated. The results show that 8-mercaptoguanosine, 8-bromoguanosine, 7-methyl-8-oxoguanosine and 7-thia-8-oxoguanosine, when injected intraperitoneally into mice, induced peritoneal phagocytes to generate reactive oxygen species as early as 1 h after injection. In vivo administration of the nucleosides induced higher levels of phagocyte activation than in vitro treatment with the same nucleosides. However, the addition of interferon alpha/beta in vitro significantly increased the magnitude of phagocyte activation by the nucleosides, suggesting an important role for cytokines/lymphokines in the nucleoside-induced phagocyte activation in vivo. Furthermore, pre-treatment of phagocytes in vitro with Bordetella pertussis toxin, before treatment with the guanosines, inhibited their capacity to induce the respiratory burst. These observations establish these low-molecular-weight compounds as interesting probes for the study of stimulus-response coupling in phagocytes.

In vitro sensitization and stimulation of bovine lymphocytes with encapsulated or nonencapsulated Smith strain of Staphylococcus aureus.

An in vitro immunization procedure was developed, whereby bovine blood and mammary gland lymphocytes were isolated, and their blastogenic responses (measured by [3H]thymidine uptake) to sensitization and subsequent stimulation with selected antigens were determined. Capsular extracts of Staphylococcus aureus, encapsulated S aureus, and nonencapsulated S aureus were used as test antigens. Differences were observed between kinetics of the secondary response to encapsulated and nonencapsulated S aureus. The secondary response to nonencapsulated S aureus peaked in 48 hours, whereas the secondary response to the encapsulated S aureus peaked in 72 hours. The delayed peak response to encapsulated S aureus was observed only when encapsulated S aureus was used for sensitization of lymphocytes, regardless of whether the encapsulated or nonencapsulated strain was used for stimulation. Sensitization of lymphocytes with the nonencapsulated strain and stimulation with the encapsulated strain did not alter the kinetics of the secondary response of cells sensitized with the nonencapsulated strain. Seemingly, T and B cells were responsive to in vitro immunization with S aureus antigens.

In vitro depression of bovine lymphocyte function by treatment of cultured bovine lymphocytes with physiologic concentrations of hydrocortisone.

The effect of hydrocortisone (hydrocortisone sodium succinate) on bovine lymphocyte blastogenesis in response to Staphylococcus aureus antigens and phytohemagglutinin was measured in vitro. Lymphocytes isolated from the blood of cows were treated for 6 to 8 days with physiologic hydrocortisone concentrations known to be inducible by environmental stress (10 ng/ml), acute clinical mastitis (25 ng/ml), or adrenocorticotropin treatment (45 ng/ml). All 3 concentrations of hydrocortisone caused a depression (P less than 0.01) in lymphocyte blastogenesis in response to phytohemagglutinin and S aureus antigen extract. Hydrocortisone concentrations as low as 10 pg/ml caused a depression in the lymphocyte blastogenic response to phytohemagglutinin. Marked variation existed among cows in the normal response of their nontreated lymphocytes and in the degree of depression of lymphocyte function after the in vitro treatment with hydrocortisone. Macrophage depletion experiments showed that the suppressive effect of hydrocortisone was not mediated by induction of suppressor macrophages. The data suggest that T-cell function was impaired directly by hydrocortisone treatment.

Plasmodium berghei sporozoites are mitogenic for murine T cells, induce interferon, and activate natural killer cells.

Enhanced natural killer (NK) activity was detected in the spleens of mice as early as 24 hr after single i.v. inoculation with gamma-irradiated Plasmodium berghei sporozoites. The activity peaked at 48 hr post-injection, and declined below baseline level by day 8. Reinoculation of mice with irradiated sporozoites produced an increased NK activity significantly smaller than the original activity. Spleen cells sensitized in vivo as well as nonsensitized spleen cells stimulated in vitro with sporozoites produced high levels of interferon (IFN) and displayed enhanced NK activity. Characterization of the IFN through the use of specific antibodies revealed that it was mainly IFN-gamma. The cellular basis for IFN-gamma induction was linked to the mitogenicity of P. berghei sporozoites for T cells. The possibility exists that IFN-gamma may have a regulatory effect on antibody production against P. berghei sporozoites.

Silicate antibodies in women with silicone breast implants: development of an assay for detection of humoral immunity.

Silicon, in the form of sodium silicate (Na2SiO3), adsorbed onto bovine serum albumin (BSA)-precoated plates served as the solid-phase antigen in an enzyme immunoassay to detect silicate-reactive antibodies in the plasma of 40 symptomatic women with silicone breast implants, 91 asymptomatic women with silicone breast implants, 50 healthy control women, and 52 women with rheumatic diseases and without silicone breast implants, Silicate-reactive antibodies of immunoglobulin G (IgG) or IgM isotypes were detected in the plasma of 30% (12 of 40) of the symptomatic women with silicone breast implants; 9% (8 of 91) of the asymptomatic women with silicone breast implants; 5% (1 of 20) of the women without implants who had systemic lupus erythematosus; and 0% (0 of 32) of the women without implants who had either Sjögren syndrome, scleroderma, or rheumatoid arthritis. Only 2% (1 of 50) of the sera from the healthy control women contained silicate-reactive antibodies. Preincubation of sera with silicate and eight other metal compounds (including SiO2) demonstrated that the IgG and IgM antibodies bound specifically to silicate, because preincubation with Na2SiO3 inhibited more than 90% of the activity, whereas CrO3, Li2SO4, MgSO4, NiSO4, HgCl2, ZrOCl2, BeSO4, and SiO2 failed to inhibit the IgG or IgM antibody binding to the silicate-BSA plates. Furthermore, the F(ab')2 portion and not the Fc portion of the silicate-reactive IgG was reactive with BSA-bound silicate in the enzyme immunoassay. The assay for silicate-reactive antibodies was quantified by assigning arbitrary units to a standard curve composed of serial twofold dilutions of high-positive (ten times higher than the cutoff) silicate antibody sera. This novel assay is a useful method for detecting and quantifying humoral immune response to silicate.

Prevalence of IgM antibodies to human herpesvirus 6 early antigen (p41/38) in patients with chronic fatigue syndrome.

To evaluate the association between human herpesvirus 6 (HHV-6) and chronic fatigue syndrome (CFS), 2 geographically separate groups of CFS patients (125 and 29 patients, respectively) and healthy controls (150 and 15 controls, respectively) were compared, using an EIA, for antibodies to HHV-6 early antigen p41/38 (EA). Sixty percent (93/154) of CFS patients were were positive for HHV-6 EA IgM, 40% (61/154) were positive for IgG, and 23% (35/154) were positive for both. A total of 119 (77%) of the CFS patients were positive for HHV-6 EA IgG or IgM (or both); only 12% (20/165) of the controls had IgG or IgM to HHV-6 EA. These data demonstrate that more CFS patients than controls had elevated levels of HHV-6 EA-specific IgM, perhaps indicating active replication of HHV-6 in CFS.

Decreased natural killer cell activity is associated with severity of chronic fatigue immune dysfunction syndrome.

Natural killer (NK) cell activity was measured blindly in vitro with blood specimens from 50 healthy individuals and 20 patients with clinically defined chronic fatigue immune dysfunction syndrome (CFIDS) who met the criteria established by the Centers for Disease Control and Prevention (Atlanta). In accordance with a group scoring system of 1-10 points, with 10 being the most severe clinical status, the patient population was stratified into three clinical groups: A (> 7 points), B (5-7 points), and C (< 5 points). NK cell activity was assessed by the number of lytic units (LU), which for the 50 healthy controls varied between 20 and 250 (50%, 20-50 LU; 32%, 51-100 LU; 6%, 101-130 LU; and 12%, > 150 LU). In none of the 20 patients with CFIDS was the NK cell activity > 100 LU. For group C, the 10 patients stratified as having the least severe clinical condition, the measure was 61.0 +/- 21.7 LU; for group B (more severe, n = 7), it was 18.3 +/- 7.3 LU; and for group A (most severe, n = 3), it was 8.0 +/- 5.3 LU. These data suggest a correlation between low levels of NK cell activity and severity of CFIDS, which, if it is confirmed by additional studies of larger groups, might be useful for subgrouping patients and monitoring therapy and/or the progression of CFIDS.

Novel in vitro method for identification of individuals at risk for beryllium hypersensitivity.

Beryllium-specific lymphocytes were generated by in vitro immunization of peripheral blood mononuclear cells (PBMC) from healthy unexposed individuals. Measurement of blastogenic responses of PBMC by [3H]thymidine uptake demonstrated that sensitization of PBMC with beryllium salts followed by stimulation with unrelated salts resulted in a negative response, whereas sensitization and restimulation of PBMC with beryllium salts produced a positive response. Flow cytometric and cell depletion analyses showed that all of the responding cells were CD4+ T cells. The in vitro immunization system was used to screen 52 human subjects for susceptibility to beryllium sensitization in vitro. The results show that of the 52 healthy unexposed subjects tested, only 1 (2%) was highly responsive, 4 subjects (8%) were moderately responsive, 20 subjects (39%) were low-level responders, and 27 subjects (52%) were nonresponders. The results showing 2% high-level responsiveness to beryllium sensitization in vitro correlate with the 1 to 5% prevalence of chronic beryllium disease in individuals sensitized to beryllium dust in vivo and thus support the thesis that the in vitro immunization system may permit the identification of individuals at risk for beryllium hypersensitivity.

A novel guanosine analog, 7-thia-8-oxoguanosine, enhances macrophage and lymphocyte antibody-dependent cell-mediated cytotoxicity.

Intraperitoneal treatment of mice with a novel guanosine analog, 7-thia-8-oxoguanosine (7-thia-8-oxoGuo), gives rise to activated splenic lymphocytes and peritoneal macrophages with enhanced capacity to mediate antibody-dependent cellular cytotoxicity (ADCC). ADCC activities against both chicken red blood cells and P815 murine plasmacytoma cells were enhanced, indicating that macrophages as well as lymphocytes functioning as K-cells in the two distinct cytolytic systems, were activated by 7-thia-8-oxoGuo. Furthermore, 7-thia-8-oxoGuo enhanced lymphocyte-mediated ADCC activity in beige (bgJ/bgJ) mice against P815, thus indicating the ability of 7-thia-8-oxoGuo to function as a potent immunomodulator even in an animal that is known to possess selective impairment of naturally occurring killer lymphocytes. These results suggest that 7-thia-8-oxoGuo could serve as an agent for immunomodulation and immunorestoration.

Concentrations of circulating beta-chemokines do not correlate with viral load in human immunodeficiency virus-infected individuals.

The CC or beta-chemokines MIP-1alpha, MIP-1beta, and RANTES are the primary components of human immunodeficiency virus type 1 (HIV-1)-suppressive soluble factors in vitro. We studied the relationship between the concentrations of MIP-1alpha, MIP-1beta, and RANTES in plasma and HIV viral load in HIV-infected subjects. The HIV-positive patient group (n = 140) had significantly lower concentrations of all three beta-chemokines (MIP-1alpha, P < 0.0005; MIP-1beta, P < 0.005; RANTES, P < 0.0005) than the control group (n = 58 for MIP-1alpha, n = 27 for MIP-1beta, and n = 59 for RANTES). In addition, we divided the patient group into three subgroups (high, moderate, and low) based on the number of HIV-1 RNA copies in the plasma (as measured by quantitative HIV RNA PCR). Again, all three subgroups had significantly lower concentrations of the beta-chemokines than the HIV-negative control group. However, there was no significant difference in plasma beta-chemokine concentrations among the three subgroups within the patient group (P < 0.3). Although our results demonstrate that HIV-infected individuals had significantly lower concentrations of circulating beta-chemokines than healthy uninfected control subjects, we found no correlation between the concentrations of beta-chemokines in plasma and HIV-1 viral load in HIV-infected individuals.

Association of low concentrations of serum mannose-binding protein with recurrent infections in adults.

Low concentrations of mannose-binding protein (MBP; also known as mannose-binding lectin) are associated with common opsonic defect in immunodeficient children. We compared the concentrations of MBP in the sera of 47 adults with non-human immunodeficiency virus-related recurrent infections (group I) and 50 healthy adult controls. Mean serum MBP concentrations in the patient group did not differ significantly from those in the control group (P < 0.4). Nevertheless, the proportion of individuals with less than 5 ng of serum MBP per ml was significantly larger in the patient group (21%, P = 0.01) than in the control group (4%). Group II consisted of 73 pediatric and 56 adult patients with recurrent infections. Pediatric patients had significantly lower mean concentrations of serum MBP than their controls (P < 0.005), and there was no significant difference between the concentrations in sera of adult patients and adult controls (P < 0.4). Again, the proportion of individuals with less than 5 ng of serum MBP per ml was significantly larger in both pediatric (22%, P = 0.045) and adult (38%, P = 0.000016) patients than in their respective controls (4%). Our results demonstrate that, as in children, low concentrations of serum MBP can be associated with recurrent infections in adults.

Elevated concentrations of interleukin-1 beta and interleukin-1 receptor antagonist in plasma of women with silicone breast implants.

Plasma from 27 women with silicone breast implants (SBIs) and 50 age-matched control women without SBIs were examined by enzyme immunoassay for the presence of interleukin-1 beta (IL-1 beta) and its naturally occurring receptor antagonist, IL-1ra. The results show that 74% (20 of 27) of women with SBIs had elevated concentrations of IL-1ra, whereas only 2% (1 of 50) of controls without SBIs had elevated concentrations of IL-1ra. In contrast to the IL-1ra results, the frequency of elevated IL-1 beta concentrations among women with SBIs was only 40% (11 of 27), but this was significantly higher than the 0% (0 of 50) in control women without SBIs. These findings suggest that there is a chronic ongoing inflammatory process in some women with SBIs, the implications of which are discussed in the context of silicone as an antigenic stimulant of the immune system.

Plasmodium falciparum parasites induce interferon production in human peripheral blood 'null' cells in vitro.

Human peripheral blood mononuclear cells were found to produce interferon (IFN) when stimulated by free P. falciparum parasites in vitro. On the other hand parasite-infected, intact erythrocytes were unable to induce IFN synthesis. When the IFN was characterized according to sensitivity to anti-IFN-alpha antibodies and pH 2 treatment it was found to consist of IFN-alpha. Cell fractionation procedures and analysis of each cell fraction with regard to natural killer (NK) cell activity and IFN-producing capacity revealed that both activities were confined to the same cell fraction. The possible relevance of the IFN-NK cell system in malaria is discussed.

A rapid and sensitive chemiluminescence assay for evaluation of functional opsonic activity of Haemophilus influenzae type b-specific antibodies.

Luminol-enhanced chemiluminescence (CL) of heterologous neutrophils was used to assess the capacity of a 1-ng/ml concentration of Haemophilus influenzae type b (Hib)-specific antibodies to induce opsonization of Hib with autologous heat-inactivated sera from children immunized with Hib capsular polysaccharide-polyribosylribitolphosphate (Hib-PRP) conjugate vaccine. Serum samples from 15 of 36 children (42%) vaccinated with Hib-PRP conjugate vaccine had protective levels of Hib-specific antibodies of > or = 1,000 ng/ml. Ten of these 15 (67%) had poor or nonfunctional opsonic activity. Of the 10 children whose sera lacked opsonic activity, 5 (50%) presented with recurrent Hib infection. In contrast, none of the sera of 20 healthy adults lacked opsonic capability. CL intensity was proportional to the concentration of anti-Hib antibodies used for opsonization. Furthermore, the titers of Hib-PRP-specific antibody in children and adults did not correlate with opsonic activity. These results suggest that luminol-enhanced CL as described here with minute concentrations of antibody for opsonization can be used to assess functional capacity of anti-Hib antibodies after vaccination or natural infection in the evaluation of patients with recurrent infections.

Silicone-specific blood lymphocyte response in women with silicone breast implants.

A blinded cross-sectional study was carried out with 99 women, 44 of whom had silicone breast implants. Group I consisted of 55 healthy volunteer women without breast implants; group II comprised 13 volunteer women with breast implants or explants who felt healthy; group III comprised 21 volunteer women with breast implants who had chronic fatigue, musculoskeletal symptoms, and skin disorders; and group IV comprised 10 women who had their prostheses explanted but still presented with clinical symptoms similar to those of the women in group III. Proliferative responses of peripheral blood mononuclear cells from all 99 women were measured by [3H]thymidine uptake after exposure to SiO2 silicon, or silicone gel. The levels of proliferative responses were expressed as stimulation indices, which were obtained by dividing the counts per minute of stimulated cells by the counts per minute of unstimulated cells. Abnormal responses to SiO2, silicon, or silicone gel were defined as a stimulation index of > 2.8, > 2.1, or > 2.4, respectively. Abnormal responses were observed in 0% of group I, 15% of group II, 29% of group III, and 30% of group IV (P < 0.0005 for group I versus groups II and IV). Thirty-one percent of symptomatic women with silicone gel breast implants had elevated serum silicon levels ( > 0.18 mg/liter); however, there was no significant correlation between abnormal cellular responses and silicon levels in blood serum, type of implant, time since first implantation, prosthesis explantation, number of implants, or report of implant leakage or rupture.(ABSTRACT TRUNCATED AT 250 WORDS)

Positive correlation between degree of parasitemia, interferon titers, and natural killer cell activity in Plasmodium falciparum-infected children.

Natural killer (NK) cell activity and interferon levels have been measured in the peripheral blood of children acutely ill with Plasmodium falciparum infection. The NK cell levels were found to be raised in the malaria-infected children, with a positive correlation between the degree of parasitemia and lytic activity. Comparatively high titers of antiviral activity was discovered in sera from the majority of P. falciparum-infected children, again positively correlating with the degree of parasitemia and NK levels. The characteristics of the antiviral factor indicated alpha-type interferon to be the dominating agent involved. Addition of exogenous interferon in vitro potentiated the NK levels of PBL from normal children while having no significant impact on cells from malaria-infected children.

Antibodies to human immunodeficiency virus in human sera induce cell-mediated lysis of human immunodeficiency virus-infected cells.

The capacity of human immunodeficiency virus (HIV) antibody-positive sera from homosexually active men without acquired immune deficiency syndrome to lyse the HIV-infected T cell lines MOLT-4f and CCRF-CEM (CEM) in cooperation with lymphocytes from normal donors was investigated. Twenty-seven HIV antibody-positive sera, most of which enhanced the killing of HIV-infected MOLT-4f and CEM target cells by normal mononuclear cells were studied in detail. HIV antibody-positive sera resulted in lysis at dilutions as high as 1/10,000. HIV antibody-negative sera did not augment lysis of infected target cells. In addition, lysis of uninfected targets was not enhanced in the presence of HIV antibody-positive sera. Because fractionation of the HIV antibody-positive sera on a protein A affinity column resulted in recovery of the activity from the IgG fraction, the extra cytotoxic activity mediated by nonimmune cells in the presence of immune sera appears to be antibody-dependent. Furthermore, the cytotoxic effector cells were in the nonrosetting fraction of lymphocytes and expressed Leu-11 (cluster designation (CD)15) antigens, which is characteristic of cells participating in antibody-dependent cellular cytotoxicity reactions. The antibody specificity of the sera, determined by radioimmunoprecipitation, provides evidence that antibody-dependent cellular cytotoxicity can occur even when there are no detectable antibodies directed against gag proteins. Sera which lacked detectable antibodies to the envelope protein gp120 by radioimmunoprecipitation did not mediate antibody-dependent cellular cytotoxicity.

Hypoestoxide, a novel anti-inflammatory natural diterpene, inhibits the activity of IkappaB kinase.

Most inflammatory agents activate nuclear factor-kappaB (NF-kappaB), resulting in induction of genes coding for cytokines, chemokines, and enzymes involved in amplification and perpetuation of inflammation. Hypoestoxide (a bicyclo [9,3,1] pentadecane) is a diterpene from Hypoestes rosea, a tropical shrub in the family Acanthacea, several members of which are used in folk medicine in Nigeria. Here, we demonstrate that hypoestoxide (HE) abrogates the production of pro-inflammatory cytokines (IL-1beta, IL-6, and TNF-alpha) in lipopolysaccharide (LPS)-activated normal human peripheral blood mononuclear cells. Moreover, HE inhibits the production of nitric oxide (NO) by IL-1beta- or IL-17-stimulated normal human chondrocytes. In vivo, oral administration of HE to mice significantly ameliorated hind paw edema induced by antibodies to type II collagen plus LPS. Furthermore, topical administration of HE to mice also significantly inhibited phorbol ester-induced ear inflammation. The anti-inflammatory activity of HE may be due in part to its ability to inhibit NF-kappaB activation through direct inhibition of IkappaB kinase (IKK) activity. Thus, HE could be useful in treating various inflammatory diseases and may represent a prototype of a novel class of IKK inhibitors.