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[Diphtheria in the Maritime Territory].

The results of the analysis of the present epidemiological situation in diphtheria in the Maritime Territory are presented. The data on absolute and intensive characteristics, death rate due to this infection, the vaccination status of diphtheria patients, as well as the results of the study of the level and intensity of antidiphtheria immunity in the healthy population of the territory. The study revealed that the defects of collective antidiphtheria immunity correlated with morbidity rate among adults and children. Adults aged 40-50 years and children aged 6-7 years were regarded as risk groups; among them the highest proportion of nonimmune persons and the highest diphtheria morbidity rate were registered. Stabilization achieved by the present moment was the result of the mass immunization of the adult population, ensuring the necessary coverage (92%) of vaccination in 1995.

Adolescent↗

Failure to vaccinate children against measles during the second year of life. An analysis of immunization practices in two Tennessee county health departments.

In many Tennessee counties, children under the care of health departments have low measles vaccination levels. An immunization survey and a health department record audit of 2-year-olds were undertaken in two counties to determine the reasons for this situation. The results indicated that faulty clinic procedures played a large part in the failure to vaccinate against measles. Nearly half of the unvaccinated 2-year-olds with health department records had been present in the health department clinic at the appropriate age for measles vaccination; the remainder had dropped out of the well-child program before their first birthday. Emphasis on tuberculin skin testing and delay in the administration of the basic series of DTP immunizations correlated with the failure to vaccinate against measles. For more than half of the children who attended the clinic after their first birthday, no reason was recorded for the failure to vaccinate them against measles. Improved clinic procedures could bring measles vaccination levels within the acceptable range. These procedures would include new methods for correcting immunization delinquency, simultaneous tuberculin skin testing and measles vaccination of children without a history of tuberculosis exposure, emphasis on vaccinating at-risk groups, and more convenient vaccination clinic hours.

Age Factors↗

Analysis of genetic heterogeneity, antigenicity, and biological characteristics of HIV-1 in a maternal transmitter and nontransmitter patient pair.

To obtain insight into the factors involved in vertical transmission, we compared the sequence diversity, seroreactivity, and biological characteristics of human immunodeficiency virus type 1 (HIV-1) derived from a transmitter and nontransmitter mother pair. Forty-two clones from the transmitter and 20 from the nontransmitter, spanning the principal neutralization determinant (PND) of the env gene, were sequenced and analyzed. The intrapatient sequence variation in transmitter and nontransmitter viruses was 12% and 36%, respectively, and the interpatient variation was 38%. In an effort to correlate immune responses to viral genetics, we analyzed the sera from these patients against a number of V3 peptides from known HIV-1 isolates. We observed that (i) both the transmitter and nontransmitter sera demonstrated higher binding to V3 peptides based on SF-2 and MN sequences than to IIIB and Z6 isolates; (ii) the vertical transmission of HIV-1 is correlated with the absence of high maternal antibody responses to the PND; and (iii) the high-affinity binding of the sera to SF-2 and MN V3 peptides correlated with the sequence analysis, indicating that the V3 sequences from both patients are more closely related to ADA, SF-162, and MN than to IIIB or Z6. Biological analysis of the viruses from these patients demonstrate that the transmitters' viruses infect a number of T-cell lines in vitro, whereas the nontransmitter viruses do not infect cell lines or the primary lymphocytes.

Amino Acid Sequence↗

Transfusion-induced immunosuppression results in diminished host survival in a murine neuroblastoma model.

Perioperative blood transfusion has been associated with decreased survival in cancer patients. The immunologic consequences of H-2 incompatible blood transfusion as related to neoplasia are unclear. This report examined the effect of multiple allogeneic blood transfusions, compared to syngeneic transfusions and saline infusion, on cellular immunity, tumor growth, and host survival in a murine C1300 neuroblastoma model. A/J mice were randomized to receive two weekly transfusions of washed whole blood cells from C57 Bl/6 or A/J donors or saline. Animals transfused with allogeneic blood, compared to syngeneic transfusions or saline infusions, had a significantly diminished lymphocyte response to mitogen (P less than 0.001), reduced donor-specific (P less than 0.001) and third party alloantigen (P less than 0.01) MLR, and reduced cytotoxicity against a natural killer (NK) cell-sensitive target (P less than 0.001). These in vitro deficits in cellular immunity correlated with a significantly greater Day 21 tumor weight to total body weight ratio in the allogeneic group (0.33) compared with the syngeneic (0.25) and saline (0.28) groups P less than 0.05). Median host survival was reduced in the allogeneic group (24 days) compared with the syngeneic (30 days) and saline (31 days) groups. There were no significant differences in cellular immunity, tumor growth, or survival between syngeneic and saline control groups. Allogeneic blood transfusion had an adverse affect on NK and T-lymphocyte function which was associated with enhanced tumor growth and reduced survival in tumor-bearing mice.

Animals↗

Rational development of prophylactic HIV vaccines based on structural and regulatory proteins.

The severity of the AIDS epidemic clearly emphasises the urgent need to expedite HIV vaccine candidates into clinical trials. Prophylactic HIV vaccine candidates have been evaluated in non-human primates. Based on specific proof of principle studies the first phase III clinical studies have recently begun in humans. However, a truly effective HIV vaccine is not yet at hand and many problems related to specific properties of the virus remain to be overcome. Previously proven empirical approaches have largely failed and now rational thinking based on an understanding of immunity to lentiviral infections is needed. This review addresses the scientific problems and complications facing the development of an HIV vaccine as well as the possible strategies currently available to overcome these problems. Recent attention has focussed on identifying the immune correlates and mechanisms of protection from either HIV infection or protection from disease progression. Based on these observations, the logic and rational behind the development of multiple component vaccine strategies are highlighted.

AIDS Vaccines↗

Correlation between serum IgG-2 concentrations and the antibody response to bacterial polysaccharide antigens.

We measured serum concentrations of immunoglobulin classes and IgG subclasses in 53 patients who had completed treatment for Hodgkin's disease and in 10 healthy adults. We wished to determine the relation of these classes and subclasses to the subjects' antibody responses to bacterial polysaccharide and viral protein antigens. Mean levels of the IgG-2 subclass were significantly lower in patients treated with both radiation and chemotherapy than in controls (P less than 0.05). The level of IgG-2 before immunization correlated directly with the mean antibody response both to 11 pneumococcal antigens (r = 0.71, P less than 0.001) and to the Haemophilus influenzae Type b antigen (r = 0.40, P less than 0.01). The correlation between IgG-2 concentration and pneumococcal antibody response was also significant in the 10 healthy adults ( r = 0.70, P less than 0.05). The levels of no immunoglobulin class or subclass correlated significantly with antibody responses to influenza A/Victoria/75 and A/New Jersey/76 hemagglutinins, both of which are protein antigens. The serum concentration of IgG-2 appears to provide a marker for predicting the ability to produce antibodies to polysaccharide, but not viral protein, antigens.

Adult↗

Specific depletion of human anti-adenovirus antibodies facilitates transduction in an in vivo model for systemic gene therapy.

Recombinant adenoviral (rAd) vectors are capable of mediating high-efficiency gene transfer in vivo. Under conditions requiring systemic administration, however, the use of rAd vectors can be problematic due to the presence of circulating anti-adenovirus antibodies developed either through natural infection or during the course of treatment. We developed a passive immunization model in SCID/Beige mice to assess the effect of human and mouse anti-adenovirus antibodies on systemic administration of a rAd vector expressing beta-galactosidase (rAd-betagal). In this model, the in vitro neutralizing activity of human or mouse antibodies used for passive immunization correlated well with inhibition of transduction of the liver following i.v. administration of rAd-betagal. Depletion of antibodies to individual adenovirus structural proteins (hexon, penton, fiber) by affinity chromatography demonstrated that antibodies to each of the three virion components contributed to neutralization of infectivity in vitro and to inhibition of transduction in vivo. Depletion of antibodies against all three structural proteins from human or mouse immune serum prior to passive immunization restored in vivo transduction activity to levels comparable to those obtained with nonimmune serum. Our data suggest that depletion of both murine and human anti-adenoviral antibodies can restore transduction in vivo during systemic rAd gene therapy in hosts previously exposed to adenovirus.

Adenoviridae↗

Induction of protective immunity against Schistosoma mansoni by a non-living vaccine. VI. Antigen recognition by non-responder mouse strains.

Previous studies have shown that many strains of mice develop partial resistance to Schistosoma mansoni as a result of intradermal vaccination with soluble schistosome antigens plus BCG. However, P and BALB/c mice are non-responsive to this intradermal vaccination protocol. In this study, humoral and cellular responses to schistosome antigens in vaccinated P and BALB/c mice were compared to those in protected C57BL/6 mice to identify an immune correlate to resistance in this model. Levels of circulating IgG and IgM antibodies to soluble adult worm antigens, as measured by ELISA, were comparable between strains. Moreover, Western blot analysis revealed no qualitative differences in antibody reactivity, with sera from vaccinated animals of all three strains recognizing the antigen previously identified as Sm-97 (paramyosin). However, vaccinated P and BALB/c mice showed specific defects in cell-mediated immunity to schistosome antigens, including decreased production of macrophage-activating lymphokines and an inability to produce activated macrophage effector cells in vivo at the site of antigen challenge. These observations strengthen our hypothesis that the intradermal vaccine acts through induction of T-cell-mediated immune resistance mechanisms.

Animals↗

Characterization of blood-borne transmission of simian foamy virus.

BACKGROUND: Simian foamy virus (SFV) is an endemic, nonhuman primate (NHP) retrovirus that is transmitted to individuals who work with or hunt NHPs. The cross-species transmission of simian retroviruses is believed to be the etiology of human immunodeficiency virus and human T-lymphotropic virus infections in humans. Although SFV is not pathogenic in the native host, the shared ancestry with other simian retroviruses has brought into question the potential for acquired pathogenicity after cross-species transmission. This study examines whether SFV also shares the traits of transmissibility through the blood supply. STUDY DESIGN AND METHODS: Within a controlled environment, blood from an SFV-infected monkey was transfused into an SFV-uninfected monkey. Evidence of infection, pathogenic effects, immune correlates, and viral shedding were followed for 6 months after transfusion. RESULTS: Molecular evidence of SFV infection manifested 8 weeks after transfusion followed by seroconversion 1 week later. Quantitative analysis demonstrated that the highest level of detectable virus was concomitant with seroconversion followed by establishment of a viral "set-point." Analysis of circulating lymphocytes revealed changes early in infection. Potential routes of transmission of SFV and roles of site-specific immune response are suggested by the late appearance of SFV shedding in the saliva of the transfused animal. CONCLUSION: The blood supply has historically provided a portal through which novel, occult viruses can become disseminated among humans. The demonstration of transmissibility of SFV through whole-blood transfusion, in an NHP model, contributes to the understanding of potential risks associated with blood donation by SFV-infected humans.

Animals↗

[Mechanism of augmented anti-tumor immunity in reconstituted lymphopenic mice immunized with melanoma vaccine].

OBJECTIVE: To explore mechanisms of the augmented anti-tumor immunity observed in reconstituted lymphopenic mice (RLM) receiving melanoma vaccination. METHODS: The study is to investigate the anti-tumor immunity of tumor vaccination during early immune reconstitution period following irradiation and cyclophosphamide (CY)-induced lymphopenia. Lymphopenic mice were subsequently reconstituted with naive splenocytes from syngeneic mice and immunized with irradiated melanoma cells F10 (irradiation experiment) and GM-CSF-modified D5 melanoma cells (D5-G6) (CY experiment). Controls included normal C57BL/6 mice receiving the corresponding vaccination, un-immunized naive mice and RLM. 8 - 10 days after vaccination, tumor vaccine draining lymph nodes (TVDLN) were harvested and phenotyped by FACS analysis. T cells purified from TVDLN were stimulated with anti-CD3 and anti-TCRbeta and proliferation was assessed by [(3)H]-TdR incorporation and FACS assay was performed for CD69 expression. RESULTS: The augmented anti-tumor immunity correlated with a significant increase in the percentage of T cells with activation/memory phenotype in the TVDLN of vaccinated RLM, compared to that of the controls. There was also a significant increase in the density of DCs in TVDLNs. The activation threshold of T cells generated from vaccinated RLM was significantly decreased, resulting in markedly enhanced proliferating capability upon anti-CD3 stimulation. CONCLUSION: This study suggests that the augmented anti-tumor immunity observed in vaccinated RLM is due to down regulated activation threshold of T cells during lymphopenia-driven T cell proliferation, which may in turn facilitate the breaking down of immune tolerance to weak tumor antigens upon vaccination with tumor cell vaccines.

Animals↗

The immune response to BCG vaccination of newborns.

The aim of this study is to identify immune correlates of protection against tuberculosis induced by the current vaccine, Bacille Calmette Guerin (BCG). This knowledge should be valuable for developing and testing novel tuberculosis vaccines. Blood from 5675 10-week-old South African infants, routinely vaccinated with BCG at birth, was collected, processed, and stored. Subsequently, infants who have developed tuberculosis disease-"not protected by the vaccine"-and infants who have remained healthy despite exposure to adults with tuberculosis-"protected by the vaccine"-have been identified. Recall immune responses to mycobacterial antigens in whole blood samples from the infants have been elicited; the next step will be to retrieve stored blood of "unprotected" and "protected" infants and compare immunity induced by BCG in the two groups. To guide the immune analysis, various pilot studies are being conducted to characterize the vaccination-induced host response. Preliminary results indicate that BCG does indeed induce a potent CD8 T-cell response, with cytokine-producing or cytotoxic potential, in infants. An induction of FoxP3 mRNA expression in some mycobacteria-stimulated whole-blood samples is also being found, which suggests the presence of BCG-induced regulatory CD4 T cells. Finally, stimulation of whole blood with mycobacterial antigens has resulted in a consistent pattern of cytokine release: significant numbers of infants make either large amounts of the effector cytokine interferon-gamma, or large amounts of the regulatory cytokine interleukin-10, but not both. Tests will, therefore, be made to determine whether CD8 or regulatory CD4 T-cell responses, as well as "outlier" cytokine responses, are associated with vaccination-induced protection against tuberculosis.

Adjuvants, Immunologic↗

Identification of murine T-cell epitopes in Ebola virus nucleoprotein.

CD8 T cells play an important role in controlling Ebola infection and in mediating vaccine-induced protective immunity, yet little is known about antigenic targets in Ebola that are recognized by CD8 T cells. Overlapping peptides were used to identify major histocompatibility complex class I-restricted epitopes in mice immunized with vectors encoding Ebola nucleoprotein (NP). CD8 T-cell responses were mapped to a H-2(d)-restricted epitope (NP279-288) and two H-2(b)-restricted epitopes (NP44-52 and NP288-296). The identification of these epitopes will facilitate studies of immune correlates of protection and the evaluation of vaccine strategies in murine models of Ebola infection.

Amino Acid Sequence↗

Heme oxygenase-1 in lesions of rat experimental autoimmune encephalomyelitis and neuritis.

The enzyme heme oxygenase-1 (HO-1) is reducing heme to the gaseous mediator carbon monoxide, to iron and the antioxidant biliverdin. The inducible expression of HO-1 is considered a protective cellular mechanism against reactive oxygen intermediates. Further, carbon monoxide (CO) is a regulator of cGMP synthesis, of NO-synthetases and cyclooxygenases, thereby indirectly modulating reactive processes. Here we report expression of HO-1 in rat experimental autoimmune encephalomyelitis (EAE) and neuritis (EAN). With both models, similar results were obtained: HO-1 was localized predominantly to infiltrating, monocytic, but only rarely to ramified microglial cells or astrocytes surrounding the inflammatory lesions. Prominent expression by monocytic cells was seen from day 11 after immunization correlating with the development of neurologic disease. Further, local expression is persistent for long after cessation of neurologic signs. Thus, HO-1 could be considered a factor in the formation and resolution of inflammatory autoimmune lesions of the nervous system.

Animals↗

CpG oligodeoxynucleotides and interleukin-12 improve the efficacy of Mycobacterium bovis BCG vaccination in mice challenged with M. tuberculosis.

Mycobacterium bovis bacillus Calmette-Guérin (BCG) is the only vaccine approved for prevention of tuberculosis. It has been postulated that serial passage of BCG over the years may have resulted in attenuation of its effectiveness. Because interleukin-12 (IL-12) and oligodeoxynucleotides (ODN) containing cytidine phosphate guanosine (CpG) motifs have been shown to enhance Th1 responses in vivo, they were chosen as adjuvants to increase the effectiveness of BCG vaccination. In this report, mice were vaccinated with BCG with or without IL-12 or CpG ODN and then challenged 6 weeks later via the aerosol route with the Erdman strain of M. tuberculosis. Mice vaccinated with BCG alone showed a 1- to 2-log reduction in bacterial load compared with control mice that did not receive any vaccination prior to M. tuberculosis challenge. Moreover, the bacterial loads of mice vaccinated with BCG plus IL-12 or CpG ODN were a further two- to fivefold lower than those of mice vaccinated with BCG alone. As an immune correlate, the antigen-specific production IFN-gamma and mRNA expression in spleen cells prior to challenge were evaluated. Mice vaccinated with BCG plus IL-12 or CpG ODN showed enhanced production of IFN-gamma compared with mice vaccinated with BCG alone. Finally, granulomas in BCG-vaccinated mice were smaller and more lymphocyte rich than those in unvaccinated mice; however, the addition of IL-12 or CpG ODN to BCG vaccination did not alter granuloma formation or result in added pulmonary damage. These observations support a role for immune adjuvants given with BCG vaccination to enhance its biologic efficacy.

Adjuvants, Immunologic↗

Dose-related immunologic effects of levamisole in patients with cancer.

PURPOSE: This phase I study was conducted to determine the maximum-tolerated dose (MTD) and the immunologic properties of levamisole in cancer patients when administered alone and in combination with interferon gamma (IFN-gamma). PATIENTS AND METHODS: Twenty patients with advanced cancer and 36 patients with completely resected melanoma (n = 33) or renal cell cancer (n = 3) received levamisole orally every other day for six doses at 1.0, 2.5, 5.0, or 10.0 mg/kg. Ten days later, patients restarted levamisole and began IFN-gamma 0.1 mg/m2 by subcutaneous injection every other day. Blood samples were collected for measurement of neopterin and soluble interleukin-2 receptor (sIL-2R), and for flow-cytometric analysis. RESULTS: The MTD of levamisole was 5 mg/kg, and this was not changed by the addition of IFN-gamma. Dose-related increases in serum levels of neopterin and sIL-2R were noted. Multiple doses of > or = 5 mg/kg of levamisole were required to elicit immune changes, which were more prominent in patients with minimal tumor burdens. Increased expression of CD64 and class I and class II major histocompatibility antigens on monocytes was also observed. The combination of IFN-gamma and levamisole did not result in greater immunologic effects than those observed in previous trials of IFN-gamma alone. CONCLUSION: Levamisole induces dose-related immunologic changes in patients with large or minimal tumor burdens. These changes may be involved in the beneficial effects noted in recent adjuvant trials of levamisole. Ongoing clinical trials should correlate immune changes with response, and trials exploring different schedules of administration using higher, more immunologically active, doses of levamisole should be performed.

Adult↗

Humoral and cellular immune responses in rhesus macaques infected with human immunodeficiency virus type 2.

Eighteen rhesus macaques were inoculated with either an infectious molecularly cloned human immunodeficiency virus type 2 (HIV-2)SBL/ISY, or with one of eight mutants defective in one or more accessory genes. The immune responses generated by the macaques were monitored for up to 2 years postinfection. All the macaques except those that received mutants lacking the vpr or vif genes demonstrated low to moderate antibody titers. Macaques inoculated with vpx- mutants exhibited a persistent serological response, suggesting continuous virus expression even in the absence of detectable virus in the peripheral blood mononuclear cells (PBMCs). Neutralizing antibodies developed in only four macaques. In general, low-level cytotoxic T lymphocyte (CTL) activity, not clearly HIV-2 specific, was detected in PBMCs. However, one virus-negative macaque exhibited significant HIV-2-specific CTL activity in an enriched CD8+ cell population from PBMCs, suggesting clearance of the viral infection. In addition, CTL activity against the Env and Gag/Pol epitopes of HIV-2 by CD8+ lymphocytes from the spleens and lymph nodes of two infected macaques, in one case requiring CD8+ T cell enrichment and in the other clearly evident in unfractionated tissue lymphocytes, was demonstrated for the first time. This sequestration of tissue CTLs occurred in the absence of significant levels of circulating CTLs in the blood. Our results suggest that routine monitoring of PBMCs may sometimes be inadequate for detecting cell-mediated immune responses. Elucidation of immune correlates of vaccine protection may therefore require sampling of lymphoid tissues and assessment of enriched CD8+ populations.

Acquired Immunodeficiency Syndrome↗

Highly active anti-retroviral therapy (HAART)-induced maintenance of adaptive but not innate immune parameters is associated with protection from HIV-induced mortality.

Immunosuppression induced by the human immunodeficiency virus (HIV-1) increases the risk of death. We measured the influence of immunological and virological factors and the type of highly active anti-retroviral therapy (HAART) on this risk. Adaptive (lymphocyte) and innate (natural killer) immune correlates and maximum HIV viral loads were assessed for association with mortality using univariate and multivariate analyses. The protective effect of HAART regimens, containing protease inhibitors (PI) and/or non-nucleoside reverse transcriptase inhibitors (NNRTI) on mortality were also examined in a prospectively recorded cohort of 9621 HIV-infected individuals. From this entire cohort, 5873 HIV infected individuals (61%) have been followed-up in the HAART era and of these 499 (8.5%) have died. In multivariate analyses, CD4 counts below the 50th centile and CD8 and CD19 counts below the 25th centile were significantly associated with mortality, as was increased age (P < 0.001). Innate immune subset levels had no effect on mortality. A maximum HIV viral load greater than the 75th centile was also associated independently with mortality (P < 0.035). Exposure to either a PI or an NNRTI-containing HAART regimen, or both together, was protective against death compared with no anti-retrovirals (P < 0.001). Effective HAART-induced maintenance of the adaptive immune system (CD4, CD8 and CD19 counts) protects from HIV-related mortality.

Adult↗

The relationship of circulating IgA to cellular immunity in head and neck cancer patients.

The relationship of circulating IgA titers and multiple parameters of cell-mediated immunity was examined in 97 patients with head and neck cancer. In 26% of the patients, IgA titers were above one standard deviation of controls, with highest levels noted in patients with advanced disease. In 40 patients for whom multiple immune parameters were tested in vitro, increasing concentrations of IgA were associated with an enhanced immunologic helper state defined by a generalized hypergammaglobulinemia, increased percentage of T4+ lymphocytes, higher T4/T8 ratio, and an increased lymphocyte blastogenesis response to mitogens. IgA concentrations were inversely related to percentages and absolute number of Leu 11+ natural killer cell subsets, and also to disease-free survival (p less than 0.005 by Cox proportional hazards model). The immune correlations identified here are similar to those noted in many autoimmune diseases. Head and neck cancer patients are an immunologically heterogeneous population, among whom elevated IgA blood levels may reflect the autoimmune nature of cancer, an immunologic state defined by its tumor-promoting capacity.

Adult↗