Molecular Identification of Mutations Conferring Resistance to Azoxystrobin in Cercospora nicotianae

Cercospora nicotianae, the causal agent of frogeye leaf spot (FLS) of tobacco, has been exposed to quinone outside inhibitor (QoI) fungicides for more than a decade through azoxystrobin applications targeting other major foliar diseases. From 2016 to 2018, a total of 124 isolates were collected from tobacco fields throughout Kentucky. Sensitivity of these isolates to azoxystrobin was previously characterized by determining the effective concentration to inhibit 50% conidial germination (EC₅₀). Based on azoxystrobin EC₅₀, isolates were categorized into three discrete groups: high sensitivity (<0.08 µg/ml), moderate sensitivity (0.14 to 0.64 µg/ml), and low sensitivity (>1.18 µg/ml). Variability in sensitivity in a limited number of C. nicotianae isolates was previously shown to be a result of resistance mutations in the fungicide target gene. To improve understanding of C. nicotianae cytochrome b (cytb) structure, the gene was cloned from three isolates representing each EC₅₀ group, and sequences were compared. Our analysis showed that cytb gene in C. nicotianae consists of 1,161 nucleotides encoding 386 amino acids. The cytb sequence among the cloned isolates was identical with the exception of the F129L and G143A point mutations. To more rapidly determine the resistance status of C. nicotianae isolates to azoxystrobin, a polymerase chain reaction (PCR) assay was developed to screen for mutations. According to this assay, 80% (n = 99) of tested C. nicotianae isolates carried an F129L mutation and were moderately resistant to azoxystrobin, and 7% (n = 9) carried the G143A mutation and were highly resistant. A receiver operating characteristic curve analysis suggested the PCR assay was a robust diagnostic tool to identify C. nicotianae isolates with different sensitivity to azoxystrobin in Kentucky tobacco production. The prevalence of both the F129L and G143A mutations in C. nicotianae from Kentucky differs from that of other pathosystems where resistance to QoI fungicides has been identified, in which the majority of sampled isolates of the pathogen species have a broadly occurring cytb mutation.

Cytochrome b Mutations F129L and G143A Confer Resistance to Azoxystrobin in Cercospora nicotianae, the Frogeye Leaf Spot Pathogen of Tobacco

Azoxystrobin is the only synthetic, systemic fungicide labeled in the United States for management of frogeye leaf spot (FLS) of tobacco (Nicotiana tabacum L.), caused by Cercospora nicotianae. Though traditionally considered a minor disease in the United States, FLS has recently become yield and quality limiting. In 2016 and 2017, 100 C. nicotianae isolates were collected from symptomatic tobacco from eight counties in Kentucky, United States. Prior to azoxystrobin sensitivity testing, some C. nicotianae isolates were found to utilize the alternative oxidase pathway and, after assay comparisons, conidial germination was utilized to evaluate sensitivity in C. nicotianae as opposed to mycelial growth. Azoxystrobin sensitivity was determined by establishing the effective concentration to inhibit 50% conidial germination (EC50) for 47 (in 2016) and 53 (in 2017) C. nicotianae isolates. Distributions of C. nicotianae EC50 values indicated three qualitative levels of sensitivity to azoxystrobin. Partial cytochrome b sequence, encompassing the F129L and G143A mutation sites, indicated single-nucleotide polymorphisms (SNPs) conferring the F129L mutation in C. nicotianae of moderate resistance (azoxystrobin at 0.177 ≤ EC50 ≤ 0.535 µg/ml) and the G143A mutation in isolates with an azoxystrobin-resistant phenotype (azoxystrobin EC50 > 1.15 µg/ml). Higher frequencies of resistant isolates were identified from greenhouse transplant (4 of 17) and conventionally produced (58 of 62) tobacco samples, as compared with field-grown tobacco (<4 weeks prior to harvest; 4 of 62) or organically produced samples (1 of 7), respectively. Together, these results suggest that resistance to azoxystrobin in C. nicotianae occurs broadly in Kentucky, and generate new hypotheses about selection pressure affecting resistance mutation frequencies.

Exploring the association between a cholecystokinin promoter polymorphism (rs1799923) and posttraumatic stress disorder in combat veterans

BACKGROUND

Cholecystokinin (CCK) is a neuropeptide that has been implicated in understanding the acquisition and extinction of fear. Research on CCK in anxiety has primarily focused on understanding panic attacks and panic disorder. Emerging data suggests that CCK may also hold promise in understanding the development and maintenance of posttraumatic stress disorder (PTSD).

METHOD

The present study examined whether a single nucleotide polymorphism in the promoter region of the CCK gene (C>T; rs1799923) was associated with an increased prevalence of PTSD as well as with severity of PTSD symptoms among a sample of 457 combat veterans.

RESULTS

Results demonstrated that participants with either the heterozygous or homozygous T allele had an increased prevalence of PTSD relative to participants with the CC genotype (OR=2.17; 95% CI [1.37-3.43]).

LIMITATIONS

The relatively small sample size precluded examination of racial/ethnic differences. Findings were also limited by the absence of a systematic assessment of comorbid anxiety psychopathology.

CONCLUSIONS

These data offer preliminary evidence supporting an association between the rs1799923 polymorphism in the CCK gene and PTSD. Additional research is needed to better understand the nature of this relationship.

Identifying genes in Fusarium verticillioides through forward and reverse genetics

The increasing availability of sequenced genomes for plant pathogenic fungi has revolutionized molecular plant pathology in recent years. However, the genetic regulatory networks underlying many important components of pathogenesis remain poorly defined. Although the protocols outlined in this chapter can be utilized to identify genes regulating a wide range of biological processes in many filamentous fungi, we focus on describing how to identify genes through forward and reverse genetics, using the plant pathogenic fungus Fusarium verticillioides as a model for the protocol. Specifically, this chapter explains how to create a collection of insertional mutants via Restriction Enzyme Mediated Integration (REMI) and how to screen mutants with a high-throughput method to visualize defects in amylolysis. Next, techniques are described to define the genomic lesions in REMI mutants with genome-walker PCR in order to identify candidate genes. Finally, protocols are presented describing a reverse-genetic approach to disrupt candidate genes in the wild-type strain with a split-marker strategy to confirm the phenotype observed in the REMI mutant.

First Report of Rust Caused by Puccinia emaculata on Switchgrass in Arkansas

In May 2007, switchgrass (Panicum virgatum L.) cv. Alamo and a breeding line, OSU-NSL 2001-1, were planted at the Arkansas Agricultural Research and Extension Center, Fayetteville. In August 2008, a high incidence of dark brown-to-black rectangular foliar lesions delineated by major veins was observed throughout plots of both lines. Lesions covered 25% to nearly 100% of total leaf tissue. Similar symptoms were also observed on unknown switchgrass cultivars in Benton County in northwest Arkansas and in St. Francis County in east-central Arkansas, suggesting that the disease was widely distributed throughout the state. The pathogen produced epiphyllous and adaxial masses of dark brown-to-black telia from erumpent fissures on leaf surfaces. Dark brown teliospores were observed under magnification and were two-celled, oblong to ellipsoid, and 33 ± 3.5 μm long with an apical cell width of 17.5 ± 2.7 μm and basal cell width of 16.2 ± 2.8 μm (reported as mean ± standard deviation, n = 25). Pedicles were colorless to light brown and measured 25.4 ± 9.2 μm (n = 25). In June 2009, at the Fayetteville Research and Extension Center, several second-year stands of switchgrass developed amphigenous and adaxial foliar lesions containing urediniospores. The uredia were globose and finely echinulate, measuring 23.1 ± 2.2 μm (n = 25) with brown cell walls. Teliospore and urediniospore morphology from all collections was consistent with Puccinia emaculata Schw. (2). Genomic DNA was extracted from a representative infected leaf of cv. Alamo, collected in Fayetteville, AR in June 2009, and amplified by PCR with primer sets PRITS1F (3) and ITS4B (1), which amplified an 803-bp fragment of rDNA encoding the first internal transcribed spacer (ITS1), 5.8S subunit, and second internal transcribed spacer (ITS2). The fragment was cloned into pGEM T Easy (Promega Corp, Madison, WI) and sequenced. A BLAST search of GenBank revealed that the fragment was most similar to the rDNA of P. emaculata (GenBank Accession No. EU915294.1; 755 of 758 bases matching; 99% identity) previously reported as a pathogen on switchgrass in Tennessee (3). The incidence and severity of rust on the widely planted switchgrass cv. Alamo is considerable cause for concern as efforts are made to increase acreage and production. Climatic conditions in St. Francis County are generally consistent with locations in Tennessee where switchgrass rust was previously reported (3). However, northwest Arkansas represents the eastern edge of the southwestern United States, suggesting that P. emaculata may affect switchgrass in geographically diverse areas of the United States. To our knowledge, this study represents the first report of rust on switchgrass in Arkansas. Managing this disease will be an important consideration for large-scale switchgrass cultivation in the state. References: (1) M. Gardes and T. D. Bruns. Mol. Ecol. 2:113, 1993. (2) P. Ramachar and G. Cummins. Mycopathol. Mycol. Appl. 25:7, 1965. (3) J. Zale et al. Plant. Dis. 92:1710, 2008.

Entry overload, emergency department overcrowding, and ambulance bypass

OBJECTIVES

To describe an experience of emergency department (ED) overcrowding and ambulance bypass.

METHODS

A prospective observational study at Royal Perth Hospital, a major teaching hospital. Episodes of ambulance bypass and their characteristics were recorded.

RESULTS

From 1 July 1999 to 30 June 2001, there were 141 episodes of ambulance bypass (mean duration 187 min, range 35-995). Monday was the most common day with 39 (28%) episodes. Entry block alone was the most common reason bypass was activated (n=38, 30.4%). The mean number of patients in ED at these times was 40 (occupancy 174%), including nine in the corridor, seven awaiting admission, and 14 waiting to be seen. Episodes attributable to entry block were typically preceded by a presentation rate of >/=10 patients per hour for >/=2 hours (OR 6.2, 95% CI 4.3 to 8.5). Mid-afternoon to early evening was the most common time for activation. Ambulance bypass is increasing in frequency and duration.

CONCLUSIONS

Entry overload resulting in entry block results from overwhelming numbers of patients presenting to the ED in a short space of time. Entry block impairs access to emergency care. Unless something is done in the near future, the general public may no longer be able to rely on EDs for quality and timely emergency care. A "whole of system" approach is necessary to tackle the problem.

A humanized monoclonal antibody against respiratory syncytial virus (palivizumab) inhibits RSV-induced neurogenic-mediated inflammation in rat airways

Respiratory syncytial virus (RSV) is the most important respiratory pathogen in infancy and early childhood and may predispose to subsequent lower respiratory tract illness. Recent data indicate that RSV up-regulates the substance P receptor, making the airways abnormally susceptible to the proinflammatory effects of this peptide released from sensory nerves. The present study was designed to determine whether the administration of RSV antibodies prevents the potentiation of neurogenic inflammation in rat airways. Five days after inoculation, sensory nerve-mediated extravasation of Evans blue-labeled albumin was significantly greater in the airways of RSV-infected rats than in pathogen-free controls. Polyclonal immune globulin enriched for RSV-neutralizing antibodies (RSVIG) reduced neurogenic extravasation when injected 24 h before intranasal inoculation of the virus but not when injected before endotracheal inoculation. A humanized MAb against RSV fusion protein (palivizumab) was twice as potent as RSVIG when given before intranasal inoculation and also caused significant inhibition after endotracheal inoculation. Furthermore, palivizumab inhibited neurogenic inflammation in RSV-infected rats when given 72 h after virus inoculation. These data suggest that palivizumab protects the respiratory tract from RSV-induced inflammation when given before or in the early phase of the viral infection. The administration of palivizumab to high-risk infants may limit the severity of the acute airway inflammation and may protect against subsequent lower respiratory tract illness.

Respiratory syncytial virus immune globulin treatment of lower respiratory tract infection in pediatric patients undergoing bone marrow transplantation - a compassionate use experience

Respiratory syncytial virus (RSV) pneumonia in BMT recipients carries a mortality rate of approximately 50-70% despite ribavirin (Virazole) treatment. In both immunocompetent and immunocompromised animal models, RSV neutralizing antibodies rapidly reduce pulmonary virus load after a single dose. RSV-IGIV (RespiGam) is an IgG immune globulin with high concentrations of RSV neutralizing antibody (>19 200 MU/ml). From June 1991 to February 1996, a compassionate-use protocol using RSV-IGIV for treatment of RSV infections was conducted. Eleven children at multiple centers, mean age 3.3 years (4 months to 9 years), were undergoing BMT and met the protocol criteria. They received a single 1500 mg/kg dose of RSV-IGIV infused over 12 h at a median of 5 days (1-37 days) after RSV symptom onset. Ten of these patients received prior or concurrent aerosolized ribavirin. Serum RSV neutralizing titers were measured in five patients and showed a 3- to 30-fold increase 24 h after RSV-IGIV infusion. Adverse events were mild. One of 11 (9.1%) patients died from their RSV illness (91% RSV survival). In comparison to previously published reports, RSV-IGIV treatment of RSV pneumonia in BMT patients may increase survival above that in such patients treated with ribavirin alone. Bone Marrow Transplantation (2000) 25, 161-165.

The prognostic significance of serum viral load, codon 215 reverse transcriptase mutation and CD4+ T cells on progression of HIV disease in a double-blind study of thymopentin

OBJECTIVE

To determine in asymptomatic HIV-infected subjects the prognostic value of virion reverse transcriptase (RT) codon 215 mutation, serum HIV RNA level, CD4+ T-cell count and immune complex dissociated (ICD) p24 level. The retrospective evaluation of thymopentin treatment effect on subjects in high risk groups for progression was a secondary objective.

PARTICIPANTS

Zidovudine (ZDV)-experienced asymptomatic HIV-infected subjects (n = 352) who had been enrolled in a 48-week placebo-controlled double-blind trial of thymopentin treatment were studied.

METHODS

Post hoc analyses were conducted to determine which subjects at study entry were at greater risk for progression to AIDS-related complex (ARC), AIDS or death, and to determine the effect of treatment on these subjects. Four potential prognostic variables (virion RT codon 215 mutation, circulating HIV virion RNA copies, CD4+ T-cell count, and ICD p24) were evaluated by dichotomizing subjects for each variable based on the median of the observed values. CD4+ T-cell count was evaluated prospectively, whereas frozen samples were evaluated under blinded conditions for the other variables after the study was completed.

RESULTS

The presence of the codon 215 mutation [P = 0.044; relative hazard (RH), 2.6], > or = 20,000 HIV RNA copies/ml (P = 0.002; RH, 5.5), and < 350 CD4+ cells 10(6)/l (P = 0.042; RH, 2.2) were prognostic factors, and > or = 30 pg/ml ICD p24 level (P = 0.52; RH, 1.4) was not a prognostic factor in predicting progression. Subjects were prestratified by previous ZDV use (< or = 6 or > 6 months). Across both strata thymopentin delayed treatment progression to ARC, AIDS, or death (P = 0.015; RH, 3.0). This effect was magnified in the ZDV-experienced subjects at greater risk, where thymopentin delayed progression compared to placebo in the presence of the codon 215 mutation (P = 0.007; RH, 10.1), > or = 20,000 RNA copies/ml (P = 0.012; RH, 8.9), and CD4+ T-cell count < 350 x 10(6)/l (P = 0.005; RH, 10.4).

CONCLUSIONS

Codon 215 mutation, serum HIV RNA and CD4 T-cell count are independent predictors of progression in ZDV-experienced asymptomatic subjects. Furthermore, thymopentin delays HIV disease progression in the presence of a key ZDV resistance mutation as well as high viral load and low CD4+ T-cell counts.

Safety and efficacy of thymopentin in zidovudine (AZT)-treated asymptomatic HIV-infected subjects with 200-500 CD4 cells/mm3: a double-blind placebo-controlled trial

Thymopentin, 50 mg subcutaneously (s.c.) 3 times per week, was evaluated in a double-blind, randomized, placebo-controlled trial of zidovudine (AZT)-treated asymptomatic human immunodeficiency virus (HIV)-infected subjects with 200-500 CD4 cells/mm3 at entry. The 352 subjects were prestratified by prior AZT use into stratum I (235 subjects, > 6 months AZT at entry) and stratum II (117 subjects, < or = 6 months AZT at entry). Clinical end points, CD4 cell counts, serum p24, serum immune complex dissociated (ICD) p24, and safety variables were evaluated through 48 weeks, using an intent-to-treat analysis. The two strata were analyzed individually because they yielded different clinical outcomes, with a statistically significant treatment-by-stratum interaction. In stratum I (mean, 16 months AZT at entry) two AIDS or death events occurred in thymopentin and 10 in placebo recipients (p = 0.024; relative risk (RR) estimate, 4.9 [95% confidence limit (CI), 1.1 to 22.2]). There were three AIDS-related complex (ARC), AIDS, or death events in thymopentin and 18 in placebo recipients [p = 0.001; RR estimate, 5.9 (95% CI, 1.7 to 20.0)]. In stratum II (mean, 3 months AZT at entry), four AIDS or death events occurred in thymopentin and none in placebo recipients (p = 0.11), and four ARC, AIDS, or death events occurred in thymopentin and two in placebo recipients (p = 0.79). The treatment groups did not differ significantly with respect to changes in CD4 counts or p24 antigen levels or with respect to clinical adverse experiences or laboratory abnormalities. Thus, AZT-experienced placebo-treated subjects had relatively high progression rates to AIDS or death and to ARC, AIDS, or death, and these rates were reduced by thymopentin treatment. In contrast, placebo-treated subjects with little prior AZT experience had low progression rates; these were not significantly changed by thymopentin treatment. There was no increase in the incidence of adverse reactions with thymopentin.

Maintenance of CD4+ cells by thymopentin in asymptomatic HIV-infected subjects: results of a double-blind, placebo-controlled study

OBJECTIVE

To assess the efficacy and safety of thymopentin in HIV-infected patients who had not yet developed AIDS.

DESIGN

Patients were stratified into asymptomatic or symptomatic groups and randomized to receive either thymopentin (50 mg) or placebo, subcutaneously, double-blind for 24 or 52 weeks, three times a week.

SETTING

Patients were enrolled at three sites (two hospital clinics and one private practice).

PATIENTS

Of 91 HIV-seropositive patients (52 asymptomatic and 39 symptomatic) from whom HIV could be isolated from peripheral blood, 45 were enrolled for 24 weeks and 46 for 52 weeks of double-blind evaluation.

MAIN OUTCOME MEASURES

Virological, immunological and clinical evaluations were performed before and during treatment.

RESULTS

Thymopentin-treated asymptomatic patients had more CD4+ cells, as demonstrated by a greater area under the percentage CD4+ cells curve (P = 0.03) and a shorter median time to a 20% increase in percentage of CD4+ cells (P = 0.04) in the first 24 weeks, with similar trends in the 52-week study. By 24 weeks no asymptomatic thymopentin-treated and two placebo-treated patients (9.1%, Kaplan-Meier estimate) had progressed to constitutional symptoms (P = 0.12; two-tailed Wilcoxon-Gehan test), with only one further progression in a placebo-treated patient in the subset followed for 52 weeks. Symptomatic patients receiving thymopentin or placebo were similar in both CD4+ cell levels and disease progression (two progressions to AIDS in each group). No serious adverse effects attributable to thymopentin were observed.

CONCLUSIONS

These results, if confirmed, indicate that thymopentin, by maintaining CD4+ cells, could slow or arrest immune decline and consequent disease progression at the asymptomatic stage of HIV infection.

Admissions for suspected snake bite to the Perth adult teaching hospitals, 1979 to 1988

OBJECTIVE

To describe the epidemiology of snake bite in Perth, and the likelihood of envenomation.

DESIGN

Information from case notes was retrospectively analysed.

SETTING

Emergency medicine, teaching hospitals.

PATIENTS

All patients admitted to the three adult teaching hospitals in Perth for suspected snake bite from 1979 to 1988.

MAIN OUTCOME MEASURE

Systemic envenomation, was accepted as present if there were definite symptoms, signs or laboratory evidence (vomiting, abdominal pain, ptosis, convulsions, difficulty with breathing or swallowing, coagulopathy, haemolysis, rhabdomyolysis or renal failure).

RESULTS

Ninety-nine patients were definitely bitten, with 53 envenomed, including three snake handlers. Thirty others may have been envenomed. Nearly half (44%) of the 82 patients with witnessed snake bite were envenomed. The dugite (Pseudonaja affinis) caused most cases of envenomation, most often producing coagulopathy only. The remainder were probably due to bites by the tiger snake (Notechis after occidentalis) and gwardar (Pseudonaja nuchalis), with one by a sea snake. The Commonwealth Serum Laboratories Snake Venom Detection Kit (VDK) enabled identification of the genus in 36% of definite cases of snake bite, and in 51% of cases of envenomation. It may occasionally produce false-positive results. The VDK is of greatest value in establishing the genus of snake in envenomed patients.

CONCLUSIONS

It is suggested that a mixture of brown and tiger snake antivenom be used to treat patients envenomed by an unidentified snake in the Perth metropolitan area. This does not apply to patients bitten elsewhere in Western Australia or transferred to Perth from country regions where other snakes are more prevalent.

Thymopentin therapy reduces the clinical severity of atopic dermatitis

One hundred patients with moderate to severe atopic dermatitis were entered into a two-center, double-blind trial. Patients were randomized to receive either thymopentin (Timunox, n = 48) or placebo (n = 52), administered as daily subcutaneous injections for 6 weeks. Clinical extent of disease and severity parameters were measured at baseline and at regular time intervals during the study. Both the placebo- and thymopentin-treated groups demonstrated a progressive and statistically significant (p less than 0.001) decline in the overall severity of their disease, but reduction in the clinical severity score was higher in the thymopentin-treated group and statistically significant (p = 0.04) in comparison with the placebo-treated group after 6 weeks of treatment. Of the individual symptoms comprising the total severity score, pruritus (p = 0.02) and erythema (p = 0.04) were reduced significantly when thymopentin therapy was compared to placebo therapy. In addition, both the extent of body involvement and severity index (a combined severity/extent index) were significantly reduced after 6 weeks in the thymopentin-treated group in comparison to the placebo-treated group (p = 0.04). There were no serious adverse experiences in either treatment group. We conclude that treatment with thymopentin is safe and offers significant therapeutic promise for atopic dermatitis.

The placebo effect during a double blind trial of recombinant alpha 2 interferon in multiple sclerosis patients: immunological and clinical findings

A double-blind, placebo controlled trial of recombinant alpha 2 interferon in relapsing/remitting multiple sclerosis patients was performed to assess the clinical and immunological responses to treatment. This study demonstrated that natural killer (NK) cell activity, known to be enhanced by interferon (IFN) treatment, increased during the first week of treatment in both the IFN and placebo treatment groups. After the first week of treatment NK cell activity returned to baseline levels in both groups, and subsequently declined in the IFN treatment group. Patients in both groups improved clinically, as evidenced by a reduction in the exacerbation rate. Furthermore, a similar incidence of adverse reactions to treatment were reported by both groups. The mechanism underlying the response to placebo is not known. However, it is unlikely that the long term clinical improvement (one year) in either group is related to the transient increase in NK cell activity.

OKT3 monoclonal antibody reversal of renal and hepatic rejection in pediatric patients

The monoclonal antibody OKT3 was previously shown to be superior to conventional high-dose steroid therapy for reversal of acute rejection of renal allografts. Furthermore, OKT3 was effective in reversing acute renal or hepatic allograft rejection that was resistant to treatment with steroids, anti-thymocyte globulin, or both. Our analysis demonstrates that OKT3 is also effective in pediatric patients in reversing acute rejection of renal allografts (rescue treatment) or hepatic allografts (primary or rescue treatment).

Vaccine-associated poliomyelitis in a household contact with Netherton's syndrome receiving long-term steroid therapy

Paralytic poliomyelitis developed in a man 51 days after his two-month-old daughter received her first dose of trivalent live oral poliovirus vaccine. The patient was receiving long-term glucocorticosteroid therapy (tapered to 12.5 mg per day for the eight months prior to his poliomyelitis) for Netherton's syndrome, a congenital syndrome characterized by bamboo-like hair, hyperkeratotic and hyperhidrotic skin, and multiple allergies. The patient was ventilator-dependent and quadriplegic throughout most of his hospital stay and died in the hospital 10 months after the onset of paralysis. "Vaccine-like" type 3 poliovirus was isolated from a stool specimen and his serum showed a significant rise in neutralizing antibody titer against type 3 virus. This case report represents the first documented case of vaccine-associated poliomyelitis in a household contact receiving glucocorticosteroids, although evidence of immunosuppression was not documented. Nevertheless, the case reinforces current recommendations not to administer oral poliovirus vaccine to persons known to be immune deficient or suppressed or to normal persons with close contacts known to be immune deficient or suppressed.

Treatment of multiple sclerosis with gamma interferon: exacerbations associated with activation of the immune system

We treated 18 clinically definite relapsing-remitting MS patients with recombinant gamma interferon in a pilot study designed to evaluate toxicity and dosage. Patients received low (1 microgram), intermediate (30 micrograms), or high (1,000 micrograms) doses of interferon by intravenous infusion twice a week for 4 weeks. Serum levels of gamma interferon were proportional to dose and no interferon was detected in CSF. Seven of the 18 patients had exacerbations during treatment, a significant increase compared with the prestudy exacerbation rate (p less than 0.01). Exacerbations occurred in all three dosage groups and were not precipitated by fever or other dose-dependent side effects. There were significant increases in circulating monocytes bearing class II (HLA-DR) surface antigen, in the proliferative responses of peripheral blood leukocytes, and in natural killer cell activity. These results show that systemic administration of gamma interferon has pronounced effects on cellular immunity in MS and on disease activity within the CNS, suggesting that the attacks induced during treatment were immunologically mediated. Gamma interferon is unsuitable for use as a therapeutic agent in MS. Agents that specifically inhibit gamma interferon production or counteract its effects on immune cells should be investigated as candidates for experimental therapy.

Exacerbations of multiple sclerosis in patients treated with gamma interferon

In an open, randomised study, 18 patients with clinically definite, relapsing-remitting multiple sclerosis (MS) received 1 microgram, 30 micrograms, or 1000 micrograms doses of recombinant gamma interferon (IFN-gamma), given by intravenous infusion twice a week for four weeks. 7 patients had exacerbations during treatment. This exacerbation rate, compared retrospectively with the pretreatment rate and prospectively with the post-treatment rate, was significantly greater than expected. Exacerbations were not precipitated by fever or other dose-dependent side-effects. A concomitant increase in circulating monocytes bearing class II (HLA-DR) surface antigen suggested that the attacks induced during treatment were immunologically mediated. IFN-gamma is unsuitable for treatment of MS.

Impending United States Energy Crisis

The U.S. oil and gas industry has been dramatically weakened by the recent oil price collapse. Domestic drilling activity reached a new post-World War II low during the summer of 1986. Given a weak, unstable oil price outlook, U.S. capability will continue to deteriorate. In the last year U.S. imports of foreign oil have risen significantly, and if market forces alone dominate, U.S. dependence is expected to rise from 32% in 1983 to the 50 to 70% level in the not-too-distant future. The 1973 oil embargo and the subsequent attempts to improve U.S. energy security vividly demonstrated the huge costs and long periods of time required to change our energy system. These facts, coupled with the nation's generally short-term orientation, suggest a strong likelihood of a new U.S. energy crisis in the early to middle 1990s.

Activation of the alternative complement pathway by mumps infected cells: relationship to viral neuraminidase activity

An inverse relationship exists between the sialic acid content of a particle and its ability to activate the alternative complement pathway. The present studies were performed to determine if the neuraminidase (NANase) activities of different mumps virus strains could influence the ability of mumps virus infected cells to activate the alternative pathway. CV-1 cells were infected with three different mumps virus strains (RW, O'Take, and Kilham) and after 24 hours, 10 percent guinea pig serum (GPS) treated with EGTA/MgCl2 or GPS lacking the 4th component of complement (C4DGPS) was added to the cell monolayers. After 30 minutes, the percentage C3 consumed was determined by a functional hemolytic assay. Cells infected with RW (high NANase) consumed significantly more C3 (23.2 per cent) than cells infected with Kilham (5.7 percent, low NANase). Cells infected with O'Take were intermediate in their ability to activate C3. The degree of C3 deposition on the surface of infected cells, detected by fluorescence microscopy, was also greater for cells infected with the RW than the Kilham strain of mumps virus. These studies suggest that the NANase activity of mumps virus can influence the ability of infected cells to activate the alternative pathway and thereby, the ability of complement to participate in host defense against mumps virus infection.

The effects of long-term administration of recombinant alpha-2 interferon on lymphocyte subsets, proliferation, and suppressor cell function in multiple sclerosis

The immunological effects of long-term treatment with recombinant alpha-2 interferon (rIFN-alpha 2) were investigated in multiple sclerosis (MS) patients treated with 2 X 10(6) units of IFN or a placebo three times per week for one year. A mild lymphopenia was observed in IFN patients who also showed a decrease in the absolute number of total T cells in the blood (OKT3 binding cells); however, the percentage of cells reacting with OKT3, OKT4, and OKT8 antibodies did not change significantly during the study. The percentage of cells reacting with the Leu-7 antibody, which recognizes NK cells, was unchanged. During MS exacerbations, placebo patients showed a tendency for decreased levels of OKT3 and OKT8 cells. In contrast, IFN patients did not demonstrate a decrease in either OKT3 or OKT8 cells during disease attacks. Concanavalin A (ConA)-induced suppressor cell activity was depressed in both IFN and placebo-treated patients during attacks. Lymphoproliferative responses to phytohemagglutinin, pokeweed mitogen, and ConA were unchanged. These studies demonstrate that long-term treatment with rIFN-alpha 2 induces a generalized T-cell lymphopenia, but at this dose does not significantly affect the profiles of T-cell subsets and suppressor cell function in MS patients.

Defective autologous mixed lymphocyte reactivity in multiple sclerosis

T cells from patients with multiple sclerosis (MS) and normal controls were assessed for their ability to respond in the autologous mixed lymphocyte reaction (AMLR). Cells from stable MS patients demonstrated a significant defect in their proliferative response to non-T cells in comparison to normal controls. Despite the defective AMLR response, T cells from MS patients reacted as well as T cells from normal controls to allogeneic stimuli. Furthermore, MS non-T-cells were fully capable of stimulating allogeneic MLR responses by normal and MS T cells. Since the T4+ cell is the major subpopulation which proliferates in the AMLR, these studies suggest a functional defect in a subpopulation of T4+ cells in MS patients. Since the AMLR may represent an important mechanism by which immune responses are regulated, a defect in the ability of MS T cells to respond to autologous cells could account for several of the autoimmune features of the disease.

Natural killer cell activity in multiple sclerosis patients treated with recombinant interferon-alpha 2

Natural killer (NK) cell activity was evaluated in multiple sclerosis (MS) patients during a phase II trial of recombinant interferon-alpha 2 (IFN). Spontaneous NK activity against the K562 myeloid target cell increased significantly during the first week of treatment in the IFN treatment group. However, NK activity was also increased in the placebo treatment group. Long-term administration of IFN caused a decline of NK activity, below the pretreatment values. This decline was not paralleled by a decline in the percentage of Leu-7 cells in the peripheral blood. The ability of IFN to enhance NK activity during treatment was also evaluated. Enhancement of NK activity by IFN was depressed for the duration of the study in the IFN treatment group. After treatment was stopped, IFN enhancement of NK activity returned to the pre-study value. These studies demonstrate that spontaneous and IFN enhanced NK activity are profoundly affected by the administration of recombinant IFN-alpha 2 in MS patients.

Lymphocytes from multiple sclerosis patients produce elevated levels of gamma interferon in vitro

The production of gamma interferon (IFN) by mononuclear cells (MNC) from patients with exacerbating/remitting multiple sclerosis (MS) and controls was evaluated. After 3 days of culture with concanavalin A, the amount of gamma IFN in supernatant fluids was determined by radioimmunoassay. MNC from MS patients produced significantly (P less than 0.001) more gamma IFN than MNC from either normal controls or patients with other neurologic diseases. Levels of gamma IFN in the serum and CSF were also measured. Despite the relative absence of gamma IFN in serum (4 positive of 30), all CSF samples tested had low, but detectable, levels of gamma IFN (0.3 to 1.4 U/ml). These studies suggest that some of the autoimmune features and immunologic abnormalities in MS may be related to elevated gamma IFN production.

T8 antigen density on peripheral blood lymphocytes remains unchanged during exacerbations of multiple sclerosis

Fluorescence-activated cell sorter (FACS) analysis was used to quantitate the antigen density of the lymphocyte markers T3, T4, T8, and Leu 7 on the surface of peripheral blood mononuclear cells (MNC) from exacerbating/remitting multiple sclerosis (MS) patients. Serial studies showed that the mean fluoresce intensity for all the markers studied did not change significantly during exacerbations. There was a tendency for a generalized decline in T-cells, evidenced by a drop in both T8+- and T4+-cells; however, these changes were not statistically significant. It appears, therefore, that the lymphocyte markers studied here are not useful as markers of disease activity in exacerbating/remitting MS.

Changes in plasma IgE levels during complicated and uncomplicated measles virus infections

Plasma IgE levels were measured in 214 samples from 182 Peruvian patients with acute measles virus infections. Plasma IgE levels were significantly elevated early in infection compared to later time points. Plasma levels of IgG from the same patients rose during the same time period, whereas levels of IgA and IgM did not change. In patients with postmeasles encephalomyelitis, IgE remained elevated longer than it did in patients either with uncomplicated measles or measles complicated by pneumonia. It is proposed that the elevation of IgE is another manifestation of the altered immunoregulatory function in patients with measles.

The effect of recombinant alpha 2-interferon on defective natural killer cell activity in multiple sclerosis

Natural killer (NK) cell activity was evaluated in exacerbating/remitting MS patients. Peripheral blood mononuclear cells (MNC) from MS patients had impaired NK-cell cytotoxicity against the K562 myeloid target cell. NK activity was depressed, irrespective of the interval (2 to 13 months) after the last exacerbation. Recombinant alpha 2-interferon (100 U/ml) enhanced NK activity of both MS and control MNC. Cytotoxicity mediated by interferon-treated MS MNC was increased to the level of untreated control MNC. These studies show that MNC from exacerbating/remitting MS patients possess a defect in NK-cell activity that can be corrected in vitro by treatment with interferon.

Cellular immune responses during complicated and uncomplicated measles virus infections of man

Lymphocytes from patients with measles showed profound and prolonged suppression of proliferative responses to mitogens. The degree of suppression was similar in patients with uncomplicated measles virus infection and in those with pneumonia or postinfectious encephalitis. Despite this suppression, lymphocyte responses to measles antigen and PPD were demonstrated in patients with encephalitis and uncomplicated disease, even early in infection. Most patients with pneumonia did not have demonstrable antigen-specific responses. The proportions of T helper (OKT 4) and T suppressor (OKT 8) cells and functional tests of Con A suppressor cell activity showed no significant difference between control and measles patients but, in contrast to controls, cells from measles patients cultured in the absence of any stimulant significantly suppressed the proliferation of allogeneic responder cells. Nine of 20 supernatant fluids from these cultures possessed a soluble suppressor factor. These studies indicate varied disruptions of immune reactivity during measles.

Development of antibody to measles virus polypeptides during complicated and uncomplicated measles virus infections

Immune precipitation of 181 sera from 152 patients with natural measles was studied to determine the temporal course and frequency of antibody responses to nucleocapsid, fusion, hemagglutinin, and matrix proteins of measles virus. Large amounts of antibody to nucleocapsid protein developed in all patients by day one of the rash. Antibody to hemagglutinin and fusion proteins developed in all patients over the next 3 weeks, the former to high levels and the latter to low levels. Antibody to matrix protein developed to very low levels and was detectable in only 41% of the patients; this poor response to matrix protein was not correlated with the age of the patient or the acute neurological complications of measles.

Measles encephalomyelitis--clinical and immunologic studies

We studied 19 patients with postinfectious encephalomyelitis complicating natural measles-virus infections, and our results support the hypothesis that this demyelinating disease has a pathogenesis similar to that of experimental allergic encephalomyelitis. Early myelin destruction was demonstrated by the presence of myelin basic protein in cerebrospinal fluid, and lymphocyte proliferative responses to myelin basic protein were found in 8 of 17 patients tested. A lack of intrathecal synthesis of antibody against measles virus suggests that measles encephalomyelitis may not be dependent on virus replication within the central nervous system. Similar lymphoproliferative responses to myelin basic protein of lymphocytes from single patients with encephalomyelitis after rabies vaccine or after varicella or rubella virus infections suggest a common immune-mediated pathogenesis for the perivenular demyelinating disease that can follow the injection of neural tissues or infection by a variety of viruses.

Immunosuppression in goats inoculated with parainfluenza type 3 virus

The humoral and cellular immune responses of goats experimentally infected with an ovine isolate of parainfluenza type 3 virus (PI-3) were examined. Virus neutralization and enzyme-linked immunosorbent assays were used to determine antibody in the serum and CSF. Lymphocyte stimulation, measured by [3H]thymidine incorporation into peripheral blood leukocytes, was used to determine cellular responses to phytomitogens and virus. There were significant suppression of peripheral blood leukocyte responses to T-cell mitogens early in the course of infection and delayed onset of virus-specific cell-mediated immunity. Delay in antibody formation did not occur. The suppression of mitogen response has been reported with other paramyxovirus infections. The importance of the suppressed cellular immune response for potentiating other infective agents is discussed.

Changes in serum C-reactive protein during complicated and uncomplicated measles virus infections

Serum C-reactive protein levels become elevated coincident with the onset of the rash in patients with measles. Serum C-reactive protein elevations are prolonged in measles complicated by pneumonia and may show a second elevation in measles complicated by encephalitis.

Natural immunity to Sindbis virus is influenced by host tissue sialic acid content

Recent studies have shown that the sialic acid content of Sindbis virus influences both its ability to active the alternative pathway in vitro and its susceptibility to complement dependent clearance from the bloodstream in vivo. Other studies have shown that the sialic acid content of Sindbis virus is determined by the host in which it is propagated. Because individuals vary in their cell surface sialic acid content, it is possible they also vary in their ability to defend themselves against Sindbis virus infection by virtue of their ability to modify the virus sialic acid content and thereby the capacity of the virus to activate the alternative pathway. To test this hypothesis, outbred Swiss mice were injected subcutaneously with Sindbis virus. There was a significant positive correlation between the level of viremia 18 hr after infection and the sialic acid content of the host's erythrocytes. In addition, animals with erythrocyte sialic acid levels equal to or greater than the mean had a higher level of viremia than animals with erythrocyte sialic acid levels less than the mean. Finally, animals that had muscle sialic acid levels equal to or greater than the mean had a higher incidence of viremia than animals with muscle sialic acid levels less than the mean. These studies suggest that the amount of tissue sialic acid in an individual host influences its ability to resist Sindbis virus infection.