Association between serum interleukin-17A and clinical response to tofacitinib and etanercept in moderate to severe psoriasis.

BACKGROUND: Psoriasis is a systemic inflammatory disease with a pathophysiology involving interleukin (IL)-17. Tofacitinib is an oral Janus kinase inhibitor. Etanercept is a tumour necrosis factor-α inhibitor used in the treatment of psoriasis. Neither agent inhibits IL-17 directly. AIM: To evaluate correlations between circulating IL-17A and clinical efficacy in patients with psoriasis treated with tofacitinib or etanercept. METHODS: Serum concentrations of IL-17A homodimer and IL-17A/F heterodimer were determined by immunoassays at weeks 0, 4 and 12 in patients with moderate to severe psoriasis treated with placebo (n = 60), tofacitinib 5 mg twice daily (n = 184), tofacitinib 10 mg twice daily (n = 190), or etanercept 50 mg subcutaneously twice weekly (n = 190). Disease severity was assessed using the Psoriasis Area and Severity Index (PASI) and clinical response was defined as patients achieving ≥ 75% improvement from baseline PASI (PASI75). RESULTS: Serum levels of IL-17A homodimer at week 0 showed moderate correlation with PASI, with a Spearman correlation coefficient of 0.43. Furthermore, serum levels of IL-17A homodimer showed a clear correlation with clinical response, with a decrease of 57.1% in patients achieving PASI75 at week 12, but only 15.9% decrease in nonresponders. PASI75 responders had lower median concentrations of IL-17A (range across treatments: 0.24-0.27 pg/mL) at week 12 vs. nonresponders (0.37-0.62 pg/mL), regardless of the treatment. Serum IL-17A/F heterodimer showed similar decreases at week 12 in responders and nonresponders. CONCLUSIONS: Baseline serum IL-17A correlates moderately with psoriasis severity. Reduction in circulating IL-17A is required for disease remission regardless of therapeutic agent.

Safety and efficacy of a mutagen-attenuated Rift Valley fever virus vaccine in cattle.

OBJECTIVE: To examine safety and efficacy of a mutagen attenuated Rift Valley fever virus (RVFV) vaccine (RVF MP-12) in cattle. ANIMALS: 38 pregnant cows, 14 steers, and 10 lactating dairy cows. PROCEDURE: Pregnant cows in their third, fifth, or eighth month of gestation were vaccinated (1 ml of RVF MP-12 containing 5 log10 plaque-forming units [PFU] of virus) and were monitored daily through parturition for signs of disease, viremia, and immunologic response. Additionally, 10 vaccinated pregnant cows were challenge inoculated with virulent RVFV at post-vaccination day (PVD) 30 and were monitored daily for untoward effects. Ten unvaccinated pregnant cows also were challenge inoculated with virulent RVFV and served as challenge controls. Vaccinated lactating dairy cows were monitored for viremia and virus shedding in the milk through PVD 14. Yearling steers were vaccinated to assess their immunologic response to various doses of vaccine and were challenge inoculated with virulent RVFV at PVD 28 to assess protection. RESULTS: 10 of 38 (26.3%) cows vaccinated during pregnancy developed transient postvaccination viremia titer > or = 2.5 log10 PFU/ml of serum. All vaccinated cows delivered live, healthy calves that were RVFV seronegative at birth, but which quickly acquired colostral antibodies. Vaccinated cows and their fetuses were protected when challenge exposed with virulent RVFV at PVD 30, whereas unvaccinated pregnant cows inoculated with RVFV became febrile and viremic, and aborted. Vaccine virus was unsuccessfully sought from milk of lactating dairy cows after vaccination, suggesting that shedding of vaccine virus through milk should not be a concern. Steers, inoculated with tenfold escalating vaccine doses, beginning with 1.0 log10 PFU, were protected against virulent RVFV challenge exposure. CONCLUSIONS: RVF MP-12 may be safe and efficacious for use in pregnant or lactating bovids, and a minimal dose of vaccine may provide suitable protection against viremia.

Safety of a mutagen-attenuated Rift Valley fever virus vaccine in fetal and neonatal bovids.

OBJECTIVE: To examine effects of in utero inoculation with a mutagen-attenuated Rift Valley fever virus (RVFV) vaccine (RVF MP-12) on fetal bovids and to assess the safety and efficacy of calfhood vaccination with RVF MP-12. ANIMALS: 18 pregnant Hereford and Hereford-type cows in the third or fifth month of gestation, their progeny, and 25 calves from cows immunized with RVF MP-12 during pregnancy. PROCEDURE: Bovine fetuses were inoculated, via laparotomy, with 1 ml of RVF MP-12 containing 5 log10 plaque-forming units (PFU) of virus. Blood was obtained from newborn calves prior to their ingestion of colostrum. Immune-naive calves and calves born to RVF MP-12-vaccinated dams, ranging in age from 2 to 45 days, were vaccinated with RVF MP-12, and some were later challenge exposed with 1 ml of 5.7 log10 PFU of virulent RVFV strain ZH-501. Cows were monitored for viremia and antibody responses and for hematologic and serum biochemical alterations through parturition or abortion. RESULTS: Surviving in utero-vaccinated calves were healthy, with no noticeable defects. Except for 1 vaccine-inoculated fetus that died on postinoculation day 21, all in utero-vaccinated fetuses had serum neutralizing antibody titer > or = 1:20 at the time of delivery. All dams of in utero-vaccinated fetuses also developed neutralizing antibody titer. Calves born to cows vaccinated during gestation did not have antibody at birth, and all but 1 quickly acquired colostral antibody. Postparturient inoculation of immune-naive calves and calves with colostral antibodies resulted in no untoward effects, and all calves with detectable neutralizing antibodies were protected against virulent virus challenge exposure. CONCLUSIONS: Fetal death and abortion would be rare even if fetuses were exposed to RVF MP-12. The trauma and complications associated with in utero inoculation do not make this a practical method of immunization. RVF MP-12 was safe, immunogenic, and protective in calves as young as 2 days of age.

Susceptibility of llamas (Lama glama) to infection with foot-and-mouth-disease virus.

An experimental trial was conducted to evaluate the ability of foot-and-mouth-disease (FMD) virus (serotypes A79, C3, O1) to infect susceptible llamas exposed either directly to affected livestock, or indirectly to llamas that had been directly exposed to affected livestock. In addition, susceptible livestock species (cattle, pigs, goats, and sheep) were exposed to those llamas that had been both directly and indirectly exposed to the FMD virus to further look at potential transmission possibilities. Of 30 llamas directly exposed to the FMD virus, only three (3/30) showed evidence of infection, and of those, only two (2/30) had mild clinical signs. No FMD virus was isolated from either oesophageal-pharyngeal (OP) fluid or blood samples collected from the infected llamas beyond 14 days post-exposure. There was no evidence of virus transmission between the directly exposed and indirectly exposed llamas or between both groups of llamas and susceptible domestic livestock, as determined by the lack of clinical signs, by virus isolation, and by serology results. These results provide further evidence that llamas are resistant to FMD infection, and that they play a minor role, if any, in transmitting the virus to domestic livestock.

A two-generation reproduction study in rats receiving drinking water containing vinyl acetate.

Vinyl acetate (VA) is a commonly used chemical in polymerization and copolymerization processes and as a chemical intermediate. As part of a collaborative effort between VA producers of the United States and British Petroleum, the present study was carried out to provide a base set of data for risk assessment. Groups of male and female Crl:CD(SD)BR rats were given 0, 200, 1000, or 5000 ppm VA via the drinking water over two generations. In addition, a cross-mating trial of control and 5000-ppm male and female rats was conducted in the F1 generation to investigate the slightly decreased litter production in the high-dose group. No treatment-related mortality was observed in any of the groups. Water consumption was significantly reduced in the 5000-ppm groups in both generations and in the 1000-ppm F1 female rats. The body weights of the F0 and F1 male rats and the F1 female rats in the 5000-ppm group tended to be slightly lower than those of the control group. Body weight gain was significantly decreased during lactation in the F0 females at 5000 ppm and in the F1 females at 1000 and 5000 ppm. Pup weights in the F1 generation, but not in the F2 generation, were significantly lower than those of the control on lactation Day 21. The number of litters produced in the F1 generation in the 5000-ppm group was slightly lower than that of the control group and was attributed to lower fertility. Fewer pups were produced when control females were mated with the 5000-ppm males; however, the decrease was due to poor mating performance rather than decreased fertility. No decrease was apparent when the 5000-ppm females were mated with the control group males. Under the conditions of this study, the no-observed adverse effort level was considered to be 1000 ppm.

A comparison of three avidin-biotin complex immunoenzyme systems for detection of African swine fever virus antigen in paraffin-embedded tissues.

The sensitivity and specificity of 3 avidin-biotin complex (ABC) immunostaining systems were compared on paraffin-embedded tissues from African swine fever virus (ASFV)-infected pigs. Results were also compared with immunofluorescent detection on cryosections of the same tissue for optimal detection of ASFV antigen. The ABC-alkaline phosphatase (ABC-AP) and ABC-peroxidase (ABC-PO) systems were at least as sensitive as direct fluorescent antibody (FA) and 10-fold more sensitive than the ABC-glucose oxidase system. Three ABC-AP and 2 ABC-PO chromagens with different counterstains were compared. In addition, 2 fixatives, 2 biotinylation procedures, 7 endogenous peroxidase blocking regimes, 6 tissue adhesives, and 3 mounting media were compared. The ABC-AP system with a red chromagen and hematoxylin counterstaining was preferred and most closely approximated routinely stained pathologic sections. Fixation in paraformalde-hydelysine-periodate fixative preserved ASFV antigen for research studies for at least 3 years. Formalin-fixed tissues retained some staining for up to 10 years.

Early infection of interdigitating dendritic cells in the pig lymph node with African swine fever viruses of high and low virulence: immunohistochemical and ultrastructural studies.

The role of interdigitating dendritic cells (IDCs) in the early pathogenesis of African swine fever (ASF) was investigated using mandibular lymphoid tissue from normal pigs and pigs inoculated oronasally with highly virulent Lisbon 60 (L-60) and moderately virulent Dominican Republic 1979 (DR-2) ASF virus (ASFV) isolates. Paraffin-embedded tissue sections were immunostained for ASFV antigen and S-100 protein, a marker of IDCs, using an avidin-biotin alkaline phosphatase procedure. Swine IDCs were identified morphologically by light microscopy, electron microscopy, and S-100 immunostaining. Infection with ASFV caused a marked reduction in S-100 staining by 3 days postinfection (DPI) that persisted through 14 DPI. Early ASFV infection of IDCs was demonstrated at 3 DPI by double immunohistochemical staining of cryosections and by transmission electron microscopy. These results support the hypothesis that the failure of a humoral immune response to virulent ASFV may be due to a primary infection of IDCs and the inability of IDCs to initiate an immune response. Infection of IDCs has also been demonstrated with human immunodeficiency virus (HIV-1), and these infections have some aspects in common.

African swine fever interference with foot-and-mouth disease infection and seroconversion in pigs.

Initial oral infection of pigs with either highly virulent (L-60) or moderately virulent (DR-2) African swine fever virus (ASFV), followed in 3 days with exposure to foot-and-mouth disease virus (FMDV) (tongue inoculation and contact), failed to cause FMDV infection or seroconversion in 18 of 22 L-60-infected pigs and 13 of 34 DR-2-infected pigs. Of the 13 DR-2-infected pigs remaining free of foot-and-mouth disease (FMD), 2 pigs survived to 24 days without antibody to FMDV, despite constant contact with clinically infected pigs with FMD. Three other DR-2-infected pigs never developed FMD lesions but did develop low levels of antibody to FMDV by day 17. A group of larger pig (in which DR-2 is less virulent) infected with DR-2 and then FMDV had a rapid but suppressed immune response to FMDV. Contact pigs introduced 3 days postinoculation and inoculated with FMDV only all became infected with ASFV by contact and died. This remarkably long lasting 1-way interference with FMD infection during acute and subacute African swine fever was not anticipated. Infection with ASFV may have blocked the initial target cells (possibly dendritic cells) necessary for establishment of FMDV infection.

African swine fever virus infection of skin-derived dendritic cells in vitro causes interference with subsequent foot-and-mouth disease virus infection.

Highly purified skin-derived dendritic cells (SDDCs) isolated from swine skin by a simple novel method were cultured for 24 hours before independent or sequential inoculation with African swine fever virus (ASFV) and foot-and-mouth disease virus (FMDV). By avidin-biotin immunohistochemical staining, ASFV antigen was detected in 50% of SDDCs as early as 1.5 hours postinfection (HPI) and in 80% by 3 HPI when cytopathic effect was noted. Cell lysis was detected with FMDV infection as early as 8 HPI; immunostaining for FMDV antigen was found in 10% of the cells. African swine fever virus replication was detected by transmission electron microscopy in a high percentage of SDDCs by 11 HPI. Sequential infection with FMDV 3 hours after ASFV inoculation blocked FMDV infection. These findings demonstrate that both ASFV and FMDV infect dendritic cells of Langerhans cell type in vitro and ASFV interferes with FMDV infection.

Comparison of monoclonal antibody-based sandwich enzyme-linked immunosorbent assay and virus isolation for detection of peste des petits ruminants virus in goat tissues and secretions.

A monoclonal antibody-based sandwich enzyme-linked immunosorbent assay (S-ELISA) was developed for specific detection of peste des petits ruminants virus. Compared with virus isolation in Vero cell cultures using 89 paired tissue and secretion samples from six experimentally infected goats, S-ELISA was significantly more sensitive (71.9% versus 65.2%; P < 0.05). The S-ELISA is a suitable alternative to virus isolation.

Further studies on the efficacy of an inactivated African horse sickness serotype 4 vaccine.

The immunity induced by two inoculations of a commercial inactivated African horse sickness (AHS) serotype 4 (AHSV-4) vaccine was studied. No adverse reaction was observed in five horses following vaccination. Following challenge-inoculation, no clinical signs attributable to AHS, no viraemia indicating infection, and no anamnestic response was observed in the vaccinated ponies. Two control ponies developed clinical signs typical of AHS, high levels of viraemia, and died 7 and 8 days postchallenge-inoculation. The quality of immunity induced by the two-dose regimen was compared with a one-dose regimen from a previous study; in the one-dose study following challenge-inoculation, six of nine ponies were protected from clinical signs of AHS, seven of the nine vaccinated ponies developed an anamnestic response, and one pony had a viraemia about 10(3) 50% mouse lethal dose of AHSV-4 per ml of blood for 3 days following challenge-inoculation. The utility of an efficacious inactivated AHS vaccine in the control and eradication of AHS from a non-endemic area is discussed. The lack of viraemia following vaccination with an inactivated vaccine and the prevention of vector infection by animals exposed to field virus are important in the eradication of AHS.

Investigation of the effects of benomyl on rat nasal mucosa.

Benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate, CAS Registry No. 17804-35-2] is a widely used agricultural fungicide. Previously, olfactory epithelial lesions were produced following a 45-day inhalation exposure to 50 and 200 mg/m3 benomyl. The present study, part of a range-finding study for a two-generation reproduction study, was conducted to determine if the previously reported effects on the nasal mucosa are the result of systemic toxicity or attributable to the inhalation route of exposure. Groups of 10 7-week-old male Crl:CD BR rats were fed diets containing 0, 5000, 10000, or 15000 ppm benomyl for 32 days. Individual body weights and food consumption were determined weekly and on the last day of the study. After 32 days on test, rats were euthanatized by pentobarbital anesthesia and exsanguination and were examined for gross alterations. The nasal cavity was processed for pathological examination. Mean body weight gain was statistically significantly decreased during the first week of treatment and the overall test period (Days 0-32) at the two highest dose levels. A significant decrease in food consumption also was seen during test interval Days 0-7 for the two highest dose groups. In addition, statistically significant decreases in food consumption were observed at the Day 7-14 interval for the 15,000 ppm dose group and at the 21-28 and 28-32 intervals for the two highest dose groups compared with controls. No histopathological lesions were noted in the nasal epithelium of any of the control or benomyl-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Monoclonal antibody-based blocking enzyme-linked immunosorbent assay for specific detection and titration of peste-des-petits-ruminants virus antibody in caprine and ovine sera.

A blocking enzyme-linked immunosorbent assay (B-ELISA), using two neutralizing monoclonal antibodies (MAbs), was established and compared with the virus neutralization test (VNT) for detecting specific peste-des-petits-ruminants virus (PPRV) antibody in caprine and ovine sera. This technique was developed because VNT, the only available specific serological test for PPRV and the cross-reactive rinderpest virus (RPV), is time-consuming and unaffordable for most laboratories in regions where both peste des petits ruminants and rinderpest occur. The test depends on the blocking of the binding of the MAb to a specific epitope in the presence of positive serum. Test conditions were optimized by using peste-des-petits-ruminants and rinderpest sera that were known to be VNT positive and negative. A blocking format, in which serum is preincubated with a solid-phase PPRV antigen and then incubated with the MAb, yielded levels of sensitivity and specificity superior to those of a competitive format, in which the two reagents are added simultaneously. A threshold value of 45% inhibition, representing the mean for a negative population (n = 277) plus 2.7 standard deviations, was adopted for routine screening. A total of 605 serum samples were screened by B-ELISA and the VNT. The sensitivity and specificity of B-ELISA relative to the VNT were 90.4 and 98.9%, respectively. Of 264 field serum samples tested, 11 (4.2%) could not be assayed by the VNT because of contamination or cytotoxicity; the overall agreement quotient between results of the two tests (n = 253) was 0.91. A high correlation (r>/=0.98) was observed between B-ELISA and the VNT for endpoint titration of sera (n=57). Because B-ELISA proved to be nearlyas sensitive and specific as the VNT while being simpler and more rapid, it would be an adequate substitute for the VNT for assessing herd immune status and for epidemiologic surveillance.

The use of thermostable Vero cell-adapted rinderpest vaccine as a heterologous vaccine against peste des petits ruminants.

The thermostable Vero cell-adapted rinderpest vaccine was evaluated in terms of immunogenicity as a heterologous vaccine against peste des petits ruminants. A titration to establish the minimum immunising dose was performed in American mixed breed goats by vaccinating test subjects with dilutions of Vero cell-adapted rinderpest vaccine and then challenging 26 days later with virulent peste des petits ruminants virus. All animals were followed for virus neutralising antibodies against both rinderpest and peste des petits ruminants virus after vaccination and challenge. The antibody response to vaccination was primarily against rinderpest virus with very low levels of cross-reactivity to peste des petits ruminants virus. Following challenge, animals which possessed anti-rinderpest neutralising antibodies remained clinically normal but mounted strong anti-peste des petits ruminants virus neutralising antibody responses indicating that replication of challenge virus took place without the induction of illness. The 50 per cent minimum goat immunising dose was 3 tissue culture infectious doses 50 per cent (TCID50) as established by serological response and protection against challenge. The thermostable Vero cell-adapted rinderpest vaccine is a suitable immunogen for the protection of goats against peste des petits ruminants.

Effect of gamma irradiation on reactivity of rinderpest virus antigen with bovine immune serum in enzyme-linked immunosorbent assays and virus neutralization and indirect fluorescent-antibody tests.

Gamma irradiation effectively inactivated gradient-purified rinderpest virus. Irradiated antigen and sera remained functional in enzyme-linked immunosorbent assays, virus neutralization tests, and indirect fluorescent-antibody tests. Irradiation, however, led to a dose-dependent decrease in reactivity, particularly significant (P < 0.05) when both reagents were irradiated. To avoid false-positive reactions, only one reagent (serum or antigen) may be irradiated.

African swine fever virus specific porcine cytotoxic T cell activity.

African swine fever virus (ASFV) specific, cytotoxic T lymphocyte (CTL) activity has been studied in a protection model in which SLA inbred miniature swine are experimentally inoculated with a naturally occurring, non-fatal ASFV isolate (NHV). Peripheral blood mononuclear cells (PBMC) from such infected swine show significant activity in CTL assays, using cultured ASFV-infected porcine blood derived macrophages as target cells. This CTL activity is elicited from PBMC by in vitro restimulation of effector cells with low doses (multiplicity of infection = 0.1) of the homologous virus isolate for 48 to 72 h. For SLAc/c effectors, this CTL activity appears to be SLA class I restricted because (1) blocking target cell antigens with monoclonal antibodies (mAb) against SLA class I antigens causes a major reduction in CTL activity; (2) there is preferential lysis of SLA class I matched, ASFV infected targets; and (3) depletion of effector cells with CD8 specific mAb and complement causes a reduction in CTL activity. The CTL activity is ASFV specific for all pigs tested in that infected macrophages are preferentially lysed as compared to normal (non-infected) cultured macrophages or macrophages infected with hog cholera virus (HCV). Lysis of macrophages infected with different ASFV isolates revealed that there is marked lysis of macrophages infected with the virulent L60 isolate but less lysis of macrophages infected with the DR-II and Tengani isolates. In summary, our data show that ASFV specific CTL activity is triggered in swine infected with the NHV ASFV isolate.

Rift Valley fever virus-induced encephalomyelitis and hepatitis in calves.

Three calves (Nos. 1, 2 = 7 days old; No. 3 = 21 days old) were inoculated subcutaneously with virulent Rift Valley fever (RVF) virus. All calves became viremic and clinically ill, but the two 7-day-old calves were moribund and were euthanatized subsequently on post-inoculation day (PID) 3. Highest viral titers were measured in the serum, with lesser concentrations in the brain, heart, spleen, and liver of these animals. Viral antigens were detected by immunohistochemical analysis only in the livers, where positive staining was localized in coalescing foci of hepatocellular necrosis. The 21-day-old calf appeared to recover after viremia and pyrexia but became lethargic and ataxic and was euthanatized on PID 9. The calf was no longer viremic, and RVF virus was isolated only from the brain. Microscopic examination of the central nervous system revealed diffuse perivascular infiltrates of lymphocytes and macrophages, multifocal meningitis, and focal areas of neuronal necrosis and aggregates of macrophages, lymphocytes, and neutrophils throughout all regions of the brain and cervical spinal cord. There was positive immunohistochemical staining for viral antigens within the cytoplasm of neurons and glial cells throughout the central nervous system. Thus, RVF virus can cause encephalomyelitis in calves, and the specific virologic diagnosis can be made by immunohistochemical localization of viral antigens in formalin-fixed tissues.

A pathogenesis study of foot-and-mouth disease in cattle, using in situ hybridization.

Eight calves were exposed in an aerosol chamber to nebulized foot-and-mouth disease virus. Two control animals were exposed in a similar manner to cell culture media only. Animals were euthanized at intervals and various tissues examined by in situ hybridization using a biotinylated RNA probe corresponding to a portion of the viral gene coding for the polymerase enzyme. By this technique large amounts of viral nucleic acid were found in coronary band, interdigital cleft and tongue as early as six hours postexposure, indicating a very rapid delivery from the portal of entry to the predilection sites for lesion development. This occurred well before the onset of viremia which by virus isolation was not detectable until 30 hours postexposure. The in situ hybridization signal in these tissues decreased in intensity and extent with time to focally positive areas, occasionally surrounding a vesicle. Other epidermal sites not normally thought of as sites for foot-and-mouth lesion development, such as carpus and eyelid, also had some viral nucleic acid detectable at various time intervals. In the lung by in situ hybridization, alveolar septa had viral nucleic acid early in infection (6-18 h postexposure) while later (36-96 h postexposure), the in situ hybridization signal was prominent in alveolar macrophages.