Percentage Of Positive Sera Research Articles

Seroprevalence of Actinobacillus pleuropneumoniae in swine originated from commercial farms in Serbia

Porcine pleuropneumonia caused by Actinobacillus pleuropneumoniae (A.pleuropneumoniae) is one of the most important respiratory disease of pigs and causes worldwide severe losses in pig farming. For A.pleuropneumoniae control and monitoring, the detection of ApxIV antibodies in the serum is the most frequently used serological method. The aim of this study was to investigate presence of antibodies against A. pleuropneumoniae in blood sera of gilts and sows using the ELISA test. Samples were taken from gilts and sows originating from four commercial swine farms in Serbia. For detection of ApxIV antibodies, commercial ELISA kit was used. A total of 453 blood sera samples of gilts (207) and sows (246) were examined. Antibodies against A. pleuropneumoniae were detected in 57 (12.58%) sera. Antibodies were present in 22 (10.62 %) sera of gilts and in 35(14.22%) sera of sows. Percentage of positive sera differed among the farms, ranging in gilts from 3.33-17.77 % and in sows from 8.95-22.64%. Serological methods is one of the most important procedures in the diagnosis of porcine pleuropneumonia particularly suitable for the control of animal health status in a large breeding.

A comparison of a blocking ELISA and a haemagglutination inhibition assay for the detection of antibodies to Avibacterium (Haemophilus) paragallinarum in sera from artificially infected chickens

The ability of blocking ELISAs and haemagglutination-inhibition (HI) tests to detect antibodies in sera from chickens challenged with either Avibacterium (Haemophilus) paragallinarum isolate Hp8 (serovar A) or H668 (serovar C) was compared. Serum samples were examined weekly over the 9 weeks following infection. The results showed that the positive rate of serovar A specific antibody in the B-ELISA remained at 100% from the second week to the ninth week. In chickens given the serovar C challenge, the highest positive rate of serovar C specific antibody in the B-ELISA appeared at the seventh week (60% positive) and was then followed by a rapid decrease. The B-ELISA gave significantly more positives at weeks 2, 3, 7, 8 and 9 post-infection for serovar A and at week 7 post-infection for serovar C. In qualitative terms, for both serovar A and serovar C infections, the HI tests gave a lower percentage of positive sera at all time points except at 9 weeks post-infection with serovar C. The highest positive rate for serovar A HI antibodies was 70% of sera at the fourth and fifth weeks post-infection. The highest rate of serovar C HI antibodies was 20% at the fifth and sixth weeks post-infection. The results have provided further evidence of the suitability of the serovar A and C B-ELISAs for the diagnosis of infectious coryza.

Serological Investigations on Reticuloendotheliosis in Turkey Flocks

Four meat turkey and one turkey breeding flocks were surveyed for antibodies against reticuloendotheliosis virus (REV) at different intervals using commercial enzyme‐linked immunosorbent assays. In addition, serum samples collected from 18 flocks at different ages were also tested for antibodies against REV. No antibodies were detected in any of the four meat turkey flocks that were surveyed. In the breeder flock, 20 % of tested samples from 1‐day‐old poults were positive. Between the fourth and 12th weeks all samples that were tested yielded negative results. At 16 weeks of age 15 % of samples yielded a positive reaction, but antibodies could not be detected 4 weeks later. Examination of serum samples from 18 different flocks at various ages revealed that antibodies could be detected in five flocks. The percentage of positive sera per flock ranged between 10 and 40 %.

Serological investigations on reticuloendotheliosis in turkey flocks.

Four meat turkey and one turkey breeding flocks were surveyed for antibodies against reticuloendotheliosis virus (REV) at different intervals using commercial enzyme-linked immunosorbent assays. In addition, serum samples collected from 18 flocks at different ages were also tested for antibodies against REV. No antibodies were detected in any of the four meat turkey flocks that were surveyed. In the breeder flock, 20%) of tested samples from 1-day-old poults were positive. Between the fourth and 12th weeks all samples that were tested yielded negative results. At 16 weeks of age 15% of samples yielded a positive reaction, but antibodies could not be detected 4 weeks later. Examination of serum samples from 18 different flocks at various ages revealed that antibodies could be detected in five flocks. The percentage of positive sera per flock ranged between 10 and 40%.

Serological investigation of an outbreak of Neospora caninum-associated abortion in a dairy herd in southeastern United States

An outbreak of Neospora caninum-associated abortion occurred in a South Carolina dairy wherein greater than 10% of the herd aborted over a 4-month period. Of the total number of cows at mid-late gestation, nearly 40% (28/71) aborted while the remaining 60% (43/71) gave birth to normal calves. Immunohistochemical examination of brain tissue from a subset of aborted fetuses confirmed N. caninum as the causative agent of abortion in these animals. A variety of serological assays, including indirect fluorescence antibody test (IFAT), recombinant enzyme-linked immunosorbent assay (rELISA), ISCOM-ELISA, avidity ELISA, and Neospora agglutination test (NAT), were used to evaluate sera collected during the outbreak from 240 cows for antibodies to N. caninum. IFAT and ISCOM-ELISA testing showed that nearly 80% of the dairy cows had antibodies to N. caninum. NAT and rELISA had similar levels of seropositivity relative to IFAT and ISCOM-ELISA, but the percentage of positive sera was dependent on the cut-off value chosen. As indicated by κ coefficient statistical analysis, ISCOM-ELISA and IFAT exhibited the highest level of agreement in identifying N. caninum-positive and -negative cows. A decrease in the percentage of seropositive cows as determined by ISCOM-ELISA and IFAT with increasing cow age was noted. However, no significant difference was observed between cow age and abortion status. In addition to these tests, an avidity ELISA was performed on all sera with high (≥0.4) ISCOM-ELISA readings. Avidity index (AI) increased with time post-abortion suggesting that most abortions were due to recent N. caninum infection. Of the cows at risk for abortion, the mean serological AI of aborting cows was significantly lower ( P<0.05) than mean serological AI of non-aborting cows.

Influence of internal and environmental factors on the distribution and occurrence of Hypoderma (Diptera: Oestridae) in cattle in Galicia (northwest of Spain).

This study establishes the seroprevalence of Hypoderma spp in cattle and the influence of some internal and environmental factors in the distribution of this myiasis in Galicia (northwest of Spain). Humoral antibody levels were measured by means of an indirect enzyme-linked immunosorbet assay, using as the antigen hypodermin C obtained from 1st-instar Hypoderma lineatum (De Villers). The percentage of positive sera in the total sample of 1,473 animals was 78.4%. Considering the different climatic areas in Galicia, the seroprevalence was lower in coastal areas; whereas, in the inland the percentages of positive sera were higher. The study revealed significant differences in seroprevalence between breeds; the autochthonous Rubia Gallega breed was the most prevalent, followed by the crossbreeds Brown Swiss and Friesian. The breeding system was an important factor affecting the occurrence of hypodermosis.

Frequency and potential application of HLA antibodies from pregnant women in Mumbai

Antenatal sera from 1334 pregnant women attending the Nowrojee B J Wadia Maternity Hospital and KEM Hospital in Parel, Mumbai were collected and screened for anti HLA A and B antibodies to produce an indigenous HLA tissue typing tray. One hundred and sixty three sera (12.2%) were found positive for HLA antibodies. Nonetheless, the percentage of positive sera were almost the same in women of different parity. Moreover, the incidence of anti-HLA antibodies was correlated with the allelic frequencies in the Maharastrian population. Thus in India, collection and screening of sera from pregnant females is a simple and cost-effective method of acquiring polyclonal sera for routine use in tissue typing.

Tryptophanyl-tRNA synthetase as a human autoantigen

Autoantibodies to highly purified tryptophanyl-tRNA synthetase, consisting of two ≈ 60-kDa subunits (6.1.1.2, TrpRS), were detected in some sera of donors and patients with various diagnosis using the newly developed 125I-TrypRS-radiodot, 125I-TrpRS-radioblot, ELISA and Western immunoblotting. The percentage of positive sera appears to be dependent upon the method of sera testing. The autoimmune sera recognized both the native and denatured TrpRS forms. The binding of the human serum to the 60-kDa band of tissue extract was demonstrable by the 125I-TrpRS-blot as well as Western blot techniques. The possible role of infections in the induction of anti-TrpRS antibodies and maintenance of the autoimmune response is discussed.

Influenza A viruses: epidemiologic study in fatteners in Spain (1987-89).

2,979 sera were collected from slaughtered swine in two geographic areas of Spain from 1987 to 1989. They were tested for antibodies against an H1N1- and H3N2-influenza virus by haemagglutination-inhibition tests (HI). The percentage of positive sera was higher in area I (78%-69.2%) than in area II (63.1%-60.4%) for both viruses respectively. The coexistence of high titres to both H1N1- and H3N2-influenza virus became apparent in cold months simultaneously in each area, although influenza viruses circulated in the Spanish swine population for two years. Also this study suggests the possible circulation of A/Texas/1/77-like strains in Spain, results which have not been reported before.

Presence of circulating anti‐c‐myb oncogene product antibodies in human sera

Bacterially expressed mouse c-myb protein was purified from E. coli extracts and used as antigen to screen human sera for circulating anti-c-myb oncogene product antibodies. Using Western blotting, we have found that human sera contain IgG antibodies to the c-myb gene product. The percentage of positive sera in cancer patients appears to be dependent upon cancer type and is significantly higher in breast-cancer patients than in normal donors: 43% of sera from breast-cancer patients are positive, whereas in neuroblastoma cancer patients the production of IgG anti-c-myb appears to be rare. No significant correlation was observed between the presence of circulating anti-c-myb antibodies and the expression of the c-myb gene in breast tumors.

Prevalence of antibodies to human papillomavirus type 8 in human sera

The epidermodysplasia verruciformis-associated human papillomavirus type 8 (HPV-8) poses a high risk for malignant conversion of skin lesions in patients with epidermodysplasia verruciformis. For seroepidemiological studies, the HPV-8 open reading frames for E1, E2, E4, E6, E7, and L1 were bacterially expressed as beta-galactosidase fusion proteins, which were purified by preparative gel electrophoresis. Cleavage with the protease FXa at the engineered recognition site separated the beta-galactosidase polypeptide part from the viral polypeptide. Western blot analysis of 445 serum samples from a randomly selected population with the entire L1 as antigen revealed HPV-8-specific immunoglobulin G antibodies in 20% of the samples. The percentage of positive sera did not significantly differ in different age groups. In some sera, we could also detect immunoglobulin M antibodies. The use of two shortened L1 polypeptides as antigen indicated that there are at least two reactive epitopes in the case of HPV-8 L1. Several sera contained antibodies to the early proteins E1, E2, E4, and E7. E1 and E7 were predominantly detected by sera which were negative for L1. In one case, we found antibodies to E6. Two of four sera of patients with epidermodysplasia verruciformis reacted with HPV-8 L1. The prevalence of anti-HPV-8-L1 antibodies in patients with malignant melanomas was comparable to that in the normal population (27.8%) but was significantly higher in patients with cervical cancer (37.5%), basaliomas (40%), and squamous cell skin carcinomas (72.7%) and in immunocompromised patients with Hodgkin's disease (47.7%).

A survey for haemagglutination-inhibiting antibody to West Nile Virus in human and animal sera in Nigeria

A survey for West Nile Virus (WNV) haemagglutination-inhibition (HI) antibody was carried out in humans and domestic animals. Human sera were collected from Ibadan, while the animal sera were collected from both Ibadan and Maiduguri. Out of 304 human sera tested, 123 were positive (40%). There was a higher prevalence of HI antibody in adults than children. Sex distribution of positive sera showed that 37% of males and 43% of females had WNV HI antibody. There was no significant difference in the prevalence of HI antibody in both sexes. On the 123 WNV HI positive sera tested, 104 (85%) and 78 (75%) had yellow fever and Potiskum HI antibody respectively. Monotypic WNV virus reactions were frequently found in children while polytypic reactions were frequently found in adults. A total of 200 animal sera were examined, 50 camels, 50 goats, 49 cattle and 51 sheep. The highest prevalence of HI antibody was found in camels (26%), followed by sheep (20%). Percentage of positive sera in other species were: goat (18%) and cattle (6%). Of the 35 WNV IN positive animal sera, 26 and 20% reacted with Yellow fever and Potiskum virus antigens respectively.

Detection of tumor-associated antigens in the sera of lung cancer patients by three monoclonal antibodies

One hundred sixty-one sera from lung cancer patients, including 46 samples from patients who had not yet received treatment were screened for tumor-associated antigens with 3 monoclonal antibodies, CSLEX1, CSLEA1, and CLEX5, by a new cell binding inhibition assay. We had previously determined that the antigens recognized by CSLEX1 and CSLEA1 are sialosylated Lewisx and sialosylated Lewisa, respectively. Either of these two antibodies alone reacted with about 65% of the 46 untreated patients' sera. Eighty-seven % of the 46 showed positive results with at least one of the two antibodies. The CLEX5 monoclonal antibody is presented here as recognizing a potential tumor-associated antigen. CLEX5 reacted with 54% of the 46 sera from nontreated lung cancer patients. When the results for all three antibodies were combined, the percentage of positive sera was 89% (of 46). Some interesting patterns in the serum levels of the antigens detected by these antibodies were observed. Levels of sialosylated Lewisx were significantly higher in sera from nontreated advanced stage (III and IV) patients (P less than 0.0003). In addition, levels of the antigens detected by CSLEX1 and CSLEA1 were dependent on whether or not the patient had been receiving treatment. These observations suggest potential applications of monoclonal antibodies to diagnosis and monitoring of therapies.

DEMONSTRATION OF ANTIBODIES TO HUMAN T-LYMPHOTROPIC RETROVIRUS TYPE III IN LYMPHOADENOPATHY SYNDROME PATIENTS AND IN INDIVIDUALS AT RISK FOR ACQUIRED IMMUNE DEFICIENCY SYNDROME (AIDS) IN ITALY1

An epidemiologic survey of the distribution of lymphoadenopathy syndrome in six Italian cities and its correlation with human T-lymphotropic retrovirus III (HTLV-III) is reported. Serum samples of nine patients with acquired immune deficiency syndrome (AIDS) were tested, 180 from patients with lymphoadenopathy and 349 from individuals belonging to groups such as homosexuals, drug addicts, hemophiliacs, and polytransfused considered at increased risk for AIDS. Prevalence of HTLV-III antibodies was 78% in AIDS patients and 61% in 180 patients with lymphoadenopathy syndrome (variation among drug abusers by city from 51% in Cagliari to 87% in Rome). The percentage of positive sera in individuals at risk for AIDS or lymphoadenopathy ranged from 0% in polytransfused to 8.5% in homosexuals, 14% in drug addicts, and 19.5% in hemophiliacs. No positive sera were found among 660 healthy individuals including relatives of patients with AIDS or lymphoadenopathy or in 342 patients suffering from immunologic or infectious diseases. These results strongly suggest that HTLV-III is the causative agent of AIDS and lymphoadenopathy. Since none of the healthy subjects were positive while a substantial percentage of people at risk for AIDS showed antibodies to HTLV-III, it may be presumed that this infection is also prevalent in the Italian population group in which AIDS and lymphoadenopathy are most likely to develop.

Immunological and virological investigation in patients with lymphoadenopathy syndrome and in a population at risk for acquired immunodeficiency syndrome (AIDS), with particular focus on the detection of antibodies to human T-lymphotropic retroviruses (HTLV III).

Thirteen patients affected with unexplained lymphoadenopathy, fever, weight loss, and diarrhea (lymphoadenopathy syndrome; LAS) were evaluated for the possible appearance of acquired immunodeficiency syndrome (AIDS) and for immunological and virological characterization. The patients belonged to categories of individuals at risk for AIDS and were homosexual and/or drug abusers or hemophiliacs. Lymph node biopsy showed the histological picture of a follicular hyperplasia. The study of cell-mediated immunity (CMI), humoral immune response, and natural killer (NK) activity demonstrated a significant decrease in T cells with the helper/inducer phenotype (OKT4+ cells) and a relatively increased number of lymphocytes with the suppressor/cytotoxic phenotype (OKT8+ cells). NK activity was significantly lower than in normal controls. The in vitro response to polyclonal activators (phytohemagglutinin; PHA) and the cutaneous responsiveness to recall skin tests were impaired, whereas immunoglobulin production was increased, mainly in the IgG fraction. Virological studies showed high serum antibody titers to cytomegalovirus (CMV) but a lack of specific CMI as assayed by the leukocyte migration inhibition test (LMIT). CMV was also isolated from the urine specimen of one patient. The antibody pattern to Epstein-Barr virus (EBV) showed the uncommon contemporary presence of both Epstein-Barr nuclear antigen (EBNA) and early antigen (EA) antibodies. Antibodies to human T-lymphotropic retroviruses (HTLV III) were positive in 10 patients and the virus was isolated in 3 of them. In some patients the presence of serum antibodies to HTLV III was not associated with an impairment of the immune function. A group of individuals at risk for AIDS without LAS was also evaluated for the presence of HTLV III antibodies; the percentage of positive sera was 11.4.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the Epstein-Barr virus (EBV) antibodies against viral capsid antigen (VCA) and early antigen (EA), in two populations of hospital children from 0 to 15 years old differing with regard to socio-economic status

We have studied the presence of antibody against EBV in two populations: the first included 561 children mostly immigrants of low socio-economic status and the second included 2189 children representing a large sample of the belgian population. From 1 to 5 years of age, the percentage of positive sera against VCA rose rapidly within the first population (69% by the age of 2, 79% by the age of 3 and 78% by the age of 4). In the second group, the percentage of VCA positive sera rose more slowly (49% by the age of 2, 53% by the age of 3 and 49% by the age of 4). The differences between the two groups are statistically significant (α<0.05). From the age of 5, no more differnce was found. The percentage of EA positive sera in the 2 groups were respectively 31% and 21%. In spite of the fact that the difference between the 2 groups was not statistically significant, these high percentages of EA positive sera reflected a status of active immunization in the age groups of 1 to 5 years in the 2 populations. By contrast, in a group of school children of 10 to 15 years, we have found only 12% of EA positive sera. This difference is statistically significant (α<0.05). In the first population, 55 patients (9.75%) had anti EA titer ≥ 1/16, suggestion of a recent infection. Eleven of them (20%) had a clinical picture suggesting of actual EBV infection.

モルモットにみられたブドウ球菌性皮膚剥離症の血清学的および細菌学的検索

A skin disease showing marked erythema and subsequent epidermal exfoliation has recently been observed in our breeding colony of guinea pigs. The distribution of staphylococcal antibodies and the frequency of Staphylococcus aureus isolation were studied in 5 guinea pig groups, three of which were in the clinical stages of the exfoliative skin disease, and two control groups. The mean titers of anti-alpha-toxin antibodies exhibited peak levels in the group of the middle clinical stage (titer of 24.0), when compared to those in the groups of the early (titer of 3.5) or the late clinical stages (titer of 4.1). The percentage of positive sera (titers greater than or equal to 5) for this antibody was also greater in the group of the middle clinical stage (100%) than in the groups of the early (55%) or the late clinical stages (64%). The agglutinating antibody was detected only in the groups of the early and the middle clinical stages. Staphylococcus aureus was isolated from 73% of the animals in the early stage, and from only 11% of those in the late stage.

Hepatitis B antigenaemia on Wuvulu Island.

A survey of the population of Wuvulu Island was undertaken to determine the prevalence of hepatitis B antigenaemia (HBsAg). Seventy-five percent of the population were tested, and 17.7% of those tested were positive for HBsAg. The percentage of positive sera increased with age but declined in the 5th decade of life. There was a marked difference in positivity between the two villages on the island (25.9% and 9.9%) which cannot be explained by several existing hypotheses for HBsAg transmission.

Antibodies to Epstein-Barr Virus in Nasopharyngeal Carcinoma and Other Neoplastic Conditions

Sera from patients with nasopharyngeal carcinoma (NPC) or other malignant diseases and from apparently healthy controls were examined for Epstein-Barr virus (EBV) antibodies. A difference existed in the percentage of positive sera among the groups studied. High-titer antibody levels were observed in the NPC group, but no statistical difference was found among other groups of patients and controls. The data reaffirmed the association of EBV with NPC but did not support its etiologic role in the development of other human neoplasms.

Viral-specific humoral immunity to herpes simplex-induced antigens in patients with squamous carcinoma of the head and neck

Serum antibodies to herpes simplex virus-induced antigens (HSVIA) were quantitated in 122 patients with head and neck squamous carcinoma, 93 patients tumor-free after treatment for these malignant lesions, 27 patients with nonsquamous malignant lesions, 30 heavy smokers, and 36 nonsmokers. Serum IgA anti-HSVIA antibodies were detected in a greater percentage of sera of patients with squamous carcinoma (61 per cent), patients previously treated for these malignant lesions (56 per cent), and heavy smokers (57 per cent) than in patients with nonsquamous malignant lesions (11 per cent) or nonsmokers (8 per cent). Furthermore, titers of these antibodies were higher in patients with squamous carcinoma than in smokers. In patients tumor-free more than three years after treatment, the percentage of positive sera was significantly lower than that in untreated patients and in patients three years or less after treatment. This study demonstrates for the first time a high frequency of antibodies to HSV-induced antigens confined to subjects at high risk of developing head and neck squamous carcinoma and in patients with these malignancies as well as a correlation between the levels of these antibodies and clinical course after treatment.