Temperature influence on Arctic charr (Salvelinus alpinus L.) antibody response to a cellular antigen

In order to elucidate the immune responses of Arctic charr in relation to temperature, groups were acclimated to a moderate (9°C) and a cold temperature regime (4°C), as well as subjected to a temperature decrease (from 9 to 4°C) immediately prior to an immunization with sheep red blood cells. The charr kept at 9°C responded with increased primary and secondary antibody titres, as seen by direct haemagglutination, while fish at 4°C, as well as the fish subjected to a temperature reduction, displayed lower and lowest antibody titres, respectively, and only after a second immunization. It is concluded that Arctic charr can respond to a cellular antigen with a humoral immune response typical for other teleosts, but that the immune response is delayed and diminished at low temperatures. This temperature-induced immune suppression is intensified if the fish have not been acclimated to cold water prior to immunization. Accepted: 10 October 1999     

Chlamydophila pneumoniae in horses: a seroepidemiological survey in Italy

We tested 731 sera from apparently healthy light horses against Chlamydophila pneumoniae, by a microimmuno-fluorescence (MIF) test. To verify cross-reactions with other species of chlamvdiae, all sera with an antibody titre > or = 32 to C. pneumoniae were tested against both C. psittaci and C. abortus. Antibodies to C. pneumoniae were detected in 194 out of 731 (26.5%) samples tested, with antibody titres ranging from 32 to 1024. No antibody titre > or = 32 was detected in sera to C. abortus. Only few sera with a high antibody titre to C. pneumoniae reacted weakly with C. psittaci at the dilution of 1:32.     

Use of the indirect hemagglutination reaction for detecting antibodies to Pseudomonas pyocyanea in acute suppurative destructive pneumonia]

No less than 4-fold increase in the antibody titres to Pseudomonas aeruginosa during the infectious process served as laboratory confirmation of its participation in the infectious process. In 49 of 91 patients hemagglutining titre exceeded the diagnostic one (1:640). In 9 patients (chiefly in infants) hemagglutinin titre remained low, but there was a rise of antibody level to Pseudomonas aeruginosa during the disease. High hemagglutinin titres were noted in 12 patients on admission to the clinic, with reduction of the antibody titres at the late periods of the disease. Antibody titres remained unchanged during the disease in 15 patients. In 3 cases the indirect hemagglutination test was assesed as negative. In the rest of the patients hemagglutinin titres varied within the range of the diagnostic titre. Thus, the indirect hemagglutination test with erythrocytic diagnostic agent permitting to determine antibodies to Pseudomonas aeruginosa could be used at the clinic in combination with bacteriological and other investigations for establishing etiology of the destructive process.     

The effect of sodium chloride on phage formation by staphylococci at elevated temperatures

In experiments with the K strain of Staphylococcus aureus and the K race of bacteriophage suspended in tryptose phosphate broth and maintained at 42 degrees C. it was found that the presence of 1 M NaCl produced certain drastic changes in the relationship between the host cells and the infecting virus: 1. Staphylococci grown at 42 degrees C. in plain broth or in NaCl-broth are "activated," i.e. when growth is stopped by lowering the temperature to 5 degrees C. and phage is added, the activity titre immediately displays a rise of 15- to 16-fold. 2. 1 M NaCl tends to prevent the sorption of phage by cocci and this effect is more pronounced at 42 degrees C. than at 5 degrees C. When the activation test is conducted at 5 degrees C. (the usual temperature) most of the phage is picked up by the cells and the described increase in activity titre follows. If the test takes place at 42 degrees C. there is little sorption and correspondingly little rise in phage titre. 3. Mixtures of staphylococci and phage incubated at 42 degrees C. in NaCl-broth fail to produce phage; the final plaque and activity titres are identical with the initial titres. Here, also, the influence of 1 M NaCl in preventing contact of phage with cocci appears to account for the results. 4. Similar mixtures held at 42 degrees C. in plain broth exhibit a drop of about 60 per cent in activity and plaque titres. The loss of phage may be due to adsorption on dead cells accumulating in the suspension or to the thermolability of the bacterium-phage complex, or to both.     

Effect of anti-oestradiol-17B antibodies on the reproductive response of ewes superovulated with PMSG

A field experiment was conducted to examine the effect of anti-oestradiol-17B antibody titre on the oestrous and ovulatory responses of ewes to low (600 i.u.) or high (1200 i.u.) doses of pregnant mare's serum gonadotrophin (PMSG). Merino ewes were treated with intravaginal sponges and were subsequently used as vehicle-treated controls or were immunized to produce reciprocal anti-oestradiol-17B antibody titres less than 1000 or greater than 1000. Ewes were then treated with PMSG and the incidence of oestrus and ovulation, ovulation rate, and yield of embryos recorded. Treatment of immune ewes with 1200 i.u. PMSG resulted in both a higher proportion of ewes ovulating and a higher ovulation rate than in immune ewes treated with 600 i.u. (86% v. 67% and 13.4 v. 6.0 respectively). As anti-oestradiol-17B titres increased there was a reduction in the proportion of ewes exhibiting oestrus. The proportion of ewes ovulating decreased as antibody increased in ewes treated with 600 i.u. PMSG but not in those treated with 1200 i.u., suggesting an increased positive feedback of oestradiol with high PMSG doses. Fertilization rates were highest at the lower PMSG dose (68% v. 42%) and increased with increasing titre. Overall, there was no increase in ovulation rate or in yield of embryos over control values from either low (less than 1000) or high (greater than 1000) antibody titres.     

Seroprotection against serogroup C meningococcal disease in adolescents in the United Kingdom: observational study

Objective To determine the persistence of bactericidal antibody titres following immunisation with serogroup C meningococcal glycoconjugate vaccine at age 6-15 years in order to examine changes in persistence of antibodies with age.Design Observational study.Setting Secondary and tertiary educational institutions in the United Kingdom.Participants Healthy adolescents aged 11-20 years previously immunised between 6 and 15 years of age with one of the three serogroup C meningococcal vaccines.Intervention Serum obtained by venepuncture.Main outcome measures Percentage of participants with (rabbit complement) serum bactericidal antibody titres of at least 1:8; geometric mean titres of serogroup C meningococcal serum bactericidal antibody.Results Five years after immunisation, 84.1% (95% confidence interval 81.6% to 86.3%) of 987 participants had a bactericidal antibody titre of at least 1:8. Geometric mean titres of bactericidal antibody were significantly lower in 11-13 year olds (147, 95% confidence interval 115 to 188) than in 14-16 year olds (300, 237 to 380) and 17-20 year olds (360, 252 to 515) (P<0.0001 for both comparisons). Within these age bands, no significant difference in geometric mean titres of bactericidal antibody between recipients of the different serogroup C meningococcal vaccines was seen. More than 70% of participants had received a vaccine from one manufacturer; in this cohort, geometric mean titres were higher in those immunised at aged 10 years or above than in those immunised before the age of 10.Conclusions Higher concentrations of bactericidal antibody are seen five years after immunisation with serogroup C meningococcal vaccine at age 10 years or above than in younger age groups, possibly owing to immunological maturation. This provides support for adolescent immunisation programmes to generate sustained protection against serogroup C meningococcal disease not only for the vaccine recipients but also, through the maintenance of herd immunity, for younger children.     

Stability of 17D Yellow Fever Virus Vaccine Using Different Stabilizers

To optimize the thermostability of lyophilized 17D vaccine, the authors investigated parameters important for the freeze-drying process. Six different stabilizers with different sugars and amino acids were analysed in a freeze-thaw cycle for their crystallization characteristics and their stabilizing effect under thermal treatment conditions of 37 degrees C for 28 days. This test indicated that three out of six stabilizers (B, C, F) kept the vaccine significantly more stable than the three others (A, D, E). Under storing conditions of 4 degrees C over 96 days stabilizers A, B and C produced the lowest decrease in titre of about 10% in contrast to stabilizers D, E and F with a higher decrease in infectivity titre. Analysing the stability of the 17D vaccine using five different reconstitution solutions, we found that 90% D2O shows the best stabilizing effect under thermal treatment of 37 degrees C up to 24 h.     

Xylanase production by Aspergillus awamori. Development of a medium and optimization of the fermentation parameters for the production of extracellular xylanase and beta-xylosidase while maintaining low protease production

A growth medium was developed for maximal production in batch culture of extracellular xylanase and beta-xylosidase by Aspergillus awamori CMI 142717 and a mutant (AANTG 43) derived from the wild-type strain. The optimum pH for the production of xylanase and beta-xylosidase was 4.0. The best temperature of xylanase production was 30 degrees C; 35 degrees C was optimal for beta-xylosidase. Protease production was never completely suppressed under any of the conditions tested. However, protease titre was 3.5-fold less than the control in medium in which proteose peptone and yeast extract were omitted: the level of xylanase was not affected (8.6 U mL(-1)) but beta-xylosidase titre was increased 4.7-fold to 1.5 U mL(-1). When corn steep liquor was used as the sole nitrogen source, xylanse and beta-xylosidase titres were further increased by 1.5- and 1.9-fold, respectively. Of the carbon sources investigated, ball-milled oat straw or oat spelt xylan produced the highest titres of xylanse and beta-xylosidase. None of the soluble carbon sources investigated produced the high titres of xylanase or beta-xylosidase induced by either oat straw for xylanse and beta-xylosidase was 2% and the optimum spore inoculum was between 10(6) and 10(7) spores/mL(-1) final concentration. The level of xylanse activity obtained in the culture filtrates of the mutant was a remarkable 820 U mL(-1) when the reducing sugar released was measured by the dinitrosalicylic acid method. This enzyme titre would appear to be the highest reported so far. The xylanases system contained the correct balance of enzymes to effect extensive hydrolysis of oat spelt xylan. The protease titre was very low.     

Stability-related studies on 17D yellow fever vaccine

Yellow fever (YF) vaccine using the 17D strain of YF attenuated virus has been produced at the Institut Pasteur in Dakar since 1962. Until now, the stabilised YF had an expiry date of utilization of two years from the end of the lot control process under storage at +4 degrees C. We conducted a stability study to assess the three full year validity of this preparation, when correctly stored at +4 degrees C to optimise the conditions of production, storage and availability of such a vaccine. The activity of 19 consecutive batches of vaccines kept for three years at +4 degrees C was compared to that of the same batches that were kept three years at -20 degrees C. Using the in vitro microculture method, we found that three-year storage at +4 degrees C induced a higher loss of activity than storage at -20 degrees C or than the accelerated degradation test of vaccines kept for 14 days at 37 degrees C. Whatever the conditions of storage, in all cases decreases in activity were below the WHO's requirements, i.e., < 1 log PFU/dose, and residual activity of the selected batches was over 1000 mouse LD50 per dose. We demonstrated that the 17D YF vaccine produced in Dakar has a shelf-life of three years and that its required potency was maintained at +4 degrees C, after reconstitution with saline diluent, following three-year storage at +4 degrees C.     

Response to Influenza Vaccine by Renal Transplant Patients

Twenty-five renal transplant patients and 17 controls were vaccinated with influenza vaccine. Antibody titres were estimated before and one, three, and 12 months after vaccination. On the basis of antibody titre measurements the transplant group showed a similar qualitative and quantitative response to that of the controls. No rejection episodes occurred among the transplant patients as a result of vaccination and nobody in the trial developed influenza. We conclude that it is safe to vaccinate transplant patients with an inactivated influenza vaccine and that protection (haemagglutination-inhibiting antibody) can be induced.     

Complement-fixing antibodies against rotaviruses in healthy children in the Czech Socialist Republic and People's Democratic Republic of Yemen

Levels of complement-fixing antibodies against rotaviruses were evaluated in the sera of 900 healthy children aged 1-9 years 300 sera were collected in the People's Democratic Republic of Yemen in September-October 1985, 300 sera were obtained in the Czech Socialist Republic in the same period and another 300 also in the Czech Socialist Republic in September-October 1986. The latter two groups were investigated in the framework of immunological surveys. A complement-fixation antigen was prepared from a simian strain of the rotavirus type SA-11 in a tissue cell line MA-104. The sera from Yemen featured lower mean titres in the age groups and thus the lowest overall titre. As the antibody titre increased, the portion of seropositive sera from Yemen declined by far more rapidly than in the Czech children, where it remained virtually the same. The sera from Yemen showed the lowest negative rate and lowest ratio of high titres. The antibody titre of 1:64 and higher was not detected in children from Yemen, while they occurred in the two groups of Czech children. There was no correlation between antibody titres and probands' sex, nor was there linear dependence of titre magnitude on age. The mean positivity rate in each group as assessed by the antibody titres was the lowest in the sera from Yemen. The percentage of positive sera in all age groups was higher in the Czech children with the exception of children from Yemen aged 6 and 9 years. The aim of the present study was to evaluate the antibody status in infant populations and thus expand knowledge of rotavirus epidemiology.     

The effect of storage at different temperatures on the stability of Hepatitis C virus RNA in plasma samples.

One important issue related to Hepatitis C virus (HCV) RNA nucleic acid amplification testing (NAT) is the storage conditions of plasma samples in order to obtain reliable results. Many authors have reported that the storage conditions could affect the RNA stability and, hence, HCV RNA detection. We have studied HCV RNA stability in plasma samples after storage at different temperatures (-70, -20, 5 and 25 degrees C). Samples containing different HCV titres were stored and analysed by qualitative or quantitative NAT techniques at defined time points. At -20 degrees C, samples containing high HCV RNA titres were followed-up during approximately 2.6-2.7 years, samples with intermediate concentrations during approximately 1 year and samples with 100 International Units/millilitre (IU/ml) during 2.5 years. Independently of the HCV RNA concentration, the results show absence of decay in HCV RNA detectability. Samples stored at 25 degrees C maintain their HCV RNA titre during 14 days and samples at 5 degrees C were stable for at least 3 months.     

The persistence of antibodies induced by meningococcal polysaccharides of groups A and C in human volunteers

Ninety-nine college students (58 males and 41 females) aged 17 to 23 years were each injected subcutaneously with 50 micrograms of meningococcal polysaccharides A and C. Titrations of antisera obtained at various time intervals during the two subsequent years were made by passive haemagglutination microtitration using human O Rh-negative red blood cells from a single source. The percentage of responders (those who developed a fourfold increase in titre) to polysaccharide A was 97.9% and that to polysaccharide C was 94.8%. Pre-immunization titres of 16 to polysaccharide A and 8 to polysaccharide C were considered to be threshold values above which the response might be impaired. There was a significant (P less than 0.01) difference in the geometric mean HA titre between vaccinees and control groups after vaccination at each time interval studied. The majorities of both the vaccinees and the controls had a higher peak titre to polysaccharide A than to polysaccharide C.     

Immunity to equine herpesvirus 1 infection in foals during the first year of life.

A band of 23 pregnant mares on a Thoroughbred breeding farm all had serum virus-neutralizing antibody titres to equine herpesvirus 1 (EHV-1). Antibody was not transferred to their foals in utero. All foals received antibody from colostrum and developed antibody titres similar to their dams. The serum virus-neutralizing antibody titres were observed in 10 of these foals for 1 year. Decay of passive immunity occurred at the rate of 3.25 two-fold dilutions in 100 days and reached zero at the mean time of 180 days. The foals were exposed to EHV-1 twice. Foals with a geometric mean titre of 1 : 25 experienced infection and a rise of titre, while those with a geometric mean titre of 1 : 76 resisted infection.     

Development and significance of antibodies to salmon calcitonin in patients with Paget's disease on long-term treatment.

Sixteen consecutive patients in one unit were studied during long-term treatment of Paget''s disease of bone with salmon calcitonin. Eleven patients developed detectable antibody titres at some time during treatment. In one patient with a high antibody titre evidence of resistance to treatment emerged two years after the development of antibodies, but no other patient showed evidence of resistance. The clinical and biochemical response could be maintained in the absence of an acute calcium-lowering effect of calcitonin. Although antibodies often develop during treatment with heterologous calcitonin, they are only rarely the cause of clinical resistance.     

Natural antibodies in healthy adults.

The serum of 100 adults living in Budapest was examined for isohaemagglutinin titre with haemaglutination, for staphylococcal-antitoxin titre with haemolysis inhibition and for bacterial antibody titre against 17 different groups of bacteria with passive haemagglutination. Antibody levels in males, except for certain bacterial antibodies, were somewhat lower than in females. The antibody titres, especially in men, decreased gradually from 20 to 50 years of age and were usually lower in Rh negative than in Rh positive persons.     

Comparison of one- and two-dose regimens of influenza vaccine for elderly men.

In November and December 1984, 102 male residents of a long-term care facility (mean age 74.6 [extremes 59 and 97] years) received 0.5 ml of trivalent inactivated whole-virion influenza vaccine, containing 15 micrograms of the hemagglutinin of each of A/Philippines/2/82 (H3N2), A/Chile/83 (H1N1) and B/USSR/83. A second dose of the vaccine was administered to a subgroup of 55 randomly chosen subjects 8 weeks later. Serum samples were collected from all the subjects before and 4, 8, 12 and 16 weeks after administration of the first dose and were assayed for hemagglutinin-inhibiting (HAI) antibody to each of the three antigens. At 8 weeks there were significant increases (p less than 0.05) in the geometric mean titre of antibody and in the proportion of subjects with HAI antibody titres of 1:40 or more (except to the B/USSR antigen) in both groups. There were no differences between the groups at 8 weeks or at 16 weeks (8 weeks after administration of the second dose of vaccine) in the frequency of seroconversion, the geometric mean titre or the proportion of subjects with HAI antibody titres of 1:40 or more. Overall, 60%, 32% and 13% of the 102 subjects had titres of 1:40 or more to the A/Philippines, A/Chile and B/USSR antigens respectively at 16 weeks. The results suggest that a second dose of influenza vaccine given 8 weeks after the first does not enhance the immune response in elderly men and that a substantial proportion of this population remains unprotected against infection (having HAI antibody titres of less than 1:40) during the influenza season.     

Rabies Antibodies in Vaccinated Dogs

Forty-seven healthy, owned dogs were vaccinated with Madivak and 85 with Rabisin. Geometric mean titres of 17.40 and 1.03 IU/ml were measured by the rapid immunofluorescent focus inhibition test 30–40 and 350–370 days, respectively, after a single injection. Four out of 130 (3.1%) and 18 out of 106 (17% ) dogs had a titre of less than 0.5 IU/ml in serum 30–40 and 350–370 days after vaccination. Twenty-one dogs (19.8%) had a titre of 0.5 IU/ml 350–370 days after vaccinaton. There was no significant difference in antibody levels between animals vaccinated with Rabisin or Madivak. Our results indicate that a booster is always necessary after a single injection to ensure that all dogs have a lasting antibody titre.     

Persistence of antibodies of the IgG class against cytomegaloviruses in blood donors

High titre plasmas gained from blood donors are the initial material used for producing human immunoglobulin containing cytomegalovirus antibodies (CMV-HIG). For this purpose the sera gained from 467 permanent donors at the District Institute for Blood and Transfusion Service in Berlin were investigated on their CMV antibody content of IgG class by means of an indirect immunofluorescence test (IFT). The infection rate of blood donors amounted to 62% (291/467). CMV-IgG titre greater than or equal to 1:40 was determined in 88 sera (18.8%) and greater than or equal to 1:160 in 14 sera (3%). Two CMV-HIG laboratory samples (charges 3113 and 3117) were produced from these plasmas. Particularly immunoglobulin fraction of charge 3117 (No. 3117 N II) revealed excellent antibody titres (IFT 1:640 [CMV-IgG] or 1:40 [CMV-IgM] respectively, neutralisation test 1:32). Checks made with the donors' CMV-IgG titres after repeated application of plasmapheresis resulted in maximal titres changes of two dilution stages in a period of 15 months. Thus, in producing CMV-HIG a sure, tested pool of donors can be resorted to.     

Serological Studies in Infectious Mononucleosis

Serological investigations performed on 27 patients with illnesses resembling infectious mononucleosis showed a significant increase in high antibody titres (more than 1:40) to EB virus in 11 of the 12 who developed heterophile antibodies. Two of these patients, however, had a significant increase in antibody titre to cytomegalovirus and rubella virus, respectively. Of 15 patients who failed to develop heterophile antibodies, one had a high antibody titre to EB virus, the others generally having undetectable or low antibody titres. The insidious onset of the illness in many patients together with the fact that EB virus antibodies rose to high titres rapidly reduced the value of this investigation diagnostically.EB virus antibody was still present in the sera of five patients who had had well-authenticated heterophile-antibody-positive infectious mononucleosis some four to seven years previously. Twenty-seven out of 70 (39%) healthy nurses had antibody at a level of more than 1:10 to EB virus. The presence of EB virus antibody in different population groups appears to be related to such factors as age and socioeconomic status.