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Immunoglobulin isotype of specific antibodies in reproductive tract secretions and sera in Tritrichomonas foetus-infected heifers.
1990
Skirrow S.Z. | BonDurant R.H.
Four virgin heifers were experimentally inoculated intravaginally with 7 X 10(6) Tritrichomonas foetus, and 2 heifers served as uninfected controls. The durations of infection were 13, 20, 21, and 28 weeks, respectively. An ELISA that used whole T foetus antigen was used to detect anti-T foetus immunoglobulins (IgA, IgG1, IgG2, and IgM) in vaginal, cervical, and uterine secretions, and sera during the course of infection. The vaginal and cervical antibody responses were characterized by significantly increased T foetus-specific IgA and IgG1 at 7 to 9 weeks of infection, whereas uterine IgA and IgG1 responses peaked at 10 to 12 weeks. The antibody response in serum was predominantly of the IgG1 and IgG2 subclasses. In all reproductive tract regions, IgA persisted at least until the time of T foetus clearance, and usually longer. The next most persistent isotype was IgG1, lasting longest in the vagina, then cervix, and for the shortest time in the uterus. In local secretions, IgG2 was seen only transiently, increasing at weeks 13 to 15 in the vagina, and at weeks 10 to 12 in the cervix. Little IgM, relative to that present before infection, was detected in any secretion or serum, although cervical secretions had the greatest amount. Eight to 12 weeks after clearance, the 4 experimental heifers were inoculated intravaginally with 1 x 10(5) T foetus, transient infections (2 to 3 weeks' duration) were established in only 2 of 4 heifers, as determined by culturing of reproductive tract secretions. The lag times of antibody responses during this reinfection were shorter than in the initial infection, and ELISA optical densities were at least as high as during the primary infection, suggesting an anamnestic response.
Показать больше [+] Меньше [-]Evaluation of serologic and cellular immune responses of cattle to a nonlipopolysaccharide antigen from Brucella abortus.
1990
Hoffmann E.M. | Shapiro S.J. | Nicoletti P.
Cows naturally infected with Brucella abortus developed antibody (Ab) responses to a nonlipopolysaccharide antigen (NLA) purified from B abortus strain 1119-3. Sera from strain 19-vaccinated cows did not have detectable amounts of Ab. Weak lymphoproliferative responses to NLA were observed in blood mononuclear cell suspensions obtained from infected cows. There was no evidence of NLA-specific lymphoproliferation in cell suspensions from healthy cows. Nonlipopolysaccharide antigen binding to bovine blood mononuclear cells was observed by antigen-consumption assays and direct binding of radiolabeled antigen. Cells from infected cows bound less NLA than did cells from healthy cows when assays were conducted with intact blood mononuclear cell preparations (monocytes plus lymphocytes). Monocytes obtained from any group did not bind NLA. Purified B lymphocytes from infected and healthy vaccinated cows bound about 3 times more NLA than did T lymphocytes, but there were no apparent differences between the 2 groups in extent of binding. Results of the study indicate that bovine lymphocytes have binding sites for a NLA purified from B abortus strain 1119-3.
Показать больше [+] Меньше [-]Immune response to pulmonary injection of Pasteurella haemolytica-impregnated agar beads followed by transthoracic challenge exposure in goats.
1990
Purdy C.W. | Straus D.C. | Livingston C.W. Jr. | Foster G.S.
A method of inducing Pasteurella haemolytica serotype 1 (Ph1) lung infection in goats, using low numbers of bacteria and without impairing host immunity, was developed. Two trials were conducted. Results of trial 1, using 10 principals (Ph1 agar beads) and 6 controls (agar beads alone), indicated that Ph1 organisms imbedded in agar beads could survive host lung defenses for 32 days. Results of trial 2 indicated that lung immunity in the inoculated goats (principals) was high and they were more protected than controls against a transthoracic challenge of Ph1 (1.18 X 10(7) colony-forming units) injected into lung of each goat on posttreatment day 35. When comparing challenge-exposed principals with controls, the controls developed rectal temperatures above normal for a longer time, duration of anorexia was longer, and sign of depression were seen. The controls developed large are of consolidated lung tissue, more Ph1 isolates were recovered from nasal turbinates and lung tissue, and higher Ph1 concentrations were found in the lungs. The serum Ph1 indirect hemagglutination antibody titers in the principals of both trials increased, compared with titer in controls. Principal goats in trial 2 had higher Ph1 indirect hemagglutination antibody titers after injection of Ph1-impregnated agar beads and less severe lung lesion after challenge exposure than did controls. The small pneumonic consolidated lesions in the principals, compared with extensive lesions in controls after Ph1 challenge exposure, indicated a high degree of immunity after exposure to Ph1 organisms imbedded in agar beads.
Показать больше [+] Меньше [-]Orally administered clonidine as a secretagogue of growth hormone and as a thymotrophic agent in dogs of various ages
1990
Morrison, W.B. | Goff, B.L. | Stewart-Brown, B. | Incefy, G.S. | Arp, L.H. | Roth, J.A.
The growth hormone (GH) secretagogue activity of variable dosages of clonidine (16.5, 50, 150, and 450 microgram/kg of body weight), given orally mixed with the daily food ration, was evaluated in young and old dogs. Significant (P < 0.05) increase in plasma GH concentration was detected at all dosages tested in young dogs and in response to all but the lowest dose tested in the old dogs fed the clonidine-containing diet. Old dogs had plasma GH concentration that exceeded that of young dogs when higher doses of clonidine were used. A clonidine (100 microgram/kg)-supplemented diet was fed to middle-aged dogs twice daily for 30 days. Significant (P < 0.01) increase of plasma GH concentration was observed on the first day of the feeding trial, but was undetectable by day 30. After feeding the clonidine-enhanced diet for 30 days, the effects on thymic morphology were variable, and there was no effect on plasma thymulin titer. Clonidine-fed dogs had significantly increased lymphocyte blastogenic responsiveness to mitogens, compared with that of control dogs, when evaluated as stimulation index.
Показать больше [+] Меньше [-]Evaluation of serologic and cellular immune responses of cattle to a nonlipopolysaccharide antigen from Brucella abortus
1990
Cows naturally infected with Brucella abortus developed antibody (Ab) responses to a nonlipopolysaccharide antigen (NLA) purified from B abortus strain 1119-3. Sera from strain 19-vaccinated cows did not have detectable amounts of Ab. Weak lymphoproliferative responses to NLA were observed in blood mononuclear cell suspensions obtained from infected cows. There was no evidence of NLA-specific lymphoproliferation in cell suspensions from healthy cows. Nonlipopolysaccharide antigen binding to bovine blood mononuclear cells was observed by antigen-consumption assays and direct binding of radiolabeled antigen. Cells from infected cows bound less NLA than did cells from healthy cows when assays were conducted with intact blood mononuclear cell preparations (monocytes plus lymphocytes). Monocytes obtained from any group did not bind NLA. Purified B lymphocytes from infected and healthy vaccinated cows bound about 3 times more NLA than did T lymphocytes, but there were no apparent differences between the 2 groups in extent of binding. Results of the study indicate that bovine lymphocytes have binding sites for a NLA purified from B abortus strain 1119-3.
Показать больше [+] Меньше [-]Systemic and secretory antibody responses to sequential bovine respiratory syncytial virus infections in vaccinated and nonvaccinated calves
1990
Stewart, R.S. | Gershwin, L.J.
To investigate the influence of humoral immunity on the severity of disease caused by infection with bovine respiratory syncytial virus (BRSV), an experimentally induced infection study was performed on vaccinated and nonvaccinated calves. Fifteen weanling calves were allotted to 3 groups: 1 group of 6 calves was exposed to 2 live virus aerosols, 35 days apart; another group of 6 calves was vaccinated prior to the same aerosol exposures; and the remaining 3 calves served as controls. Clinical signs of infection were converted to a numerical score for evaluating disease severity. For 14 days after each virus exposure, BRSV-specific IgG and IgM concentrations in serum and BRSV-specific IgA concentration in nasopharyngeal exudate and lung lavage fluid were measured by ELISA. Serum BRSV-specific IgG and IgM and secretory BRSV-specific IgA concentrations did not correlate with disease sign expression. There was a strong correlation between viral isolation and disease scores. Vaccination prior to virus exposure appeared to have little or no effect on severity of the disease, but it did appear to affect disease persistence. Findings indicate that the immunoglobulins evaluated may be primarily protective in nature and do not contribute to disease severity.
Показать больше [+] Меньше [-]Differential reactivity of bovine lymphocytes to species of Brucella
1990
Smith, R. III. | Kapatsa, J.C. | Sherwood, S.J. III. | Ficht, T.A. | Templeton, J.W. | Adams, L.G.
The reactivity of bovine lymphocytes to 4 species of Brucella was tested in thymidine-uptake assays, using long-term cultured lymphocytes and freshly obtained blood mononuclear cells. Lymphocytes were taken from cows that had been challenge exposed with a virulent strain of B abortus at midgestation. The cows were classified retrospectively as being naturally resistant or susceptible to brucellosis. Lymphocytes taken from these cows had 3 patterns of reactivity with species of Brucella: pattern 1 was defined by reactivity with 4 species (B abortus, B canis, B suis, and B melitensis); pattern 2 was defined by reactivity with all these species, except B melitensis; pattern 3 was defined by reactivity with B abortus and B canis, but not with B suis or B melitensis. There was a statistically significant correlation between susceptibility to brucellosis and expression of lymphocyte cross-reactivity with B suis (P < 0.01) and with B melitensis (P < 0.001).
Показать больше [+] Меньше [-]Complement resistance in Actinobacillus (Haemophilus) pleuropneumoniae infection of swine
1990
Rycroft, A.N. | Cullen, J.M.
The possible role of the complement-mediated bactericidal system in protection of swine against contagious pleuropneumonia was investigated. Strains of Actinobacillus (Haemophilus) pleuropneumoniae representing serotypes 2, 3 and 5 were found to be fully resistant to the bactericidal action of porcine serum from precolostral, clinically normal adult, and chronically infected pigs. All strains were also resistant to hyperimmune rabbit serum, but 3 of 4 strains were sensitive to normal human serum. This bactericidal effect was lost when human serum was previously absorbed with the homologous bacteria, indicating that antibody was necessary for killing. Addition of human serum to porcine serum or to absorbed human serum did not restore the bactericidal system. Pretreatment of the bacteria with undiluted heat-treated human serum also failed to sensitize the bacteria to the absorbed serum, indicating that a heat-labile, absorbable factor may have been required for killing of A pleuropneumoniae. None of the strains was sensitized to porcine serum by sublethal treatment with polymyxin B, a treatment that is known to disrupt the integrity of the outer membrane and induce serum sensitivity in gram-negative bacteria. The ability of A pleuropneumoniae to resist complement killing in vitro may reflect a virulence mechanism in vivo that assists bacteria in avoiding the pulmonary defenses of swine and promotes bacterial invasion of the lungs.
Показать больше [+] Меньше [-]Adverse immune reactions and the pathogenesis of Ostertagia ostertagi infections in calves
1990
Wiggin, C.J. | Gibbs, H.C.
The possible development of type-1 hypersensitivity reactions in the abomasal mucosa caused by soluble L3 products of Ostertagia ostertagi was studied in 4-month-old calves sensitized by repeated exposure to L3 over a 50-day period followed by anthelmintic treatment. Four groups each of 4 calves were used. Group 1 served as nonsensitized controls and group 2 as sensitized controls, group 3 was challenge exposed at 2-week intervals beginning at week 10 with a soluble L3 product (OAG), and group 4 was challenge exposed at 2-week intervals with an oral dose of L3, followed by anthelmintic treatment 3 days later. All calves infected with L3 became sensitized, as indicated by a positive reaction to an intradermal skin test. However, a passive cutaneous anaphylaxis was only partly effective in indicating the presence of homocytotropic antibody in the infected calves. Sensitized calves had significantly (P < 0.05) higher eosinophil counts and plasma pepsinogen values for the entire 14 weeks than uninfected controls. Globule leukocyte and mast cell counts from the abomasal mucosa were also significantly (P < 0.05) higher. Studies for possible immunomodulation revealed that lymphocyte counts decreased between every 2-week challenge-exposure period for groups-3 and -4 calves. A transient depression of blood lymphocyte (BL) responses to phytohemagglutinin (PHA), a T-cell mitogen, was observed over the first 8 weeks in the infected calves. Increases in BL responses to OAG were also observed. Differences were not observed in BL responses to pokeweed mitogen, a T- and B-cell mitogen. Blood lymphocyte responses to PHA in group-3 calves were low following the initial challenge exposure with OAG. The sensitized calf lymphocytes did not have suppressive activity on the response of control calf lymphocytes to PHA. Differences were not observed in lymphocyte responses to PHA in a suppressive assay done on abomasal lymph node lymphocytes. Increases in abomasal lymph node mass and lymphocyte responses to PHA, pokeweed mitogen, and OAG were observed in all sensitized calves. Histologic examination of abomasal lymph node sections from challenge-exposed calves revealed increased mitotic activity in germinal centers. Plasma pepsinogen values in groups 3 and 4 increased between each challenge exposure, which further suggested that type-1 hypersensitivity reactions had occurred in the abomasal mucosa, resulting in increased permeability and leakage of macromolecules.
Показать больше [+] Меньше [-]Immunodominant proteins of Sarcocystis cruzi bradyzoites isolated from cattle affected or nonaffected with eosinophilic myositis
1990
Granstrom, D.E. | Ridley, R.K. | Baoan, Y. | Gershwin, L.J.
Sarcocystis cruzi sarcocysts were isolated from eosinophilic myositis (Em)-affected and nonaffected bovine hearts. Isolates were ruptured and used to prepare a bradyzoite antigen extract from each heart. The nonaffected heart from one newborn calf contained no apparent sarcocysts when examined histologically and was used to prepare Sarcocystis-negative control antigen. Blood samples were taken from the heart approximately 20 minutes after slaughter. Serum was obtained and evaluated, using a radioimmunoassay to measure Sarcocystis-specific IgG and IgE titers. Sarcocystis cruzi extract from a heart without EM lesions was used for antigen in the radioimmunoassay. Sarcocystis-specific IgG titer ranged between 1:1,280 and 1:2,560 in EM-affected cattle and was 1:640 in nonaffected cattle. Sarcocystis-specific IgE titer ranged between 1:640 and 1:1,280 in Em-affected and nonaffected cattle. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein (western) immunoblot analysis were used to compare antigen extracts and serum samples from EM-affected vs nonaffected cattle. Twenty protein bands, ranging from approximately 22 to 215 kD, were detected consistently on bradyzoite blots probed with anti-bovine IgG after incubation with serum samples. Seven of these bands, 37, 44, 53, 57, 94, 113, and 215 kD, were also detected consistently on bradyzoite blots probed with monoclonal anti-bovine IgE. One additional band, 61 kD, was detected consistently on bradyzoite blots probed for IgE, but was seldom recognized when probed for IgG. Sixteen protein bands were evident in silver-stained gels of S cruzi-negative, newborn calf antigen, but none were recognized by antisera on western blots. Consistent differences were not found among antigen extracts or among serum from EM-affected vs nonaffected cattle on silver-stained gels or western blots.
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