Feline leukemia virus vaccine: new developments.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
K Haffer
Publications and source records attributed to K Haffer.
Feline leukemia virus: current status of the feline induced immune depression and immunoprevention.
This is a review of the current knowledge of feline leukemia virus (FeLV) associated with immune depression observed in cats. It will focus on the clinical and experimental observations associated with feline retroviral infection and presence in vivo and in vitro. We will briefly describe retroviral-associated acquired immune deficiency syndrome associated with FeLV infection in the cat and specific cellular pathology associated with FeLV latency. In addition, we will focus on the action of FeLV-p15E in vitro and describe possible mechanisms of the FeLV-associated immunosuppression observed both in vivo and in vitro. Lastly, we will evaluate the current status of immunoprevention of FeLV. We will not attempt an in-depth analysis of the current literature; our focus is to review current findings as they relate to feline AIDS and immunotherapy.
Acquired Immunodeficiency Syndrome↗
Modifications of cell-mediated immune responses by moderate dietary protein stress in immunologically immature and mature BALB/c mice.
Female BALB/c mice at 5, 6 (immature) and 35 weeks of age (mature) were placed on isocaloric control (20% protein) or experimental (4% protein) diets. Cell-mediated immune responses [theta-bearing cell percentages, phytohemagglutinin (PHA) induced mitogenesis, mixed lymphocyte reaction (MLR) and antibody-dependent lymphocyte-mediated cytotoxicity (ADLMC)] of splenic lymphocytes were measured. A significant decline in percentages of theta-bearing cells, PHA and MLR responses occurred as early as two weeks for the immature mice on the restricted diet and continued for up to 8 weeks. In mature mice, protein restriction did not influence theta-bearing cell percentages, but did suppress PHA and MLR responses between 7 and 13 weeks. A significant suppression of ADLMC responses were also noted at 16 weeks. These results indicate that developing cellular immune systems of immature BALB/c mice are more sensitive to moderate protein restriction (i.e. immunosuppression occurs after a shorter interval) than those of mature mice. They suggest that moderate protein malnutrition retards but does not prevent immunological maturation.
Aging↗
Indirect hemagglutination test for pseudorabies antibody detection in swine.
An indirect hemagglutination test for the detection of antibodies in swine serum specific for pseudorabies virus is described. The indirect hemagglutination test was less time consuming than the standardized virus nertralization test while being highly sensitive and accurate. Serum samples that were toxic to virus neutralization indicator cells were readily tested in the indirect hemagglutination test. The indirect hemagglutination test may also be more sensitive than the virus neutralization test for determining early titers in pseudorabies virus infections. Complete methodology is described.
Animals↗
Detection of pseudorabies virus antibodies: time of appearance by two serotests.
This report describes a time-course comparison of detection of pseudorabies virus antibodies in experimentally infected swine by the virus-neutralization (VN) and indirect hemagglutination tests. Specific antibody titers were observed by the IHA test at 5 days after swine were inoculated, but not until 12 days by the VN test. The predominant immunoglobulin (Ig) class present in the serums of the swine at 5 and 7 days after inoculation was IgM, as determined by sulfhydryl reductions. The VN test lacked sensitivity to early Ig levels (IgM) in these experimentally infected swine, while the indirect hemagglutination test was highly sensitive to these same levels. On the basis of these results, it is possible that the VN test may read early infections as pseudorabies virus negative, due to the low presence of IgG in these samples.
Animals↗
The role of the macrophages in Marek's disease: in vitro and in vivo studies.
Macrophages form S- and K-strain Leghorn chickens, susceptible and restant to Marek's disease (MD) respectively, were studied to determine the macrophage contribution to the dynamics of MD infection, tumorigenesis and genetic resistance to this disease. In vitro studies demonstrated that macrophages from bothstrains were similar in their responses toward JM strain of Marek's disease virus (MDV) and JM-1 tumor cells. Macrophages were observed to phagocytize JM virus, but the interiorized virus was not seen to replicate within the macrophage or induce antigenic changes of the cell membrane. Clearance of JM-1 tumor cells was by both cytolytic and phagocytic mechanism. In vivo selective suppression of macrophage functions by antimacrophage serum or trypan blue inoculations resulted in significantly elevated viral titers and increased tumorigenesis, as compared to infected, non-suppressed or non-infected control groups. Results from this study indicate that genetic susceptibility or resistance to MD, as exhibited by S- and K-strain chickens, respectively, is not controlled at the macrophage level. The role of the macrophage in MD infection appears to be specifically surveillance.
Animals↗
Effects of age on cellular immune responses in BALB/cJ mice: increase in antibody-dependent T lymphocyte mediated cytotoxicity.
Two in vitro cell-mediated immune (CMI) responses of splenic lymphocytes of BALB/cJ mice of various ages (1.25, 2.5, 4, 10.5 and 30 months) were examined. These were the antibody-dependent lymphocyte-mediated cytotoxicity (ADLMC) responses, mediated by the K cell subclass to T lymphocytes, and phytohemagglutinin (PHA) induced mitogenesis, mediated by the theta positive T lymphocytes. ADLMC responses increased with age, culminated at 10.5 months, then slowly declined. Lymphocytes of young mice (2.5 or 4 months of age) were significantly more responsive to PHA than lymphocytes of mature (10.5 months) or aged adults (30 months) (p less than 0.01), indicating progressive suppression of this type of CMI response with age, as observed previously. The difference in time of maturation and extent of suppression of ADLMC and PHA responses was not influenced by changes in numbers of specific effector cells, since percentages of these did not change with age (as measured by immunofluorescence and rosetting techniques). The increase with age of ADLMC responses may be due to deregulation of earlier suppressor activity which allows the K cell to be fully responsive, but other mechanisms may be involved.
Aging↗
In vitro studies on the role of the macrophages of resistant and susceptible chickens with Marek's disease.
Macrophages, from susceptible S- and resistant K-strain White Leghorn chickens, were studied in vitro to determine their contribution to the dynamics of Marek's disease (MD) and possible role in genetic resistance to this disease. In relation to basic macrophage properties (morphology, cell spreading, enzyme levels, pinocytosis, and phagocytosis) there were no significant differences between S- and K-strain macrophages. Both macrophage strains were observed to respond to JM virus by phagocytic responses, but no viral replication or transference of infectivity was observed within inoculated macrophage cultures. In general, there were no differences between S- and K-strain macrophages in vitro that may account for the genetic resistance or susceptibility to MD.
Animals↗
The effects of sonication, freezing and lyophilization on JMV leukosis strain.
JMV lymphoblastic leukemic cells were subjected to sonication, followed by freezing and lyophilization in an attempt to learn the tolerance of JMV cells to these treatments. Sonication experiments indicated that a high percentage of cell breakage (greater than 89%) is necessary for any decrease in lethality to be observed. Freezing experiments involving a wide range of cryoprotectors demonstrated 2M glycerol to be the best for JMV preservation. Subsequent freeze-drying of sonicated, frozen JMV preparations, of high titer, consistently resulted in all loss of lethality.
Animals↗
In vitro and in vivo studies with an avian reovirus derived from a temperature-sensitive mutant clone.
A temperature-sensitive (ts) mutant of avian reovirus isolate Maine 1-203 was obtained at 41 C. The 19th passage of this mutant (ts 19) was utilized for in vitro studies comparing its replication in macrophage cultures with that of its parent strain and an apathogenic S1133 virus. In vivo studies were initiated to determine the ts mutant's pathogenicity for day-old chicks, safety and protective levels for 6-day-old chicks, and interference with Marek's disease, Newcastle, and infectious bronchitis vaccinations. Although the results of in vitro trials indicated no difference among the three reoviruses in the in vitro pathogenicity for macrophage cultures, in vivo studies found the mutant to differ from its parent strain in pathogenicity for day-old chicks. When the ts mutant was administered at 6 days of age, it was a safe and effective vaccine against viral arthritis, with no resulting suppression of other vaccine responses.
Animals↗
Field test studies of the 2512 strain of infectious bursal disease.
Responses to an infectious bursal disease vaccine made from the 2512 strain were studied in broiler flocks under field conditions and management. Pre- and post-vaccination sera were analyzed by agar-gel-precipitin tests and beta virus neutralization. Specific measurements of broiler performance (livability, weight, feed conversion, and condemnations) were also analyzed. When possible, contemporary licensed products were compared at the same time in adjacent houses. Results of these trials indicate that the vaccine made from the 2512 strain of infectious bursal disease was highly immunogenic and safe under field conditions.
Animals↗