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Biomedical subjects

B W Calnek

Publications and source records attributed to B W Calnek.

At least 55 records · Page 3Linked to original sources
PubMed1978

Demonstration of Marek's disease tumor-associated surface antigen in chickens infected with nononcogenic Marek's disease virus and herpesvirus of turkeys.

The presence of Marek's disease tumor-associated surface antigen (MATSA) was demonstrated on spleen cells from P-line chickens inoculated 5--6 days earlier with herpesvirus of turkeys and SB-1 (a nononcogenic Marek's disease virus). Antisera against MATSA expressed on five Marek's disease lymphoblastoid cell lines were able to recognize the MATSA present on SB-1-infected spleen cells. No viral membrane antigens and only a low incidence of viral internal antigens could be demonstrated.

Animals↗
PubMed1978

Pathogenesis of Marek's disease: early appearance of Marek's disease tumor-associated surface antigen in infected chickens.

Marek's disease tumor-associated surface antigen (MATSA) appeared in different lymphoid tissues of P-line chickens soon after they were infected with BC-1 strain of Marek's disease virus. MATSA-bearing cells first appeared in spleens by 5 days post infection (PI) and were observed through a 21-day experimental period at mean levels varying from 3.8 to 21.9% of the total cells examined. Lower percentages of MATSA-bearing cells were observed in the thymus, in the bursa of Fabricius, among peripheral blood lymphocytes, and among bone marrow cells beginning 7 days PI. The antigen was not detected on normal lymphocytes from chickens or chicken embryos, nor was it detected on cultured chicken embryo fibroblasts infected or transformed by avian RNA tumor viruses.

Animals↗
PubMed1977

Comparative effects of host and viral factors on early pathogenesis of Marek's disease.

A series of experiments on the early pathogenesis of Marek's disease was conducted according to a uniform scheme. In each experiment, there was a single variable-age, genetic strain, or virus strain. Virus assays from spleen, buffy coat, and bone marrow, and fluorescent antibody tests on spleen, bursa of Fabricius, and thymus were conducted on five birds per group daily from the 3rd through the 10th day postinoculation. From these data, it was apparent that the response could be divided into two periods: 4 to 6 days = early; 8 to 10 days = late. Serological tests showed all groups except the 1-day-old group to have neutralizing antibody by the end of the 10-day period. With few exceptions, none of the variables tested exerted any appreciable influence on the level of virus growth in spleen, bursa, or thymus during the early period. High levels of infection occurred in all birds during that period. Changes in infection pattern which occurred during the late period were significant and could be correlated with occurrence of Marek's disease in test samples of birds held until 7 weeks after infection. Infectivity levels dropped appreciably in the case of resistant N-line birds given JM virus, and, during the late period, infection levels were significantly higher in GA-infected birds than in those given viruses of lower virulence. Whereas the virus titers during the 8- to 10-day period usually reflected the eventual clinical pattern of Marek's disease, the levels of viral antigen (fluorescent antibody tests) were much less consistent. One further experiment conducted by the same uniform scheme demonstrated no significant effects on early pathogenesis or course of Marek's disease in birds given continuous oral medication with amino-ureido-sulfone.

Aging↗
PubMed1977

Broad antigenicity exhibited by some isolates of avian adenovirus.

Ten of 16 isolates of avian adenovirus could be readily classified as members of serotypes 2, 5, or 7. However, 6 exhibited broad neutralization reactions which created typing problems. Detailed studies of these interactions revealed that our prototype for serotype 5 (i.e., T-8; subsequently found to be an "intermediate" strain) contributed to this broad cross-reactivity because it shared antigens with members of serotypes 5 and 7. As a result of this study, TR-59 or 58-1 is recommended as the suitable prototype for the serotype 5 viruses. The 6 broadly reactive isolates were classified as serologic "variants" of serotypes 5 and 7.

Adenoviridae↗
PubMed1976

Some effects of silical treatment on Marek's disease.

Treatment of newly hatched chicks with silica by the intraperitoneal route delayed the onset of mortalities due to the JM strain of Marek's disease (MD' virus inoculated at 6 days of age. During the 88-day observation period fewer silica-treated chicks died of MD, but this difference was not usually statistically significant. Silica treatment had no effect on the susceptibility of 4-week-old birds. Silica treatment reduced the antibody response to MD but, in general, not significantly. The antibody response to bovine serum albumin was significantly enhanced if measured by the indirect hemagglutination test but not if measured by the agar gel diffusion test, whereas the response to Brucella abortus was enhanced significantly in N-line (MD-resistant) chicks but not significantly in P-line (MD-susceptible) chicks. Five days after infection, silica-treated chicks had significantly less fluorescing antigen in thymus and bursa than did untreated chicks; no difference was observed in the spleen. After silica treatment the glass-adherent cell population in the buffy coat was increased by up to 10-fold compared with untreated chicks. It is suggested that silica treatment induced macrophage proliferation, with subsequent restriction of MD virus spread, yet allowed an adjuvant-type effect with other antigens.

Animals↗
PubMed1975

Fowl immunoglobulins: quantitation and antibody activity during Marek's disease in genetically resistant and susceptible birds.

Five-week-old birds of resistant (N) and susceptible (P) genetic lines were inoculated with the JM strain of Marek's disease (MD) virus. MD occurred only in P-line birds; one-third had died by the end of the experiment (63 days after inoculation). Sera were examined for antibodies (precipitating, virus neutralizing,and fluorescing), and immunoglobulins were measured. Antibodies were associated with immunoglobulin classes by density gradient centrifugation and utilization of specific antisera to gowl immunoglobulins in indirect immunofluorescence. Precipitating antibodies were found in both lines; they first appeared 7 days after inoculation in P-line birds and 14 days after inoculation in N-line birds, but thereafter there was no difference between the two genetic lines. A peak of neutralizing antibody occurred in both lines between 6 and 12 days. Thereafter neutralizing antibodies increased gradually throughout the experiment. Neutralizing antibody levels were at this stage often higher in N-line than in P-line birds. The fluorescent antibody test showed transient immunoglobulin (Ig) M antibody from 7 to 9 days in N-line birds and 5 to 12 days in P-line birds; this corresponded with the initial peak of neutralizing antibody. Antibodies were seen from 7 to 8 days after inoculation and increased gradually durin gthe experiment, generally paralleling the secondary increase in neutralizing antibodies. Ultracentrifugation confirmed the presence of IgM and IgG antibodies as described. Antibodies of the IgA class were not found. The alterations in serum immunoglobulin levels occurred in three phrases: (i) 1 to 9 days postinfection, there was an increase in IgM and IgA compared with uninfected control birds; (ii) 10 to 20 days postinfection, Ig M and IgA levels were lower than in control birds; and (iii) 21 days postinfection, until the end of experiment, IgA returned to normal levels, IgG increased to about eight times higher than in control birds, and IgM in P-line birds returned to normal levels and in N-line birds reached and maintained levels about double those of control birds. Another experiment was designed to examine the separate effects of moving and inoculation of uninfected kidney cells and virus-infected kidney cells. The changes in immunoglobulins observed in the first experiment occurred only after infection with MD virus and were not related to movement or handling stress. It was concluded that no significant primary difference exists in the humoral immune system between fowls resistant and susceptible to MD; all differences could be related to the immunosuppressive effects of MD, which are greater in susceptible birds apparently due to the greater lymphoid tissue damage in these strains.

Animals↗
PubMed1975

Fowl Immunoglobulins: Quantitation in Birds Genetically Resistant and Susceptible to Marek's Disease.

The development of serum immunoglobulins was observed in chicks genetically resistant (N line) and susceptible (P line) to Marek's disease (MD), in conditions free from infection with MD. IgG was present at hatching at about 5.0 mg/ml and decreased to about 0.5 mg/ml by 12 to 15 days. Active production of IgG was apparent at about 20 days of age and reached levels of 2.0 to 3.0 mg/ml by 67 days. Low levels of IgM were present at hatching, and a gradual increase was seen to 1.0 to 2.0 mg/ml by 67 days. IgA was not detectable at hatching; it appeared in N-line birds at 5 days and in P-line birds at 13 days, and by 67 days was about 0.10 to 0.13 mg/ml. After 30 to 40 days, immunoglobulin levels were generally higher in N-line than in P-line birds. However, it was concluded that no primary immunoglobin deficiency existed sufficient to explain the susceptibility of the P-line birds to MD.

Journal Article↗
PubMed1972

Effects of passive antibody on early pathogenesis of Marek's disease.

The effects of passive Marek's disease virus (MDV) antibody were characterized in three experiments in which 1- or 2-day-old PDRC chickens were inoculated with cell-associated MDV. Antibody acquired naturally from the dam, or injected prior to, or at the time of, virus inoculation, failed to prevent infection, but the incidence and severity of the acute necrotizing disease were reduced. Also, the number of tissues with viral antigen (fluorescent antibody test) and the amount of antigen in positive tissues was lowered, and fewer infected cells in spleen (in vitro assay) were detected in antibody-positive chicks. Serum containing MDV antibody was efficacious when injected prior to infection and had some protective effect when first given at day 4 but not at day 7 after virus inoculation. Normal antibody-free serum was ineffective, and chickens with naturally acquired (maternal) antibody against turkey herpesvirus (a virus antigenically related to MDV) were not protected against MDV infection.

Age Factors↗
PubMed1970

Lyophilization of cell-free Marek's disease herpesvirus and a herpesvirus from turkeys.

Cell extracts of the JM and GA strains of Marek's disease herpesvirus and the FC 126 strain of turkey herpesvirus were lyophilized with various stabilizers. Much higher virus titers were obtained with stabilizer than without stabilizer. Titers increased even further in the case of the Marek's disease virus strains by the addition of a chelating agent, disodium ethylenediaminetetraacetate.

Albumins↗