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PubMed1977

Tumor growth and antibodies after RSV-challenge in normal chickens and in chickens congenitally infected with avian leukosis virus.

Normal chickens and chickens congenitally infected with an avian leukosis virus (ALV) of antigenic subgroup A were challenged with strains of Rous sarcoma virus (RSV) of two different antigenic subgroups (B and C) and tumor induction and growth as well as humoral antibody to viral envelope antigen (VEA) and tumor-specific surface antigen (TSSA) were measured. There was no effect of congenital ALV infection on RSV tumor incidence or latent period but the growth rate and size of the tumors were much higher in congenitally infected birds as compared to controls. Whereas most tumors in the RSV-challenged normal birds regressed, tumors in ALV-infected birds grew progressively. There were no striking differences in the number of birds in either group in the incidence of anti-TSSA or anti-VEA antibodies nor did the presence of either type of antibody reflect the tumor status of the host.

Animals↗

PubMed1978

T cell tolerance in the chicken. I. Parameters affecting tolerance induction to human gamma-globulin in agammaglobulinemic and normal chickens.

T cell-mediated delayed hypersensitivity (DH) to human gamma-globulin (HGG) can be induced in chickens by subcutaneous injection of the antigen in complete Freund's adjuvant (CFA). In the present work, it has been demonstrated that specific tolerance of the cells mediating this DH can readily be induced in both normal and bursectomized (BX) FP strain chickens by simple i.v. injection of soluble antigen, regardless of the presence of antibody production to the tolerogen. A significant degree of tolerance at the DH and helper T cell levels could be generated in BX birds by injection of as little as 0.5 mg of HGG; such a dose only induced tolerance in normal birds when it had been previously deagregated by ultracentrifugation. Regular, nondeaggregated antigen could produce tolerance in normal animals, but only at doses of greater than 5 mg. The tolerizing injection induced a primary antibody response in normal birds in all cases, but a secondary response could not be obtained in animals rendered tolerant at the T cell level. Establishment of tolerance appeared to be very rapid, and animals remained refractory to induction of DH for at least 3 weeks after the tolerizing injection. The mode in which the antigen was presented to the animals appeared to be crucial in determining whether tolerance or sensitivity would be established.

Agammaglobulinemia↗

PubMed1978

Identification of different antigenic determinants within the synthetic multichain Co-polymer poly(LTyr,LGlu)-poly(DLAla) -- poly (LLys), (T,G)-A--L, as recognized by the chicken. II. Fine-specificities of the anti-(T,G) part of chicken anti-(T,G)-A--L antisera.

Sera from three chickens obtained from a genetic high-responder inbred strain immunized with the multichain polypeptide poly(LTyr,LGlu)-poly-(DLAla)--poly(LLys) (T,G)-A--L) were analysed for possible restrictions in the fine-specificities of anti-(LTyr,LGlu) antibodies. A panel of synthetic hexa- and heptapeptides composed of L-Tyr and L-Glu residues linked to a C-terminal spacer tripeptide, and with L-Tyr as N-terminal, were used as inhibitors in a double-antibody radioimmunoassay. Results showed that all peptides tested possessed some inhibitional potential, although the percentage of displacement for the different sequences varied between 43% and 58%,20% and 56%, and 48% and 85%, respectively, for the three sera tested at a given inhibitor concentration. Different peptide sequences appeared as the most efficient inhibitor in the three sera tested. No simple relationship was found between substitution/elongation of inhibitor peptides and their inhibitional potential, as would have been expected from a simple conception of (T,G)-A--L possessing only one sequential determinant. Possible evidence for conformational determinants in the (T,G)-A--L antigen is discussed.

Amino Acid Sequence↗

PubMed1979

Local antibody response in chickens: analysis of antibody synthesis to Newcastle disease virus by solid-phase radioimmunoassay and immunofluorescence with class-specific antibody for chicken immunoglobulins.

The antibody response to Newcastle disease virus was monitored in the sera and salivas of adult chickens immunized by two methods: (i) combined intratracheal-intranasal vaccination followed by intratracheal revaccination or (ii) intramuscular vaccination followed by intratracheal revaccination. By solid-phase radioimmunoassay, only immunoglobulin G (IgG) and IgA antibodies to Newcastle disease virus were detected in the salivas, whereas IgA and IgM antibodies were present in egg whites. The first method produced the highest antibody levels in both serum and saliva and, in addition, prevented detectable virus multiplication in the respiratory tracts upon revaccination 4 weeks later. Plasma cells of all three classes were distributed throughout the tissues lining the oral cavities. The highest densities of plasma cells were in the Harderian glands; IgG was the predominant class, whereas IgA and IgM plasma cells were present in almost equal but lower numbers. The Harderian plasma cells were the most likely source of the antibody found in saliva.

Animals↗

PubMed1979

Effect of chicken hypothalamus on prolactin and growth hormone secretion in male chickens.

The effects of a chicken hypothalamic extract (HE) on the secretion of prolactin and growth hormone (GH) in vivo have been investigated by radioimmunoassay in the domestic fowl. Different i.v. doses of HE (0.25--25 HE equivalents/kg body weight) had no effect on GH secretion in conscious or anaesthetized cockerels. In both groups of birds the concentration of plasma prolactin was significantly increased within 10 min of administration of the extract. Extracts of other brain tissues (cerebral cortex, cerebellum and medulla oblongata) had no stimulatory effect on prolactin or GH secretion. Release of both prolactin and GH by dispersed pituitary cells and by hemipituitary glands in vitro was enhanced following incubation with HE (5 hypothalami equivalents/ml) or with single whole hypothalami respectively. Other brain tissues (cerebellum, optic lobes and medulla oblongata) had no effect on the concentration of prolactin or GH released by incubated hemipituitary glands.

Animals↗

PubMed1978

Development of parathyroid hormone- and calcitonin-activated adenylate cyclases in embryonic chicken limb and in cultured cells from embryonic chicken limb.

Activation of adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] by parathyroid hormone (PTH) and calcitonin was measured as a function of stage of development in embryonic chicken limb buds. Responsiveness to both hormones develops in the tissue at the time when nascent bone is forming. In addition, a temporal sequence of development of hormone response was observed, with a PTH-activated adenylate cyclase appearing earlier than the calcitonin-activated enzyme. The responsiveness to the two hormones was additive, indicating the presence of two receptor populations. Undifferentiated cells obtained from limb buds prior to appearance of hormonal responsiveness were cultured and were found to develop a PTH-activated adenylate cyclase in vitro. However, a calcitonin-stimulated enzyme did not appear in such cultures. The PTH-activated enzyme was found to be similar to that present in bone in regard to its sensitivity to PTH. The enzyme did not respond to other hormones, and myoblast cultures did not develop a PTH-activated adenylate cyclase, indicating that a true bone adenylate cyclase was being measured.

Adenylyl Cyclases↗

PubMed1975

Presence of chicken cell surface antigen on Rous virus activated in heterokaryons of transformed non-permissive hamster cells and chicken cells.

Incubation with antiserum to chick embryo (CE) cells, in the presence of complement, inactivates Rous sarcoma virus (RSV) produced by heterokaryons formed by non-permissive RSV-transformed hamster cells and CE cells as well as RSV produced by heterokaryons is observed following incubation with antiserum to the transformed hamster cells, plus complement. Hence, the envelope of RSV activated in heterokaryons, as that of RSV produced by CE cells, must contain a surface antigen of the CE cell, and the virus must mature only, or preferentially, at chicken-specific sites of the heterokaryon surface.

Animals↗

PubMed1979