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Biomedical subjects

K Isaković

Publications and source records attributed to K Isaković.

At least 37 records · Page 2Linked to original sources
PubMed1978

Ontogeny of this immuno-neuro-endocrine relationship. Changes in lymphoid tissue of chick embryos surgically decapitated at 33-38 hours of incubation.

The prosencephalon, and primordium of the hypophysis were surgically removed from chick embryos at 33-38 hours of incubation. The thymus, bursa of Fabricius, spleen, bone marrown and liver were examined cytomorphologically on day 15, 17 and 19. T marker-bearing and Bu marker-bearing lymphocytes were identified by immunofluorescence. Decapitated embryos tended to be smaller than sham-decapitated controls of the same age, and exhibited retarded development of the thymus, bursa, spleen and liver. Decapitation particularly affected the cellular composition of the bursa and spleen, induced a decrease in the number of lymphocytes, and caused a striking depletion of lymphocytes bearing Bu antigen. This experiment showed an interdependence between lymphoid (immune), nervous and endocrine centers in the chick embryo.

Animals↗
PubMed1977

Immunological capacity of the chicken embryo. II. Humoral immune responses in embryos and young chickens bursectomized and sham-bursectomized at 52--64 h of incubation.

White Rock embryos surgically "bursectomized" at 52--64 h of incubation, and shambursectomized embryos were injected with 10(6) guinea-pig red blood cells on day 12 of incubation, and tested for plaque-forming cells and serum haemagglutinins 3, 5, 7, 10, 15 and 19 days after immunization, i.e. as 15- to 19-day-old embryos and 1- to 10-day-old chickens. The number of natural plaque-forming cells detected by direct or indirect techniques was small in nonimmunized shambursectomized and bursectomized embryos, but increased in very young chickens. The injection of guinea-pig red blood cells induced a significant increase in the number of direct and indirect plaque-forming cells in the spleen of bursectomized and sham-bursectomized embryos and chickens. Agglutination of papain-treated guinea-pig red blood cells and indirect anti-chicken globulin (Coombs) test revealed the presence of natural agglutinins for guinea-pig and for sheep erythrocytes in non-immunized sham-and bursectomized embryos. A small number of sera from nonimmunized bursectomized and sham-bursectomized embryos contained IgM. The immunization with guinea-pig red blood cells increased the antibody production in both bursectomized and sham-bursectomized embryos and chickens. Sham-bursectomized embryos responded better to antigenic stimulation than bursectomized embryos. The injection of guinea-pig red blood produced an enlargement of the spleen only in bursectomized embryos and chickens. The first plasma cells appeared in nonimmunized sham-and bursectomized 6-day-old chickens. The number of plasma cells increased in chickens immunized as embryos. Cytomorphological analysis of the thymus, bone marrow and liver did not reveal apparent differences between bursectomized, sham-bursectomized embryos and very young chickens. It has been postulated that the chicken embryo has an antibody-producing system composed of the bursal and the nonbursal (or accessory "bursal") microenvironment, the latter being bursa-independent. The final microenvironmental network for the formation of Bu lymphocytes is the result of coordinated activities of a variety of intrinsic cellular and humoral factors.

Animals↗
PubMed1976

Nonbursal origin of humoral immunity: immune capacity and cytomorphological changes in chickens bursectomized as 52- to 64-hours-old embryos.

Chickens sham-bursectomized as 52- to 64-hours-old embryos (SBx), chickens bursectomized at hatching (NeoBx) and chickens from which the bursal primordium was removed at 52-64 h of embryonation (EBx) were immunized with guinea pig red blood cells when 21 days old. Following the second injection of antigen, EBx chickens were found to elaborate ME-sensitive and ME-resistant hemagglutinins, to produce direct and indirect plaque-forming cells, and to contain lymphocytes bearing a specific bursa (Bu) antigen. These immune properties were more often expressed in sham-bursectomized and neonatally bursectomized chickens. Cytomorphological changes in the spleen, bone marrow and cecal tonsil of EBx chickens were typical for birds lacking the bursa. The number of lymphocytes and plasma cells in the bone marrow and liver of SBx, NeoBx and EBx chickens was very low. These results suggest that a very early embryonic bursectomy of chickens does not abolish humoral immunity completely and does not prevent the differentiation of Bu antigen-bearing lymphocytes.

Animals↗
PubMed1975

Bursa lymphocytes and IgM-containing cells in chicken embryos bursectomized at 52-64 hours of incubation.

A technique of surgical removal of the bursal primordium ("bursectomy") of chicken embryos at stage 17, approximately 52-64 hours and 29-32 somites, is described. The survival rate of bursectomized (Bx) embryos approached a level of 50% on the 21st day. About 20% of correctly Bx embryos exhibited malformations of the anal sphincter and the large intestine. Using a rabbit anti-bursacyte serum, which did not react with thymocytes, the specific bursa-derived cell (Bu) marker was detected on the surface of bursa, spleen, bone marrow and thymus lymphocytes. Early embryonic bursectomy caused a moderate depletion of Bu marker-bearing and IgM-containing cells. It has been postulated that embryonic Bu cells can be recruited from sites other than the bursa and in the absence of the bursa.

Animals↗
PubMed1975

Preparation of specific anti-thymocyte and anti-bursacyte sera in rabbits.

A method of producing anti-thymocyte and anti-bursacyte sera in rabbits is described. Chickens which served as donors of cells were thoroughly perfused with saline to remove plasma proteins and circulating blood elements. For immunization, thymocytes were obtained from neonatally bursectomized birds, and bursacytes from chickens thymectomized at hatching. The purification of rabbit anti-lymphocyte sera included absorptions with leucocyte-free suspension of chicken erythrocytes, chicken liver cell membranes, thymocytes from bursectomized-irradiated and bursacytes from thymectomized-irradiated chickens, and chicken IgM and IgG immunoadsorbents. Cytotoxicity and fluorescent-antibody assays revealed that anti-thymocyte and anti-bursacyte sera thus produced clearly distinguished the surface antigenic determinants of thymocytes from those of bursacytes.

Absorption↗
PubMed1975

Immunological capacity of the chicken embryo. I. Relationship between the maturation of lymphoid tissues and the occurrence of cell-mediated immunity in the developing chicken embryo.

In an investigation of the ontogeny of lymphoid tissue in chick embryos to relate maturation of lymphocytes with immunological competence, the numbers and sizes of lymphocytes were determined in the thymus, bursa of Fabricius, spleen, femoral marrow and peripheral blood of embryos from the 12th to 21st day of incubation, and in 6-day-old chicks. Results showed the thymus to be the first fully developed and most active lymphocytopoietic organ, followed by the bursa. The bone marrow was not lymphocytopoietic; the spleen and bone marrow were mainly granulocytopoietic and erythropoietic; some morphological differences between thymic and bursal lymphocytes were shown by light microscopy. It appears that in embryos and young chicks the lymphocytes are derived from the thymus and bursa, but not the bone marrow. In tests of immunological competency, cells of the thymus, bursa, spleen, bone marrow and peripheral blood from 12--21-day-old embryos and 6-day-old chicks were transferred to chorioallantoic membranes of 12-day-old recipient embryos. There were distinct differences between the ability of various lymphoid tissues to induce formation of chorioallantoic pocks or splenic enlargement. The thymus, spleen and peripheral blood elicited both lymphocytic pocks and splenomegaly, the bursa elicited splenomegaly only, and the bone marrow was ineffective. The bone marrow, however, induced formation of nonlymphocytic pocks. It is concluded that the immunological activity of the chicken embryo is primarily effected by the thymus and bursa and that cell-mediated immunity appears in the 2nd week of incubation.

Age Factors↗