The cellular response of lambs to Brucella ovis before and after birth.

The immunological response of lambs to Brucella ovis before and after birth was investigated. The establishment of indwelling cannulas in the efferent prescapular lymphatic ducts of foetal lambs allowed continual monitoring of the immune response of a single lymph node. Foetal lambs in the last trimester of pregnancy were shown to mount a strong cell-mediated immune response to B.

Response of leucocyte populations in the illeal Peyer's patch of fetal lambs treated with ferritin per os.

A combination of immunohistochemical techniques, a panel of monoclonal antibodies, and computer-assisted morphometric analysis was used to examine the response of the ileal Peyer's patch of fetal lambs 7 days after treatment with ferritin per os. Consistent with previous studies in fetal lambs that have reported the ileal Peyer's patch to be indifferent to antigen, the present study did not find any significant changes in the size of the predominantly B-cell dome/follicle compartment or the predominantly T-cell interfollicular area, nor were differences identified in the distribution of IgM-positive (+), CD4+, and CD8+ cells in these two compartments. However, both compartments showed a significant increase (p < 0.

Immunoelectron microscopy of cell populations in regional and central lymph of sheep.

The immunoreactivity and the ultrastructural localization of monoclonal anti-sheep lymphocyte antibodies conjugated with colloidal gold particles were examined in free-floating cells of sheep central lymph from the thoracic duct, postnodal lymph draining either the popliteal nodes or the mesenteric nodes, and prenodal lymph draining the pregnant uterus. The monoclonal antibodies used in this study were SBU-T1 (CD5), SBU-T4 (CD4), SBU-T8 (CD8), SBU-II (anti DR antibody), and E53 which are reported to be sheep homologues of human T1, T4, T8, HLA-DR, and pan B cell antibodies, respectively. Colloidal gold particles were evenly distributed or segmentally aggregated on the surfaces of lymphocytes and macrophages incubated with monoclonal antibodies and in vesicles in the cytoplasm of anti DR antibody labeled macrophages.

Transfer of carbonic anhydrase-positive particles from the follicle-associated epithelium to lymphocytes of Peyer's patches in foetal sheep and lambs.

Carbonic anhydrase cytochemistry of the ileal Peyer's patch in foetal and neonatal lambs has indicated secretion from the follicle-associated epithelium to the follicles. Reaction for carbonic anhydrase in the follicle-associated epithelium was found in the luminal plasma membrane, in cytoplasmic vesicles, and in vacuoles containing 50-nm membrane-bounded particles that seemed to be shed to the intercellular space. The lateral plasma membrane was negative for carbonic anhydrase, indicating that formation of carbonic anhydrase-positive particles was restricted to vacuoles.

The immune response of the sheep popliteal lymph node to a purified phenoloxidase from larval cuticle of the sheep ectoparasite, Lucilia cuprina.

The popliteal lymph node of the sheep can mount a strong immune response to a phenoloxidase, enzyme A, purified from larval cuticle of a major sheep ectoparasite, the sheep blowfly, Lucilia cuprina. Continuous sampling from a cannulated efferent lymphatic allowed monitoring of changes in both cellular output (total cells and large blast cells) and specific antibody production (by ELISA) following primary and secondary challenge with antigen. Anti-enzyme A antibodies in lymph selectively precipitated enzyme A but not a second cuticular phenoloxidase, enzyme B, a finding that will prove useful in immunolocalization of the enzymes and in elucidating their origins.

The role of gut-associated lymphoid tissues in the generation of immunoglobulin-bearing lymphocytes in sheep.

Experiments were designed to examine the relative contributions of Peyer's patches and mesenteric lymph nodes to the population of circulating immunoglobulin-bearing lymphocytes in sheep. The ileum, with more than 90% of the total Peyer's patches, the mesenteric lymph nodes, or both, were removed from lambs at different stages of development and the composition of the cell populations in lymph from different sources and in the blood was examined. Lambs which had had the ileum removed before or within a few days of birth were deficient in small lymphocytes bearing membrane immunoglobulin.

The long-term collection of lymph from single lymph nodes of foetal lambs in utero.

Surgical techniques are described for the long-term collection of lymph from both prescapular efferent lymph ducts of foetal lambs in utero. Lymph ducts in foetal lambs 95 to 136 days post-conception were cannulated with a high rate of success. Lymph flow from the cannulas was not compromised by deliberate primary or secondary challenge of the lymph nodes with a wide variety of antigens, and often continued for long periods after the lambs were born naturally.

The lymph-borne response of foetal lamb lymph nodes to challenge with Brucella abortus in utero.

The cannulated prescapular lymph node of the foetal lamb was challenged with killed Brucella abortus. Usually, both efferent prescapular ducts were cannulated and one node left as a control. Nodes were given primary or secondary challenges with doses of 10(9) - 2 X 10(10) brucella organisms and the lymph-borne response of the nodes followed.

Reassortment of cell populations within the lymphoid apparatus of the sheep.

As lymphocytes recirculate through the blood tissues and lymph they are sorted into populations which have varying morphological and functional characteristics. Lymphocytes are added, deleted and transformed within the lymphoid apparatus as a consequence of non-random migration and antigenic stimulation. There is evidence that the physiological characteristics of peripheral and central lymph nodes vary as a result of differences in the origins of the cells entering the nodes.

The physical and functional heterogeneity of circulating lymphocyte populations.

There is a considerable heterogeneity amongst populations of both fixed and circulating lymphocytes other than that determined by the organs from which these cells originate. The functional differences with which these cells are endowed during their primary differentiation are further modified by the changing environments they encounter during their life and by reassortitive processes occurring during their migration. The range of inductive and modulating stimuli applied to the free-floating and fixed lymphoid cell populations in different parts of the lymphatic apparatus is changing continually and this leads to patterns of cell differentiation which persist for variable periods of time.

DUST AND COLLAGEN CONTENT OF LUNGS OF COAL-WORKERS WITH PROGRESSIVE MASSIVE FIBROSIS.

In order to test the silica theory of the origin of progressive massive fibrosis (P.M.F.