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Biomedical subjects

S Jalkanen

Publications and source records attributed to S Jalkanen.

136 records · Page 8Linked to original sources
PubMed1983

Immune capacity of the chicken bursectomized at 60 hours of incubation: transplantation of bone marrow cells of the bursectomized chickens into cyclophosphamide-treated newly hatched recipients.

Chickens bursectomized at 60 h of incubation are known to be able to produce immunoglobulins (Ig) but not specific antibodies. In the present work bone marrow (BM) cells of 2- and 10-week-old embryonically bursectomized (Bx) chickens were transferred to newly hatched cyclophosphamide-treated chickens for the purpose of studying whether the transplanted cells home into the bursa and gain a capacity to produce specific antibodies. BM cells of normal 2- and 10-week-old chickens were transferred as controls. Cells of 2-week-old control (Co) and of 2- and 10-week-old Bx chickens could to some extent reconstitute serum Ig of the recipients, but were totally incapable of homing into the bursa and of restoring the specific antibody production. Only BM cells of 10-week-old Co chickens could restore the production of specific antibodies without homing into the bursa, indicating their postbursal nature. These findings indicate (a) that 2- and 10-week Bx BM cells have irreversibly bypassed the bursal phase of education, (b) that also the normal BM at the age of 2 weeks contains cells that are capable of Ig but not of specific antibody synthesis and (c) that bursal microenvironment is not necessary for isotype switch, but is essential for creation and expansion of the antibody repertoire.

Aging↗
PubMed1983

Immune capacity of the chicken bursectomized at 60 hours of incubation: failure to produce immune, natural, and autoantibodies in spite of immunoglobulin production.

Chickens surgically bursectomized at 60 hr of incubation were immunized at the ages of 6, 7, 8, and 9 weeks with Escherichia coli lipopolysaccharide, levan, tetanus toxoid, and dinitrophenyl-bovine serum albumin. All antigens were given on each occasion. All embryonically bursectomized (BX) chickens had detectable concentrations of serum IgM, IgG, and IgA. On the whole, the IgG level was markedly decreased and the levels of IgM and IgA were normal. Concentrations of serum immunoglobulins did not change during immunization in the BX chickens. In spite of the production of serum immunoglobulins the BX chickens were unable to respond to the immunization by production of specific antibodies, whereas the control (CO) chickens produced good antibody response to each antigen used. The BX chickens also lacked both natural antibodies to phosphorylcholine, fecal bacteria, rabbit red blood cells (RRBC), and MHC antigens and autoantibodies to the liver, kidney, and thyroidea. Neither were any antibodies to the bursal structures observed. These results support the hypothesis that the bursal influence is not necessary for isotype switch, but is essential for the production of specific antibodies.

Animals↗
PubMed1983

Immune capacity of the chicken bursectomized at 60 hr of incubation: surface immunoglobulin and B-L (La-like) antigen-bearing cells.

Chickens were surgically bursectomized at 60 hr of incubation before the bursal anlage appears. Completeness of the bursectomy was confirmed at autopsy at 10 wk of age. These embryonically bursectomized (Bx) chickens are known to produce immunoglobulins of IgM, IgG, and IgA classes, but so far no specific antibodies have been observed even after heavy immunization. Regarding the appearance of surface immunoglobulin positive (s-Ig+) cells, the most striking effect of bursectomy was observed in the frequency of s-IgG+ cells, which were markedly decreased in the spleen, peripheral blood, and thymus of the Bx birds when compared with the age-matched controls. s-IgM+ cells were significantly decreased in the peripheral blood and s-IgA+ cells in the spleen of the Bx birds. In contrast to these findings, s-Ig+ cells of all three classes were present in normal frequency in the bone marrow. Bursectomy had no effect on the total lymphocyte and other white cell counts in the peripheral blood. Likewise, no effect on the frequency of B-L (Ia-like) antigen-positive cells in different organs was observed.

Animals↗
PubMed1983

Immune capacity of the chicken bursectomized at 60 hours of incubation: mitogen-induced cell proliferation and immunoglobulin secretion.

Chickens were bursectomized surgically at 60 hr of incubation. Bone marrow cells from the bursectomized (Bx) and control (Co) chickens responded equally well by proliferation to B cell mitogens (dextran sulfate, anti-mu, anti-gamma) when studied at the age of 10 weeks. In contrast, spleen cells of Bx chickens responded significantly less to anti-mu and anti-gamma than did spleen cells of the Co chickens. When observed at the age of 10 days, a significantly depressed secretion of IgM, IgG, and IgA by the Bx cells was observed in vitro. This difference between the Bx and Co chickens had disappeared when studied at the age of 10 weeks.

Aging↗
PubMed1983

Immunological detection of proteins after isoelectric focusing in thin layer agarose gel: a specific application for the characterization of immunoglobulin diversity.

A simple and relatively rapid method was developed for the characterization of immunoglobulins from serum samples. After isoelectric focusing in a thin layer agarose gel proteins were transferred on to a nitrocellulose sheet by pressuring the focused gel against the sheet. A certain immunoglobulin class was stained on the sheet using alkaline phosphatase conjugated anti-immunoglobulins and the specific colour staining of the enzyme. The method allows the use of serum dilutions up to one thousand and conjugate dilutions up to two thousands. It was possible to strengthen the weak staining of antigens using a longer staining period and changing the substrate-dye solution without any background colorizing of the sheet. A specific application for the characterization of serum immunoglobulins of IgG class of a myeloma patient is presented.

Alkaline Phosphatase↗
PubMedDate not supplied

A mouse molecular mimic of human vascular adhesion protein-1.

Human vascular adhesion protein-1 (VAP-1) is an endothelial sialoglycoprotein which exists in forms of Mr 90000 and 170000 and mediates lymphocyte binding to vessels under shear. VAP-1 is functionally defined by an inhibitory mouse mAb 1B2. A large-scale immunoaffinity purification of VAP-1 from human tonsil lysates was performed to determine the protein sequence for VAP-1 cDNA cloning. A dominant protein of molecular weight 90000 was obtained which yielded an N-terminal sequence of 20 amino acids which bore no significant identity to any protein sequence in the data banks. A mouse mAb (5B11) against a synthetic peptide from this sequence was raised and found to stain tissues in an identical manner to mAb 1B2, to inhibit lymphocyte adhesion to endothelial cells and to recognize VAP-1. Later, the N-terminal sequence obtained from the 1B2 immunoprecipitations was found to be identical to a mouse cyclophilin C associated protein (mCyCAP) subsequently published by others. We show here by several criteria at the protein and DNA level that VAP-1 is distinct from mCyCAP. Moreover, we elucidate the mechanism which results in binding of mCyCAP to mAb 1B2 during antibody synthesis in hybridoma cells and the sequelae of co-precipitation of mCyCAP during the immunoaffinity chromatography. Binding of mCyCAP to a mouse mAb has not been described before and suggests a new function for this molecule in immunoglobulin synthesis and/or secretion. Moreover, these data indicate that the N-terminal peptide of mCyCAP is a molecular mimic of a functionally important epitope of VAP-1.

Amine Oxidase (Copper-Containing)↗
PubMedDate not supplied

Defect in the generation of light-chain diversity in bursectomized chickens.

The avian bursa of Fabricius has been regarded as a central organ for B-cell development, but there is controversy about the existence of other sites for differentiation of B cells. We have recently shown that chickens surgically bursectomized as early embryos, before the bursal primordium appears, can produce cytoplasmic, surface and serum immunoglobulins of IgM, IgG and IgA classes but are unable to generate specific antibodies in response to antigen. We have therefore examined the structure and diversity of immunoglobulins of bursectomized chickens. Analysis of serum IgG revealed normal gamma-heavy chains but altered light chains with more basic and less diverse isoelectric points than normal. These light chains may represent germ-line specificities not diversified by somatic mutations. Thus the bursa of Fabricius appears not to be necessary for the production of immunoglobulin molecules as such but to function in the creation and expansion of the antibody repertoire, possibly by providing a microenvironment for somatic mutations.

Animals↗
PubMedDate not supplied

Pre-eclampsia does not change the adhesion molecule status in the placental bed.

During normal placentation trophoblast cells invade maternal tissues and remodel the uterine arteries into low-resistance channels. In pre-eclampsia, trophoblast invasion is impaired and this, along with endothelial dysfunction, has been suggested to play a role in the pathogenesis of pre-eclampsia. We studied the expression of adhesion molecules important for leukocyte extravasation in the placental bed with immunohistochemistry and compared the expression in pre-eclampsia to that in normal pregnancy. Our major finding was that only invasive trophoblasts expressed cutaneous lymphocyte antigen-1 (CLA-1) in the third trimester of pregnancy, whereas villous trophoblasts did not. In the first trimester both villous trophoblasts and invasive trophoblast cells in decidua remained negative for CLA-1. Pre-eclampsia did not change the expression of leukocyte-endothelium adhesion or lymphocyte homing-associated antigens, ICAM-1, ICAM-2, VCAM, P-selectin, E-selectin, L-selectin, CLA-1, CD73, VAP-1 and alphaEbeta7 in the placental bed. Furthermore, pre-eclampsia was not associated with an aberrant accumulation of lymphocytes carrying antigens of any particular known organ-specific homing systems. The results on the unchanged pattern of adhesion molecule expression in pre-eclampsia suggests that there is no major change in the adhesive properties of the endothelium of the placental bed in pre-eclampsia.

Antigens, Differentiation, T-Lymphocyte↗