Effects of placental tissue on immunological responses

Using in vivo assays for alloreactivity, the responsiveness of maternal lymph node cells was shown to be increased when cells were harvested from both syngeneically and allogeneically pregnant mice. In addition, foetal liver and thymus cells induced a state of delayed type hypersensitivity to alloantigens whereas trophoblastic tissue, in the form of 12 to 15 day metrial glands, did not.

The influence of mouse placenta on in vitro immune responses was tested using 7-day ectoplacental cones as sources of trophoblastic tissue. Ectoplacental cones increased a T cell dependent but not a T cell independent antibody response, whereas T cell dependent cytotoxicity was reduced. The findings reported in this paper suggest that murine ectoplacental cones are a particularly useful tissue with which to study both specific and non-specific immunological activities of the trophoblast in syngeneic and allogeneic pregnancies.

     

Free immunoglobulin light chain synthesis by lymphocytes from patients with hypogammaglobulinaemia.

Lymphocytes from six individuals with reduced or deficient serum immunoglobulins of one or more class were assessed for immunoglobulin production in vitro. There was no clinical evidence of a secondary cause for hypogammaglobulinaemia and three of the cases were receiving immunoglobulin therapy. The predominant immunoglobulin product in the culture supernatants form four cases was free light chain. In contrast, peripheral lymphocytes from two cases with partial IgA deficiency and from normal individuals exhibited a balanced synthesis of heavy and light chains. These findings are discussed with particular reference to free light chain synthesis by immature neoplastic B lymphocytes and to normal B lymphocyte differentiation.     

Polyoma virus high molecular weight nuclear RNA codes for capsid protein VP2 in vitro.

RNA extracted from the nuclei of 3T6 mouse cells late after infection by pot yoma virus (Py) has been translated in vitro to give one predominant polypeptide, which was identified as virion protein VP2 by polyacrylamide gel electrophoresis, specific immunoprecipitation, and tryptic peptide analysis. The active nuclear RNA species sediment between 15 and 50 S on sucrose gradients after denaturation, and resediment true after further denaturation and recentrifugation on 50% formamide-sucrose gradients. The bulk of the active viral nuclear RNA does not bind to oligo(dT)-cellulose and synthesis of Py VP2 is inhibited by m⁷Gp under conditions where translation of Py-cRNA and EMC RNA are not inhibited. These experiments suggest that large viral nuclear RNA molecules, which are probably capped but not polyadenylated, can serve as messengers for Py VP2.     

Role for copper in transient oxidation and nuclear translocation of MTF-1, but not of NF-kappa B, by the heme-hemopexin transport system

Heme-hemopexin (2-10 microM) is used as a model for intravenous heme released in trauma, stroke, and ischemia-reperfusion. A transient increase in cellular protein oxidation occurs during receptor-mediated heme transport from hemopexin which is inhibited by the nonpermeable Cu(I) chelator, bathocuproinedisulfonate. Thus, participation of surface redox process involving Cu(I) generation are proposed to be linked to the induction of the protective proteins heme oxygenase-1 (HO-1) and metallothionein-1 (MT-1) by heme-hemopexin. The region (-153 to -42) in the proximal promoter of the mouse MT-1 gene responds to heme- and CoPP-hemopexin in transient transfection assays and contains metal-responsive elements for MTF-1 and an antioxidant-responsive element (ARE) overlapping a GC-rich E-box to which USF-1 and -2 bind. No decreases in DNA binding of the diamide-oxidation sensitive USF-1 and -2 occur upon exposure of cells to heme-hemopexin. MTF-1 and the ARE-binding proteins are relatively resistant to diamide oxidation and are induced approximately eight- and two-fold, respectively, by heme-hemopexin. BCDS prevents the nuclear translocation of MTF-1 by both heme- and CoPP-hemopexin complexes as well as MT-1 mRNA induction by CoPP-hemopexin. Thus, copper is needed for the surface oxidation events and yet the nuclear translocation of MTF-1 in response to hemopexin occurs via copper, probably Cu(I),-dependent signaling cascades from the hemopexin receptor rather than the oxidation per se.     

Lymphoproliferative disease in antibody deficiency: a multi-centre study

We have undertaken a retrospective study of antibody deficient patients, with and without lymphoma, and assessed the ability of specific polymerase chain reaction (PCR) primers to determine if the detection of clonal lymphocyte populations correlates with clinical and immunohistochemical diagnosis of lymphoma. We identified 158 cases with antibody deficiency presenting during the past 20 years. Paraffin-embedded biopsy specimens or slides were available for analysis in a cohort of 34 patients. Of these patients, 29 had common variable immunodeficiency, one X-linked agammaglobulinaemia, one X-linked immunoglobulin deficiency of uncertain cause and three isolated IgG subclass deficiency. We have confirmed that lymphoma in antibody deficiency is predominantly B cell in origin. Clonal lymphocyte populations were demonstrated in biopsies irrespective of histology (16/19 with lymphoma and 11/15 without). Isolated evidence of clonality in biopsy material is therefore an insufficient diagnostic criterion to determine malignancy. Furthermore, our data suggest that clonal expansions are rarely the result of Epstein-Barr virus-driven disease.     

Genomic instability in scleroderma

Scleroderma is an enigmatic rheumatic disorder of uncertain etio-pathogenesis. Cancer has an approximately two-fold higher incidence in scleroderma patients than in the general population. There are preliminary data of acquired genetic damage in scleroderma but the significance of these observations are uncertain. To determine somatic mutation frequency at the glycophorin-A (GPA) locus in patients with limited and diffuse cutaneous scleroderma. The GPA assay measures the total somatic mutation frequency (Vf), composed of gene inactivating mutations (NO) and mutations arising from mitotic recombination (NN) in individuals heterozygous for the GPA MN blood group. Mutation frequency was determined using a validated GPA flow cytometric assay using fluorescent labeled monoclonal antibodies specific for the GPA blood groups M and N. This assay detects and enumerates progeny of red blood cell (rbc) precursor cells which have acquired genetic damage resulting in a loss of expression of one of the GPA alleles. It was found that patients with scleroderma (n = 23) had significantly elevated Vf as compared with young healthy controls (p < 0.001) and elderly controls (p = 0.03). Patients with diffuse scleroderma had higher mean Vf as compared with limited scleroderma (p = 0.055). In comparison with controls, patients with scleroderma exhibit a higher proportion of mitotic recombinant mutations than inactivating mutations (p < 0.002). There was no correlation between Vf and disease duration, age at onset or autoantibody status. We have documented evidence of acquired genetic damage at the GPA locus in scleroderma. Evidence of acquired genetic damage in this disorder may be importance in explaining both the etio-pathogenesis of scleroderma and the association of scleroderma with cancer.     

Effects of glucocorticoids on the rabbit carotid body

Weekly intramuscular injections of slow-release, depot methyl prednisolone to 15 adult Dutch rabbits did not bring about an increase in the volume of their carotid bodies. However, they caused swelling of chief cells with discrete areas of pallor in the cytoplasm. Factors responsible for these changes appear to be increased storage of catecholamines and an increased number of swollen mitochondria.     

Axotomy affects calcium-sensitive potassium conductance in sympathetic neurones

Following peripheral nerve section, the cell body and proximal axon undergo various physiological and morphological changes which may be associated with regrowth. We found that axotomy reduced the amplitude and duration of the afterhyperpolarization (AHP) of the action potential (AP) of bullfrog sympathetic neurones. In addition, the repolarization of the AP was slowed. The Ca2+-channel blocker, Cd2+ (200 microM) produced similar effects in normal cells by blocking the Ca2+-sensitive K+ conductances (gK, Ca) which contribute to the AHP and to AP repolarization. Although Ca2+-channel function was preserved after axotomy, Cd2+ did not affect axotomized neurones. This suggests that axotomy promotes a functional loss of gK, Ca which could reflect a regenerative response of the cell to injury.