Transfer of specific immunity from donor to recipient of an allogeneic bone marrow graft: evidence for donor origin of the antibody producing cells

A rapid recovery of specific humoral immunity in the recipient of an allogeneic bone marrow transplantation (BMT) can be observed after immunization of the donor before graft sampling. This has been attributed to transfer of specific immunity from donor to recipient. However, to maintain the concept of transfer the origin of the antibody producing cells in the recipient after BMT must be demonstrated. To this end, donor-recipient pairs with differences in Gm-allotypes were selected and immunized before BMT with the neo-antigen Helix pomatia haemocyanin (HPH) according to three immunization protocols. Additionally, the recipients were immunized at day 42 after BMT. Serum samples were weekly obtained from the recipients in the first 100 d after BMT. The origin of HPH-specific antibody producing cells was assessed by two approaches: (1) determination of the Gm-allotypes of anti-HPH antibodies within a distinct IgG subclass, (2) analysis of anti-HPH antibody spectrotypes by isoelectric focusing combined with immunoblotting. The results obtained with these two approaches show concordance in most instances and led to the conclusion that the antibody producing cells are of donor origin.     

An ATP-activated channel is involved in mitogenic stimulation of human T lymphocytes

We investigated the effect of pharmacologic modulation of the ATP receptor on intracellular ion changes and proliferative response of human peripheral blood lymphocytes (PBLs) and purified T lymphocytes. Extracellular ATP (ATPe) triggered in these cells an increase in the cytoplasmic Ca2+ concentration ([Ca2+]i) and plasma membrane depolarization. Whereas both Ca2+ release from intracellular stores and influx across the plasma membrane were detected in the whole PBL population, only Ca2+ influx was observed in T cells. In the presence of near physiologic extracellular Na+ concentrations (125 mmol/L), Ca2+ permeability through the ATPe-gated channel was very low, suggesting a higher selectivity for monovalent over divalent cations. The selective P2Z agonist benzoylbenzoic ATP (BzATP) increased [Ca2+]i in the presence but not the absence of extracellular Ca2+ and also caused plasma membrane depolarization. The covalent blocker oxidized ATP (oATP), an inhibitor of P2X and P2Z receptors, prevented Ca2+ influx and plasma membrane depolarization, but had no effect on Ca2+ release from stores. Stimulation with ATPe alone had no significant effects on PBL 3H-thymidine incorporation. On the contrary, ATPe or BzATP had a synergistic effect on DNA synthesis stimulated by selective T-cell mitogens such as phytohemagglutinin, anti-CD3 monoclonal antibody, or allogenic PBLs (mixed lymphocyte cultures). Treatment with oATP inhibited mitogenic stimulation by these receptor-directed agents but not by the combined application of the Ca2+ ionophore ionomycin and phorbol myristate acetate. Interleukin-2 partially relieved inhibition by oATP. These results suggest that human T lymphocytes express a plasma membrane channel gated by ATPe that is involved in mitogenic stimulation.     

Analysis of resin tags formation in root canal dentine: a cross sectional study

Aim  To evaluate the length, density and quality of resin tags formed by penetration of various types of adhesive systems into dentinal tubules at various cross section levels of the root canal in correlation to the density of dentinal tubules.
Methodology  Thirty mandibular premolars were instrumented and fibre posts were inserted with three different adhesive systems with and without activator: etch & rinse XP Bond and XP Bond/Self Cure Activator; self-etch (two-step) AdheSE and AdheSE/AdheSE DC Activator and self-etch (one-step) Hybrid Bond and Hybrid Bond/Hybrid Brushes. The resin tags were evaluated from slices obtained from sections perpendicular to the long axis of the teeth at 3, 6, and 9 mm from the root apex under a Confocal Laser Scanning microscope.
Results  In all groups, lack of continuity of resin tag length, density and quality was observed not only from the cervical to the apical region of each root canal, but also in a mesio-distal direction to the long axis of the root. Application of etch & rinse adhesive in contrast to the self-etch adhesives provided the formation of the shorter, but considerably denser, more homogeneous and not interrupted resin tags with similar length. Use of the activator for all types of adhesives significantly increased the completeness ( P  = 0.014) and continuity ( P  = 0.024) of resin tags.
Conclusions  None of the investigated adhesives were able to completely infiltrate the dentinal tubules in the entire root canal. Use of the etch & rinse adhesive system and the activators significantly increased the density and the quality of resin tags.     

Recent developments in the epidemiology of virus diseases and BSE

There is a continuous change in viral epidemics with respect to clinical symptoms, their duration or disappearance and the emergence of new diseases. This can be observed both in human and animal diseases. This evolution of virus diseases is mainly related to three factors: etiological agent, host and environment. As far as genetic alterations of the virus are concerned, two major mechanisms are involved: 1) mutations such as recombination and reassortment; 2) selection for resistance or susceptibility. The epidemiology of newly emerged virus diseases in man and animals, such as AIDS and hemorrhagic fevers, and bovine spongiform encephalopathy (BSE), canine hemorrhagic gastroenteritis or respiratory syndrome in horses will be discussed.     

Use of biotechnical methods in veterinary medicine

Biotechnological methods offer promising approaches for improved diagnostic and prophylactic purposes. The following biotechnological techniques are used in the Institute of Virology at the Hanover Veterinary School:--Production of monoclonal antibodies directed against viral and bacteria-specific antigens such as bovine virus diarrhoea virus, classical swine fever (hog cholera) virus, feline leukaemia virus, animal parvoviruses, Alphavirus, Brucella and Francisella--Establishment of improved and sensitive diagnostic enzyme immunoassays (ELISA) using monoclonal antibodies--Molecular cloning and sequencing of classical swine fever virus RNA and parvovirus DNA--Development of diagnostic hybridisation techniques (dot, slot, Southern and Northern blot, in situ, oligonucleotides)--Detection of viral genomes in tissues of infected animals--Development of synthetic oligopeptides as diagnostic antigens and as potential immunogens for vaccines. Currently available techniques used in basic research (e.g. pathogenesis studies) will be tested for their application in routine diagnosis of viral diseases, e.g. by molecular hybridisation. Some techniques need to be simplified (e.g. RNA extraction procedures) and, particularly, alternative labelling schedules must be developed (e.g. biotin or sulfone labelling instead of radionuclides).     

Epitopic mapping of structural and nonstructural Aleutian disease virus proteins

Common antigenic properties for p85 and p75 but a different antigenic character for p71 Aleutian disease virus (ADV) proteins were demonstrated by Western blot analysis with monoclonal antibodies. It was shown that four hybridomas (ADV-Hy 47, 66, 77 and 84) with specific reactivity for structural proteins p85 and p75 also recognized p25 but not the p71, nonstructural, protein. In turn, the monoclonal antibody ADV-Hy 2 recognized the p71 protein only. For further studies of their antigenic properties, the ADV proteins were subjected to enzymatic or chemical cleavage. The derived peptide fragments were analyzed by epitopic mapping. Depending on the cleavage reagent and monoclonal antibody applied, specific peptide maps were revealed. The maps of p85 and p75 were very similar, indicating that both proteins shared an extensive antigenic relationship. After cleavage with alpha-chymotrypsin and N-chlorosuccinimide and by using the ADV-Hy 84 monoclonal antibody, unique peptide fragments were identified with p85 which had no counterparts in p75 fragments.     

Blood donation leads to a decrease in natural killer cell activity: a study in normal blood donors and cancer patients

Transfusion-induced immunosuppression has long been known to be beneficial for organ transplantation patients, but recent retrospective studies suggest that blood transfusions may be detrimental for patients with cancer. If autologous blood is used to avoid immunosuppression, the assumption is that the procedure, involving blood donation, is immunologically neutral. In the present study, this assumption was evaluated by monitoring 33 normal blood donors and 16 colorectal cancer patients before and after donation of 1 (500 mL) and 2 units of blood, respectively. The cancer patients belonged to the autologous arm of a randomized trial in which the effects of allogeneic versus autologous blood on cancer prognosis were studied. The patients donated 2 units of blood with an interval of 3 to 4 days between donations. Flow cytometric analysis revealed that blood donation by normal donors and cancer patients had no effect on the proportion of B, T, and natural killer (NK) cells. Only the total number of lymphocytes was significantly decreased in the normal donors on Day 12 after donation. Blood donation had no significant effect on T-cell function assessed by phytohemagglutinin stimulation in normal donors or in cancer patients donating 2 units of blood. A significant depression of NK cell function (88% and 74% of predonation levels) was observed in normal donors on Days 2 and 5 after donation; on Day 12, the activity was again normal. Colorectal cancer patients had a significantly depressed NK cell activity (54% of predonation activity) on Day 12 after the first donation.(ABSTRACT TRUNCATED AT 250 WORDS)