ABSTRACT
The rat testis is considered to be an immunologically privileged site because of its reduced capacity to support antigen-specific immune responses. To understand this phenomenon, it is essential to characterize both the lymphocyte subpopulations normally present in the testis and their regulation by testicular cytokines. Peripheral blood was obtained from adult male Dark Agouti or Sprague-Dawley rats, and testicular interstitial tissue was collected after perfusion of the testes to remove blood. Blood and testis lymphocytes were isolated using discontinuous Percoll density gradients, and the testicular lymphocytes were further purified by selective adherence to remove mononuclear phagocytes. The isolated lymphocytes were analyzed by flow cytometry using specific monoclonal antibodies and fluorescein labeling and were enumerated as total T cells, CD4+ T cells, CD8+ T cells, B cells, and natural killer (NK) cells. In contrast to peripheral blood, in which the CD4+ T-cell subset was the major lymphocyte subset, rat testis T cells were predominantly of the CD8+ subset, and a large population of NK cells also were present. Subsequently, peripheral blood lymphocytes were stimulated with the polyclonal T-cell activator, phytohemagglutinin, and cultured in the presence of activin, inhibin, or transforming growth factor beta (TGFbeta) prior to flow cytometric analysis. Activin and TGFbeta suppressed T-cell proliferation without any selective effect on either T-cell subset, and inhibin had no effect. The predominance of CD8+ T cells and NK cells, and the relatively minor proportion of CD4+ T cells, are consistent with both increased cellular immune surveillance and a reduced capacity for initiating antigen-specific immune responses in the adult rat testis.
Subject(s)
Flow Cytometry , Inhibins/pharmacology , Lymphocytes/immunology , Testis/cytology , Testis/immunology , Transforming Growth Factor beta/pharmacology , Activins , Animals , Antibodies, Monoclonal , B-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Cell Separation , Fluorescent Antibody Technique , Fluorescent Dyes , Killer Cells, Natural/immunology , Lymphocyte Activation/drug effects , Lymphocyte Count , Male , Rats , Rats, Sprague-DawleySubject(s)
Birth Injuries , Brain Damage, Chronic , Congenital Abnormalities , Humans , Infant, Newborn , Infant, PrematureABSTRACT
A project of joint consultation between a paediatrician and several general practitioners serving a group practice of 15,000 patients has shown that outpatient clinics held at a group-practice centre (when 36 children were seen at 78 consultations over 18 months) reduced the overall work-load, eliminated dual care, and directly benefited the doctors, the children, and their families.