Serological identification and separation of canine lymphocyte subpopulations.

In vitro treatment of bone marrow grafts with absorbed rabbit-antidog thymocyte globulin (ATG) prevented graft-versus-host disease in a substantial number of the dogs differing by one DLA haplotype. Absorbed ATG has now been used for serological identification of canine lymphocyte populations. Specific labeling of canine T-lymphocytes by absorbed ATG could be demonstrated by (a) a distribution of ATG-positive cells in suspensions of canine lymphoid organs similar to that of T cells observed in other species and by specific staining of paracortical thymus-dependent lymph node areas in immunohistochemistry, (b) complementary labeling of nylon-wool-separated cells by ATG and antiimmunoglobulin sera, and (c) correlation of ATG surface labeling with responder activities in mixed lymphocyte cultures.

Subtypes of T-cell chronic lymphatic leukemia.

Thirteen cases of T-cell chronic lymphatic leukemia (T-CLL) (including T-cell prolymphocytic leukemia) are presented. Five subtypes were distinguished according to morphologic and functional parameters of the leukemic cells: prolymphocytic; lymphocytic, small; lymphocytic, Sézary-like; lymphocytic, abundant cytoplasm; lymphocytic, abundant cytoplasm and granules. The subtype can be recognized by light and by electron microscopic investigation.

Independent expression of the surface markers 5'-nucleotidase and cALLA on leukemic cells.

High levels of the ectozyme 5'-nucleotidase (5'-N) and the common ALL-antigen (cALLA) are coexpressed on leukemic blast cells in common ALL, in the lymphoid blast crisis of CML and also on the lymphoblastoid cell-line Nalm-1. Clinically this coexpression can help to subclassify leukemias and may be of diagnostic and prognostic significance. In an attempt to study the mechanism underlying this simultaneous expression plasmamembrane subfractionation was undertaken on Nalm-1.

Antilymphocytic antibodies and marrow transplantation. VI. Absence of immunosuppression in vivo after injection of monoclonal antibodies blocking graft-versus-host reactions and humoral antibody formation in vitro.

The in vivo and in vitro effectiveness of several monoclonal antimouse T and B cell antibodies, of anti-Th-1 and of Iak serum, as well as of ATG were compared. The parameters were prolongation of skin graft survival, prevention of graft-versus-host disease (GVHD), antibody and primary and secondary plaque formation against sheep redblood cells (RBCs), and T cell depletion of lymphoid tissues. In general, in vitro effectiveness of the monoclonal antibodies exceeded their in vivo effectiveness.