Genetic control of specific immune suppression. IV. Responsiveness to the random copolymer L-glutamic acid(50)-L-tyrosine(50) induced in BALB/c mice by cyclophosphamide

Previous reports from our laboratory have demonstrated the stimulation of specific suppressor T cells in genetic nonresponder mice after immunization with the terpolymer of L- glutamic acid, L-alanine, and L-tyrosine (GAT) (1,2) and with the copolymer of L-glutamic acid and L-tyrosine (GT) (3-5). These findings raise two important questions: (a) do the specific suppressor T cells inhibit an antibody response which would otherwise develop in nonresponder mice; and, (b) can specific helper T cells inhibit an antibody response which would otherwise develop in nonresponder mice; and, (b) can specific helper T-cell activity be detected in these animals. Responsiveness appears to be completely dominant over suppression in (responder x suppressor)F(1) hybrids, therefore, we have been unable to detect suppressor cells in these hybrids after conventional immunization with GAT (2). However , using special conditions of antigen administration, GAT helper activity could be demonstrated in nonresponder DBA/1 (“suppressor”) mice. Thus, GAT-specific helper activity was not detected in these nonresponder animals after immunization with GAT irrespective of the adjuvant used, but could be stimulated by macrophage-bound GAT or by GAT complexed with methylated bovine serum albumin GAT-MBSA (6). In the current report we have taken advantage of the fact that suppressor T-cell activity is more sensitive to cyclophosphamide treatment than T-cell helper activity (7) to demonstrate the presence of GT-specific helper activity in “nonresponder” BALB/c mice. We describe: (a) the dose of cyclophosphamide and conditions of treatment which inhibits the well-documented stimulation of specific suppressor T cells in BALB/c mice injected with GT previous to immunization with GT-MBSA, and (b) the ability of cyclophosphamide to permit the development of primary PFC responses to GT in these “nonresponder” mice. These cyclophosphamide-induced responses are not characterized by the high levels of antibody detected in genetic responder animals.     

Richter's syndrome with different immunoglobulin light chains and different heavy chain gene rearrangements

In a patient with Richter's syndrome, the chronic lymphocytic leukemia (CLL) expressed lambda, mu, and delta immunoglobulin (lg) chains and the non-Hodgkin lymphoma (NHL) kappa, mu, and delta lg chains. The difference in lg light chain expression suggests that the CLL and NHL are independent malignancies, or that the oncogenic event occurred in a B cell differentiation stage after the heavy chain gene rearrangements but before the selection of the light chain. Analysis of DNA by Southern blotting revealed that the lg heavy chain genes of the two malignancies were rearranged in a different way. We therefore conclude that in this patient the NHL cannot be regarded as a progression of the CLL but should most likely be considered as an independent B cell malignancy, which arose in a susceptible host.     

The presence of clonogenic cells in high-grade malignant lymphoma: a prognostic factor

A culture system has been developed that promotes growth of clonogenic lymphoma cells of some patients with intermediate and high-grade malignant lymphoma. The formation of colonies in bone marrow, lymph nodes, and peripheral blood samples is best supported by human plasma. Colony formation of some patients was dependent upon growth factors, which in this study were added in the form of medium conditioned by phytohemagglutinin (PHA)-stimulated leukocytes (PHA-LCM). Some gave rise to lymphoma colonies without PHA-LCM but improved their frequency with PHA-LCM; others were completely independent of PHA-LCM. Colonies grown in primary cultures were routinely recloned and propagated as Epstein-Barr virus (EBV)-negative cell lines with stable B cell phenotype. The cell lines showed the same immunoglobulin rearrangement pattern as that observed in the primary lymphoma sample. In addition, a significant clinical correlation was observed between culture data and clinical outcome. Survival of patients who formed lymphoma colonies at any time during their clinical course was significantly shorter than survival of patients who did not give rise to colonies (P = 0.0009). The same observation was made when the survival assessment was performed for the subset of patients studied at diagnosis (P = 0.0014).     

The coagulant-active phospholipid content is a major determinant of in vivo thrombogenicity of prothrombin complex (Factor IX) concentrates in rabbits

In vitro evaluation of prothrombin complex concentrates in a thrombin generation assay, using DAPA and purified components of the prothrombinase complex, demonstrated significant levels of coagulant- active "phospholipid replacing" activity. Quantification of this activity showed a significant correlation (r = 0.8747, p less than 0.01) with thrombogenicity measured in vivo in a stasis model in rabbits. Extracted lipid material retained full phospholipid replacing activity in the vitro assay. Thin-layer chromatographic characterization confirmed the presence of phospholipids with known coagulant activity in vitro. In vivo, the extracted material was nonthrombogenic but augmented the thrombogenicity of purified factor Xa. Substitution of a synthetic coagulant-active phospholipid (phosphatidylcholine-phosphatidylserine lipid vesicles) for the extracted phospholipid produced a similar augmentation of a factor-Xa- induced thrombogenicity in vivo. It is concluded that the coagulant- active phospholipid content of prothrombin complex concentrates is a major determinant of thrombogenicity but requires the presence of activated clotting factors for its expression in vivo.     

A technique for the flow cytometric analysis of lymphocytes bearing histamine receptors

Histamine receptors have been demonstrated on lymphocyte membranes by a variety of techniques. We now report a method that allows for the flow cytometric analysis of histamine receptors on human peripheral T cells. Histamine is conjugated to fluoresceinated human albumin by the coupling agent ECDI. This conjugated histamine compound (FHA-his) binds to approximately 45% of T cells. Fluoresceinated human albumin alone (FHA), not conjugated to histamine, does not bind to T cells. In addition, unconjugated histamine can inhibit completely the binding seen with FHA-his. We conclude that this technique demonstrates specific FHA-his binding to histamine receptors on T cells and can be used to determine the number of cells bearing such receptors. In addition, the reagent could be used with a cell sorter to isolate distinct histamine-receptor-bearing (HR+) cells for further immunologic study.     

Functional studies on c.1347C>T,a polymorphism modulating phenotypic outcome in X-linked adrenoleukodystrophy

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