Christoph Huber

The biology of interferon actions.

SummaryThe interferons comprise a group of proteins which were first identified by their ability to protect cells against virus infections. They are synthesized and secreted by a variety of cell types in response to various inducers and exert their effects in vivo by interaction with specific cellular receptors. In this sense the interferons are analogous to polypeptide hormones. In recent years it has become clear that the interferons are capable of influencing cellular physiology and behavior in a number of ways. Their effects include antiviral actions, inhibition of cell growth and proliferation, regulation of the expression of specific genes, modulation of cell differentiation and activation of various cell types in the immune system. This review aims to summarize the current state of biology of interferon actions with special emphasis on the hemopoetic system.

Restimulation in secondary MLC by a non-D-locus determinant within the MHC

By testing a family in which one offspring had inherited a chromosome including a recombination between theHLA-B andD loci, we sought to obtain some insight into whether determinants other than those atHLA-D are capable of restimulating in a secondary MLC. Results obtained in the primary MLC indicated that the recombinant child did not express products of theHLA-D region normally associated with this haplotype. When sensitization in a primary MLC was to the entire haplotype, everyone who had the sensitizing haplotype restimulated strongly and specifically. In addition, however, weak to moderate stimulation was obtained when the cells of the recombinant child were used to restimulate. Presumably these cells possessed determinants coded for within theHLA-A toB chromosomal segments of the sensitizing haplotype, but not those coded for by theHLA-D locus. Our results indicate that a simple structure atHLA-D is not the sole factor in the secondary MLC. Either the products of loci outside theHLA-D locus can also restimulate or the recombination occurred within theD locus, suggesting that theD region contains more than one locus coding for restimulating determinants.

Alpha-interferon induces remission in hairy cell leukemia without enhancement of natural killing

SummaryThe number of large granular lymphocytes (LGL) and the capacity of peripheral blood mononuclear cells (PBMC) to lyse K 562 target cells in a natural killer (NK)-like fashion was evaluated in seven hairy cell leukemia (HCL) patients undergoing treatment with recombinant interferon-alpha-2 (rIFN-alpha-2). In HCL patients, whose peripheral blood showed high numbers (≧15×103/μl) of leukemic cells the number of LGL and their capacity to lyse K 562 tumor target cells were very low prior to treatment but increased significantly (p<0.05) following interferon (IFN) therapy. In patients with low numbers of hairy cells (HC) in their peripheral blood, both these parameters were higher and remained largely unaffected throughout IFN treatment. In vitro, HC proved to be completely insensitive to natural killing when tested against unstimulated and IFN-activated LGL from healthy donors. These results fail to support the concept of IFN-mediated enhancement of host antitumor actions, responsible for the favourable clinical results in HCL.

Redistribution of immunoglobulin determinants on human lymphocytes in lymphoproliferative disorders

Abstract Using 125I- or FITC-labelled anti-immunoglobulin antisera we studied the redistribution of surface Ig-anti-Ig complexes on the surface of human normal and neoplastic B lymphocytes, obtained from patients with chronic lymphocytic leukaemia and lymphosarkoma. The results were compared with those obtained from murine spleen cells. Whereas the majority of mouse lymphocytes exhibited cap formation under appropriate conditions, this staining pattern was only demonstrable on a very small, but distinct percentage of normal human lymphocytes and lymphosarcoma cells. In contrast typical cap formation was not observed on leukaemic blood lymphocytes. These findings are discussed with respect to the functional impairment of leukaemic lymphocytes.

Treatment with low dose human recombinant interferon-alpha-2-ARG induces complete remission in patients with hairy cell leukemia.

Five cases with advanced hairy cell leukemia refractory to treatment with splenectomy and chemotherapy as well as one patient presenting with a stage-A response to splenectomy were treated with rhu-IFN-alpha 2-arg. 5 X 10(6) were administered intramuscularly every day. Both patients, with advanced disease resistant to conventional therapy and treated for six or more months with rhu-IFN-alpha 2-arg, achieved complete clinical remissions. Three further cases treated for less than half a year and also with advanced disease achieved partial remission states with marked reduction of circulating hairy cells and with recovery of normal hemopoiesis. Minimal residual disease in the remaining patient during a three-month period of treatment did not respond. Side effects of rhu-IFN-alpha 2 low dose therapy were minimal in 5 cases and comprised a severe leukopenia reversible after dose reduction in one patient.

Surface immunoglobulins and receptor sites for aggregated IgG on leukemic reticuloendotheliosis cells

SummaryOn blood lymph nodes and spleen cells of 4 patients with leukemic reticuloendotheliosis (LR) the binding of125J-labelled IgG aggregates as well as binding of125J-labelled anti immunoglobulin sera was studied. Moreover the capacity to form spontaneous rosettes with sheep red blood cells to bind immune complement complexes as well as the proliferative response in the presence of PHA were investigated.On the surface of hairy cells a variety of immunoglobulins were demonstrable. IgG of both types was found to be the predominant surface bound immunoglobulin and evidence was obtained, that these antibodies were adsorbed from the serum via Fc-receptors. In all LR-cases the percentages of T-cell rosettes as well as the PHA responses were decreased when compared with the normal controls. The numbers of immune complement complex binding cells were in the range of the normal controls. Results are discussed with respect to the origin of hairy cells in LR.ZusammenfassungAn Blut-Lymphknoten und Milzzellen von 4 Patienten mit leukämischer Retikuloendotheliose (LR) wurde die Bindung125J-markierter IgG-Aggregate sowie von125J-markierten monospezifischen und polyvalenten Antiimmunglobulin-Serenuntersucht. Ferner wurde die Fähigkeit dieser Zellen zur spontanen Rosettenbildung mit Schaferythrozyten zur Bindung von Immun-Komplement-Komplexen sowie der proliferative Respons in Gegenwart von PHA getestet.An der Oberfläche von Haarzellen wurde eine Vielfalt von Immunglobulinen nachgewiesen. IgG beider Typen war das vorherrschende Immunglobulin, und Hinweise wurden erhalten, daß dieser Antikörper aus dem Serum durch Fc-Rezeptoren absorbiert wird. In allen Fällen von LR war der Prozentsatz von T-Zell-Rosetten ebenso wie der PHA-Respons gegenüber den Normalen vermindert. Der Anteil Immun-Komplement-Komplex bindender Lymphozyten war dagegen im Normbereich gelegen. Die Ergebnisse werden im Hinblick auf die Herkunft der Haarzellen bei LR besprochen.

Restimulation in Secondary MLC by Autologous Non‐T Cells

Lymphocytes sensitized in mixed leucocyte culture (MLC) were restimulaied with non‐T or complete cells. Cells primed against autologous non‐T cells and restimulated with autologous cells gave responses with the kinetics of a secondary response. In contrast, cells primed against either type of autologous cell responded to restimulation by allogeneic cells with the kinetics of a primary MLC response. Following priming against alloantigens good secondary responses against both complete and non‐T allogeneic restimulators were seen. Restimulation with auto‐logous non‐T colts, but not autologous complete cells, also led to secondary responses. The observation of” different responses to antigens expressed on non‐T autologous lymphocytes, in comparison to complete cells, implies that the secondary MLC involves more than a response against alloantigen. Allogeneic and autologous MLC may he qualitatively different phenomena. the latter representing the recognition of identifying structures between interacting populations of cooperating cells.

Morphological and immunological changes of hairy cell leukemia during α-2-interferon therapy

SummaryWe describe a patient who presented with the clinical picture of hairy cell leukemia (HCL). Bone marrow and peripheral blood lymphoma cells showed morphological and immunological features of HCL. Under recombinant α-2-interferon (α-2-IF) therapy the characteristic morphology changed from HCL to prolymphocytic leukemia (PLL). At diagnosis the lymphoma cells expressed CD24 and FMC7 surface antigen, but stained negative for surface immunoglobulins, light chains and anti-CD5. During α-2-IF treatment surface antigen expression changed to CD24, CD5 and FMC7. Surface IgD and lambda light chains became strongly positive. Southern Blot analysis of peripheral blood mononuclear cells showed two rearranged immunoglobulin bands at diagnosis but only one upon α-2-IF therapy. These data suggest, that this patient suffered from a biclonal lymphoma, HCL and PLL. While undergoing α-2-IF treatment the HCL came into remission, whereas the PLL clone proved to be poorly sensitive to α-2-IF therapy.

Role of Lymphokines in the Induction of Graft-Versus-Host Disease

It is now generally accepted that acute graft-versushost disease (GvH-D) is mediated by alloreactive T cells (1). Surprisingly, evidence accumulates that this alloresponsiveness can be amplified by exposure to environmental antigens: the relative resistance of gnotobiotic animals to (2) and the association of cytomegalovirus (CMV) disease with GvH-D (3) represent examples of this relationship. The hypothesis presented here implies that T cells stimulated by environmental antigens release excessive amounts of lymphokines, which enhance alloreactivity. As far as interleukin-2 (IL-2) and its capacity to mediate clonal expansion and generation of alloreactive T killer cells is concerned, a vast body of information has been published (4). In this respect, only little is known about the impact of interferon-gamma (IFN-y), the other well characterized lymphokine released by activated T cells. This article presents experimental evidence in support of the above hypothesis. In detail, we demonstrate that (i) IFN-Y enhances alloreactivity by virtue of its capacity to induce the expression of functional MHC class II antigens; (ii) endogenous interferon release is dramatically increased around the time of hemopoietic reconstitution and preceded clinical manifestation of GvH-D; (iii) this burst of endogenous cytokine production takes place independent of the presence of histocompatability barriers.

Linear density gradient separation of human lymphocyte subsets: II. Characterization of cells responding in secondary MLC and CML

Abstract Lymphocytes were separated on linear density gradients (LDG) after they had been sensitized in vitro against allogeneic cells and had reverted to small cells. Cells from individual density fractions were restimulated with autologous, specific, or third-party cells and assayed 48 hr later for their response in secondary mixed leukocyte culture (MLC) and cell-mediated lympholysis (CML). Memory cells capable of responding in secondary MLC were broadly distributed and found in both heavy and light fractions. The various density classes of memory cells differed with respect to the degree of their specificity for the restimulating cells. In secondary MLC the greatest specificity for the originally sensitizing cells and the least cross-reactivity for third-party cells were primarily features of light- and medium-density cells. Memory killer cells for CML were fairly homogeneously grouped. Following restimulation, killers were enriched in light to medium fractions also, as was previously seen at the peak of the response on Day 6.