Bone marrow origin of immunologically competent lymphocytes in the rat

Cyclosporin A and Tacrolimus (FK506) Differentially Alter T-cell Receptor ExpressionIn Vivo

Cyclosporin A (CSA) and tacrolimus (FK506) are two common immunosuppressive agents used post blood and marrow transplantation. Despite similarity in their accepted modes of action, we observed polarized effects of CSA and FK506 on the in vivo human T cell repertoire. To determine the possible mechanism for this difference, the effects of CSA and FK506 on cell viability, cell proliferation, interleukin-2 production, and calcineurin inhibition were determined in vitro. Our data suggest that a secondary mechanism of action exists for the different T-cell repertoire induced by exposure to CSA and FK506.

Contribution of a thymic humoral factor to the development of an immunologically competent population from cells of mouse bone marrow

The hypothesis that cells located in mouse bone marrow can acquire immunological competence by a process that involves interaction with a noncellular component of the thymus was tested using an in vitro assay of graft-versus-host reactivity as a criterion of cell competence. When suspensions of C57BL bone marrow cells were incubated in thymus extract and injected into mice incapable of inducing a response in the graft-versus-host assay as a result of neonatal thymectomy, or adult thymectomy plus irradiation, or because of genetic similarity with the (C3H x C57BL)F₁ tissue used for challenge in the assay, competent cells were recovered from the spleens of the injected mice. The reactive cells were shown to be of bone marrow origin since immune reactivity was related to the genetic makeup of the bone marrow cells rather than that of the intermediate recipients. A thymic factor was involved in the process leading to immune reactivity by these cells, as bone marrow cells incubated in xenogeneic or syngeneic thymic extracts induced a graft-versus-host response after passage through nonresponsive mice, whereas incubation of bone marrow cells in xenogeneic lymph node or spleen extracts or in culture medium only did not lead to subsequent reactivity. Participation of peripheral lymphoid tissue seemed essential in this process since bone marrow cells tested directly after exposure to thymic extract failed to induce a graft-versus-host response. C57BL bone marrow cells exposed to thymus extract and cultured together with fragments of (C3H x C57BL)F₁ spleen tissue in vitro were competent to induce a graft-versus-host response; thus, these components would seem to be sufficient as well as necessary for the immunodifferentiation process leading to graft-versus-host activity. It is concluded that one step in the process by which bone marrow cells acquire competence vis-a-vis the graft-versus-host response depends upon a thymic agent that is noncellular and extractable, and that another stage in this process is under the influence of components found within the peripheral lymphoid tissue environment. It is suggested that differentiation of precursor cells to competence could occur by progressive development of the cells in separate compartments of the lymphoid system.

Management of cancer treatment-related diarrhea. Issues and therapeutic strategies

The cancer treatment-related diarrhea caused by acute graft-versus-host disease (GVHD) and chemotherapeutic agents, particularly fluoropyrimidines and irinotecan, significantly affects patient morbidity and mortality. The mechanisms causing cancer treatment-related diarrhea are not fully understood, but histopathologic evidence points to a multifactorial process that causes an absorptive and secretory imbalance in the small bowel. Cancer treatment-related diarrhea could be life-threatening, yet assessment and treatment are not currently standardized. Several clinicians participated in a closed roundtable meeting to review the mechanisms of chemotherapy-induced diarrhea (CID) and GVHD-induced diarrhea, management issues in cancer treatment-induced diarrhea, and pharmacologic approaches to treatment. The meeting produced a proposal for new treatment guidelines and an algorithm, which include the use of octreotide for the management of CID- and GVHD-induced diarrhea. The development of diarrhea assessment guidelines that expand on the current National Cancer Institute criteria and allow for better patient management was also proposed.

Graft-vs.-host reactions: mechanisms and contemporary theories

A graft-vs.-host (GvH) reaction can be initiated by injection of immunocompetent lymphocytes into a histoincompatible host that is unable to reject these cells. The reaction is characterized by splenomegaly, hepatomegaly, lymph node atrophy, body weight loss, dermatitis, and diarrhea, often leading to mortality. The onset and severity of the GvH reaction are determined by differences in histocompatibility antigens between the donor and the acceptor, and by the number and nature of the transplanted allogeneic cells. Many different in vivo and in vitro systems have been devised for experimental studies of the GvH reaction. In several of these models, however, different parameters are measured. Furthermore, the conclusions drawn from these investigations sometimes contradict each other. This paper reviews the experimental data, and discusses the mechanisms underlying the GvH reaction.

Dyskeratosis congenita: hematologic evaluation of a sibship and review of the literature

Dyskeratosis congenita is a rare genodermatosis whose hematologic complications include pancytopenia of variable time of onset, a propensity for opportunistic infections, and neoplasia. A family in which the disorder segregated in 3 generations and involved 9 members is reported, and the hematologic data of the 46 previously reported cases are reviewed.

Dyskeratosis congenita: clinical features and genetic aspects. Report of a family and review of the literature

A large family with dyskeratosis congenita is reported. There were nine affected males, the findings in five of who are reported. We review 46 cases selected from the literature. The cardinal findings of this inherited multisystem disorder are delineated from these 51 cases. The complications of the disease, including opportunistic infection, are described. The parallel is made between dyskeratosis congenita and Fanconi's anaemia. The X-linked transmission of dyskeratosis congenita is confirmed by the family pedigree in this report. From the analysis of the families reported in the literature, there appears to be genetic heterogeneity in this disease. This study in our family indicates absence of close linkage between the Xga locus and the X-linked recessive form of dyskeratosis congenita.

Anatomical distribution of T and B lymphocytes in the rat. Development of lymphocyte-specific antisera

A method is described whereby antisera raised in rabbits to rat thoracic duct lymphocytes were made specific for the plasma membrane antigens of T and B lymphocytes. These lymphocyte-specific antisera were used in immunofluorescence assays to study the distribution of B and T cells in lymphocyte containing tissues and body fluids of the rat. Rabbit antirat B-cell serum (ALS(B)) reacted selectively with the surfaces of lymphocytes in the lymphoid follicles of lymph node cortex and in the follicles and marginal zones of splenic white pulp, but not with the surfaces of germinal center cells or plasma cells. An identical pattern of fluorescent staining was obtained with rabbit antirat Ig serum. It was shown by blocking, absorption, and immunoprecipitation studies that ALS(B) was composed in large part of antibodies to rat Ig, but that it contained antibodies to other B-cell antigens as well. Rabbit antirat T-cell serum (ALS(T)) reacted selectively with the surfaces of lymphocytes in the paracortex of lymph node and in the periarteriolar sheath of spleen, and with thymocytes. ALS(T) did not display anti-Ig activity. ALS(T) reacted with approximately 100% thymocytes and with 90% thoracic duct, 80% lymph node, 60% blood, 50% spleen, and 10% bone marrow lymphocytes in suspensions of cells from these sources. ALS(B) reacted with the remainder of the lymphocytes in the suspensions, except for bone marrow in which only 59% of lymphocytes had detectable B- or T-cell surface antigens. The population of T lymphocytes in rat bone marrow was depleted by drainage of lymphocytes from a thoracic duct fistula, thereby establishing their membership in the pool of recirculating T cells. Approximately 14% of lymphocytes issuing from the thoracic duct of TxBM donors reacted with ALS(T). The presence in these animals of a small number of T cells, calculated to be approximately 2% of the normal value, may account for the limited capacity of TxBM rats to respond to antigens that induce a cell-mediated immune response.

The mediator of cellular immunity. VI. Effect of the antimitotic drug vinblastine on the mediator of cellular resistance to infection

The antimitotic drug vinblastine (Vbl) has a profound impact upon the specifically sensitized lymphocytes that transfer cellular resistance to Listeria monocytogenes. A 12-h pulse of the drug given to prospective donors during the first week of an immunizing Listeria infection inhibits the delivery of protective lymphocytes to the thoracic duct and their subsequent movement into an inflammatory exudate induced in the peritoneal cavity. The effect of Vbl is clearly related to its antimitotic activity, not to an effect on lymphocytes regardless of their position in the division cycle. This conclusion was drawn from an autoradiographic analysis of cells in the lymph of Vbl-treated rats and from failure of the drug to abrogate a known function of small lymphocytes, namely, their ability to initiate a graft-vs.-host reaction. The results imply that large lymphocytes, the rapidly proliferating cells in central lymph, are the principal effector cells responsible for transmitting resistance to L. monocytogenes and provide a plausible explanation for their rapid turnover and short circulating life-span.

Blastogenic response of lymphocytes separated from bone marrow to allogeneic lymphoid cells in vitro

Fractions of cells were separated from the bone marrow and spleen of Lewis rats by brief centrifugation in linear sucrose-serum density gradients and were cultured in vitro either alone or mixed with F₁ (Lewis × Brown Norway) hybrid rat lymphoid cells. After 4 days the incorporation of [³H]thymidine into DNA was measured by scintillation counting, and the morphology and incidence of [³H]thymidine-labelled cells were determined in radioautographs.

Lymphocyte-rich, slowly-sedimenting fractions of Lewis rat bone marrow cells showed increased incorporation of [³H]thymidine and the development of many large proliferating blast-like cells when cultured with F₁ hybrid cells. This blastogenic response was greater than could be ascribed to contaminating intravascular blood lymphocytes. Slowly-sedimenting fractions of spleen cells, consisting mainly of small lymphocytes, showed a greater blastogenic responsiveness to F₁ hybrid cells than that of whole spleen, while rapidly-sedimenting spleen cell fractions, containing many large cells, showed a reduced responsiveness. Paradoxically, rapidly-sedimenting marrow cell fractions containing few small lymphocytes, showed an increment in [³H]thymidine incorporation when cultured with F₁ cells but this was due to active macrophage proliferation as well as to blastogenesis.

The results demonstrate that some parenchymal bone marrow lymphocytes undergo blastogenic transformation in response to allogeneic lymphocytes in vitro.

Lymphopenic immunologic deficiency in identical twins: lymphocyte allografting and graft-versus-host disease following treatment with albumin-gradient-separated paternal bone marrow cells

The clinical, immunologic and pathologic features of the first recorded examples of lymphopenic immunologic deficiency in twins are presented. Eleven-month-old male identical twin infants were found to be severely lymphopenic and lacked demonstrable cell-mediated immunity and antibody formation. Each first-degree relative differed from the probands by one chromosome at the major human histocompatibility locus, HL-A. Because of their rapidly deteriorating clinical conditions, allogeneic bone marrow transplantation was undertaken. Circumvention of graft-versus-host disease was attempted by separation of donor bone marrow cells on a discontinuous-albumin-gradient and administration of only 5×10⁶ immature nucleated marrow cells per kilogram infant body weight. Additionally, immunologic enhancement was attempted by pretreating the infants with human isoantisera to identifiable infant HL-A antigens not present in the marrow donor. Paternal lymphocyte allografting occurred, as demonstrated by lymphocyte cytotoxicity testing, but both infants succumbed to graft-versus-host disease at the end of 3 weeks.

Cells involved in the immune response. VII. The demonstration, using allotypic markers, of antibody formation by irradiation-resistant cells of irradiated rabbits injected with normal allogeneic bone marrow cells and sheep erythrocytes

Bone marrow cells obtained from rabbits of one allotype were injected into irradiated rabbits of a different allotype. The recipients were also injected with sheep red blood cells, and their spleen cells were tested for plaque-forming capacity 7 days later. Spleen cells of all recipients gave large numbers of plaques as did spleen cells incubated with antiserum, directed toward donor allotype. However, incubation of the recipient spleen cells with antiserum directed toward recipient allotype completely suppressed plaque formation. These results demonstrate that antibody-formation in irradiated recipients of transferred lymphoid cells is a property of the recipient animal and that the antibody-forming cell is relatively irradiation-resistant. It was also demonstrated that only viable normal bone marrow cells are capable of transferring antibody-forming capacity to irradiated recipient rabbits. Neither sonicates nor heat-killed preparations of normal rabbit bone marrow cells possessed this capacity.

Cells involved in the immune response. VI. The immune response to red blood cells in irradiated rabbits after administration of normal, primed, or immune allogeneic rabbit bone marrow cells

Irradiated rabbits given allogeneic bone marrow cells from normal adult donors responded to an injection of sheep red blood cells by forming circulating antibodies. Their spleen cells were also capable of forming many plaques using the hemolysis in gel technique, and were also capable of undergoing blastogenesis and mitosis and of incorporating tritiated thymidine upon exposure to the specific antigen in vitro. However, irradiated rabbits injected with allogeneic bone marrow obtained from rabbits injected with sheep red blood cells 24 hr prior to sacrifice (primed donors) were incapable of mounting an immune response after stimulation with sheep red cells. This loss of reactivity by the bone marrow from primed donors is specific for the antigen injected, since the immune response of the irradiated recipients to a non-cross-reacting antigen, the horse red blood cell, is unimpaired. Treatment of the bone marrow donors with high-titered specific antiserum to sheep red cells for 24 hr prior to sacrifice did not result in any diminished ability of their bone marrow cells to transfer antibody-forming capacity to sheep red blood cells. The significance of these results, with respect to the origin of the antigen-reactive and antibody-forming cells in the rabbit, is discussed.

Effect of tritiated thymidine and 5-bromodeoxyuridine on development of immunologically competent lymphocytes

Results of the present experiments suggest that dividing cells in rat bone marrow can generate lymphocytes capable of initiating a systemic graft-versus-host reaction. In these experiments, Lewis bone marrow cells were incubated in vitro with either tritiated thymidine ([³H]thymidine) or 5-bromodeoxyuridine (BUDR)—agents which inhibit cell proliferation. Bone marrow cells prepared in this way and injected into an intermediate (Lewis×DA)F₁ host were unable to proliferate and mature into circulating immunologically competent lymphocytes.

Concentrations of [³H]thymidine and BUDR which inhibited the development of putative lymphocyte precursors in bone marrow had no obvious effect on the immunological performance of thoracic duct lymphocytes. Lewis lymphocytes, cultivated in medium containing these agents, caused a vicious graft-versus-host reaction in X-irradiated (Lewis×BN)F₁ hybrid rats. The results strengthen the view that [³H]thymidine and BUDR exert their inhibitory effect on replicating lymphocyte precursors and not on long-lived members of the circulating lymphocyte pool.