Studies of the T-lymphocytes resident in the spleens of thymectomized, irradiated, bone marrow-reconstituted (TXB) mice.

The T-lymphocytes resident in the spleens of thymectomized, lethally irradiated mice that had been reconstituted with syngeneic bone marrow (TXB) were characterized. Both recently reconstituted N-TXB, (approximately 3 weeks after bone marrow injection) and aged (>6 months after reconstitution) A-TXB animals were studied. The T-lymphocytes from spleens of recently reconstituted N-TXB donors did not respond to PHA but did react significantly to Concanavalin A (Con A). The lack of PHA sensitivity was not due to dilution of reactive cells by other cell types. Removal of adherent cells, likewise, did not restore N-TXB spleen cell PHA responsiveness. N-TXB splenic T-cells were cortisone resistant. N-TXB spleen cells by themselves did not cause a graft vs host response. However, N-TXB spleen cells amplified the graft vs host response of normal lymph node cells but not N-TXB lymph node cells. Addition of cyclic GMP enhanced [³H]thymidine uptake of N-TXB spleen cells caused by Con A. N-TXB spleen cells were exclusively spleen seeking. The Con A reactive cell within N-TXB spleens was demonstrated to be of donor origin. Fetal liver as well as syngeneic bone marrow contained cells capable of reconstituting the Con A response. Spleen cells from aged. (>6 months) A-TXB were found to be PHA sensitive. Competitive inhibition assays measuring θ expression in A-TXB spleen cells indicate a significant increase in the θ positive lymphocyte population occurred with time. The data indicate that considerable reconstitution of θ positive cells had occurred in A-TXB donors. The results also suggest that the T-lymphocyte population of the TXB spleen may be a unique subpopulation of T-lymphocytes that resides exclusively in spleen and bone marrow.     

Transfer of tubulointerstitial nephritis in the Brown Norway rat with anti-tubular basement membrane antibody: quantitation and kinetics of binding and effect of decomplementation

Lewis (LEW) rats immunized with Brown Norway (BN) rat renal basement membrane (RBM) and adjuvants produce high titer circulating anti-BN tubular basement membrane (TBM) antibodies, in addition to developing an autoimmune cell-mediated form of nodular tubulointerstitial nephritis (TIN). This immune LEW serum, which reacted with BN TBM but not LEW TBM by immunofluorescence, was capable of passively transferring TIN as early as 24 hr after administration of volumes as low as 3 ml i.v. to normal BN recipients, producing focal lesions histologically and immunopathologically similar but less extensive than those studied previously in this strain after active immunization with heterologous RBM. In contrast, a total of 45 ml of serum (in multiple doses) from BN rats immunized with bovine RBM and adjuvants produced only one small lesion of TIN in a recipient BN rat. This difference in serum transferability of anti-TBM-associated TIN appears to relate to quantitative differences in anti-particulate and soluble (collagenase-extracted) BN RBM antigen reactivity measured by radioimmunoassay. Paired-label quantitative studies of passively transferred LEW anti-BN RBM IgG demonstrated a slow accumulation of renal-bound antibody over 6 days, and corresponded with kidney elution and immunofluorescence studies after transfer of immune LEW sera to normal BN rats. Approximately 167 micrograms of kidney-fixing antibody per gram of kidney were calculated to be required for the development of the earliest cellular infiltration. C3 depletion with cobra venom factor greatly diminished the development of destructive TIN lesions associated with multinucleate giant cells after passive transfer of LEW anti-BN RBM antibody to BN rats. This study, using immune LEW sera containing high levels of anti-BN RBM antibody, has defined and quantitated a role for anti-TBM antibody and complement in the initiation of TIN in BN rats.     

Immune mechanisms in leukemia: protective capacity of the major lymphoid cell compartments.

The capacity of immune spleen, lymph node, peritoneal, bone marrow, and thymic cells to protect C58/wm mice from syngeneic transplanted line Ib leukemia was quantified. Cells harvested 14 to 15 days after primary immunization were used for adoptive protection tests. Regression curves were computer analyzed and log10, PD50 values compared. For immune spleen, lymph node, peritoneal, bone marrow, and thymic cells the PD50 values were 4.53, 5.92, 4.88, 5.51, and 5.59, respectively. When immune spleen cells were treated with anti-Thy 1.2 serum the PD50 value was increased from 4.73 to 6.09, i.e., protection was reduced greater than or equal to 95%. Similar treatment of immune thymic cells reduced protection below measureable values. Anti-B cell sera (anti-IgM and anti-Ly 4.2) did not reduce the protective effect of immune spleen or marrow cells. These results indicate that a major protective cell population in each of these compartments was theta-positive. Experiments were carried out to characterize the cortisone (CS) and x-ray sensitivity of immune spleen, thymic, and marrow cells .When donor mice were treated with 12.5 mg of cortisone acetate/day for 2 days before lymphoid cells were harvested, the orotective effects of immune spleen cells, but not immune thymic or marrow cells, was reduced. When immune spleen cells were x-irrated in vitro, their protective effect was reduced by 350 R and abolished by 1000 R. When mice received whole boyd x-irradiation 24 hr before immune spleen cells were transferred their protective effect was reduced by 1000 R but only slightly lowered by 350 R. The possible significance of the multicompartmental nature of immunity to leukemia was discussed.     

Definition of a differentiation antigen on the surface of phagocytic cells of thymic reticulum which is down-regulated by interferon gamma

Monoclonal antibodies (MoAb) were raised against phagocytic cells of thymic reticulum (P-TR) grown in vitro. Each of the two MoAb (TR-1N, TR-3N) defined two polypeptides of 46-57 kDa on P-TR membrane. TR-1N and TR-3N recognize respectively 48 and 81% of P-TR, but do not recognize any cells in spleen, lymph node, thymic lymphocytes, or bone marrow. They bind to part of peritoneal macrophages and to macrophage cell lines J 774 and P 388 D1. Cell binding of TR-1N and TR-3N was compared by immunofluorescence to that of anti-CR3 antibody (Mac-1) which recognizes P-TR, a small number of cells in bone marrow and spleen, and a much higher percentage of peritoneal macrophages. The polypeptides recognized by TR-1N/TR-3N may be defined as differentiation antigens on accessory cells as they appear on bone marrow cells during maturation in vitro in the presence of L-cell supernatant which contains colony stimulating factor (CSF-1). Interferon gamma is able to down-regulate the expression of TR-1N/TR-3N antigen on P-TR membrane while that of Mac-1 is unchanged and that of Ia is up-regulated.     

The effect of colony stimulating factor on the synthesis of ribonucleic acid by mouse bone marrow cells in vitro.

The effect of granulocyte-macrophage colony stimulating factor (GM-CSF) on the synthesis of RNA in liquid cultures of mouse bone marrow, spleen, thymus, peritoneal, peripheral blood leukocytes and lymph node cells was investigated. GM-CSF appeared to stimulate RNA-synthesis in syngeneic bone marrow cells within ten minutes of adding it to the culture. In the presence of GM-CSF bone marrow cultures maintained their initial rate of RNA synthesis for approximately ten hours. GM-CSF had no apparent effect on the uptake of 3H-uridine into bone marrow cells. This stimulation was still observed in the presence of puromycin and cycloheximide, but was abrogated by actinomycin D. The magnitude of the stimulation was not affected by the density of cells between 1 and 20 x 10(6) cells/ml but was slightly smaller at 0.1 and 40 x 10(6) cells/ml. Increasing concentration of GM-CSF (up to 2 X 105 units per ml) led to increased stimulation of RNA synthesis in bone marrow cells, but a significant stimulation could be detected at concentrations as low as 800 units/ml. GM-CSF did not significantly stimulate RNA synthesis in spleen, thymus, mesenteric or subcutaneous lymph node cells. However a small stimulation was observed in peripheral blood leukocytes and peritoneal cells. Autoradiographic studies showed that GM-CSF stimulated RNA synthesis in blast cells, myelocytes, metamyelocytes and polymorphs. Nucleated erythroid cells showed no increased labeling with GM-CFS. Labeling in lymphoid-like cells was highly variable but the level of labeling did not appear to be influenced by GM-CSF.     

BN大鼠和豚鼠对卵清白蛋白致主动过敏反应的免疫学特性比较

目的 比较BN大鼠和豚鼠对卵清白蛋白(OVA)致敏前后机体免疫学特性的变化.方法 BN大鼠和豚鼠分别用OVA(每只1 mg)隔日致敏(i.p.),共5次;于末次致敏第10天以OVA(每只2 mg)激发致敏(i.v.);分别设正常对照组和OVA致敏组.于激发致敏后1h处死动物,分离腹腔肥大细胞、脾脏和骨髓,并制备脾脏和骨髓淋巴细胞.以annexin-V作为标志检测肥大细胞活性,同时以Fluo-3/AM标记胞内钙离子,检测钙离子水平;以PHA和LPS作为有丝分裂原,分别检测脾脏和骨髓T、B淋巴细胞活性.结果 ①致敏BN大鼠和豚鼠脾脏及骨髓T、B淋巴细胞活性均升高,其中骨髓淋巴细胞活性BN大鼠显著高于豚鼠,脾脏淋巴细胞活性两种属间差异无显著性;②致敏后,腹腔肥大细胞活性两种属间差异无显著性,但BN大鼠致敏后是致敏前的6倍,豚鼠是3倍;③肥大细胞内钙离子水平两种属致敏后均升高,豚鼠致敏前后钙离子水平具有统计学意义.结论 OVA致敏后,BN大鼠骨髓淋巴细胞活性明显高于豚鼠,豚鼠肥大细胞内钙离子较BN大鼠升高明显,肥大细胞活性两者无明显差异.因此,在实验中可以根据两种属在过敏反应中的特点以及具体的实验要求选择动物模型.     

Antigenic relationship between bone marrow lymphocytes cortical thymocytes and a subpopulation of peripheral T cells in the rat: description of a bone marrow lymphocyte antigen.

Populations of rat bone marrow lymphocytes (BML) consisting of approximately 90 percent, “tnull” cells were prepared by density gradient centrifugation, passage through a column of fine glass beads, and treatment with anti-T cell and anti-B cell serum plus complement. Antisera to these bone marrow lymphocytes were raised in rabbits. After absorption with RBC and peritoneal exudate cells, the anti-BML sera were found by immunofluorescence to react selectively with “null” cells in bone marrow, with cortical thymocytes, and with a cortisone-sensitive subset of T cells in blood and in spleen, possibly in red pulp. The antigen that is common to these cell types is designated the rat bone marrow lymphocyte antigen (RBMLA). Lymphocytes that are positive fur KBMLA are negative for another lymphocyte-specific heteroantigen, rat musked thymocyte antigen (RMTA). As shown previously, RMTA is present on medullary thymocytes and ou cortisone-resistant T cells in white pulp of spleen, paracortex of lymph node and thoracic duct lymph. It is postulated that two developmentally and functionally distinct lines of T cells exist in peripheral lymphoid tissues of the rat, one derived from cortical thymocytes and one derived from medullary thymocytes. It is further postulated that the “null” population of bone marrow lymphocytes contains the lymphopoietic stem cells from which these two lines of T cells originate.     

Cytotoxicity of lymphoid cells induced by Maclura pomifera (MP) lectin.

The cytotoxic activity of lymphoid cells stimulated with Maclura pomifera (MP) lectin was investigated. Spleen cells of Lewis (LEW) or Brown Norway (BN) rats induced a cell-dependent release of ⁵¹Cr from syngeneic, allogeneic, and xenogeneic erythrocytes when incubated with MP for 4–16 hr. The activity of MP differed from that of concanavalin A (Con A). MP exhibited a greater activity with spleen cells while Con A was more active when bone marrow cells were tested. Activity induced by MP required the presence of the lectin for at least 4 hr and was inhibited by melibiose, an inhibitor of MP binding. MP also stimulated phagocytosis by peritoneal macrophages of LEW rats, but phagocytosis was not responsible for the cytotoxic effect measured by ⁵¹Cr release. The ability of aggressor cells to bind MP did not correlate with their cytotoxic activity. The cytotoxic activity of spleen cells from athymic nude mice was equivalent to that of cells from euthymic littermates when stimulated with MP.     

W3/25+ T cells mediate the induction of immunologic unresponsiveness in enhanced rat recipients of cardiac allografts

Cellular suppressor mechanisms developing during the induction of immunologic enhancement were studied in LEW rats immunized actively with BN spleen cells and passively with LEW anti-BN hyperimmune serum 11 and 10 days before receiving a (LEW X BN)F1 cardiac allograft, respectively. With this regimen, graft survival is prolonged from 7.4 +/- 0.5 days in unmodified, acutely rejecting hosts to 25 +/- 12 days in enhanced recipients, with one-third of the grafts surviving indefinitely. To test for suppressor capacities, 60 X 10(6) splenic T helper/inducer (W3/25+) and T suppressor/cytotoxic (OX8+) cells were adoptively transferred 7 and 14 days after transplantation either into unmodified syngeneic LEW animals that received (LEW X BN)F1 test grafts 24 hr later or into T cell-deprived B rats with indefinitely functioning heart transplants that were reconstituted with sensitized lymph node cells (100 X 10(6). W3/25+ T cells harvested on days 7 and 14 from enhanced recipients prolonged test graft survival in unmodified hosts (13.1 +/- 2.3 and 13.3 +/- 1.3 days, respectively, p less than 0.001) and delayed rejection in reconstituted B rats from 6.7 +/- 0.5 to 18.2 +/- 6.5 and 23.3 +/- 5.8 days, respectively (p less than 0.001). OX8+ and B lymphocytes had no suppressor activity. However, enzymatic stripping of the surfaces of W3/25+ cells abrogated suppressor function. Similarly, after i.p. treatment with cyclophosphamide, W3/25+ T cells lost their suppressor properties. Lack of donor specific but not third party alloaggressiveness was demonstrated by the profoundly diminished ability of W3/25+ lymphocytes from enhanced hosts to recreate rejection in nonreconstituted B rats, even when exogenous interleukin 2 was administered. After pronase treatment, however, W3/25+ T cells were capable of inducing immunoresponsiveness at a tempo similar to naive T helper cells (31.5 +/- 12.5 vs 32.8 +/- 7.9). Thus, the present studies provide evidence for the development of a specific W3/25+ suppressor cell in the induction of active and passive enhancement. Coincident abrogation of specific T effector alloaggressiveness is apparently mediated by surface-blocking factors.     

Elevated cyclic AMP levels in mouse lymphoid tissue after stimulation by cholera enterotoxin in vitro (38468)

Addition of CT to suspensions of thymus, lymph node, spleen, or bone marrow cells in vitro resulted in a marked accumulation of cAMP with peak levels occurring 4-5 hr after incubation of cells with CT. Thymus cells showed the largest increase in cAMP, approximately 40-fold at 10 ng/ml CT. Bone marrow cells accumulated the least cAMP (1.5x), while intermediate levels were observed for spleen and lymph node cells (10-12x). Antiserum to CT prevented stimulation of increased cAMP levels. Repopulation studies using X-irradiated mice also showed that thymus-derived spleen cells accumulated more cAMP/10-7 cells than spleen cells from recipients given spleen or marrow cells. Spleen cells from athymic (nu/nu) mice also responded much less than did spleen cells from normal mice. Thymocytes appeared to bind CT to a greater degree than bone marrow cells. Spleen and lymph node cell suspensions also contained CT-binding cells and the number of CT-binding cells in these peripheral lymphoid tissues appeared approximately equal to the summation of the numbers observed in thymocyte and bone marrow cell suspensions. Stimulation of cAMP in lymphoid cells, especially thymocytes, by CT provides a pharmacological tool to investigate the mechanism and role of this nucleotide in the early events of antibody formation.     

Natural cytotoxic autoantibody against thymocytes in spontaneously hypertensive rats

A strain of SHR rats, which spontaneously develops hypertension and periarteritis nodosa, had a decreasing number of rosette-forming T cells in their thymuses and a progressive decline in cellular immune functions by aging. They were found to produce natural thymocytotoxic autoantibody (NTA) detected by a complement-dependent cytotoxicity test. This autoantibody occurred from 1 month of age and throughout life; the incidence was more than 60% of SHR rats at any age. Thymocytes from all six rat strains tested showed similarly high sensitivity to NTA but none of the strains tested produced NTA except the SHR strain. Rosette-forming thymocytes of WKA rats, which were separated by Ficoll gradient, showed much higher cytotoxic sensitivity to NTA than did whole thymocytes and nonrosetting thymocytes. The cytotoxicity of NTA was weak or negative for spleen cells, lymph node cells, bone marrow cells, and blood lymphocytes of WKA rats. However, the cytotoxic activity of NTA was completely absorbed with the thymus, spleen, lymph node cells, and brain homogenates and was partially absorbed with bone marrow cells, but not with liver and kidney homogenates. NTA in SHR rats was an IgM-globulin as determined by sensitivity to 2-ME treatment and by Sephadex G-200 column chromatography. These results suggest that NTA is responsible for the selective suppression of T-cell functions in SHR rats.     

In vitro reactivity in allograft tolerance: persistence of mixed leukocyte culture reactivity in highly tolerant rats.

Mixed leukocyte culture reactivity was studied in adult W/Fu rats judged to be highly tolerant after the inoculation of (W/Fu X BN)F1 hybrid spleen and bone marrow cells at birth. Reactivity was observed in a majority of tolerant donors tested and documented by quantitative dose-response and kinetic studies. Allograft tolerance cannot be explained by a complete lack of specific immune reactivity to tolerated alloantigens.     

The cellular basis of adjuvant arthritis. I. Enhancement of cell-mediated passive transfer by concanavalin A and by immunosuppressive pretreatment of the recipient

Two reliable systems for the cell-mediated passive transfer of adjuvant arthritis have been developed. Donor rats were sensitized with Mycobacterium butyricum in mineral oil. In the first system, intravenous injection of adjuvant-sensitized donor lymph node or spleen cells into adult-thymectomized, lethally irradiated, bone marrow cell-reconstituted syngeneic rats induced arthritis in the recipients. In the second system, adjuvant-sensitized donor lymph node or spleen cells were cultured in vitro with concanavalin A; these cells induced arthritis in normal recipients as well as in thymectomized, irradiated, bone marrow cell-reconstituted recipients. The passively transferred disease in both systems resembled classical adjuvant-induced arthritis clinically, radiographically, and histologically. Neither irradiated, adjuvant-sensitized donor cells nor cells from donors not injected with complete adjuvant could passively transfer arthritis.     

Identification of a macrophage-specific cell surface antigen.

A mouse-specific macrophage antigen (MSMA) was identified in NP-40 extracts of 125I-radiolabeled mouse preitoneal macrophages by using a rabbit anti-mouse macrophage serum (AMS) and SDS-polyacrylamide gel electrophoresis. The antigen was shown to have a m.w. of 83,000 daltons and was present on both normal and "activated" peritoneal macrophages. MSMA was also present on syngeneic adherent spleen cells, allogeneic peritoneal macrophages, a mouse macrophage cell line (P388D1), and exhibited some cross-reactivity with peritoneal macrophages from closely related species (rats and hamsters). MSMA was not present on nonadherent peritoneal exudate cells, spleen cells, erythrocytes, thymocytes, or bone marrow cells. Extensive absorptions of AMS with thymocytes and erytrocytes from mice were necessary to remove other antibodies that reacted with other mouse membrane antigens. An antiserum directed against a specific membrane antigen has great potential in elucidating structure-function relationships with regard to a number of macrophage activities.     

A novel rat monoclonal antibody directed against a population of activated mouse peritoneal macrophages

A hybridoma clone secreting rat monoclonal antibody (MAB) designated as 3F3.5F and which reacted with a population of activated tumoricidal mouse peritoneal macrophage (M phi) was produced by the fusion of mouse myeloma cells with rat spleen cells immunized against adherent BCG-activated mouse peritoneal exudate cells (adherent BCG-PEC). The antibody was cytotoxic and of the rat IgM class. The specific reactivity of the antibody with mouse primary cells and cell lines was examined by complement-dependent cytotoxicity and indirect immunofluorescence flow cytometry analysis. The antibody was found to bind to about 40% of the adherent BCG-PEC activated in vivo and elicited peritoneal macrophages activated in vitro by lymphokine and lipopolysaccharide (LPS), to about 35% of polymorphonuclear neutrophils (PMN) 15 hr after intraperitoneal injection of BCG, to about 30% of bone marrow cells from BCG-infected mice, to about 10% of P815 mastocytoma cells and to thioglycollate-induced PEC to some degree. It did not bind to other cells tested including BCG-induced peritoneal lymphocytes, non-tumoricidal PEC, thymocytes, spleen cells, resting bone marrow cells from normal mice, lymphomas, myelomas, fibroblasts, or macrophage-cell lines. Pretreatment of adherent BCG-PEC with MAB 3F3.5F and rabbit complement caused a considerable decrease in tumor cytotoxicity toward P815 cells, but the same pretreatment of non-adherent BCG-PEC had no inhibitory effect on natural killer activity for YAC-1 cells.     

Effects of B-lymphocytes from different organs on hemopoietic colony formation in the spleen by bone marrow cells]

The influence of B-lymphocytes from various sources on splenic colony formation was studied in the syngeneic system. B-lymphocytes were obtained by panning with IgG-fraction of rabbit anti-mouse Ig, absorbed on Petri dishes. In addition, adherent cells, Thy-1+ and SC-1+ were eliminated from the fraction of Ig(+)-cells. SC-1- and SC-1+ fractions, containing, respectively, stem cells and T-lymphocyte precursors, were obtained by panning with IgG-fraction of rabbit anti-SC-1 serum. SC-1- cells transferred to irradiated syngeneic mice did not induce colony formation in the spleen. Introduction of SC-1- and SC-1+ cells induced formation of colonies. A similar helper effect occurred when SC-1(-)-cells were introduced with bone marrow or lymph node B-cells, but not with splenic B-cells. Splenic, but not bone marrow and lymph node B-cells inhibited colony formation by combination of SC-1- and SC-1+ cells. All effects of Ig+ cells were abolished by treatment of cells with rabbit anti-MBLA serum. Thus, B-cells of various origin can either enhance or inhibit colony formation. The enhancing of inhibitory effect after B (MBLA+)-cells elimination from suspension of bone marrow and lymph node (but not spleen) Ig(+)-cells resulted from the activity of B-contrasuppressors.     

Tissue distribution, structural characterization, and biosynthesis of Mac-3, a macrophage surface glycoprotein exhibiting molecular weight heterogeneity

Mac-3 is a mouse macrophage differentiation antigen defined by a rat anti-mouse monoclonal antibody (MAb),M3/84. The structure, biosynthesis, quantitative surface expression, and distribution of Mac-3 have been studied by radiolabeling and isolation with MAb-Sepharose, saturation binding, absorption, and immunofluorescence flow cytometry. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Mac-3 migrates as a diffuse band with average Mr = 110,000. Labeling of intact cells with 125I and accessibility to MAb show it is present at least in part on the cell surface. Saturation labeling with 125I-MAb shows 4.2 X 10(4) cell surface sites on thioglycollate medium-elicited peritoneal macrophages. [35S]Methionine and [3H]glucosamine incorporation into Mac-3 by purified macrophages show it is a glycoprotein synthesized by these cells. Absorption shows Mac-3 is strongest in macrophages, present in lower quantities in lung, liver, bone marrow, and spleen, and undetectable in thymus, lymph node, brain, and heart. Immunofluorescent flow cytometry shows surface expression on thioglycollate-elicited macrophages but not bone marrow, spleen, lymph node, or thymus cell suspensions. Similar amounts of Mac-3 are immunoprecipitated from resident macrophages or macrophages elicited by sterile inflammatory agents, intracellular parasites, or immunomodulators, but the average Mr of Mac-3 varies from 92,000 to 110,000. Mac-3 is synthesized from precursor(s) of Mr = 74,000 and 79,000, identical in the different macrophages. Processing into the mature molecule, which migrates in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a more diffuse band and varies in Mr among macrophage elicited by different agents and to a lesser degree between different preparations of the same type of macrophage, occurs in 15 to 30 min.     

The effect of neonatal rat graft-vs-host disease (GVHD) on Fc receptor lymphocytes.

The level of Fc receptor rosette-forming lymphocytes (Fc-RFL) was examined in spleen and lymph node cell suspension from neonatal DA and BN rats inoculated within 24 hr of birth with either allogeneic L (experimental) or syngeneic (control) lymphoid cells. In addition, these levels were compared to fetal and neonatal animals that received no injection. The indicator cells (EA) were sheep erythrocytes sensitized with one-half concentration of the highest dilution of rabbit anti-sheep erythrocyte IgG(A) which agglutinated an equal amount of 1% suspension of E. Care was taken to exclude scoring macrophages by injecting colloidal carbon at least 1 hr before killing the test animals. The spleen of 19-day DA fetal rats exhibited a level of 19.3% Fc-RFL, similar to that of animals having received adult syngeneic cells at birth (40.0%) by day 7. Thereafter the level of Fc-RFL did not vary appreciably between these two groups. However, as early as 2 days after inoculation there was a significantly greater number of Fc-RFL in the spleen of experimental DA neonates compared to controls. The lymph nodes of experimental animals did not exhibit a significantly greater number of Fc-RFL until day 6 with both tissue compartments peaking at day 10 and remaining significantly higher than controls until death. In neonatal BN animals significantly higher levels of Fc-RFL in experimental animals were not evident as early and peaked later (day 12) in both tissue compartments but again these differences remained until death. Cytotoxic alloantisera demonstrated that on days 6, 10, and 12 most, if not all, of the Fc-RFL were host in origion in both DA and BN GVHD, with a very significant host plasma cell response in such GVHD animals. One-micron tissue section revealed the presence of a great number of plasma cell especially prominent in the medulla of lymph nodes with the cortex of lymph nodes and white pulp of the spleen markedly depleted of lymphocytes indicative of cytotoxicity.     

Effect of hydrocortisone and bacterial lipopolysaccharide on colony-stimulating activity production from mouse marrow adherent cells, spleen cells and peritoneal macrophages in vitro

The effect of hydrocortisone (HC) on colony-stimulating activity (CSA) production from mouse bone marrow adherent cells, spleen cells and peritoneal macrophages with or without bacterial lipopolysaccharide (LPS) stimulation was studied. CSA in the supernatant from bone marrow adherent cells incubated with HC was found to be five times higher than CSA from cultures without LPS stimulation. In contrast, the CSA production by spleen cells and peritoneal macrophages were significantly suppressed by HC in both LPS-stimulated and non-stimulated cultures. These studies suggest that the effect of HC on CSA production was quite different depending on the target cells.     

Reactivity of rabbit antiserum to guinea pig eosinophils.

Although the eosinophil has been recognized as a distinctive cell type for almost 100 years, the major functions of these cells remain unknown. As an approach to defining these functions we have treated guinea pigs with rabbit antiserum to eosinophils (AES) in an attempt to ablate these cells from tissues. Rabbits were immunized thrice with purified eosinophils and the antisera were absorbed with peripheral blood cells from guinea pigs made eosinopenic with methyprednisolone to remove antibodies reactive with serum proteins and erythrocytes. The resulting sera reacted strongly with eosinophils in cytotoxicity tests and had weak or no reactivity with neutrophils. However, absorption of AES with purified neutrophils removed antieosinophil activity. Intraperitoneal injection of potent AES into guinea pigs resulted in complete absence of eosinophils from the peripheral blood and from the peritoneal cavity with only transient or no reduction in circulating neutrophils. Eosinophils were also reduced in bone marrow, spleen, and intestine. The ability of neutrophils to absorb AES activity in spite of weak reactivity in cytotoxicity tests may reflect a quantitative difference in antigenic determinants between eosinophils and neutrophils.