Evaluation of the specificity of a lymphoid chalone.

An extract from calf spleens, injected into mice, was found to inhibit their lymphocyte proliferative response to PHA-M and PWM in vitro. Despite the ability of the spleen extract to inhibit the response of lymphocytes to stimuli in vitro, no effect was observed on the repopulation of lymphocytes in the peripheral blood of sublethally irradiated mice. The data suggest that the spleen extract acts as a specific inhibitor of the innume competent cells since neither the precursors of lymphocytes nor other haematopoietic cells were affected.     

Cyclophosphamide and abrogation of tumor-induced suppressor T cell activity

Summary Previously we have demonstrated that the in vitro generation of P815-specific anti-tumor cytotoxic T lymphocytes (CTL) was suppressed by splenic suppressor T cells from late tumor-bearing hosts (TBH). Suppression is not caused by in vitro growth of P815 from splenic metastases, since suppression was also seen with spleen cells from late TBH mice bearing a hypoxanthine/aminopterin/thymidine-sensitive subline (PHS-5) of P815 in the presence of HAT. Cyclophosphamide has been shown to inhibit theinduction of suppressor cells selectively in a number of immune responses, but evidence that it can inhibit active tumor-induced suppressor T cells is limited. We have found that suppressor T cells already induced by P815 in syngeneic late TBH are sensitive to low doses of cyclophosphamide (50 mg/kg) given 1 day before spleen harvest, but the in vitro CTL response of late TBH spleen cells could not be restored by pretreating the mice with cyclophosphamide, even when exogenous interleukin-2 was added to the cultures. Although 50 mg/kg cyclophosphamide did not inhibit the CTL response of spleen cells from mice immunized with P815 +Corynebacterium parvum, the same dose of cyclophosphamide eliminated the CTL response of spleen cells from early TBH. Interleukin-2 (IL-2) did not overcome this effect of cyclophosphamide, suggesting a direct effect on CTL. Ultra-low-dose cyclophosphamide (10 mg/kg) did not adversely effect early TBH CTL but was still able to eliminate suppressor T cell activity from late TBH. Nevertheless, late TBH CTL remained unresponsive after pretreatment of mice with ultra-low-dose cyclophosphamide, even when exogenous IL-2 was added in vitro. CTL precursor frequency analyses demonstrated that cyclophosphamide pretreatment had little or no effect on the numbers of CTL precursors from early TBH. Late TBH CTL precursor cells were not detectable in these studies, with or without suppressor T cell inhibition by cyclophosphamide pretreatment. Thus, it appears that most CTL precursor cells may be lost or irretrievably inactivated in the spleens of late TBH mice.This work was supported by grants CA42443, CA48075 and T32-CA09210 from the National Cancer Institute, Department of Health and Human Services, and an American Cancer Society Clinical Oncology Career Development Award (H. D. Bear)     

In vivo and in vitro synergistic antitumor effect of interleukin-2-cultured tumor-bearer spleen cells and immune fresh spleen cells

Summary The synergistic antitumor effect of interleukin-2(IL-2)-cultured tumor-bearer spleen cells (cultured lymphocytes) and immune fresh spleen cells was examined. Tumor-bearer cultured lymphocytes were obtained by culturing BALB/c spleen cells from syngeneic MOPC104E-tumor-bearing mice for 11 days with crude IL-2 and a soluble tumor extract. These cultured lymphocytes had weak antitumor activity when transferred i.p. into tumor-bearing mice that had been inoculated i.p. with 10⁵ tumor cells 5 days previously. Immune fresh spleen cells, obtained from mice in complete remission after the treatment with cyclophosphamide, also had weak antitumor activity when transferred at the same schedule. The cultured cells and the fresh cells, mixed together before transfer, significantly augmented the therapeutic effect. At least 1×10⁷ tumor-bearer cultured lymphocytes and 4×10⁷ immune cells were needed for the synergistic effect. A tumor-specific combination was needed for both cultured and fresh cells. The effective subpopulation of tumor-bearer cultured lymphocytes was a cytotoxic one from an Lyt2⁺ precursor, and that of the immune fresh spleen cells was noncytotoxic, Lytl⁺ and Lyt2⁺ T-cells.A similar synergistic effect was also observed during in vitro coculture of tumor-bearer and immune cells. Cytotoxicity, as assessed by the ⁵¹Cr-release test, of tumor-bearer IL-2-cultured lymphocytes was maintained most effectively after 3 or 4 days of culture without IL-2 when the lymphocytes were cocultured with immune fresh spleen cells and tumor cells.     

STUDIES ON THE REGULATION OF LYMPHOCYTE PRODUCTION IN THE MURINE THYMUS AND SOME EFFECTS OF A CRUDE THYMUS EXTRACT

Cell proliferation in the murine thymus was studied in vivo under normal conditions and from 0 to 24 hr after a single injection of a water-soluble extract from mouse thymus, mouse spleen, and mouse skin. The thymus extract reduced during the first 24 hr the mitotic activity 40%; the spleen extract had a weaker inhibitory effect. The skin extract had no such effect. The thymus extract and spleen extract inhibited the flux of cells into the S phase 0–8 hr after the injection of the extract. Initial labelling index was also reduced in this period. Eight hours after injection of the thymus or spleen extracts the inhibited cells initiated DNA synthesis. The rate of progression of blast cells through the cell cycle was normal 24 hr after the injection of the extracts. It was deduced from the analysis that the thymus extract inhibits processes triggering Go/Gi cells into DNA synthesis, the inhibition of G₂ efflux being of minor importance. Finally a model for the regulation of proliferating thymic blast cells and the emigration of small lymphocytes from the thymus is proposed.     

Immunosuppression of T lymphocyte function by fractionated serum from tumor-bearing mice.

Sera from mice with transplanted 3-methylcholantrene-induced tumors have been shown previously to inhibit the function of normal lymphoid cells. When chromatographed on Sephadex G-150, the fraction eluting with immunoglobulin has been shown to inhibit the proliferative response of normal spleen cells to concanavalin A and to inhibit the in vitro antibody response to a T-dependent antigen, but has a lesser effect on the antibody response to a T-independent antigen. This paper deals with studies on the mode of action of the serum factor. The immunoglobulin containing fraction of serum from tumor-bearing mice inhibited the in vitro generation of both allogeneic and syngeneic cytotoxic lymphocytes. Time course studies demonstrate that the serum fraction inhibits the generation of antibody-producing and cytotoxic lymphocytes if added during the first 2 days of a 5-day culture. Serum fractions added after day 2 had no effect on the in vitro response. The serum factor appears to inhibit the generation of specific T cell function during the proliferative stage of development but has no effect on the differentiation stage which leads to either antibody-producing cells or cytotoxic lymphocytes.     

Failure of NZB spleen to respond to prethymic bone marrow suppressor cells.

Mouse bone marrow contains theta-negative lymphocytes that can suppress an in vitro plaque response by spleen cells primed in vivo with burro red blood cells (BRBC). These bone marrow cells are radiosensitive and can be induced with thymosin fraction 5 or alpha 1 thymic peptides to express the theta antigen. Enrichment for these suppressor pre-T lymphocytes can be achieved by a one-step density centrifugation, macrophage depletion, or a combination of both procedures. NZB mice, which spontaneously develop an autoimmune disorder, have a suppressor abnormality revealed by this assay system. Upon analysis, they have normal BM pre-T suppressor cells but their spleen cells are refractory to the BM suppressor signal. NZB BM suppressor cells inhibit the response by DBA/2 spleen cells, but DBA/2 BM suppressor cells do not inhibit NZB spleen. This resistance to suppression is a property of the B cell fraction recovered from NZB spleen.     

Expression of T-cell immunoglobulin- and mucin-domain-containing molecules-1 and -3 (Tim-1 and Tim-3) in Helicobacter pylori infection

Background: Th immune response plays an important role in Helicobacter pylori (H. pylori) infection. Tim‐1 and Tim‐3 are expressed on terminally differentiated Th2 and Th1 cells, respectively, and participate in the regulation of Th immune response. Until now, the role of Tim in H. pylori infection remains unclear. Materials and Methods: (1) Lymphocytes isolated from the spleen of BALB/c mice were co‐cultured with different concentrations of viable H. pylori. Alternatively, mice were challenged by viable H. pylori to set up the H. pylori infection model. (2) The expression of Tim‐1 and Tim‐3 on mRNA level in lymphocytes or spleen of mice was determined by RT‐PCR. The percentage of Tim‐3‐positive cells was determined by flow cytometric analysis. The production of cytokine in supernatants was measured by standard sandwich cytokine ELISA. Results: (1) Co‐culture: At 12 hours, there was markedly decreased production of Tim‐1 and increased production of Tim‐3 in lymphocytes co‐cultured with H. pylori compared with normal control. The change of Th2 cytokine had the similar tendency as that of Tim‐1 expression; alternatively, the change of Th1 cytokine had the similar tendency as that of Tim‐3 expression. (2) Infection: Tim‐1 expression was declined in infected mice compared with control group; in the contrast, Tim‐3 expression was increased. Furthermore, the expression of Tim‐1 and Tim‐3 mRNA in spleen was significantly positively correlated with the level of Th2 and Th1 cytokine in gastric homogenized supernatant, respectively. Conclusion: H. pylori could inhibit the differentiation of T lymphocytes toward Th2 cells, promote the Th1 cell differentiation, and induce Th1‐biased immune response. The expression of Tim‐1 and Tim‐3 could reflect Th2 and Th1 immune response, respectively, which provide evidence for the prevention and treatment of H. pylori infection and correlation diseases through regulation of Tim‐1 and Tim‐3.     

Trichinella spiralis: the influence of short chain fatty acids on the proliferation of lymphocytes, the goblet cell count and apoptosis in the mouse intestine

This study was carried out to determine the influence of short chain fatty acids (SCFA) on spleen and mesenteric lymph node lymphocyte proliferation, goblet cells and apoptosis in the mouse small intestine during invasion by Trichinella spiralis. BALB/c mice were infected with 250 larvae of T. spiralis. An SCFA water solution containing acetic, propionic and butyric acids (30:15:20 mM) was administered orally starting 5 days before infection and ending 20 days post infection (dpi). Fragments of the jejunum were collected by dissection 7 and 10 dpi, and were examined for apoptotic cells in the lamina propria of the intestinal mucosa, and for goblet cells. The proliferation index of the cultured spleen and mesenteric lymph node lymphocytes with MTT test was also determined. The orally administered SCFA solution decreased the proliferation of mesenteric lymph node lymphocytes in the mice infected with T. spiralis at both examination times, but did not influence the proliferative activity of the spleen cells. Seven dpi, both in the spleen and mesenteric lymph nodes, the highest proliferation index of concanavalin A (Con A)-stimulated lymphocytes was found in the group of uninfected animals receiving SCFA animals. This tendency could still be seen 10 dpi in the mesenteric lymph nodes but not in the spleen, where the proliferation index in this group had significantly decreased. In vitro studies revealed, that butyric and propionic acids added to the cell cultures suppressed the proliferation of Con A-stimulated mesenteric lymph nodes and spleen lymphocytes taken from uninfected and T. spiralis-infected mice. Acetic acid stimulated proliferation of splenocytes taken from uninfected mice but did not affect lymphocyte proliferation in mesenteric lymph nodes from uninfected or infected mice. Orally administered SCFA increased the number of goblet cells found in the epithelium of the jejunum 7 dpi, but this number had decreased 10 dpi. The number of apoptotic cells in the lamina propria of the intestinal mucosa of animals infected with the T. spiralis and receiving SCFA was also lower, particularly 10 dpi. The above results show that SCFA can participate in the immune response during the course of trichinellosis in mice.     

Distinctive cytokinetics of blastogenic responses by spleen cells fromLegionella pneumophila-sensitized mice

Legionella pneumophila, the etiologic agent of respiratory pneumonia and systemic infections of man and some experimental animals, was studied in regard to the ability of these bacteria to induce blastogenic responses by spleen cells from normal vs sensitized mice. Antigens from this organism, including whole cell vaccine, an outer membrane extract, and a purified lipopolysaccharide-rich antigen, induced blastogenesis of normal spleen cells with peak responses on day +3 in vitro, similar to the blastogenic responses of spleen cells from the same animals exposed to the plant mitogens phytohemagglutinin and Concanavalin A, or the nonspecific bacterial antigenEscherichia lipopolysaccharides coli (LPS). Spleen cells from mice vaccinated with killedLegionella or infected with a sublethal dose of these bacteria 3–4 weeks or more previously evinced increased blastogenic responses to theLegionella antigens but not to the nonspecific mitogens or theE. coli LPS. The spleen cells from legionellae-sensitized mice evinced not only heightened blastogenic responses on day +3 of culture but also heightened responses during day +5 of culture. Spleen cells from sensitized mice showed less responses to the nonspecific plant mitogens orE. coli LPS on day +5 of culture. These results support the view that, after sensitization of mice with a bacterial antigen such asL. pneumophila, spleen cells respond in a specific heightened blastogenic manner toLegionella antigen, and this response has a higher magnitude and is more prolonged than the non-specific responses of cells from normal mice.     

Mitogenic Activity of the Cell Walls of Mycobacteria,Nocardia, Corynebacteria and Anaerobic Coryneforms

The mitogenic activity of the cell walls prepared from Mycobacterium bovis BCG, Nocardia rubra, Corynebacterium diphtheriae PW8, and four species of Propionibacterium, Corynebacterium parvum ATCC 11829, Propionibacterium acnes C7, Propionibacterium granulosum ATCC 25564 and Propionibacterium avidum ATCC 25577, were investigated. These cell walls were active as mitogens on normal spleen cells, anti-θ sera-treated spleen cells, macrophage-depleted spleen cells of C57BL/6J mice and cortisone-treated thymocytes of C57BL/6J mice. It was also shown that these cell walls were mitogenic on spleen cells and macrophage-depleted spleen cells of congenitally athymic (nude) mice. The above results suggest that the cell walls investigated in this study act as mitogens on both thymus-derived lymphocytes (T-cells) and bone marrow-derived lymphocytes (B-cells).     

Enhancement of proliferation and differentiation in bone marrow hematopoietic cells by Spirulina (Arthrospira) platensis in mice

This study evaluates whether Spirulina, including its components such as phycocyanin, enhances or sustains immune functions by promoting immune competent-cell proliferation or differentiation. The effects of Spirulina of a hot-water extract (SpHW), phycocyanin (Phyc), and cell-wall component extract (SpCW) on proliferation of bone marrow cells and induction of colony-forming activity in mice were investigated. The Spirulina extracts, SpHW, Phyc, and SpCW, enhanced proliferation of bone-marrow cells and induced colony-forming activity in the spleen-cell culture supernatant. Granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin-3 (IL-3) were detected in the culture supernatant of the spleen cells stimulated with the Spirulina extracts. Bone marrow-cell colony formation in soft-agar assay was also significantly induced by the blood samples and the culture supernatants of the spleen and Peyer's patch cells of the mice which ingested Spirulina extracts orally for 5 weeks in in vivo study. Ratios of neutrophils and lymphocytes in the peripheral blood and bone marrow, consequently, increased in the mice. Spirulina may have potential therapeutic benefits for improvement of weakened immune functions caused by, for example, the use of anticancer drugs.     

Effect of Anti-Ia Serum In Vitro on Lipopolysaccharide-Induced Proliferative Responses of Murine Bone Marrow and Spleen Cells

The in vitro proliferative response of murine bone marrow cells and spleen cells to bacterial lipopolysaccharide (LPS) and the effect of anti-Ia serum on the response were studied. The incorporation of [³H]thymidine into cells prepared from bone marrow increased in the presence of LPS, but the addition of anti-Ia serum to the cultures reduced the incorporation. Pretreatment of bone marrow cells with anti-Ia serum and complement did not abolish the ability of the cells to respond to LPS, while the same pretreatment destroyed this ability in spleen cells. These results suggest that cultures of Ia-negative bone marrow cells generate Ia-positive cells during the culture period, and the Ia-positive cells are responsive cells to LPS. The proliferative response of 1- or 2-week-old spleen cells was easily suppressed by anti-Ia serum when compared with that of 4-week-old spleen cells. Furthermore, the responses of spleen cells obtained from γ-irradiated and syngeneic bone marrow cell-reconstituted mice were prominently suppressed by anti-Ia serum in comparison with that of normal adult spleen cells. These findings suggest that LPS-responsive lymphocytes in the developmental stage are quite sensitive to anti-Ia serum. The effect of anti-Ia serum on the maturation of bone marrow-derived lymphocytes was discussed.     

Inhibition of murine humoral immune responses by substances derived from trypanosomes

Previous studies of depressed immune responses in mice infected with the mouse-specific Trypanosoma musculi have produced no evidence of major involvement of typical suppressor lymphocytes or macrophages. We continue this line of investigation in the present report by demonstrating that: a) T. musculi strongly suppress the responses of nude mouse spleen cells to the T-independent antigen, TNP-LPS; b) spleen cell preparations of infected mice display a substantial proportion of cells bearing trypanosome-derived substances (TDS) demonstrable by specific rabbit antibody against T. musculi (RATS); c) treatment of spleen cells from infected mice with RATS plus C eliminates the inhibitory effect of these spleen cells on the immune responses of co-cultivated normal spleen cells; d) incubation in vitro of normal spleen cells with an extract of T. musculi results in progressive loss of the cells to respond to antigens and, in addition, confers on the treated cells to respond to antigens and, in addition, confers on the treated cells the property of inhibiting the responses of co-cultivated normal spleen cells; e) T. lewisi, the rat-specific trypanosome, fails to inhibit murine immune responses. We conclude that the immunoinhibitory effects of T. musculi on murine immune responses are associated with the cytophilic binding of TDS (possibly in the form of immune complexes) and that this vigorous mechanism of inhibition will be shown to involve nonspecific mitogenic and/or biosynthetic activation of lymphocytes.     

THE EFFECTS OF RED BLOOD CELL EXTRACTS ON THE PROLIFERATION OF ERYTHROCYTE PRECURSOR CELLS, IN VIVO

Saline incubation extracts of mature erythrocytes were assayed in vivo by a variety of techniques in order to study their ability to modify the proliferation of maturing erythroid cells. Using comparable extracts from granulocytes and lymphocytes, the specificity of the effect of the red cell extract for erythroid cells was confirmed by measurement of autoradiographic labelling indices, radio-iron incorporation and spleen colony growth. The erythroid cells were found to be very sensitive to the effects of the extract, as little as 10 μg per mouse producing a maximum effect on iron incorporation. It was found that the extract does not block erythroid cell proliferation completely but simply lengthens the cell cycle, mainly by increasing the G₁ phase of the cycle. There was no effect on the committed erythroid precursor cells. The in vivo activity, specificity and non-toxicity to the cells, together with the cells' sensitivity to red cell extract suggest, therefore, that this inhibitor may play a physiological role in the control of red cell production.     

Virus-specific T-cell sensitization

Syngeneic, semiallogeneic, or allogeneic spleen lymphocytes were transferred intonu/nu BALB/c mice, which were infected with vaccinia virus. Specific Sensitization of transferred thymus-derived cells was determined in vivo by mean survival time and virus titer in the spleen six days after infection, and in vitro by cell-mediated cytolysis of vaccinia virus-infected syngeneic target cells. Virus-specific Sensitization took place only after transfer of syngeneic or semiallogeneic spleen lymphocytes; allogeneic lymphocytes had no influence on mean survival time or virus titer and showed no virus-specific cytolytic activity in vitro. Infection of mice with vaccinia virus-strain WR, Elstree, DIs, or DIs-infected syngeneic fibroblasts resulted in the generation of virus-specific effector cells, while injection of a high amount of inactivated virus particles caused no Sensitization. These results suggest H-2 homology for production of virus-specific effector cells. Propagation of virus is not necessary, since early surface antigens, combined with syngeneic H-2 antigens, suffice for Sensitization of cytolytic T lymphocytes.Abbreviations used in this paper are as follows CMC cell-mediated cytolysis - CTL cytolytic T lymphocyte - LCM lymphocytic choriomeningitis - MHC major histocompatibility complex - MST mean survival time - T cell thymus-derived cell - TCID₅₀ 50 percent tissue culture infective dose     

Biological characterization of T and B lymphocytes separated from normal mouse spleen by a physical adherence column method

The capacity of spleen cell populations enriched for T and B lymphocytes by a physical adherence column method to respond in vitro to phytomitogens and allogeneic lymphocytes was determined. Column filtrate cells (T lymphocytes) responded well to phytohaemagglutinin- and mitomycin-C-treated allogeneic spleen cells, but poorly to pokeweed mitogen. Adherent cell populations from the column (B and some T lymphocytes) responded well to pokeweed mitogen, but poorly to phytohaemagglutinin- and mitomycin-C-treated allogeneic cells.Purified peripheral T lymphocytes prepared from normal mouse spleen by the column method reconstituted the depleted in vitro antibody response to the thymic-dependent SRBC antigen of all B lymphocyte sources tested, namely, spleen cells from congenitally athymic mice, neonatally thymectomized mice, and adult thymectomized mice which had been reconstituted with bone marrow, and a lymphocyte population prepared by incubating spleen cells with anti-θ serum and complement. When transferred with sheep erythrocytes to congenitally athymic mice, purified peripheral T cells restored the in vivo IgM and IgG responses of these animals. These results confirm that the column filtrate is a thymus derived subpopulation of cells capable of cell-mediated immunity and cooperation with B lymphocytes in humoral immunity both in vitro and in vivo.     

葛根素对U14宫颈癌小鼠血液流变学、脾淋巴细胞增殖及细胞毒性影响

摘要 目的：研究葛根素治疗对U14宫颈癌小鼠血液流变学、脾淋巴细胞增殖活性及对宫颈癌细胞毒性的影响。方法：45只雌性昆明小鼠随机分为对照组、模型组和葛根素组。模型组和葛根素组小鼠通过腋下注射U14小鼠宫颈癌细胞建立U14宫颈癌移植瘤小鼠,并且葛根素小鼠通过葛根素灌胃进行治疗,对照组和模型组小鼠给予等量生理盐水。比较各组小鼠血流变学、脾淋巴细胞增殖活性及对宫颈癌细胞毒性。结果：经葛根素治疗的葛根素组宫颈癌小鼠肿瘤重量显著低于模型组小鼠（P<0.05）,葛根素治疗宫颈癌小鼠的抑瘤率是（42.91±12.91）%。宫颈癌小鼠低切/高切全血粘度、血浆粘度值以及血细胞比容均显著升高（P<0.05）,而葛根素治疗可显著降低宫颈癌小鼠低切/高切全血粘度、血浆粘度值以及血细胞比容（P<0.05）。宫颈癌小鼠脾脏重量、脾脏指数和脾淋巴细胞体外增殖能力均显著下降（P<0.05）,而葛根素治疗可显著提高宫颈癌小鼠脾脏重量、脾脏指数和脾淋巴细胞体外增殖能力（P<0.05）。此外,经葛根素治疗的宫颈癌小鼠脾淋巴细胞对U14宫颈癌细胞细胞毒性显著高于模型组宫颈癌小鼠（P<0.05）。结论：葛根素治疗可降低U14宫颈癌小鼠血液粘度、改善血流变性质,并且可以提高脾淋巴细胞的增殖活性和对宫颈癌细胞的杀伤力。     

An extract of seeds fromAeginetia indica L., a parasitic plant,induces potent antigen-specific antitumor immunity in Meth A-bearing BALB/c mice

Summary The antitumor activity of an extract of seeds fromAeginetia indica L., a parasitic plant, was investigated. BALB/c mice, inoculated i.p. 1 × 10⁵ syngeneic Meth A tumor cells, were administered 2.5 mg/kgA. indica extract i.p. every 2 days from day 0. The untreated mice died of an ascitic form of tumor growth within 21 days, whereas all the treated mice completely recovered from tumor challenge without any side-effects. The extract did not exert direct cytotoxic activity against Meth A in vitro. Mice that survived after the first challenge as a result ofA. indica treatment overcame the rechallenge with homologous Meth A without additional administration of the extract. On the other hand, those mice could not survive after rechallenge with Meth 1 tumor cells, which were also established in BALB/c mice but were different in antigenicity from Meth A, suggesting the development of antigen-specific concomitant immunity in theA. indica-cured mice. In the induction phase of antitumor resistance in this system, CD4⁺ T cells appeared to be the main contributors, since in vivo administration of anti-CD4 mAb completely abolished such resistance. In contrast, anti-CD8 mAb administration did not influence the effect ofA. indica. The importance of CD4⁺ T cells in antitumor immunity was again clarified by Winn assay; that is, spleen and lymph node cells depleted of CD4⁺ T cells in vitro prior to assay abolished antitumor activity on co-grafted Meth A tumor cells in vivo.     

THE KINETICS OF LYMPHOCYTE RECIRCULATION WITHIN THE RAT SPLEEN

The migration of lymphocytes from the blood into the splenic pulp and the release of lymphocytes from the spleen into the blood was studied by isolating the rat spleen and perfusing it with 15 ml of recirculating, oxygenated blood. When thoracic duct lymphocytes labelled with tritiated uridine were added to the initial perfusate the concentration of these cells fell exponentially for 2–3 hr and then rose to a flat secondary peak. From this pattern it was inferred that small lymphocytes entered the spleen at a rate proportional to their instantaneous concentration in the perfusate, traversed the splenic pulp and re-entered the perfusate with a minimum transit time of 2–3 hr. The rate of release of small lymphocytes from the spleen was not influenced by the prevailing concentration of small lymphocytes in the perfusate but probably reflected the rate of migration into the spleen over a period earlier than 2 hr before. The rate of exchange of small lymphocytes between the blood and the intact spleen in vivo was estimated to be about 84 × 10⁶ cells/hr. The size of the intrasplenic pool of recirculating small lymphocytes was probably 400–500 × 10⁶ cells. The rate of migration of small lymphocytes into the spleen was not affected by prior irradiation of the spleen donor. When either of two antigenic materials were added to the perfusate no inhibition of lymphocyte migration into the spleen was noted although the release of lymphocytes from the spleen was diminished by the addition of a large dose of sheep erythrocytes.     

Enhancement of Antibody-Dependent Cell-Mediated Cytotoxicity (ADCMC) by an Interphase Material (IPM) extracted from a non-pathogenic strain of mycobacteria

Summary Interphase Material (IPM) extracted from M. smegamtis has been previously shown to protect mice against experimental tumors, to activate macrophages as measured by in vitro growth inhibition of neoplastic cells, and to induce nonspecific blast transformation of human lymphocytes and murine B cells.In the present report IPM was studied to determine its effect on antibody-dependent, cell-mediated cytotoxicity (ADCMC). Our findings demonstrate that IPM strongly enhances the ADCMC of murine spleen cells, even if it is injected 14 or 32 days prior to the cytotoxicity assay. An adherent population of spleen cells was shown to be responsible for this effect.