Number Of Peritoneal Exudate Cells Research Articles

Effects of N-nitrosodimethylamine on tumor susceptibility.

Dimethylnitrosamine (DMN) exposure altered the activity of the macrophage and natural killer (NK) cell defense mechanisms against the B16F10 melanoma in B6C3F1 adult female mice as assessed by several immunologic assays. Following 14 daily exposures (i.p.) to 1.5, 3.0, or 5.0 mg DMN/kg, mice were injected (i.v.) with B16F10 melanoma. The incidence and number of lung nodules, determined 18 days after challenge, were decreased in the DMN-exposed animals. The initial observation indicated the mice exposed to 3 mg/kg DMN were afforded the greatest protection. However, when mice exposed to the highest dose of DMN were divided into subgroups of mice with or without ascites, there was a degree protection seen in the 5-mg/kg-treated mice without ascites that was comparable to that of the 3-mg/kg group. The development of ascites is an overt toxic effect reflecting damage to the liver and was frequently associated with exposure to 5 mg/kg DMN. Exposure to DMN produced only slight changes in the activity of splenic NK cells as determined by the cytotoxicity of 51Cr-labelled YAC-1 cells. The activity was significantly increased only in mice exposed to 3 mg/kg DMN and only at effector:target (E:T) ratios of 30:1 and 10:1. Interestingly, the activity of the NK cells was significantly decreased at all E:T ratios in mice exposed to 5 mg/kg that developed ascites. The number of peritoneal exudate cells was decreased, albeit nonsignificantly, in a dose-related fashion. The phagocytic activity, as measured by the uptake of fluorescent latex beads, was increased in a dose-related fashion with significance noted at the highest dose of DMN. The role of the macrophage in the increased resistance to the tumor challenge was assessed with bone marrow derived macrophages. The cytostatic activity versus B16F10 tumor cells, as measured by the uptake of 3H-thymidine, was markedly increased in the bone marrow derived macrophages from DMN (5mg/kg) mice when compared to vehicle controls. These results suggest that exposure to DMN alters bone marrow, particularly the differentiation of effector tumoricidal cells, which renders the host more resistant to metastatic tumor formation.

Effects of high-dose methotrexate on rat alveolar and inflammatory macrophage populations.

Methotrexate (MTX) is used clinically in high doses to treat a variety of neoplastic diseases. Although it has been recognized that such aggressive chemotherapy can result in suppression of cellular host defense mechanisms, phagocytic cell function during MTX therapy remains poorly understood. The present study was designed to examine the effects of a single high dose of MTX on alveolar and inflammatory peritoneal cell populations in the rat. Male Sprague-Dawley rats were treated with a single intraperitoneal injection of MTX (25 or 50 mg/kg) and subsequent alterations in the composition of peripheral blood white cells (WBC), a peritoneal inflammatory exudate, and the resident alveolar macrophage (AM) were measured 1-4 days after MTX treatment. A severe depression in the polymorphonuclear leukocyte (PMNL) and monocyte populations in the peripheral blood was observed 72 and 96 h after either dose of MTX. Similarly, the total number of peritoneal exudate cells, collected 72 h after a caseinate inflammatory stimulus, was reduced by 50% after MTX treatment. When the cellular composition of the peritoneal exudate was examined, it was observed that macrophage and lymphocyte numbers were selectively depressed. In addition, the number of AM obtained by lung lavage was significantly reduced 72 and 96 h after MTX injection. Although both peritoneal and alveolar macrophage numbers were diminished, in vitro phagocytic activity was not impaired 72 h after MTX injection. These studies demonstrate that a single, clinically relevant dose of MTX, in addition to depressing PMNL and monocyte levels in the peripheral blood, can also impair the accumulation of macrophages at a site of tissue injury and the influx of macrophages into lung alveoli. These findings suggest that the capacity of the mononuclear phagocyte system to respond to an infectious or tumor cell challenge may be severely compromised during MTX treatment.

Induction of Natural Killer Cells and Interferon during Mouse Hepatitis Virus Infection of Resistant and Susceptible Inbred Mouse Strains

Following infection by mouse hepatitis virus (JHM strain), an induction of natural killer (NK) cell activity was observed in C3H mice, which are considered to be sensitive to JHM virus infection. In contrast, mice of the resistant SJL strain did not show any increase of NK cell activity after JHM virus infection. However, infection of both SJL and C3H mice with mouse hepatitis virus type 3 (MHV3) resulted in an increase of NK level, comparable to that observed with the JHM virus infection in the C3H strain. No significant differences were observed in the NK cell activity of the peritoneal exudate or spleen cells of infected mice. Low levels of interferon were detected in serum or peritoneal exudate of C3H mice infected with JHM virus 18 or 24 hours before, but no detectable early interferon production was found. Also no interferon could be detected in the resistant SJL mice. After JHM virus infection, the number of peritoneal exudate cells (PEC) was increased significantly in C3H mice but not in SJL mice. Macrophages obtained from the C3H mice supported virus replication, whereas SJL macrophages did not. Our data suggest that NK cells do not play a role in the resistance of SJL mice against JHM virus infection but may participate in the defence mechanisms against this virus in C3H mice.

Potentiation of tumoricidal properties of murine macrophages by Nocardia rubra cell wall skeleton (N-CWS).

Intraperitoneal injection of squalene-treated cell wall skeleton of Nocardia rubra (N-CWS) caused increase in number of peritoneal exudate cells (PEC). Adherent macrophages obtained from N-CWS-treated PEC suppressed growth of methylcholanthrene-induced fibrosarcoma (Meth-A), when injected intradermally with the tumor cells into BALB/c mice. The macrophages showed strong cytotoxicity against Meth-A cells in vitro. When treated with 10 micrograms/ml of N-CWS in vitro, proteose peptone-induced macrophages acquired tumoricidal property but resident macrophages showed no cytotoxicity after the treatment. In the supernatant of spleen cells cultured for 72 hours in the presence of N-CWS (10 micrograms/ml), the presence of (a) factor(s) with macrophage activating effect was observed. This factor, shown to be identical to macrophage activating factor (MAF) in molecular weight, showed synergy with N-CWS in potentiating macrophage cytotoxicity against tumor cells.

Analysis of therapeutic effect in experimental chemoimmunotherapy for rat ascites tumor.

The lyophilized, squalene-treated Nocardia rubra cell wall skeleton (N-CWS) was confirmed to produce tumoricidal peritoneal macrophages resulting in inhibition of tumor growth when injected locally into the syngeneic ascites fibrosarcoma, AMC 60 in ACI/N rats. Furthermore, N-CWS was found to augment therapeutic effect when administered repeatedly after a single local injection of mitomycin-C (MMC). To analyze the effects, various in vitro cytolysis assays were performed using N-CWS-activated peritoneal macrophages. When tumor target cells were exposed in vitro to MMC, the resulting cytolysis in the presence of N-CWS-activated macrophages was similar to cytolysis of intact target cells. On the other hand, when N-CWS-activated macrophages were exposed to MMC, the tumoricidal activity was lost significantly, depending on exposure to MMC. When tumor target cells and N-CWS-activated macrophages were simultaneously exposed to MMC, tumor-cell cytolysis was strikingly depressed. In the final experiment, combined injection of MMC and N-CWS into the ascites tumor resulted in remarkable increases not only in peritoneal exudate cell number, but also in in vitro tumoricidal activity of peritoneal macrophages as compared to those induced by either agent alone. In addition, the production of tumoricidal macrophages by IP injection of MMC alone was also noticeable, as described previously. These results possibly indicate the involvement of macrophage activation in induction of therapeutic effect in chemoimmunotherapy.

Complement Synthesis by Guinea Pig Peritoneal Macrophages: Failure To Detect Chemical Carcinogens<xref ref-type="fn" rid="fn2">2</xref>, <xref ref-type="fn" rid="fn3">3</xref>

In vitro production of the second and fourth components of complement (C2 and C4, respectively) by peritoneal macrophages from noninbred Hartley guinea pigs was tested after the animals had been inoculated with known carcinogens. The system demonstrated the capacity of N-nitrosodimethylamine to decrease C2 and C4 production. However, a similar decrease in C2 and C4 production was seen with only CCl4, 1 of the 10 chemical carcinogens studied. This system had little usefulness as a short-term screening procedure for the detection of carcinogenicity. The effect of the carcinogens on several other functions of peritoneal macrophages was also determined. The number of peritoneal exudate cells (PEC) was significantly lower in carcinogen-inoculated animals than in solvent-inoculated controls for three carcinogens: BeSO4, P < 0.005; CHCl3, P < 0.025; and CCl4, P < 0.01. However, the capacity of the PEC to adhere to plastic was decreased by only CHCl3 (P < 0.05), and adherent cells from all guinea pigs produced normal amounts of total secreted protein.

Modulation of Inflammatory Peritoneal Cell Function and Metabolism by Methotrexate

Methotrexate (MTX) is widely used in cancer chemotherapy, although the effects of MTX on cellular antitumor defense mechanisms are poorly understood. To evaluate the effect of MTX on the cellular inflammatory response, male Sprague-Dawley rats were treated with four daily i.p. injections of MTX or a control vehicle. Rats treated with daily doses of 1.2 mg/kg MTX demonstrated a significant reduction in number of peritoneal exudate cells, specifically macrophages, collected 96 hours following the inflammatory stimulus. To determine if metabolic perturbations also occur upon exposure to MTX, glucose oxidation and protein synthesis by inflammatory cells were monitored in vitro. At a MTX concentration of 10(-3)M, peritoneal exudate cell 14C-1-glucose and 14C-6-glucose oxidation was significantly depressed. 14C-1-leucine incorporation into TCA precipitable protein was inhibited at 4 x 10(-3)M MTX. Peritoneal exudate cell viability was not altered at these concentrations of MTX. These results demonstrate that MTX, at therapeutic concentrations, can depress the influx of macrophages to a inflammatory site and also diminish energy metabolism and protein synthesis by inflammatory cells.

The regulatory effect of macrophages on the antigen-induced lymph node cell proliferative response

Employing an antigen-induced T cell-dependent lymph node cell (LNC) proliferative assay in the mouse we observed differences in the capacity of unstimulated and thioglycollate-activated peritoneal exudate cells (PECs) to present antigen. Antigen-primed LNCs can be induced to proliferate by a brief (2 hr) antigen exposure and the addition of various numbers of thioglycollate PECs (thio-PECs) modifies the proliferative response depending on the ratio of PEC LNC in cultures. With ratios of 3–12% both DNA and protein synthesis were enhanced, but at ratios greater than 12% suppression was significant. Treatment of thio-PECs with mitomycin C, irradiation (3000 rad), anti-Thy 1.2, or anti-Ia plus complement did not alter suppression, suggesting the possibility that the Ia negative macrophages present in the PECs were involved in the suppression. An enhancing effect on the proliferative response was noted following the addition of small numbers of thio-PECs. This was comparable to that seen with an equivalent concentration of supernatant from thio-PECs suggesting that soluble factors play an important role. Two enhancing fractions (separated on a G-75 column) which were themselves mitogenic were identified which eluted with approximate molecular weights of 15,000 and 60,000.

Macrophage Function in Tumor-Bearing Mice: Tumoricidal and Chemotactic Responses of Macrophages Activated by Infection with Mycobacterium Bovis, Strain BCG

Abstract Peritoneal macrophages from mice with syngeneic transplantable footpad tumors were less responsive in vitro to chemotactic stimuli than were macrophages from mice without tumors. The macrophage chemotactic defect was about half the normal response and was evident in mice with nonpalpable 3 to 5-day tumors. Depressed macrophage chemotaxis persisted until the death of the mouse at 6 to 8 weeks. The number of peritoneal exudate cells elicited in tumor-bearing mice 8 to 14 days after intraperitoneal infection with BCG was also depressed. This inflammatory defect was detected 1 week after tumor transplantation and persisted for more than 5 weeks. The yield of peritoneal exudate macrophages induced by BCG infection in mice with tumors was about half the normal yield. In contrast to resident peritoneal macrophages, peritoneal exudate macrophages induced by BCG in tumor-bearing mice were as responsive to chemotactic stimuli as BCG-activated macrophages from control mice. BCG-activated macrophages from tumor-bearing or control mice were cytotoxic to tumor cells in vitro; no differences in tumoricidal responses of these BCG-activated macrophages were evident. The number of BCG organisms necessary to induce activated tumoricidal macrophages in mice with or without tumors was also identical. Peritoneal exudate macrophages from tumor-bearing mice infected with BCG at a dose that did not induce tumoricidal cells showed chemotactic defects similar to those of the resident macrophages. These results suggest that the response to BCG infection in tumor-bearing mice was defective. The defect was quantitative: a sequela of abnormal inflammatory responses. BCG-activated macrophages from tumor-bearing and control mice were functionally indistinguishable.

Antitumor effect of combined use of OK-432 and yeast cell wall with mitomycin-C in mice.

Tumor-inhibitory effect of combined use of mitomycin-C and streptococcal preparation (OK-432) or yeast cell wall (YCW) was examined. Twenty-four hours after intraperitoneal inoculation of Ehrlich carcinoma cells, combination therapy was carried out and tumor growth was observed for 40 days. About one-half of mice treated with yeast cell wall at a single dose of 1 mg survived free of tumor. Mitomycin-C at a single dose of 2 microgram was not effective. However, in combination with yeast cell wall, tumor suppression was observed in 70% of the mice. This tumor-inhibitory effect was enhanced by subsequent treatment with OK-432 or yeast cell wall. When these materials were injected separately or in combination with mitomycin-C, the number of peritoneal exudate cells increased about 3 to 6 times after 3 days and these cells exhibited cytotoxic effect on tumor cells. Hemagglutinating antibody to sheep erythrocytes was hardly affected by the combination therapy.

Role of donor immunocompetent cells in allograft rejection.

Allotransplantable lines of the BALB/c (H-2d) Leydig cell tumor C4092 were established in DBA/1 (H-2q) mice after maintenance in organ culture. These modified tumors had reduced immunogenicity but were recognized and rejected by previously sensitized DBA/1 mice. The addition of 3.4 X 10(3)-1 X 10(5) peritoneal exudate cells (PEC) from untreated BALB/c mice to cell suspensions of the modified tumor did not restore Immunogenicity when the cell mixture was Inoculated sc Into DBA/1 recipients. However, when equivalent numbers of PEC or spleen cells were inoculated iv into animals receiving the tumor cell suspension sc, the acceptance of the tumors was significantly reduced or prevented. This indicated that the BALB/c lymphoid cells inoculated iv stimulated the immune system of the host, which in turn recognized the tumor cell inoculum. The lack of effect of the BALB/c lymphoid cells when admixed with the tumor did not support the assumption that the loss of passenger lymphoid cells was responsible for the allotransplantability of grafts after organ culture explantation. Additional evidence was presented that supports our view that the reduced immunogenicity was associated with a phenotypic modification of the tumor cells per se.