concanavalin-a and Leukocytosis

Investigation of peripheral blood cell count alterations in cases with hypersplenism, and an understanding of the relationship between splenic function and hematopoietic cell production require suitable experimental animal models. Previously described methods are either traumatic or require surgical intervention. We suggest a relatively simple method for achievement of a state mimicking hypersplenism in mice by intraperitoneal inoculation of syngeneic spleen cells. Mice were inoculated intraperitoneally with 3 x 10(7) splenocytes suspended in 0.3 ml phosphate buffered saline (PBS). After 2 months, the inoculated animals showed a progressive decrease in the peripheral white blood cell (WBC) counts and hyperplastic bone marrow that persisted until the experimental end point (7 months). Five days after inoculation of splenocytes stained with carboxy-fluorescein diacetate succinimidyl ester (CFSE), the majority of the stained cells was present in the peritoneal cavity (33%) and in the liver (13%), whereas the percentage of stained cells in the peripheral blood and the spleen cell suspension was negligible. The mitogen response of the peripheral blood mononuclear cells (PBMC) from treated mice to concanavalin A (Con A) remained unaltered. Splenocyte-inoculated mice that were further splenectomized did not show leukocytosis after splenectomy, as was observed in animals in which the spleen was removed without any pretreatment. The lack of any signs of discomfort in animals from the study group, in comparison with the visibly ill appearance and even death of mice in which hypersplenism was achieved by repeated injections of methylcellulose (MC), which served as controls, favors the convenience of the method.

Topics: Adoptive Transfer; Animals; Bone Marrow; Concanavalin A; Fluorescent Dyes; Hypersplenism; Injections, Intraperitoneal; Leukocytes; Leukocytes, Mononuclear; Leukocytosis; Liver; Methylcellulose; Mice; Mice, Inbred BALB C; Peritoneal Cavity; Spleen; Splenectomy; Transplantation, Isogeneic

Partial splenectomy is accepted as a treatment modality for hypersplenism permitting preservation of the spleen functions. Since a prominent leukocytosis is a marked event after total splenectomy, it was the aim of the present study to compare the peripheral white blood cell counts (PWBC) and immune response in mice following partial and total splenectomy.. Four groups of animals were included in the study: mice in which 70% of the spleen was removed, animals that underwent total splenectomy, mice with sham operation, and a group of mice that served as controls. The proliferative response of peripheral blood mononuclear cells, peritoneal cells, and splenocytes was examined using concavalin (Con) A.. In distinction from marked leukocytosis observed in mice after total splenectomy, in partially splenectomized mice the PWBC counts did not show any significant increase during a follow-up period of up to 2 months after surgery. The mitogen response of the mononuclear cells to Con A in partially splenectomized mice was similar to that of controls, while in animals after total splenectomy, it was increased in cells from the peripheral blood and decreased in those from the peritoneum.. The results indicate that removal of as much as about 70% of the spleen in mice is sufficient to maintain a normal PWBC count, suggesting a regulatory role of the spleen remnant on the PWBC production. The normal mitogen response of the cells to Con A indicates that the spleen rudiment preserves at least a part of the immune activity of the intact spleen.

Topics: Animals; Blood Cell Count; Bone Marrow; Cell Division; Concanavalin A; Female; Leukocyte Count; Leukocytosis; Mice; Mice, Inbred BALB C; Monocytes; Peritoneal Cavity; Spleen; Splenectomy; Time Factors

Increased number of peripheral white blood cells (PWBCs) has been noted after removal of the spleen.. To clarify the possible mechanisms by which splenectomy affects the PWBC number, the percentage of apoptotic PWBCs, the number and migration rate of peritoneal cells, as well as the 3H-TdR incorporation into PWBCs, were examined in splenectomized, sham-operated and control mice. In addition, the effect of control plasma injected to splenectomized animals on the number of PWBCs was examined.. One and two months after splenectomy the PWBC counts significantly increased, whereas the percentage of apoptotic PWBCs and the number of cells in the peritoneal cavity decreased in comparison with that of the control and sham-operated mice. Seventeen days after injection of carboxy-fluorescein diacetate succinimidyl ester (CFSE)-labelled peritoneal cells into the peritoneal cavity of the animals, their number was significantly higher in the peripheral blood and lower in the peritoneal cavity of the splenectomized animals in comparison with that of the control and sham-operated mice. Injection of control plasma into the splenectomized mice prevented the development of postsplenectomy leukocytosis. Finally, 3H-TdR incorporation into nonstimulated and Con A stimulated PBMCs from the splenectomized mice was higher as compared with cells from the control and sham-operated mice.. The results of the study present several mechanisms that may clarify the cause of postsplenectomy leukocytosis.

Topics: Animals; Apoptosis; Cell Division; Cell Movement; Concanavalin A; Female; Leukocyte Count; Leukocytes; Leukocytosis; Mice; Mice, Inbred BALB C; Mitogens; Peritoneal Cavity; Splenectomy

The effect of 2.5 h of treadmill running at 75.6 +/- 0.9% VO2max on circulating leukocyte and lymphocyte subpopulations, epinephrine and cortisol concentrations, and the Con A-induced lymphocyte proliferative response was investigated in 22 experienced marathon runners (VO2max 57.9 +/- 1.1 ml.kg-1.min-1, age 38.7 +/- 1.5 yrs). Blood samples were taken 15 min before (07.15h) and immediately after exercise (10.00h), with three more samples taken during 6h of recovery (11.30, 13.00, 16.00h). Ten sedentary controls (34.7 +/- 1.0 ml.kg-1.min-1, 45.3 +/- 2.3 yrs) sat in the laboratory during testing and had their blood sampled at the same time points. Serum cortisol was elevated relative to controls for more than 3 h post-exercise, and correlated significantly with the 3-h post-exercise, and correlated neutrophil/lymphocyte ratio (r = 0.68, p < 0.001). The concanavalin A- (Con A) induced lymphocyte proliferative response was decreased relative to controls for more than 3 h post-exercise, and except for the immediate post-exercise time point, tended to parallel the decrease in T cell (CD3+) concentrations.

Topics: Adult; Cell Division; Concanavalin A; Epinephrine; Exercise Test; Humans; Hydrocortisone; Leukocyte Count; Leukocytes; Leukocytosis; Lymphocyte Activation; Lymphocyte Subsets; Lymphocytes; Lymphopenia; Male; Middle Aged; Neutropenia; Neutrophils; Oxygen Consumption; Running; T-Lymphocytes

The intravenous or intraperitoneal injection of heparin fractions depleted of anticoagulant activity (HFDA) into mice, either at the time of immunization or challenge, inhibited hapten-specific delayed-type hypersensitivity (DTH) reactions. The loss was not due to functional elimination of sensitized lymphocytes, since mice sensitized with the contactant and then treated with HFDA retained their ability to transfer reactivity into normal syngeneic recipients. In contrast, lymphocytes from sensitized mice were unable to produce DTH reactivity in recipient mice pretreated with HFDA. The intravenous injection of HFDA resulted in a rapid, but transient increase in the number of circulating leukocytes. The intravenous injection of HFDA also reduced the footpad swelling that resulted from a local injection of concanavalin A. It is postulated that HFDA exercise their inhibitory effects on the DTH response by interfering with the migration of cells into the challenge site.

Topics: Animals; Anticoagulants; Concanavalin A; Heparin; Hypersensitivity, Delayed; Immunization, Passive; Immunosuppressive Agents; Injections, Intraperitoneal; Injections, Intravenous; Leukocytosis; Mice; Mice, Inbred BALB C; Trinitrobenzenesulfonic Acid