Alkaline phosphatase in human lymphocytes. I. Cytochemical detection of alkaline phosphatase in normal human peripheral blood lymphocytes

The present paper deals with a sensitive cytochemical method of identifying alkaline phosphatase (AP) in rosette-forming lymphocytes gained from the peripheral blood of healthy human beings. The percentage of AP-positive lymphocytes amounts to 5%, with all cells comprising B- and O-lymphocyte population and with T-lymphocytes being negative. In a group of healthy test persons, recently, however, having undergone various inflammatory processes or virus diseases, the number of AP-positive lymphocytes is significantly higher, from 41-73% in B- and O-lymphocytes and from 6-38% in T-lymphocytes. This observation indicates that AP in lymphocytes may have a clinical significance in reactive lymphoproliferative processes, which must be elucidated by further investigations.     

Survival and function of bursa-derived cells in bursectomized chickens

Chicken given heterologous antibodies to μ chains as embryos and again following bursectomy at hatching were rendered permanently agammaglobulinemic, whereas treatment with anti-μ alone resulted in transient hypogammaglobulinemia. These and other observations indicate that sites other than the bursa of Fabricius are unable to serve as sources of immunoglobulin-producing cells. Agammaglobulinemia did not develop in birds bursectomized at 1, 14, or 35 days after hatch during an observation period of 21–125 wk. Some bursectomized birds developed 10 × normal IgM levels but were very deficient in IgG; this pattern persisted throughout life. B lymphocytes, identified by surface immunoglobulins in high density, were permanently deficient in bursectomized animals despite development of hypergammaglobulinemia and high levels of antibodies to ferritin following hyperimmunization. In experiments employing embryonic bursectomy, the level of the circulating pool of B lymphocytes was shown to be dependent upon the time allowed for the bursa to function before removal.     

Cytochemical demonstration of phenoloxidase in peripheral blood leukocytes]

A comparative application of phenoloxidase-demonstration and Pappenheim staining allows a sure differentiation of phenoloxidase-positive cells to be made, which can be found in the peripheral blood with different activity and different pattern of response. While eosinophils, neurophils, monocytes and lymphocytes contain phenoloxidase, basophiles do not.     

Genotoxicity of pemetrexed in human peripheral blood lymphocytes

Pemetrexed (PMX) is an antineoplastic antifolate used in the treatment of non-small cell lung cancer, mesothelioma and several types of neoplasms. Its toxicity in tumor cells has been linked with the potent inhibition of thymidylate synthase, dihydrofolate reductase and glycinamide ribonucleotide formyl transferase, and subsequent depletion of both purine and pyrimidine nucleotides. However, cytogenetic toxicity of PMX in non-diseased cells has not been adequately studied; despite the increasing data on the DNA-damaging potential of antineoplastic agents on normal cells. In the present study, the genotoxic potential of PMX was evaluated in peripheral blood lymphocytes obtained from healthy human subjects using chromosome aberration (CA), sister chromatid exchange (SCE) and micronucleus (MN) assays as the cytogenetic damage markers. Human peripheral blood lymphocytes were exposed to four different concentrations (25, 50, 75 and 100 μg/mL) of PMX for 24- and 48-h treatment periods. PMX significantly increased the formation of CA in 24-h treatment, but not in 48-h treatment. PMX did not increase the mean SCE frequency in 24- and 48-h treatment periods; however, there was a striking increase (although not statistically significant, p > 0.05) in the number of SCEs at 25 μg/mL (24- and 48-h treatment) and 50 μg/mL (24-h treatment) due to an increase of SCE at the single-cell level. Interestingly, PMX did not induce MN formation in either 24- or 48-h treatment periods. PMX strongly decreased the mitotic index (MI), proliferation index (PI) and nuclear division index (NDI) in 24- and 48-h treatment periods. Our results suggest that PMX has a potent cytotoxic effect against human peripheral blood lymphocytes at concentrations which are reached in vivo in the blood plasma.     

Radiosensitivity of peripheral blood lymphocytes in autoimmune disease

The proliferation of peripheral blood lymphocytes, cultured with Con A, can be inhibited by ionizing radiation. Lymphocytes from patients with conditions associated with autoimmunity, such as rheumatoid arthritis, systemic lupus erythematosus and polymyositis, are more radiosensitive than those from healthy volunteers or patients with conditions not associated with autoimmunity. The nuclear material isolated from the lymphocytes of patients with autoimmune diseases is, on average, lighter in density than the nuclear material from most healthy controls. This difference in density is not related to increased sensitivity to ionizing radiation but the degree of post-irradiation change in density (lightening) is proportional to the initial density, i.e. more dense nuclear material always shows a greater upward shift after radiation. The recovery of preirradiation density of nuclear material, 1 h after radiation exposure, taken as an indication of DNA repair, correlates with the radiosensitivity of lymphocyte proliferation (Con A response); failure to return to pre-irradiation density being associated with increased sensitivity of proliferative response. These results require extension but, taken with previously reported studies of the effects of DNA methylating agents, support the idea that DNA damage and its defective repair could be important in the aetio-pathogenesis of autoimmune disease.     

Subpopulations of human peripheral blood lymphocytes.

Multiple staining protocols have been developed for the classification of subpopulations of human peripheral blood lymphocytes. Of the non-T (E^?) cells, roughly half (10–20% PBL) have receptors for complement components as detected with complement-coated zymosan particles, but do not show Fc receptors as detected with Ripley IgG-coated human RBC. The other half are C^?, Fc⁺, with a small percentage possessing both receptors. The C⁺, Fc^? cells can be subdivided into cells which are IgM⁺ (75%) or IgM^?. Cells with Fc receptors detected with aggregated IgG were IgM⁺.     

Lectin-dependent cytotoxicity of human peripheral blood lymphocytes

The evaluative technique of lymphocyte cytolytic activity in human peripheral blood has been designed. The target cells, lectin (Con A) concentration and incubation time for measuring cytolytic activity of lymphocytes pre-purified from adherent cells have been selected. The mean values of lectin-dependent cytotoxicity in peripheral blood of 50 healthy donors are presented.     

Modeled microgravity inhibits apoptosis in peripheral blood lymphocytes

Microgravity interferes with numerous lymphocyte functions (expression of cell surface molecules, locomotion, polyclonal and antigen-specific activation, and the protein kinase C activity in signal transduction). The latter suggests that gravity may also affect programmed cell death (PCD) in lymphocyte populations. To test this hypothesis, we investigated spontaneous, activation- and radiation-induced PCD in peripheral blood mononuclear cells exposed to modeled microgravity (MMG) using a rotating cell culture system. The results showed significant inhibition of radiation- and activation-induced apoptosis in MMG and provide insights into the potential mechanisms of this phenomenon.