Comparison of human eosinophils from normals and patients with eosinophilia.

Previous studies of the biochemistry and physiology of eosinophils have relied upon cells obtained from patients with eosinophilia (EE). It is unknown whether such cells might have been activated or partially exhausted by the pathological state causing eosinophilia. We examined cell surface charge, membrane transport of deoxyglucose, activation of lyso-somal acid phosphatase, and oxidative metabolism to provide a profile to compare EE with purified normal eosinophils (NE) and normal neutrophils. Eosinophils or neutrophils were obtained in >95% purity from normal individuals and patients with eosinophilia of diverse etiologies. Cell surface charge was determined by electrophoretic mobility in micromoles per second per volt per centimeter. Normal eosinophils demonstrated a surface charge of 2.46+/-0.03. Stimulation of the cells by zymosan-activated serum (ZAS) reduced the surface charge to 1.82+/-0.02. In contrast, the charge of "resting" EE was already reduced (1.89+/-0.05) and was not altered by ZAS. Resting and stimulated neutrophils had a charge of 1.98+/-0.01 and 1.69+/-0.02, respectively. Uptake of [(3)H]2-deoxyglucose has been shown to reflect carrier-facilitated hexose transport in granulocytes. Deoxyglucose uptake by resting NE and NE stimulated by ZAS was 2.40+/-0.40 and 5.44+/-0.39 (cpm x 10(-3)/2 x 10(5) eosinophils), respectively. Resting and stimulated EE demonstrated deoxyglucose uptake of 7.55+/-0.58 and 15.3+/-0.6, respectively.Lysosomal acid phosphatase was determined by an electron microscopic cytochemical technique. In normal eosinophils and neutrophils, lysosomal acid phosphatase in mature cells is held in a latent form. Normal eosinophils demonstrated weakly positive acid phosphatase activity in 7.8+/-1.2% of the specific granules. Normal eosinophils, stimulated by opsonized staphylococci or the calcium ionophore A23187, develop rapid activation of acid phosphatase in approximately 80% of the granules throughout the cells. Resting EE were usually already activated and demonstrated acid phosphatase in 48.6+/-8.6% of the granules (range, 2-95% granules positive; significant activation was observed in preparations in EE from 11 of 15 patients). Oxidative metabolism was monitored by measurement of the hexose monophosphate shunt (HMPS) (metabolism of 1-[(14)C]glucose to (14)CO(2)). Previous studies demonstrated that resting EE have an HMPS activity which is nearly that of stimulated neutrophils, yet EE remain capable of further 7-10-fold increase when stimulated by opsonized zymosan. In contrast, the HMPS of NE (resting and stimulated) was not significantly different from that of neutrophils. Thus eosinophils obtained from patients with eosinophilia appear significantly activated when compared with normal eosinophils by the criteria of surface charge, activation of lysosomal acid phosphatase, membrane hexose transport, and hexose monophosphate shunt activities.

Solid tumor models for the assessment of different treatment modalities. XIII. Comparison of response and recovery of host and solid tumor to cyclophosphamide and radiation.

A study of the effects of local tumor radiation alone (1500R) and cyclophosphamide alone (150 mg/kg) on the experimental solid tumor rat hepatoma 3924A has been completed. Cyclophosphamide was more effective in controlling tumor growth than either radiation or 5-fluorouracil (5-FU) (150 mg/kg) previously reported. Parallel recovery of bone marrow with increasing animal survival in "split dose" cyclophosphamide toxicity studies (as with 5-FU) indicates that bone marrow is the critical organ for sequential chemotherapy. Recovery of intestinal mucosa following cyclophosphamide (and 5-FU) occurred much earlier than recovery of bone marrow, substantiating the fact that bone marrow is the critical organ governing the time of administration of a second series of chemotherapeutic agents. The longest period of time (seven days) between delivery of radiation and administration of cyclophosphamide resulted in the most effective use of the two modalities. Tumor growth delay was 1.2 times greater than the additive effects of each agent given alone. Radiation and cyclophosphamide given at other time intervals resulted in either an additive or less than additive effect. One of the greatest difficulties to overcome in the more effective clinical use of combined modality therapy is increased toxicity. In these studies, the least host toxicity occurred when the effects of combined radiation and cyclophosphamide on the tumor were greatest. Results of experimental studies to date suggest that sequential combined modality therapy may be given at a time of maximum tumor growth rate that occurs following the previous treatment series. Since the time of maximum tumor growth rate occurs after recovery of the bone marrow from the previous treatment series, combined chemotherapy-radiotherapy schedules of this type should permit sequential administration of chemotherapeutic agents, such as 5-FU and cyclophosphamide, at the time of enhanced tumor sensitivity and diminished host toxicity.

Phagocytic properties of isolated human eosinophils.

Viable eosinophils from normal human peripheral blood were separated by sedimentation through a nutrient-enriched linear gradient of sodium hypaque. Ingestion experiments with these cells showed that eosinophils would phagocytose latex beads coated with a mixture of allergen and corresponding allergic human serum. The stimulatory activity of the allergic serum correlated with the IgG fraction and not with those properties associated with IgE. Eosinophils isolated from allergic donors were found to be inferior in their phagocytic ability when compared with eosinophils from normal cell donors.