STIMULATION OF STEM CELL GROWTH BY THE BRYOSTATINS

Abstract: In vivo and in vitro methods are taught for stimulating the differentiation of stem cells using certain bryostatins. Stem cells can be induced to form granylocytes, macrophages and erythrocytes. In addition, the cytotoxicity of mature neutrophils can be activated. These methods may substitute for those requiring human colony stimulating factors.

Description: STIMULATION OF STEM CELL GROWTH BY THE BRYOSTATINS The work reported here was partially supported by grants from National Institutes of Health. The U.S. Government may retain certain rights in this invention. TECHNICAL FIELD OF THE INVENTION This invention relates to chemical agents hav¬ ing stimulatory effects on growth and activity of hematopoietic cells. More particularly,, the inven¬ tion relates to the use of bryost tins to stimulate growth and activity of hematopoietic cells. BACKGROUND OF THE INVENTION The bryostatins are a family of macrocyclic lactones which have been isolated from specimens of marine bryozoans. The sea-mat Buqula neritina has been the source of ia«. y of the bryostatins. Others have been isolated from the marine animal Amathia convoluta, also a member of the phylum Bryozoa. All of the bryostatins are derived from the bryopyran ring system, (Pettit et al, Journal of Natural Products, Vol. 46, pp. 528-531, 1983) and all are reported to have antineoplastic activity against a single murine leukemia cell line, the P388 lymphocytic leukemia line. The bryostatins substantially inhibit P388 cell growth _in vitro, and also are able to increase the life span of mice injected with P388 lymphocytic leukemia " cells. Bryostatins 1-8 are described in Pettit U.S. 4,560,774 and U.S. 4,611,066. There are many health conditions which result in a deficiency of hematopoietic cells,, For exam¬ ple, a problem often arises in the treatment of cancers with antineoplastic agents; »ese agents can have an inhibitory effect on normal bone marrow progenitor cells (stem cells). In addition, there are many diseases in which neutropenias result, such as acquired .itnmune deficiency syndrome (AIDS). There are also many conditions in which erythroid cells are insufficient to support normal activity, such as congenital anemias, and Fanconi's anemia. Diseases such as rheumatoid arthritis and lupus erythematosus, often result in depletion of certain populations of blood cells. Therefore there is a continuing need in the art for agents which are safe to administer and which stimulate the development of various types of hematopoietic cells. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of stimulating stem cells to pro¬ liferate and to differentiate to form granulocytes,. macrophages, or erythrocytes, i_n vitro. It is another object of the invention to pro¬ vide a method of stimulating stem cell prolifera¬ tion and differentiation in a mammal. It is an additional object of the present invention to provide a method of stimulating stem cell proliferation and differentiation in tumor-bearing mammals. It is yet another object of the present inven¬ tion to provide a method of activating neutrophils and other immune regulatory cells, e.g., T lymphocytes and acrophages, _in vitro. It is still another object of the present invention to provide a method of activating neutrophils and other immune regulatory cells in a mammal. These and other objects of the invention are provided in the detailed description below. In one embodiment a method of stimulating stem cells to form granulocytes, macrophages, or erythrocytes, is provided comprising: obtaining a cell preparation containing stem cells and incubating the cell prep¬ aration jj vitro with an effective amount of a bryostatin having an acylated C20 carbon to stimu¬ late formation of granulocytes, macrophages or erythrocytes, whereby said formation is stimulated. In yet another embodiment of the present invention a method is provided for stimulating stem cell differentiation to form granulocytes, eosinophils, basophils, platelets, macrophages or erythrocytes in a mammal, comprising: administer¬ ing a bryostatin having an acylated C20 carbon to the mammal in an amount effective to stimulate for¬ mation of granulocytes, eosinophils, basophils, platelets, macrophages or erythrocytes, whereby said formation is stimulated. In yet another embodiment of the present invention, a method is provided of activating neutrophils and other immune regulatory cells, com¬ prising: obtaining a neutrophil or other immune regulatory cell preparation and incubating the cell preparation jn vitro with an amount of a bryostatin having an acylated C20 carbon effective to activate the cytotoxicity of the neutrophils and other immune regulatory cells, whereby said cytotoxicity is activated. In another embodiment of the present inven¬ tion, a method is provided. of activating neutrophils and other immune regulatory cells in a mammal., comprising: administering a bryostatin having an acylated C20 carbon to the mammal to activate neutrophil and other immuneregulatory cell cytotoxicity, whereby said cytotoxicity is activated. The methods of the present invention provide means of stimulating stem cell growth with mole¬ cules which show low levels of toxicity. The bryostatin molecules, which are based on a 37 car¬ bon macrocyclic lactone structure, can substitute for naturally occurring colony stimulating factors for some purposes. However, in other ways the activity of the bryostatins appears to differ from that of naturally occurring colony " stimulating fac¬ tors. Thus the bryostatins, but not colony stimu¬ lating factors, stimulate stem cell differentiation without also stimulating growth of neoplastic cells. BRIEF DESCRIPTION OF ^SS DRAWINGS Figure 1 depicts the chemical structures of the bryostatins. s,ι«l At bryostatin 1; panel Bj bryostatin 9; pane * , C% bryostatin 8; panel Dj bryosratin 3; panel Zt bryostatin 13. Figure 2 shovrs the effect of bryostatins on granulocyte-macrophsge colony growth in vitro. Figure 3 shows the effect of bryostatin 1 on the growth of transferred clones. Clones were ini¬ tially grown in the presence of bryostatin 1, and transferred to media containing either bryostatin 1, recombinant human GM-CSF, or media alone. Figure 4 depicts the effect of bryostatin 1 on growth of human erythroid progenitors. Figure 5 shows the generation of chemiluminescence by neutrophils incubated with bryostatins 1 and 13, as well as recombinant human GM-CSF, and phorbol 12-myristate 13-acetate (TPA). DETAILED DESCRIPTION It is a finding of the present inventors that certain bryostatins, are able to effect hematopoiesis. The morphological analysis of the colonies which are stimulated by bryostatins reveals that primarily mixed granulocyte-macrophage colσr.Hs and pure granulocyte colonies are formed from light-density, adherence-depleted, normal human bone marrow cells. The bryostatins themselves can be obtained by extraction and purification from the marine bryozoan Buqula neritina. Description of the extraction and purification techniques can be found in Pettit et al, Journal of American Chemical Soci¬ ety, Vol. 104, pp. 6846, 6848, 1982, and Pettit et al, Journal of Natural Products, Vol. 46, pp. 528-531, 1983. Some of these compounds are also described in U.S. Patents 4,560,774 and U.S. 4,611,066. Generally, the bryostatins can be iso¬ lated and purified by solvent extraction, partition chromatography, selica gel chromatography, liquid-liquid distribution in a Craig apparatus, absorption on resins and crystallization from sol¬ vents. Isolation and purification methods can be monitored at each step by performing jln vitro or in vivo anti-tumor tests, or by looking for activation of neutrophils or stimulation of formation of granulocytes, macrophages or erythrocytes frsrr. stem cells. Not all bryostatins have the same amount of activity. For example, in the granulocyte-macrophage colony growth assay, bryostatin 1 has more activity than 3 which had more activity than 8 which had more activity than 9. Bryostatin 13 was totally inactive in this assay. When the structure-activity relationships of the bryostatins are examined, the results indi¬ cate that both the hematopoietic colony stimulating activity as well as the functional activation of neutrophils may be dependent upon acylation of car¬ bon 20 (see figure 1). Thus, when the short-chain, saturated butyric acid was substituted in bryostatin 1 at carbon 20, the resulting bryostatin 9 was a much less potent stimulator of granulocyte-macrophage colony forming units (GM-CFU). This decrease in activity was restored when a substitution involving a longer acyl group at carbon 7 was made, as in bryostatin 8. However, when the acyl substitution on carbon 20 was com¬ pletely removed, as in bryostatin 13, both colony stimulating activity and neutrophil activation was lost. Furthermore, the loss of activity does not result from a toxic effect of bryostatin 13, since when bryostatin 1 was mixed with bryostatin 13, the expected degree of granulocyte-macrophage colony formation obtained with broystatin 1 alone was observed. Bryostatin 13, which is inactive in the hematopoietic stimulating activities reported herein, is reported by others to retain potent antineoplastic activity. (See Pettit, et al. Jour¬ nal of Organic Chemistry, (1957).) Bryostatins 1, 3, 8 and 9 (see Figure 1) have been found to mediate a dose dependent sitmulation of granulocyte and macrophage colony forming units (CFU-GM). The maximum effective concentration is between about 1 and 100 nM. Bryostatins 1 and 8 are the most potent of the four active congeners tested. They show colony stimulating activity at concentrations as low as 0.01 nM. Bryostatin 3 is less potent than broystatins 1 and 8 having a maxi¬ mal response between about 10 and 100 nM. Bryostatin 9 is a weaker stimulator of normal col¬ ony growth, and bryostatin 13 is completely inac¬ tive. Thus the hierarchy of bryostatin activity is that bryostatin 1 is most a i e, and bryostatins 3, 8 and 9 are increasingly less active, and bryostatin 13 is totally inactive. Cell preparations containing stem cells can be obtained from bone marrow or from peripheral blood cells. These can be purified using techniques known in the art, such as density gradient centrifugation, to remove red blood cells. Alter¬ natively, stem cells can be purified using antibod¬ ies which are specific for stem cell antigens. (See, Civin et al. Journal of Immunology, Vol. 133, p. 157, 1984.) Amounts of bryostatin which are effective for stimulating hematopoiesis or neutrophil- and- other immune regulatory cell activation, can be deter¬ mined using any of the assays known in the art. For example, early and late erythrocyte progenitors can be enumerated using the plasma clot method described in McLeod et al. Blood, Vol. 44, p. 517, 1974. Stimulation of such erythrocyte progenitors requires the presence of erythropoietin. For bryostatin 1, optimum stimulation of erythrocytes was seen at sbout 10~ 12 M to about 1C "10 M. For determining effective concentrations of bryostatins for granulocyte and macrophage colony formation, light density, adherence-depleted human bone marrow cells can be obtained. The cells can be suspended in a suitable medium, such as supple¬ mented McCoy's 5A medium containing 0.3% agar and plated in 35 mm petri dishes as described in Pike et al, Journal of Cell Physiology, Vol. 76, pp. 77-83, 1970. For the bryostatins which have been tested and found to be effective, i.e., 1, 3, 8 and 9, maximum stimulatory concentrations are between about 10 "7 M and 10 "10 M. To determine the effective amount of bryostatin for neutrophil activation, normal human peripheral blood neutrophil cells can be purified on a density gradient such as a Ficoll gradient. Other immune regulatory cells, sack as T-lymphocytes and macrophages can he isolated by standard and known techniques. The fieistrophils can be suspended in Dulbeccc 1 s plicsphate-buffereά ssline supplemented with cϊlciu end magnesium. One w to monitor neutrophil activation is to observe chemiluminescence. The neutrophils can be incubated for about fifteen minutes with tifeβ bryostatin. Then luminol (5-amino-2-3-dihydro-l, 4-phthalazinedione) can be added to a concentration of about 10 uM. Chemiluminescence can be measured in a luminometer as described in Allen et al, Bio¬ chemistry and Biophysics Research Communications, Vol. 69, pp. 245-522, 1976. Alternatively, neutrophil activation can be assayed using a cytoxicity assay. Purified neutrophils can be incubated at a density of about 3x10^ cells per ml with various concentrations of bryostatin. The cells can be washed and added to radiolabelled target cells. K562 tumor cells and 51 Cr-label can be used to measure cytoxicity. The target cells are preincubated with the radiolabelled substance to effect uptake of the radiolabel. The target cells can be mixed with the neutrophils at various effector to target cell ratios, such as between about 5 ' Θsl and 5:1, Release of label from the target cells can be mea¬ sured, either by assaying the supernatant or the cells after centrifugation. Of course, other meth¬ ods known in the art, such as using other assays of immune regulatory cell cytotoxicity can be used. Bryostatin 1 has activity toward neutrophils at about 10 ° to 10 M, with a maximum activation effect on neutrophil cytotoxicity of K562 target cells at a concentration of about 10~ 7 M. It may be advantageous to treat either cells or mammals concommitantly with bryostatin and a chemotherapeutic agent or ionizing radiation. For example, it may be desirable to purge a cell sus¬ pension of all malignant cells while sustaining the viability and proliferation of hematopoietic pro¬ genitor cells. This can be done using chemical agents known in the art, such as adriamycin, cytosine arabinoside, vincristine, cyclophos- phamide, busulfan, prednisone, and M-AMSA. Purging can also be accomplished with tumor specific anti¬ bodies. Many such antibodies are known in the art. Alternatively, chemotherapeutic agents or anti-tumor an ibodies can be administered directly to the mammal which is receiving bryostatin. Bryostatin may enhance the antineoplastic activity of the chemotherapeutic agent or antibody Alternatively, use of bryostatin should allow higher amounts of the antineoplastic agent to be used, because of a reduction in the deleterious effects upon hematopoiesis. The bryostatins may be used to counteract the effects of many types of diseases. For example, anemias in which erythroid cell populations are low often require transfusions. Use of bryostatins to stimulate erythroid cell formation could prevent the need for transfusions. Such anemias include anemia of chronic disease, congenital anemias, acquired aplastic anemia, acquired or congenital pancytopenia, and Fanconi's anemia. Similarly after or during prolonged chemotherapy, hema¬ topoietic cells are often depleted. Thus, bryostatins could serve to bolster such cell popu¬ lations. In addition, in patients who are compro¬ mised in their immune systems, either due to immunosuppressive drugs or immunosuppressive dis¬ eases, the bryostatins can be used to stimulate the patients' white cells to fight infections (by acti¬ vation of neutrophils). Other situations where bryostatins can be advantageously used are in situ¬ ations where populations of humans and other mam¬ mals have been exposed to radiation, such as from nuclear weapons or from environmental leakage from nuclear power stations. In those cases, adminis¬ tration of bryostatins could relieve the deleteri¬ ous and often- fatal effects of radiation on hematopoietic cells. The bryostatins can be administered by any means known in the art. Because the desired tar¬ gets of the bryostatins occur primarily in the bone marrow and blood system it is desirable that the method of administration allows the bryostatins to reach those tissues. Bryostatins can be adminis¬ tered parenterally by injection, rapid infiisioji,, nasopharyngeal adsorption, dermal adsorption, or orally. One preferred method of administrstbsn ©f bryostatins is continuous infusion. For - sψls 7 an osmotic micropuir.p can be implanted subctare- o s and bryostatin infused over a period of aa*'.«. Generally between 1C and 1000 ug per ki ogr„τ. p" 1 - day is desirable to stimulate hematopoietic £~. lr. The following examples are meant to illustrate the foregoing invention and do not limit the inven¬ tion, which is specifically defined by the claims appended below. EXAMPLES Example 1 This example demonstrates the stimulatory effect of bryostatins on granulocyte-macrophage colony formation. Granulocyte-macrophage colony- forming unit (CFU-GM) colonies were enumerated from light-density, adherence-depleted normal human bone marrow cells. Cells were suspended in supplemented McCoy's 5A medium containing 0.3% agar and plated in 35-mm Petri dishes as described in Pike et al, J. Cell Physiol., Vol. 76, pp. 77-83, 1970. Results are shown in Figure 2. Colonies were enu¬ merated following incubation of bone marrow with cells with rHGM-CSF at 50 ng/ l (Genetics Insti¬ tute) or bryostatin 1 (•) bryostatin 3(o), bryostatin 8 ( ) , bryostatin 9(+), or bryostatin 13 {A) at the concentrations indicated. After 14 days of culture at 37°C in a humidified atmosphere containing 7.5% CO2, colonies of greater or equal to 50 cells were scored. Representative results from one of several experiments are reported as the mean colony number from quadruplicate samples. SEM is within 10% of the mean number. Bryostatins 1, 3, 8, and 9 were found to medi¬ ate a dose-dependent stimulation of CFU-GM with the maximal effective concentration between 1 and 100 nM. Colony stimulating activity was observed with a concentration as low as O.Ol.nM for bryostatins 1 and 8, which are the most potent of the four active congeners tested. While the amplitude of granulocyte-macrophage colony response was similar for bryostatin 3 at the higher concentrations (i.e., 10-100 nM) , this agent was clearly less potent than bryostatin 1 or 8. Brjcs-jstat 3 -mss only a weak stimulator of normal colony vhersas bryostatin 13 was completely in ctive * Analysis of colony morphology reve lac that bryostarin 1, like rHGH-CSF, stimulated prixarily mixed granulocyte-macrophage and pure granulocyte colonies at 7 and 14 days of culture. Example 2 This example shows that bryostatin 1 exerts its effect directly on cells. Assays were performed essentially as described in Metcalf et al, Blood, Vol. 67, pp. 37-45, 1986. Briefly, cultures of normal human bone marrow were initiated in medium containing 10 nM bryostatin 1. Following 4 days of growth, clones of 4-8 cells were carefully removed using a glass pipette to avoid contamination by surrounding cells and trans¬ ferred to secondary plates - containing - either rhGM-CSF (50 ng/ml) or bryostatin 1 (10 nM) as the source of CSF). After an additional 10 days of culture, the number of clones that had proliferated to form a colony of 40 cells or more was deter¬ mined. Further growth was not observed in colonies transferred to plates containing no added CSF-, (See Figure 3. ) Each symbol (•) represents a colony. Its height in each column is proportional to the number of cells in that colony. The data directly above sections G of the column represent colonies composed entirely of granulocytic cells. The data above sections GM in the column represent colonies composed of both granulocytic and monocytic cells. No colonies in secondary plates were detected that were composed of macrophage-monocyte cells only. The numerator in the fraction at the top of each column represents the number of colonies that developed in the secondary plate, and the denomina¬ tor represents the total number of clones trans¬ ferred. The clones from primary plates initiated with bryostatin produced full-size colonies only on the secondary plates to which bryostatin or rhGM-CSF had been added. This indicates that the stimulatory effect of bryostatin 1 and rhGM-CSF is exerted directly. Further, an attempt to prod&ce a conditioned medium from bone marrow cells iit the presence of bryostatin was unsuccessful. Nona Eeren e-depleted human bons mε.rrov, which was composed of a mixture of progenitor plus ancillary cells, as incubated in culture medium that contained a maximal stimula¬ tory concentration of bryostatin (i,e. 1-10 nM) for 5 days. The supernatant was aspirated and tested for the presences of a GM-CSF after fractionation by passage over a Sephadex G-25 gel filtration col¬ umn to remove the bryostatin (i.e., M r , 884). The resulting void volume, which contains the large molecular weight polypeptide growth factors, was evaluated for CSF activity. This supernatant was tested at both 10% and 50% (vol/vol) final concen¬ trations in the culture plates and failed to stimu¬ late GM-CFU growth. Example 3 This example demonstrates the stimulatory effect of bryostatin 1 on human erythrocyte progenitors. Assays for both early (BFU-E) and late (CFU-E) progenitors were enumerated as described in McLeod et al, Blood, Vol. 44, p. 517 (1974) using the plasma-clot method and optimal concentrations of erythropoietin. Bryostatin 1 stimulated both early BFU-E and late CFU-E human erythroid progenitors growth in plasma clots. See Figure 4. The maximal stimulatory concentration was between 1 and 10 pM, with an inhibitory effect noted at concentrations above 1 nM. Example 4 This example demonstrates that bryostatin 1 but not 13 causes neutrophils to chemiluminesce in the presence of luminol. In addition neutrophils are shown to be activated to kill K562 target cells by bryostatin 1. Normal human peripheral blood neutrophils were highly purified on a double Ficoll density gradient and suspended in Dulbecco's phosphate-buffered saline supplemented with Ca* and Mg* . First, substances to be tested were incubated with the neutrophils for 15 min. At this point 10 uM luminol (5-amino-2 f 3-dihydro-l, 4-phtyalazinedione) was added to eacfe sample * The generation of chemiluminescence was measured in a luminometer at 1.25 min intervals for up to 22- min. Bryostatin 1, but. net bryostatin 13, was found to be a potent activatcr of neutrophil chemiluminescence, a measure of oxide radical for¬ mation. Activation follows a similar time course to that for the known activator phorbol 12-myristate 13-acetate. See Figure 5. TPA was at 150 nM and recombinant human GM-CSF at 50 ng/ml. Furthermore, activation of neutrophil cytotoxicity, as measured by killing of 51 Cr-labeled K562 tumor target cells was also sitmulated by bryostatin 1 (Table 1). Neutrophils were purified as described above. Neutrophils were incubated at a density of 3 x 10 6 cells per ml first with various concentrations of bryostatin 1 (0.1 uM to 0.1 nM), rhGM-CSF (50 ng/ml), or in medium alone for 2 hr. Following two washes, the cells were added to the 51 Cr-labeled K562 target cells at effector/target cell ratios of 30:1, 15:1, or 7.5:1 as indicated. Control plates containing 1 Cr-labeled K562 cells and either bryostatin or medium alone were evaluated to determine the spon¬ taneous release of isotope. The plates containing the cells were centrifuged at 250 x g for 2 ir. and then incubated for 3 hrs at 37°C. One hundred microliters of the supernatant was harvested from each well, and the amount of radioactivity present was determined in a gamma scintillation counter. The maximum release of 51 Cr was determined by assaying supernatant obtained from wells in which the cells were completely lysed with 6 M HC1. Neutrophil activation was maximal between 10 and 100 nM bryostatin 1, a concentration range that can promote myeloid hematopoietic growth. Whereas rhGM-CSF has been reported to activate eosinophils and neutrophils we were unable to detect either the induction of chemiluminescence or of cytotoxicity in neutrophils when rhGM-CSF at 50 ng/ml, a maximal-stimulatory concentration for granulocyte- macrophage-colony formation. Example 5 This example demonstrates that bryostatin 1 is not toxic to a mammal and stimulates multipotential hematopoietic progenitors in vivo. Using osmotic icropumps (Alzet) implanted subcutaneously in 6 week old female BDF^ mice, bryostatin infused for 7 days had no major organ toxic effects at any of the doses employed. A dose-response stimulatory effect on multi-potential hematopoietic progenitors was noted. The adminis¬ tration of 144 ug/kg/d (max. dose) increased CFU-S, CFU-GM and BFU-E compared to control animals infused with vehicle alone. CFU-S from spleen cells of treated animals were increased 2-fold (19 vs. 39 colonies per 10° cells injected), while bone marrow CFU-S was not altered. Likewise, CFU-GM colonies from spleen cells were increased 3.6-fold (52 vs. 188 per 10° cells injected), and increased 2-fold (73 vs. 150 per 10 5 nuc. cells) in bone mar¬ row. Erythroid BFU-E colonies from spleen cells also demonstrated a 2-fold increase (28 vs. 58 per 10° cells), while no change in bone marrow BFU-E progenitors was found. The increment in progenitor cells was not accompanied by a significant change in the differential peripheral white blood cell, hemocrit, bone marrow cellularity or spleen weights. The results demonstrate that continuous infu¬ sion of bryostatin is non-toxic and can stimulate effectively murine multi-potential hematopoietic progenitor cells in vivo. The stimulatory effect of bryo is similar to its effect on multipotential progenitor cells in vitro and mimics the reported effect of infusion of rIL-3 and rGM-CSF. TABLE 1 Activated neutrophil cytotoxicity for K562 target cells Assessment of neutrophil-cytotoxicity-induced by bryostatin 1. K562 cells were labeled with Na^' I "Cr2θ and adjusted to a concentration of 10^ cells per ml in RPMI 1640 medium. Activated neutrophil cytotoxicity was determined. The results are expressed as the percentage of specific isotope released at the indicated effector/target cell ratio calculated as follows: % specific lysis = [(mean cpm of sample - mean cpm spontaneously released)/(mean cpm maximal -mean cpm spontaneously released) 3 x 100. Maximum induced cpm released as 7364 ± 149. The maximum mean % specific lysis from triplicate determinations from a representative experiment is shown.

Claims: CLAIMS 1. A method of stimulating stem cells to stimulate and differentiate to form granulocytes, macrophages, or erythrocytes, comprising: obtaining a cell preparation containing stem cells; and incubating the cell preparation in vitro with an effective amount of a bryostatin having an acylated C20 carbon to stimulate formation of granulocytes, macrophages, or erythrocytes, whereby said formation is stimulated. 2. The method of claim 1 wherein the stem cells are obtained from bone marrow. 3. The method of claim 1 wherein the stem cells are obtained from peripheral blood cells. 4. The method of claim 1 wherein the concen¬ tration of bryostatin is about 10 "12 M to about 10 "7 M. 5. The method of claim 4 wherein the concen¬ tration of bryostatin is about 10 °M to about 10 " M and wherein erythropoietin is incubated with the cell preparation, and the cells formed are erythrocytes. 6. The method of claim 4 wherein the concen¬ tration of bryostatin is about 10~^M to about 10~ 7 M and the cells formed are granulocytes and macrophages. 7. The method of claim 1 wherein a chemotherapeutic agent is also added to the cell preparation in an amount affective to kill malig¬ nant cells. 8. The method—of- -claim " 1 " wherein a monoclonal antibody is used to remove malignant cells from the cell preparation. 9. The method of claim 7 wherein the chemotherapeutic agent is bryostatin 13. 10. The method of claim 7 wherein the chemotherapeutic agent is selected from the group consisting of: adriamycin, cytosine arabanoside, vincristine, cyclophosphamide, busulfan, prednisone, and M-AMSA. 11. The method of claim 1 wherein the cell preparation, after incubation to form granulocytes. macrophages or erythrocytes, is administered to a mammal. 12. The method of claim 1 wherein the bryostatin is selected from the group consisting of 1, 3, 8, and 9. 13. The method of claim 1 wherein the cell preparation is treated with ionizing radiation in an amount effective to kill malignant cells. 14. A method of stimulating stem cell differ¬ entiation to form granulocytes, eosinophils, basophils, platelets, macrophages, or erythrocytes in a mammal, comprising: administering a bryostatin having an acylated C20 carbon to the mammal in an amount effective to stimulate formation of granulocytes, eosincphils, basophils, platelets, macrophages, or erythrocytes, whereby said formation is stimulated. 15. The method of claim 14, comprising: administering bryostatin 13 to the mammal in an amount effective to arrest the growth of a tumor; and administering bryostatin 1 to the mammal in an amount affective to stimulate formation of granulocytes, macrophages, or erythrocytes. 16. The method of claim 14 wherein the bryostatins are administered by continuous infusion. 17. The method of claim 14 wherein the bryostatins are administered subcutaneously. 18. The method of claim 14 wherein the bryostatin is is selected from the group consisting of 1, 3, 8, and 9. 19. A method of activating the cytotoxicity of neutrophils and other immune regulatory cells, comprising: obtaining a cell preparation containing neutrophils or other immune regulatory cells; and incubating the cell preparation in vitro with an amount of a bryostatin having an acylated C20 carbon effective to activate the neutrophils or other immune regulatory cells, whereby said cells' cytotoxicity is activated. 20. The method of claim 19 wherein the con¬ centration of bryostratin is between about 10 "7 M abd 10 "10 M. 21. The method of claim 19 wherein the broystatin is selected from the group consisting of 1, 3, 8, and 9. 22. A method of activating neutrophils and other immune regulatory cells in a mammal, comprising: administering a bryostatin having an acylated C20 carbon to the mammal to activate neutrophil or other immune regulatory cell cytotoxicity, whereby said cytotoxicity is stimulated. 23. The method of claim 22 wherein the bryostatin is selected from the group consisting of 1, 3, 8, and 9.

Inventors: MAY STRATFORD W, SENSENBRENNER LYLE LEE, MAY, STRATFORD, W., SENSENBRENNER, LYLE, LEE
Applicants: UNIV JOHNS HOPKINS, THE JOHNS HOPKINS UNIVERSITY
Application year: 1988
Main classification: C12N5
IPC codes: A61K31, A61P7, A61P37, C07D493, C12N5