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Biomedical subjects

E Mihich

Publications and source records attributed to E Mihich.

At least 91 records · Page 5Linked to original sources
PubMed1984

Induction of suppressor T cells in culture--I. Cell-cell interactions.

The present study was designed to examine the cellular requirements for the generation of the suppressor T cells induced in the presence of fetal calf serum in culture. When C57Bl/6 mouse spleen cells were cultured for 4-5 days, these precultured cells were shown in mixing experiments to suppress the generation of cytotoxic effector cells (CTL) against allogeneic P815 cells or the generation of anti-SRBC humoral response by freshly explanted C57Bl/6 spleen cells. Spleen cells cultured in the presence of silica (0.5 mg) for 4 days, did not develop suppressor activity. However, when silica was added 3 days after the start of the suppressor generation culture, the development of suppressor cells was only slightly affected, although the phagocytic activity of these spleen cells was still totally abolished. When plastic or G-10 Sephadex column nonadherent spleen cells were cultured alone for 4-5 days, these cells did not suppress the generation of CTL or anti-SRBC humoral response. When the nonadherent spleen cells were cultured with plastic adherent spleen cells, however, suppressor cells developed and the suppressor activity of these cells was dependent on the number of adherent spleen cells co-cultured with the non-adherent spleen cells. This activity of the adherent spleen cells was insensitive to treatment with anti-Thy 1.2 serum plus complement and to X-irradiation. Furthermore, adherent PEC could not substitute for adherent spleen cells, indicating a possible tissue specificity for the macrophages in the adherent cell fraction which can function in supporting and/or accelerating the differentiation of "immature" suppressor T cells. Finally, culture-induced suppressor T cells were sensitive to X-irradiation and their activity was refractory to IL2 (TCGF), whereas the activity of alloantigen-induced suppressor cells was sensitive to IL2.

Animals↗
PubMed1984

Induction of suppressor T cells in culture--II. Modification by adriamycin.

The present study was designed to examine the effects of Adriamycin treatment of spleen donor mice on the subsequent generation of the suppressor T cells induced in culture in the presence of fetal calf serum. When mice treated with Adriamycin (5 mg/kg; i.v.) 5 days before sacrifice were used as donors of the spleen cells, the suppressive activity which developed in culture was somewhat greater than that which developed with spleen cells from untreated mice; particularly in terms of suppression of PFC development. The suppressive activities of the cultured spleen cells from untreated and treated mice were equally sensitive to X-irradiation and anti-Thy 1.2 antibody plus complement treatment. When only those cells which were nonadherent to plastic were used in the suppressor generation culture, suppression did not develop until day 6 of culture. Again, cells from Adriamycin treated mice developed somewhat greater suppressive activity than that which developed with cells from untreated mice. The effects of Adriamycin treatment of the mice on the subsequent development of suppressive activity in culture was also dependent upon the day of drug administration. Finally, spleen cells from Adriamycin treated mice, also, developed somewhat greater suppressive activity in response to alloantigen but when used as the source of progenitor cytotoxic T cells they were less sensitive to suppression; particularly by alloantigen-induced suppressor cells. Possible correlation between Adriamycin induced modifications of both the development and function of suppressor T cells in culture and its reported modifications of CTL and phagocytic activities are discussed.

Animals↗
PubMed1983

The effects of dichloro-trans-dihydroxy-bis-isopropyl-amine-platinum IV on the primary cell-mediated cytotoxic response.

The effects of diamino-dichloro-cis-platinum II (DDP) and dichloro-trans-bis-isopropyl-amine-platinum IV (DDIP or CHIP) on the primary cell-mediated cytotoxic (CMC) response developed in a mixed lymphocyte tumor cell culture (MLTC) were investigated. DDP as well as CHIP added on day 0 augmented the CMC response when spleen cells from C57Bl/6 mice were cultured for 4 days with supraoptimal numbers of irradiated (4000 rads) allogeneic P815 mastocytoma cells. A similar effect was observed when mice were treated with either of the two platinum compounds 1 or 5 days prior to spleen removal and sensitization of the spleen cells in a MLTC. Augmentation was not observed at optimal or suboptimal R:S. When spleen cells were preincubated with CHIP, only inhibitory effects on the CMC response could be demonstrated. Decreasing Cl- -ion concentrations in the preincubation medium increased the inhibitory effect of CHIP. After CHIP administration to spleen donor mice, the development of antigen specific suppressor cells was inhibited only at doses higher than those required to inhibit the development of nonspecific suppressor cells. Spleen responder cells from CHIP-treated donors exhibited a lower sensitivity to both antigen-specific and nonspecific suppressor cells than spleen responder cells from untreated control donors.

Animals↗
PubMed1983

Modification by biological products of the generation of suppressor cells in culture.

This report describes the effects of prostaglandin E2 (PGE2), indomethacin, and human prealbumin on the generation of culture-induced and allo-antigen-induced suppressor cells. The ability of the suppressor cells to affect cell-mediated immunity (CMI) generation cultures was assessed by 3H-thymidine uptake and cell-mediated lympholysis (CML). The generation of culture-induced suppressor cells is dependent on the fetal calf-serum (FCS) used in the medium and at least 4 days are necessary for their generation. Suppression is totally abolished by 2,000r X-irradiation of suppressor cells prior to their testing in CMI generation cultures. Spleen cells cultured in the presence of 0.03 to 3 microM PGE2 are not suppressive, while 3 nM PGE2 only partially abolishes their suppressive activity. Indomethacin has little effect on the development of this suppressor cell activity. Spleen cells cultured in the presence of human prealbumin have augmented cellular proliferation but do not develop suppressor cell activity. Alloantigen-activated cells added to CMI generation cultures suppress cellular proliferation (3H-thymidine uptake), but suppress CML development only after X-irradiation. PGE2 inhibits the proliferation of alloantigen-activated cells in a dose dependent manner. The ability of PGE2 to abolish their suppressive activity (after X-irradiation) in CMI generation cultures is directly proportional to its effects on cell proliferation. Indomethacin augments the proliferation of alloantigen-activated cells but does not further augment suppression. Human prealbumin augments the cellular proliferation of alloantigen-activated suppressor cell culture systems, but does not affect the generation of alloantigen-activated suppressor activity.

Animals↗
PubMed1983

The effect of PS-K, a protein bound polysaccharide, on immune responses against allogeneic antigens.

A single dose of PS-K administered to C57B1/6J mice after immunization augmented both the humoral and cellular allogeneic responses against P815 tumor cells. PS-K addition to primary alloantigen sensitization cultures (C57B1/6J spleen cells against X-irradiated P815 cells) resulted in augmented 3H-thymidine uptake and cell mediated cytolytic activity. Ten daily administrations of PS-K to DBA/2J mice after implantation of a mammary tumor of DBA/2HaDD origin results in increased tumor regression and prolonged survival of the mice. PS-K addition to human mixed lymphocyte cultures caused an augmentation of both cell mediated cytolytic activity and 3H thymidine uptake. The dose dependence of the PS-K effects were described by a bell shaped curve and PS-K did not appear to affect the day of peak development of the various responses. The effects were consistently greater if PS-K was administered at the same time or after antigen presentation. Thus, the immunoaugmenting effects induced by PS-K were similar in each model system tested.

Adjuvants, Immunologic↗
PubMed1983

Adriamycin induced immunomodulation: dependence upon time of administration.

The immunomodulating capabilities of the anti-neoplastic agent, Adriamycin, were investigated. The day of Adriamycin administration to mice was varied from -15 to -1, day 0 being when mice were either immunized or sacrificed and their spleen cells sensitized in culture. Humoral and cellular immune responses against allogeneic or xenogeneic cellular antigens in mice and in culture, as well as phagocytic and ADCC activities were evaluated using spleen cell populations. The cellular responses and phagocytic activities were affected in a cyclical manner with time after Adriamycin's administration. Peaks of increased activity were seen subsequent to day -5 and day -11, administration and low activities following day -1, -3 and day -7, -9 administration. The humoral responses were not affected in a biphasic manner but single peaks of increased activity were seen which corresponded to the times of low cellular cytolytic and phagocytic activities. The ADCC was independent of time of Adriamycin administration. The significance of these findings to the design of therapeutic protocols is discussed.

Animals↗
PubMed1982

Reversal by citrovorum factor of methotrexate-induced suppression of cell-mediated and humoral immune response in mouse model systems.

C3H/HeHa mice were immunized (day 0) with 5 X 10(8) sheep red blood cells (SRBC) or 3 X 10(7) EL-4 lymphoma cells (i.p.), and C57B1/6J mice were immunized (day 0) with 3 X 10(7) P815 mastocytoma cells (i.p.). Methotrexate (MTX, 100 mg/kg) was given i.p. on day +2, with or without citrovorum factor (CF) at equimolar dose. In the absence of CF in C57B1/6J mice, the complement-independent cellular cytotoxicity (CICC) response did not recover in 18 days from MTX suppression to levels seen in immunized controls, while in C3H mice, with EL-4 as antigen, the response equalled that of controls by day 18 and was similar to or greater than that of controls through day 28; in both cases the serum antibody response returned to control levels by day 20. In both mouse strains, CF produced immediate recovery of the responses measured. In contrast, with SRBC as antigen, while the MTX suppression of complement-dependent cellular cytotoxicity (CDCC) in the absence of CF recovered by day 7, the CICC response recovered much more slowly. CF administration produced a rapid (day 4) return of CDCC activity to control levels, but only a partial restoration of CICC activity by day 6. In conclusion, the kinetics of recovery of the CICC and CDCC responses and of CF rescue of MTX-induced immunosuppression were dependent on mouse strain and on immunogens used, as well as on the type of response measured. Thus, selectivity of MTX action is indicated.

Animals↗
PubMed1982

Human prealbumin fraction: effects on cell-mediated immunity and tumor rejection.

The effect of human prealbumin fraction as allogeneic cell-mediated immunity in primary sensitization cultures of murine spleen cells was studied by 3H-thymidine uptake and specific 51Cr release assays. Prealbumin caused a dose-dependent augmentation of these responses. Human serum albumin, bovine serum albumin, and calf-thymosin fraction 5 had little effect. Prealbumin was active when added on day 0 or 1 but not thereafter. Prealbumin added to effector cells from immunized mice did not change their lytic activity. Prealbumin, but not human serum albumin or thymosin fraction 5, augmented secondary cell-mediated immunity in culture after primary immunization in mice. A slow growing mammary tumor line, which originated as a spontaneous mammary tumor in a DBA/2 HaDD breeder mouse, initially grows in 100% of DBA/2J mice but is then rejected in 10-20% of them. When prealbumin (59 microgram/day) was given subcutaneously for 2 weeks to DBA/2J mice and the tumor implanted 2 weeks later. 78% of the mice rejected the tumor and were then resistant to a rechallenge.

Animals↗
PubMed1982

Augmentation of the phagocytic activity of murine spleen cell populations induced by Adriamycin.

C57B1/6 mice were injected i.v. with Adriamycin (5 mg/kg) and various days later, spleen cells were tested for Fc dependent phagocytic activity by measuring protection of 51Cr-labelled, antibody coated SRBC from hyptonic shock. No difference in phagocytic activity was observed with spleen cells from untreated mice or mice treated with Adriamycin 1-7 days prior to killing. Increases in phagocytic activity were, however, seen with spleen cells from mice treated 9 to 13 days prior to killing. Phagocytic activity of spleen cells from mice treated 5 days prior to killing was increased after these cells were cultured for 5 days when compared to cultured cells from untreated mice. Despite depletion of mature phagocytic cells from spleen cells suspensions by silica treatment, followed 24 hours later by silica removal by density gradient centrifugation, phagocytic activity was observed with spleen cells from ADM treated mice (day-5) after 5 days in culture. No phagocytic activity was seen with spleen cells from untreated mice using the same silica treatment and culture conditions. When cultured spleen cells from untreated or ADM treated mice (day-5) were fractionated by plastic adherence, twice as many adherent cells were removed compared to controls. Their phagocytic activity (per cell) was, however, the same. Thus, ADM may increase the number of immature nonphagocytic macrophages in the spleen resulting in increased mature macrophages after culture.

Adjuvants, Immunologic↗
PubMed1982

Effects of prostaglandins on the development of cell-mediated immunity in culture and on the cytolytic activity of in vivo-generated effector cells.

This study was undertaken in an attempt to better understand the rôle of prostaglandins in the development of the primary cell-mediated immunity (CMI) response in culture. Primary sensitization cultures with C57Bl/6 mouse spleen cells as responder cells (R) and X-irradiated P815 mastocytoma cells as allogeneic stimulator cells (S) were established in the presence and absence of test agents. The ability of effector cells to lyse P815 target cells was measured by 51Cr-release assay on day 4. 3H-Thymidine uptake into the cultured cells was also analyzed on the same day. Prostaglandins of the E series were shown to exert selective effects on the CMI response depending on dose, schedule of administration, and culture conditions. PGE1 or PGE2 enhanced the CMI response at 30 pM but inhibited it by 50% at 30 nM. At an optimal R/S ratio, 30 nM PGE1, or PGE2 always inhibited 3H-thymidine uptake more than cytotoxicity while at suboptimal ratios it inhibited both equally. PGE1 did not affect the kinetics of development of the CMI responses. PGE1 was inhibitory when added 20 h before, at the same time as or as late as 24 h after antigen. The inhibitory effect was prevented by removal of PGE1 within 24 h of addition. Pretreatment of spleen cells with PGE1 for 20 h did not affect their subsequent response to sensitization. It seems that PGE1 must be present during the early phase of lymphocyte activation and that it has a relatively long half-life in spleen cell cultures. The development of secondary CMI in culture was less sensitive to inhibition by PGE than that of the primary CMI. PGD2 and PGA2 also inhibited the induction of the primary CMI while PGF2 alpha enhanced it. On the other hand, PGI2 and TXB2 had no effect. The effect of prostaglandins on the lytic activity of the in vivo-generated effector cells was also examined. The addition of PGE2, PGI2, PGD2 or PGA2 to the 51Cr-release assay resulted in significant depression of the cell-mediated lympholysis; whereas, addition of 6-keto-PGF1 alpha, TXB2, and PGF2 alpha caused little effect. PGE2, PGA2 or PGD2 inhibited the rate of lytic activity. In order to exert this effect, these compounds must be present during the 51Cr-release assay and pretreatment of the effector cells had little effect on their cytotoxicity. These results indicate that prostaglandins have immunomodulating activity affecting the early phase of the development of the CMI response in culture; they also have the ability to inhibit the cytolytic effect of effector cells generated in vivo.

Alprostadil↗
PubMed1982

Toxicity and pharmacokinetics of a new antifolate, 2,4-diamino-5-adamantyl-6-methylpyrimidine, in dogs.

The toxicology of a potentially useful antitumor agent, 2,4-diamino-5-adamantyl-6-methylpyrimidine (DAMP), and its ethanesulfonate salt has been studied in beagle dogs after 1 to 20 doses. Two types of toxicity could be discerned: the acute central nervous system toxicity manifested by vomiting, convulsions, and minor hypothermia; and the antiproliferative toxicity, similar to that of other folate antagonists, manifested by diarrhea, anorexia, loss of body weight, and hematological changes as well as changes in blood chemistry. There is evidence of a cumulative effect of the drug with respect to antiproliferative toxicity. Characteristically, the animals could be protected against the antiproliferative toxicity by simultaneous administration of folinic acid. The pharmacokinetics of the ethanesulfonate salt of DAMP was studied after i.v. administration of sublethal doses (5 mg/kg) of tritium-labeled drug. Sixty-three % of the administered dose was excreted in the urine and 10% was excreted in the feces within 48 hr after drug administration. Thus, about 27% of the drug was not recovered, and it is possible that it persists in the tissues for a period of several days. Analysis of the plasma and urine revealed that DAMP was metabolized rapidly. At least 2 metabolites were found in plasma and urine, one lipophilic and one hydrophilic, the latter being the predominant form. Pharmacokinetic data were successfully fitted to a model consisting of central and peripheral DAMP compartments and a DAMP metabolite compartment. DAMP was very rapidly sequestered in the peripheral compartment with a rapid phase half-life of 23 sec. The slower phase of DAMP plasma disappearance had a half-life of 3 hr. The short plasma half-life and rapid metabolism distinguished this drug from other lipophilic antifolates.

Adamantane↗