Gloria Carandang

Enhanced Yields of Gamma Interferon in Prolactin Treated Human Peripheral Blood Mononuclear Cells

Abstract Prolactin is a peptide hormone with effects on a number of target organs including the immune system. It has been shown that animals rendered hypoprolactinemic have impaired delayed hypersensitivity, impaired macrophage activation and altered secretion of gamma interferon (IFN). Using peripheral blood mononuclear cells (PBMC) and inducing the cells to produce gamma IFN with a range of inducers, we have studied the effects of a number of hormones on IFN production. Using cells from normal donors, we have found that prolactin in concentrations of 10-8 M or greater, can significantly enhance the production of gamma IFN. The effect was dose related and was observed when lectins (PHA and Con A), but not anti CD3 antibodies, ionophones, or IL-2 were used to induce the cells. The presence of prolactin in concentrations above that encountered in the fetal bovine serum used to incubate the cells resulted in a doubling or more of the IFN produced. The tests were performed on 30 occasions with cells drawn from 21 individuals. On all but three occasions, yield enhancement was observed in the presence of prolactin. The mechanism of the effect was investigated, and genistein, a tyrosine kinase inhibitor, was found to abort the influence of prolactin on gamma IFN production. These studies indicate prolactin in physiological concentrations can enhance the production of gamma IFN from cells from normal donors.

The paradoxical effects of somatostatin on the bioactivity and production of cytotoxins derived from human peripheral blood mononuclear cells.

Somatostatin (SMS), a naturally occurring peptide is known to inhibit the production of certain protein molecules and to diminish the ability of peripheral blood mononuclear cells to proliferate. We tested the effects of three forms of SMS on the bioactivity of both lymphotoxin (LT) and tumour necrosis factor (TNF). We also tested the effects of these agents on production of cytotoxins by peripheral blood mononuclear cells. We found the 28 amino acid form of SMS significantly enhanced the bioactivity of both LT and TNF (10(-9) M concentration) when tested in mouse L cells. The 14 amino acid form of SMS enhanced LT (10(-9) M concentration) activity but not TNF activity. The first 14 amino acid form of SMS-28 (amino terminal) did not affect bioactivity of the cytotoxin. In contrast, the naturally occurring 14 amino acid form of SMS (10(-8) M concentration) significantly diminished production of cytotoxin by human peripheral blood mononuclear cells. Cytotoxin produced by the latter was shown to be a combination of both LT and TNF. Similarly after SMS exposure, the cytotoxin produced remained a mixture of LT and TNF in roughly similar proportions. It thus appears that certain forms of SMS can enhance the bioactivity of cytotoxins, but at the same time decrease the production of these cytotoxins.

The Effect of Somatostatin on the Production of Human Interferons by Mononuclear Cells

Abstract Somatostatin (SMS) is a tetradecapeptide which can inhibit the secretion of a number of peptides produced by the endocrine or nervous systems. SMS 201-995 (octreotide) is a somatostatin analogue with very potent somatostatin activities. We have been investigating the effects of both SMS and octreotide on the production of human interferon (IFN). We obtained human peripheral blood mononuclear cells from normal donors and induced them to produce IFN in the presence or absence of a number of peptides possessing somatostatin activities. SMS and octreotide were shown to inhibit the secretion of INF-γ but not IFN-α. Concentrations of 10-6 M were shown to decrease yields when Concanavalin A or phytohemagglutin were used as the inducer. Higher concentrations had a progressively greater effect. No effects were observed on IFN-γ production if interleukin 2, ionomycin, or various natural antigens were used to induce the cells. The 28-amino acid form of somatostatin had some effects on gamma IFN yields but the first 14-amino acid fragment of this peptide moiety did not. No effect of any of these compounds was observed on IFN bioactivity. These studies indicate SMS may have some regulatory action on the secretion of immunomodulators in vitro but the concentrations required are well above those encountered under physiologic circumstances, suggesting SMS may not play an important regulatory role governing such secretion in vivo.

Interferon responses in maternal and fetal mice.

The kinetics of maternal-fetal interferon and a chemical interferon inducer were studied in Swiss-Webster white mice at 8, 15, and 19 days of gestation. Crude interferon was administered by maternal tail vein injection to one group. There was no transfer of interferon to the fetus despite high maternal levels. A chemical interferon inducer (10-carboxymethyl-9-acridanone) was given intramuscularly to a second group. Both maternal and fetal interferon responses rapidly reached significant levels, although the fetal response was less than that of the mother. Presence of the inducer was demonstrated in both maternal and fetal samples, indicating placental transport of the chemical to the fetus. The implications of these findings for the fetal immune response are discussed.

Effect of acetyl salicylic acid on production and action of leukocyte-derived interferons.

Although acetylsalicylic acid does not itself induce interferon, acetylsalicylic acid was found to significantly enhance the production of both human alpha interferon and human gamma interferon when added with the appropriate inducers to cultures of human peripheral blood mononuclear cells. The mechanisms associated with this effect were investigated.

Evaluation of the in Vitro Production of Interferon γ and Other Lymphokines in Uremic Patients

Abstract It has been suggested that a deficient immune response can be responsible at least partially for the high risk of infections and neoplasia in uremic patients. Since interferon (IFN) is critical to the immune response, we have evaluated the in vitro production of IFN-γ and other lymphokines by peripheral blood mononuclear cells (PBMC) drawn from patients with end-stage renal disease and appropriate controls. We have correlated production of lymphokines by these cells with proliferative response to different mitogens. It was found that the secretion of IFN-γ in response to all three mitogens was elevated in these patients compared with the control group. This elevation was significant with both phytohemagglutin and staphylococcal enterotoxin A, but not with Con A. No significant difference was observed in production of lymphotoxins, IL-2, and leukocyte migration inhibition responses. In contrast the proliferative response appeared diminished in the PBMC of uremic patients. We concluded that defective lymphokine generation is not a major immunological problem in patients with end-stage renal disease. Indeed, they appear to release excess amount of IFN-γ which is known to be a macrophage-activating factor. It is suggested that high IFN-γ activity could enhance the secretion of IL-1 or endogenous pyrogen and result in development of febrile reactions in dialysis patients.