Production of five human lymphokines (granulocyte-macrophage colony stimulating factor, interferon-gamma, interleukin 2, macrophage cytotoxicity factor and macrophage migration inhibitory factor) from Con A stimulated lymphocyte cultures in bioreactors

Lymphocyte expansion in bioreactors: upgrading adoptive cell therapy

Bioreactors are essential tools for the development of efficient and high-quality cell therapy products. However, their application is far from full potential, holding several challenges when reconciling the complex biology of the cells to be expanded with the need for a manufacturing process that is able to control cell growth and functionality towards therapy affordability and opportunity. In this review, we discuss and compare current bioreactor technologies by performing a systematic analysis of the published data on automated lymphocyte expansion for adoptive cell therapy. We propose a set of requirements for bioreactor design and identify trends on the applicability of these technologies, highlighting the specific challenges and major advancements for each one of the current approaches of expansion along with the opportunities that lie in process intensification. We conclude on the necessity to develop targeted solutions specially tailored for the specific stimulation, supplementation and micro-environmental needs of lymphocytes’ cultures, and the benefit of applying knowledge-based tools for process control and predictability.

Porcine blood cell separation by porous cellulose acetate membranes

Leukocytes were separated from whole porcine blood using laboratory prepared polymeric asymmetric porous membranes from cellulose acetate (CA) and by applying standard blood cell separation methods: centrifugation in a Ficoll solution gradient and in sucrose solution concentration gradient. Leukocytes, obtained by different separation methods were characterised by their quantity, type, viability and growth ability. Membranes prepared by a wet phase inversion process from different cellulose acetate/acetone/water and magnesium chlorate VII systems, were characterised according to: permeability to deionised water, surface morphology and by the determination of the flux of the permeate during the whole porcine blood separation. Cellulose acetate membranes prepared from 300 μm thick cast solution (14.8 wt% of cellulose acetate, 19.9 wt% of water, 2.3 wt% of Magnesium perchlorate, and 63.0 wt% of acetone), have separation characteristics comparable with the standard separation methods; in the dead-end mode filtration, 21.3% of leukocytes from porcine whole blood are separated. The leukocyte number in peripheral blood before separation was 450,000 ml(-1); the number passed through after was 95,000±6620. The main interest of the study was to introduce the CA membrane filters for the continus technological separation of the leukocyte/lymphocytes from animal (= porcine, bovine, horse..) blood.

Large scale production and purification of human IL-2 from buffy coat lymphocytes stimulated with 12-O-tetradecanoylphorbol 13-acetate and calcium ionophore A23187

Methods for the production of high titers of interleukin-2 (IL-2) from human buffy coat lymphocytes, and subsequent purification of the IL-2 are described. 50 buffy coats containing 1 X 10(11) leukocytes were first depleted of erythrocytes by batchwise leukapheresis using a Haemonetics model 15 blood wash centrifuge. Further lymphocyte enrichment was achieved using a one-step sedimentation in the presence of hydroxyethyl starch, which produced suspensions of more than 90% lymphocytes. This degree of lymphocyte purity was important since phagocytes were inhibitory to 12-O-tetradecanoylphorbol 13-acetate/calcium ionophore (TPA/A23187)-induced IL-2 production when their concentration exceeded 15% of the total cells. Cell culture was performed in stirred fermenters. Using TPA/A23187 induction, up to 500 micrograms of IL-2 per liter were produced. The IL-2 was purified by absorption from the supernatants onto controlled pore glass and elution with 50% ethylene glycol, followed by Fractogel chromatography, and then preparative high-performance liquid chromatography (HPLC) using an RP-6 column and elution with a gradient of n-propanol. A final HPLC rechromatography step using an analytical RP-6 column gave a homogeneous preparation with specific activity of 1.2 X 10(7) U/mg and a recovery from the starting supernatant of 22%.

Intralymphatic interleukin-2 treatment of a hemophiliac AIDS patient with defective interleukin-2 production

To improve immune functions in an interleukin-2 (IL-2) deficient hemophiliac AIDS patient suffering from severe Pneumocystis carinii pneumonia, treatment with IL-2 was started in addition to standard antimicrobial therapy. Highly purified IL-2 was administered subcutaneously and then repeatedly intralymphatically in a manner similar to pedal lymphography. No toxicity was observed. The patient temporarily improved clinically as well as with regard to immunological functions. Particularly the in vitro response to phytohemagglutinin (PHA) could partly be restored, and skin tests revealed improved response to recall antigens. These findings indicate that IL-2 can be administered safely and effectively by the intralymphatic route and may--in addition to antibiotics--be of value in AIDS patients with severe opportunistic infections.

Inhibitory effects of interferon-gamma on the T suppressor cell circuit in contact sensitivity

The effects of a partially purified, splenocyte-derived murine interferon (MuIFN-gamma N) and a recombinant IFN-gamma (MuIFN-gamma R) on the T suppressor pathway and on the T effector cells of delayed type hypersensitivity were investigated in a 2,4-dinitrofluorobenzene contact sensitivity model. Various T cell subpopulations, suppressor T cells of afferent and efferent types, and an auxiliary T suppressor cells as well as a T effector cell of delayed type hypersensitivity were induced and the functions assessed in transfer experiments. Confirming the results of earlier experiments obtained with IFN-alpha, beta, the MuIFN-gamma N preparation and the rec. MuIFN-gamma R: enhanced the decreased response in animals sensitized with an antigen overload to an optimal response; inhibited the afferent-acting T suppressor cell in vivo and in vitro; inhibited the Ts-eff response; blocked the auxiliary T suppressor cell response after intravenous injection to recipients of Ts-eff cells on day 0 and 1; and did not suppress the activity of the T effector cell of delayed type hypersensitivity in vivo and in vitro (the MuIFN-gamma R was not tested). We conclude that IFN-gamma preferentially inhibited the T suppressor cell circuit of contact allergy. These results are similar to our observations on the inhibitory effects of a pure interferon-alpha, beta on the regulatory T suppressor cell circuit in contact allergy. Selective suppression of different T subpopulations by IFN-gamma may be an important regulatory mechanism in delayed type hypersensitivity.

Murine and human interleukin 2 can substitute for the thymus in immune responses to TNP-Ficoll in Xenopus laevis, the South African clawed toad

Extirpation of the thymuses of Xenopus laevis abrogates the capacity to respond to trinitrophenol (TNP)-Ficoll regardless of the age of the animal. This thymus requirement can be substituted for by a variety of treatments which stimulate thymus-derived (T)cell activity in the periphery, such as the rejection of allogeneic skin grafts, immunologic challenge with thymus-dependent immunogens, (e.g., heterologous erythrocytes), or plant-derived lectins (e.g., concanavalin A). Here we report that interleukin 2 (IL-2), a T-cell-produced hormone of mammalian origin also substitutes for this thymus requirement in thymectomized toads.

In vivo effects of interleukin 2 on lymphocyte subpopulations in a patient with a combined immunodeficiency

This report describes a clinical trial with Interleukin 2 (IL-2) on a 17-month old male child with combined immunodeficiency (Nezelof's syndrome). IL-2 was prepared from conditioned media of phytohemagglutinin-stimulated leukocytes from buffy coats. The purification of IL-2 involved chromatography on Matrex Blue A sepharose and gel filtration chromatography. The preparation was free of macrophage cytotoxicity factor, macrophage migration inhibition factor and colony-stimulating factor. It contained negligible activity of interferon-gamma. IL-2 activity was adjusted to 1600 U/ml, which corresponds to about 0.8 micrograms homogeneous IL-2/ml. The patient was treated over a 50-day period with a total dose of 20,000 U IL-2, which was injected subcutaneously. IL-2 was well tolerated. Within 3 weeks, the treatment led to a normalization of a lymphocytosis which had prevailed for the previous 3 months. A pronounced eosinophilia also improved but did not reach normal levels. The most striking effect was a normalization of the OKT4+/OKT8+ ratio with a concomitant relative increase in OKT3+ cells in the peripheral blood. No effects were seen on E rosette formation, B cell counts or serum Ig levels. Also NK or ADCC activity remained high, as before the treatment. Infectious episodes and requirement for antibiotic treatment were less frequent during IL-2 therapy. Some effects of IL-2 were transient, e.g., the counts of OKT4+ and OKT3+ cells which returned to pathological values a few weeks after the treatment was discontinued.

The glycosphingolipid globoside as a serological marker on cytolytic T lymphocyte precursors and alloantigen-responsive proliferating T lymphocytes in murine spleen

Biochemical analyses of murine lymphocytes have shown that the glycosphingolipid globoside (Glo) is present exclusively on alloantigen-stimulated murine T lymphocytes (Gruner, K. R., Van Eijk, R. V. W. and Mühlradt, P. F., Biochemistry 1981. 20: 4518). An anti-Glo antibody has now been raised in rabbits immunized with purified antigen. Most activity was recovered in the IgM fraction. The specificity of the antibody was ascertained in an enzyme-linked immunosorbent assay with purified glycosphingolipids bound to the solid phase. In antibody-dependent complement lysis experiments the anti-Glo eliminated about 20% of nylon wool-nonadherent splenic T cells of CBA/J mice. To determine the functional identity of these Glo+ cells, the effects of Glo+ cell elimination on mitogen stimulation with concanavalin A and lipopolysaccharide, as well as the effects on the mixed lymphocyte culture (MLC) reaction and cell-mediated lympholysis with mitomycin-treated DBA/2 splenocytes as stimulator cells were studied. Whereas lipopolysaccharide stimulation was not affected by elimination of Glo+ cells, there was a slight inhibitory effect on the concanavalin A stimulation, and a severe inhibition of the MLC reaction and the generation of H-2d-specific cytolytic T lymphocytes. Addition of interleukin 2 increased the MLC reaction, but interleukin 2-saturated cultures were also severely inhibited by anti-Glo and complement treatment. Combined treatment with anti-Glo and anti-Lyt-1 or anti-Lyt-2 antibodies, and determination of cytolytic T lymphocyte precursor frequencies in limiting dilution cultures after Glo+ cell elimination showed that a large proportion of T cells proliferating in a primary MLC are Lyt-1+,2+,3+Glo+, whereas in secondary MLC they are Lyt-1+,2-,3-,Glo+. Fifty % of the cytolytic T lymphocyte precursors in primary as well as secondary MLC are Glo+. The Glo marker is lost upon differentiation to cytolytic T lymphocyte effector cells. It is discussed herein that Glo is a marker for alloantigen-stimulated precursor T lymphocytes of both helper and cytolytic T cells.

Purification of the T lymphocyte growth factor interleukin-2 from culture media of human peripheral blood leukocytes (buffy coats)

Interleukin 2 was purified 100 000-fold to apparent homogeneity from the supernatants of mitogen-stimulated human blood leukocytes. A sequence of three purification steps was used: affinity chromatography on the bound dye cibacron blue, gel filtration on Ultrogel AcA44, and reversed-phase high-performance liquid chromatography on hexyl phase. The resulting interleukin 2 had a specific activity of 2 X 10(6) U/mg protein, and was free of pyrogenicity in the rabbit test. The final purification product showed two bands in sodium dodecyl sulfate/polyacrylamide gels with apparent molecular masses of 15 kDa and 17 kDa respectively. Both bands were biologically active.