Industrial production of monoclonal antibodies and therapeutic proteins by dialysis fermentation.

A novel and powerful fermentation method is reported for the large-scale growth of mammalian cells and their secreted products. The system described illustrates many of the advantages of conventional batch fermentation processes but in addition has been shown to yield cell densities in excess of 1 x 10(7) cells/ml with concomitant increase in product concentration.

[Regulatory factors in cellular immunity reactions]. / Regulatorische Faktoren der zellulären Immunreaktion.

The activation of B-cells can be studied by in vitro experiments. Various stages have been described: activation, proliferation and isotype specific differentiation into plasma cells are regulated by T-cells and macrophages. Their function is in part replaced by soluble factors. The availability of lymphokines derived from cloned T-cells allows a more precise analysis of the various differentiation steps for B-cells. A summary of the various lymphokines obtained from the murine and human system is demonstrated. As has been shown lymphokines reveal immunoregulatory properties which have to be correlated to in vitro results. The various unresolved questions concerning IgE-antibody regulation will be clarified when more defined lymphokines are available.

[Regulatory factors of the cellular immune reaction]. / Regulatorische Faktoren der zellulären Immunreaktion.

The activation of B-cells can be studied by in vitro experiments. Various stages have been described: activation, proliferation and isotype specific differentiation into plasma cells are regulated by T-cells and macrophages. Their function is in part replaced by soluble factors. The availability of lymphokines derived from cloned T-cells allows a more precise analysis of the various differentiation steps for B-cells. A summary of the various lymphokines obtained from the murine and human system is demonstrated. As has been shown lymphokines reveal immunoregulatory properties which have to be correlated to in vitro results. The various unresolved questions concerning IgE-antibody regulation will be clarified when more defined lymphokines are available.

Regulation of IgE antibody synthesis.

It is well established that IgE-antibodies against allergens are involved in allergic diseases. Thus, the regulation of IgE antibody synthesis appears to be a fundamental approach to its treatment. The mechanisms of the IgE-antibody response are somehow different from IgG production. It appears that the immunocompetent cells involved are distinct and exert a different susceptibility with regard to IgE- and IgG antibody production. A more precise under-standing of the cellular processes involved in IgE-antibody production will lead to novel immunotherapeutic approaches of allergic disease processes.

[Cell biology basis of IgE antibody regulation. Immunotherapeutic approaches]. / Zellbiologische Grundlagen der IgE-Antikörperregulation. Immuntherapeutische Ansatzpunkte.

Recent developments as to the IgE-antibody synthesis in rodents and in the human model are summarized and discussed in reference to our own data. It is by now established that the IgE-antibody response is regulated by interdependent interactions of cellular, humoral and genetic factors. The IgE-bearing B-lymphocyte develops from a surface IgM carrying B-lymphocyte. The transformation into an IgE secreting plasma cell requires T-cell help or soluble T-cell factors. Recent advances in the characterization of human lymphocytes as well as more sophisticated cell biological approaches facilitated the analysis of IgE-antibody synthesis in the human in vitro model. In most of the studies at present available the effect of the polyclonal B-cell mitogen (PWM) was analyzed. PWM either enhanced, suppressed or unlike to other Ig-classes did not affect the IgE-antibody synthesis at all. Immunotherapeutic approaches have to consider to establish the allergen induced in vitro model of IgE-antibody synthesis in humans, to modulate the interactions of T-helper and/or suppressor cells or to generate soluble suppressor factors. In any case the analysis of the IgE-antibody synthesis in humans could be a valuable tool to assess IgE-B-cell memory towards various allergens and to determine the IgE-mediated in patients.

[Biochemical aspects of the pathogenesis of the asthma syndrome]. / Biochemische Aspekte der Pathogenese des Asthmasyndroms.

The induction of asthma is more easily understood by the increasing knowledge of intercellular interactions. It is obvious that a major role for the initiation of extrinsic and mixed form asthma is attributed to IgE-immunoglobulin, which after interaction with the appropriate antigen leads to the release of preformed and newly generated mediators (e.g. leukotriene with chemotactic and spasmogenic [SRS] properties) from mast cells and basophils. The latter mediators are also released from polymorphonuclear neutrophils and macrophages in the course of bacterial adherence, phagocytosis, by bacterial toxins, and via anaphylatoxin dependent mechanisms. It appears likely that the induction of intrinsic asthma might be triggered by these mediators also during viral adsorption and penetration. The interdependency of cellular reactions might be responsible for the complexity of the disease process in asthma.

Leukotrienes and lipoxygenase factors: mediators and modulators of the allergic reaction.

Lipoxygenase factors of arachidonic acid (mono- and di-Hetes) are not only mediators but also modulators of inflammatory reactions. They have chemotactic and spasmogenic properties; the latter are similar to those induced by the slow reacting-substance of anaphylaxis (SRS-A). The eosinophil chemotactic factor has been identified as a lipoxygenase product. Among the chemically mono- and di-Hetes the 5-S-12-R di-Hete (LTB4) and the 5-S 12S di-Hete demonstrated the most pronounced eosinophil chemotactic activity. The phospholipase-arachidonic acid sequence is involved in the IgE induced activation and secretion of human basophils. With arachidonic acid analogs the lipoxygenase transformation pathway is inhibited.

IgA-associated inhibition of polymorphonuclear leukocyte chemotaxis in neutrophilic dermatoses.

The chemotactic activity of normal human polymorphonuclear leukocytes (PMNs) confronted with heat inactivated sera from patients with psoriasis as well as various chronic proliferative diseases was determined using modified Boyden chambers. By the addition of phorbol myristate acetate (PMA) at a concentration of 1 ng/ml the chemoattractant activities of the sera were greatly potentiated. However, the chemotactic migration of normal PMNs was strongly inhibited by sera from patients with long standing and wide spread psoriasis, pyoderma gangrenosum, severe acne conglobata, Sweet syndrome, and some patients with chronic arthritis following rheumatoid fever. In acute guttate psoriasis and atopic dermatitis increased migratory activities were seen. The inhibition of chemotaxis correlated with increased serum IgA levels as determined by radial immuno diffusion. Column chromatography (Sephacryl S-300) revealed serum fractions of strong inhibitory potency at a molecular weight near 200,000 Dalton. These inhibitory fractions were seen in patients with long standing neutrophil related diseases and could not be detected in normal control sera. It appears that inhibition of PMN chemotaxis is a secondary phenomenon and may play an autoregulatory role in PMN related inflammation.

Polymorphonuclear leukocyte chemotaxis in psoriasis: enhancement by self-activated serum.

The chemotactic activity of polymorphonuclear leukocytes (PMNs) directed against serum was determined in a modified Boyden chamber assay. In a total of 176 experiments PMNs and sera from healthy controls were compared with PMNs and sera from patients with psoriasis. When PMNs from patients with psoriasis were confronted with psoriatic serum greatly enhanced chemotaxis was demonstrated. Non-psoriatic PMNs in the presence of psoriatic serum showed no enhancement. However, psoriatic PMNs in the presence of normal serum were chemotactically more active compared to non-psoriatic PMNs. Heat inactivation (56 degrees C, 30 min) reduced the chemotactic activity of all sera by nearly 50%. However in psoriatic sera the enhancement of chemotaxis was still present after heat treatment. The results indicate the presence of a functional abnormality of chemotaxis in psoriasis. This is likely to be caused by the in situ generation of chemotactically active fragments of complement. Experiments showing increased chemotactic activity of sera exposed to migrating PMNs support this concept.