Education in ethics for Biotechnologists

Bioethics lies at the interface between Biology and Society, and therefore its development is heavily influenced by Society's values and concerns, and by its changing attitudes and beliefs. After a period during which authors have almost exclusively focused on medical/personal Bioethics, the new planetary disasters are stimulating the growth of Ethics of Biotechnology in its various and different aspects. This article underlines the importance of the educational and didactic aspects of Bio-Ethics. The natural targets of these efforts are the young scientists and students of the disciplines included in Biotechnology. In particular, candidates for a European Qualification as Doctor in Biotechnology, who will form the leading class of tomorrow's applied biology, must be equally proficient in understanding the moral issues that will guide their decision-making

QUANTITATIVE STUDIES OF THE ADOPTIVE IMMUNOLOGICAL MEMORY IN MICE : II. LINEAR TRANSMISSION OF CELLULAR MEMORY

A calibrated cell transfer system allows detection of the anamnestic response to albumin without interference from the host's immune machinery; it was used to study the immunological memory of mouse spleen cell populations. The secondary antibody-forming capacity of the transferred cells was measured by challenging them at periods up to 6 months after transfer. The peak levels attained show a declining pattern in two phases: during the first month with a half-life of 15 days; thereafter, with a half-life of 100 days. The corresponding half-lives of the cellular memory are 26 and 190 days. In the light of these and of radioinactivation data, immunological memory is defined as the persistence of a specifically determined stem cell line, along which the information necessary to give rise to an antibody-forming cell population is transmitted from mother to daughter cells

QUANTITATIVE STUDIES OF THE ADOPTIVE IMMUNOLOGICAL MEMORY IN MICE : I. AN AGE-DEPENDENT BARRIER TO SYNGENEIC TRANSPLANTATION

Antibody-forming cells suspended from a mouse spleen and transferred to intact animals of the same genotype face a barrier which severely affects their capacity to implant and/or to function. This phenomenon was quantitatively studied in a model system which, utilizing the immunogenic properties of human serum albumin in mice, allows the secondary response of the transferred cells to be followed without interference from the host's own reactivity. The barrier to syngeneic transplantation was found (a) to be radiosensitive (500 R X-rays to the recipient abolishes it and insures optimal functional conditions to the donor cells) in the same order of magnitude of other mammalian systems involving rapidly dividing cell populations, and (b) to depend upon the age of the recipient: its linear rise is documented from birth time (when ∼50% of the maximal immune capacity of the transfer is expressed) to the age of 2 months (∼ 1 %). The significance of these findings to the immune response and to cell growth and differentiation is discussed

Transition between immune and disease states in a cellular automaton model of clonal immune response

In this paper we extend the Celada-Seiden (CS) model of the humoral immune response to include infectious virus and cytotoxic T lymphocytes (cellular response). The response of the system to virus involves a competition between the ability of the virus to kill the host cells and the host's ability to eliminate the virus. We find two basins of attraction in the dynamics of this system, one is identified with disease and the other with the immune state. There is also an oscillating state that exists on the border of these two stable states. Fluctuations in the population of virus or antibody can end the oscillation and drive the system into one of the stable states. The introduction of mechanisms of cross-regulation between the two responses can bias the system towards one of them. We also study a mean field model, based on coupled maps, to investigate virus-like infections. This simple model reproduces the attractors for average populations observed in the cellular automaton. All the dynamical behavior connected to spatial extension is lost, as is the oscillating feature. Thus the mean field approximation introduced with coupled maps destroys oscillations.Comment: 27 pages LaTeX + 7 Figures Postscrip

Computer simulations of heterologous immunity: Highlights of an interdisciplinary cooperation

The relationship between biological research and mathematical modeling is complex, critical, and vital. In this review, we summarize the results of the collaboration between two laboratories, exploring the interaction between mathematical modeling and wet-lab immunology. During this collaboration several aspects of the immune defence against viral infections were investigated, focusing primarily on the subject of heterologous immunity. In this manuscript, we emphasize the topics where computational simulations were applied in conjunction with experiments, such as immune attrition, the growing and shrinking of cross-reactive T cell repertoires following repeated infections, the short and long-term effects of cross-reactive immunological memory, and the factors influencing the appearance of new clonal specificities. For each topic, we describe how the mathematical model used was adapted to answer specific biological questions, and we discuss the hypotheses that were generated by simulations. Finally, we propose rules for testing hypotheses that emerge from model experimentation in the wet lab, and vice-versa

Antibody-induced conformational changes in proteins.

[No abstract available