STUDIES ON THE IMMUNOLOGICAL RESPONSE TO FOREIGN TUMOR TRANSPLANTS IN THE MOUSE : I. THE ROLE OF LYMPH NODE CELLS IN CONFERRING IMMUNITY BY ADOPTIVE TRANSFER

The transfer of transplantation immunity by lymph node cells has been the subject of investigation. Transplantable tumors have been used to provoke and to measure transplantation immunity. Cells from the lymph nodes draining a tumor homograft were transferred as mince or in suspension into the peritoneum of a secondary host to confer immunity. These cells could confer immunity while the immunizing graft was undergoing breakdown during the primary, and also during the more rapid secondary, response. Cells from other nodes and from the spleen, and also whole blood or serum failed in these experiments to transfer immunity. In one combination of tumor and host, serum from immunized donors enhanced tumor growth. Evidence has been presented favoring the hypothesis that the lymph node cells were immunologically activated before transfer, and that they conferred immunity by continuing to function in their host. Immunization by tumor cells transferred along with the cells of the nodes could not account for the failure of lymph node transferred into susceptible animals to give rise to tumors; nor for the failure of tumor cells to give rise to immunity as rapidly as transferred lymph node cells. Freezing and thawing of the transferred cells prevented transfer of immunity. Cells from donors immunized against an isoantigen failed to confer immunity on hosts which carried that isoantigen, offering evidence of absorption of antibody. The duration of immunity transferred within an inbred strain was shorter than actively induced immunity, but longer than could have been expected of passively transferred immunity. After transfer of cells into foreign hosts, immunity declined more rapidly, as if the transferred cells were destroyed by the homograft reaction of the host. The possibility that cells of the host were activated has also been discussed. A brief review showed that similar problems are raised in other systems of transfer of immunity by cells

STUDIES ON THE IMMUNOLOGICAL RESPONSE TO FOREIGN TUMOR TRANSPLANTS IN THE MOUSE : II. THE RELATION BETWEEN HEMAGGLUTINATING ANTIBODY AND GRAFT RESISTANCE IN THE NORMAL MOUSE AND MICE PRETREATED WITH TISSUE PREPARATIONS

The relation between serum antibody and resistance to tumor homografts in the mouse has been investigated. Production of serum antibody in response to homografts of a transplantable sarcoma (Sarcoma 1) was demonstrated, by cytotoxic action on the cells of the tumor, and also by a hemagglutinin test. The simpler and more repeatable hemagglutinin test was further investigated. Peak hemagglutinin titres were reached after the immunizing homografts underwent breakdown. Following transfer of lymph node cells from immunized mice into hosts of the same strain, hemagglutinin could be detected in the host serum. The course of its production showed that this secondary antibody was not elicited by transferred antigen, nor could it be due to transfer of preformed antibody. The cells developed the capacity to transfer hemagglutinin production later than the power to transfer heightened graft resistance. Spleen cells also transferred hemagglutinin production, at a later stage after immunization and to a lesser extent than cells from the regional lymph nodes. Implantation of the sarcoma in mice pretreated with certain preparations of lyophilized or frozen tissue stimulated hemagglutinin production, although the tumor grew progressively. The regional lymph nodes participated in the response: they could transfer hemagglutinin production into secondary hosts, but not graft resistance, and indeed appeared to diminish resistance. Lymph node cells from immunized donors conferred protection against the tumor on pretreated mice. Lymph nodes from normal donors also appeared in some experiments to confer protection although the effect was obscured by the rapidity with which the growing tumor became immunologically invulnerable. The fate of lymph node cells stained with acriflavine was followed after transfer. No effect of the staining on the power of the cells to confer immunity could be detected. Cells transferred to the peritoneal cavity passed into various host tissues, but were not found in test homografts. The conclusion is drawn that the hemagglutinating antibody is distinct from the antibody effective in combating homografts. The similarity in this respect between the homograft reaction and sensitization is emphasized in discussion

Learning from Minimum Entropy Queries in a Large Committee Machine

In supervised learning, the redundancy contained in random examples can be avoided by learning from queries. Using statistical mechanics, we study learning from minimum entropy queries in a large tree-committee machine. The generalization error decreases exponentially with the number of training examples, providing a significant improvement over the algebraic decay for random examples. The connection between entropy and generalization error in multi-layer networks is discussed, and a computationally cheap algorithm for constructing queries is suggested and analysed.Comment: 4 pages, REVTeX, multicol, epsf, two postscript figures. To appear in Physical Review E (Rapid Communications

Testing the theory of immune selection in cancers that break the rules of transplantation

Abstract Modification of cancer cells likely to reduce their immunogenicity, including loss or down-regulation of MHC molecules, is now well documented and has become the main support for the concept of immune surveillance. The evidence that these modifications, in fact, result from selection by the immune system is less clear, since the possibility that they may result from reorganized metabolism associated with proliferation or from cell de-differentiation remains. Here, we (a) survey old and new transplantation experiments that test the possibility of selection and (b) survey how transmissible tumours of dogs and Tasmanian devils provide naturally evolved tests of immune surveillance

Autonomous quantum clocks: does thermodynamics limit our ability to measure time?

Time remains one of the least well understood concepts in physics, most notably in quantum mechanics. A central goal is to find the fundamental limits of measuring time. One of the main obstacles is the fact that time is not an observable and thus has to be measured indirectly. Here we explore these questions by introducing a model of time measurements that is complete and autonomous. Specifically, our autonomous quantum clock consists of a system out of thermal equilibrium --- a prerequisite for any system to function as a clock --- powered by minimal resources, namely two thermal baths at different temperatures. Through a detailed analysis of this specific clock model, we find that the laws of thermodynamics dictate a trade-off between the amount of dissipated heat and the clock's performance in terms of its accuracy and resolution. Our results furthermore imply that a fundamental entropy production is associated with the operation of any autonomous quantum clock, assuming that quantum machines cannot achieve perfect efficiency at finite power. More generally, autonomous clocks provide a natural framework for the exploration of fundamental questions about time in quantum theory and beyond

Further development of the 12-item EDEQS: identifying a cut-off for screening purposes

Background: The Eating Disorder Examination – Questionnaire Short (EDE-QS) was developed as a 12-item versionof the Eating Disorder Examination Questionnaire (EDE-Q) with a 4-point response scale that assesses eatingdisorder (ED) symptoms over the preceding 7 days. It has demonstrated good psychometric properties at initialtesting. The purpose of this brief report is to determine a threshold score that could be used in screening forprobable ED cases in community settings.Methods: Data collected from Gideon et al. (2016) were re-analyzed. In their study, 559 participants (80.86% female;9.66% self-reported ED diagnosis) completed the EDE-Q, EDE-QS, SCOFF, and Clinical Impairment Assessment (CIA).Discriminatory power was compared between ED instruments using receiver operating characteristic (ROC) curveanalyses.Results: A score of 15 emerged as the threshold that ensured the best trade-off between sensitivity (.83) andspecificity (.85), and good positive predictive value (.37) for the EDE-QS, with discriminatory power comparable toother ED instruments.Conclusion: The EDE-QS appears to be an instrument with good discriminatory power that could be used for EDscreening purposes