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Immune Class Regulation and Its Medical Significance Part II of a Report of a Workshop on Foundational Concepts of Immune Regulation
Author(s) -
Bretscher P. A.,
Corthay A.,
Anderson C. C.,
Dembic Z.,
Havele C.,
Nagy Z. A.,
Øynebråten I.
Publication year - 2017
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/sji.12525
Subject(s) - immune system , antigen , context (archaeology) , biology , cd8 , immunology , mhc class i , t cell , major histocompatibility complex , mhc class ii , phenotype , mechanism (biology) , genetics , gene , epistemology , paleontology , philosophy
We discussed different proposals for how the nature of the Th1/Th2 phenotype of an immune response is determined, and favoured one, the Threshold Hypothesis, as plausible and so useful as the basis for further discussions. The activation of a target CD 4 T cell can be facilitated by helper CD 4 T cells when the CD 4 T cells interact via an antigen‐presenting cell. The Threshold Hypothesis states that tentative and robust antigen‐mediated CD 4 T cell cooperation results in the target CD 4 T cell, respectively giving rise, upon activation, to Th1 and Th2 cells. We primarily discussed four topics. We briefly discussed in the background section certain limitations of the Th1/Th2 paradigm in understanding immune class regulation, and the remarkable anti‐inflammatory properties of human IgG 4 antibody. Secondly, we assessed the role of class II MHC molecules in determining the number of mature CD 4 T cells and so affecting the Th1/Th2 phenotype of immune responses. We also discussed the controversial role of CD 8 T cells in affecting the Th1/Th2 phenotype of responses to MHC and other antigens, and the potential role of their relative scarcity in neonates in biasing responses towards an antibody, Th2 mode. Lastly, we examined the regulation of the Th1/Th2 phenotype of both primary and ongoing immune responses in the context of the intriguing proposal that antigen initially generates different classes/subclasses of immunity and then selects, by a feedback mechanism, the most effective class. We found this interesting idea difficult to reconcile with various observations.