ANTIGEN-REACTIVE CELLS IN NORMAL, IMMUNIZED, AND TOLERANT MICE

The numbers of antigen-reactive cells (ARC) responding to a purified protein, the polymer of S. adelaide flagellin, have been assayed in cell populations derived from several lymphoid tissues of mice. The assay, which employs the cell transfer into lethally irradiated mice, indicates that there is a response of ARC in bone marrow in the absence of thymus cells. This suggests that the immune response to this protein antigen is not thymus dependent. The presence of relatively large numbers of ARC in Peyer's patches argues for their direct participation in the immune response in the adult mouse. The kinetics of ARC and antibody-forming cells in the early primary response employing the transfer system is described. The numbers of ARC declined during the first 2 days of the immune response, but by day 6 had increased to about five times the number in unprimed spleen cells. The rise is believed to be a result of the primary injection of antigen and therefore may be described as memory; however, these experiments have not been able to further elucidate any specific qualities of the "memory cell." Tolerance induction in C57BL/Brad mice produced by repeated injections of a cyanogen bromide digest of the antigen is described. The ARC or its precursor is shown to be the site of the lesion of tolerance by direct investigation

Making sense of law and disorder

This article tells the story of a cross-cultural encounter on a beach at King George\u27s Sound in the south west of Australia in 1826, when Major Edmund Lockyer arrived to establish a British military garrison. The account we have of those early encounters come from the pen of Lockyer, and by taking a close reading of his journal this article attempts to reveal the meanings and context of Aboriginal actions. It also analyses how the Aborigines and the British made sense and subsequently responded to the encounter. Whilst this story is not given iconic status in Australian historiography, it is valuable in opening up a porthole into this contact zone at the moment when precarious relationships were being formed.<br /

Innate immunity defines the capacity of antiviral T cells to limit persistent infection

Effective immunity requires the coordinated activation of innate and adaptive immune responses. Natural killer (NK) cells are central innate immune effectors, but can also affect the generation of acquired immune responses to viruses and malignancies. How NK cells influence the efficacy of adaptive immunity, however, is poorly understood. Here, we show that NK cells negatively regulate the duration and effectiveness of virus-specific CD4+ and CD8+ T cell responses by limiting exposure of T cells to infected antigen-presenting cells. This impacts the quality of T cell responses and the ability to limit viral persistence. Our studies provide unexpected insights into novel interplays between innate and adaptive immune effectors, and define the critical requirements for efficient control of viral persistence

Mechanism of induction of immunological tolerance. VI. Tolerance induction following thoracic duct drainage or treatment with anti- -lymphocyte serum.

Adult Wistar rats were injected with flagellin from Salmonella adelaide three times weekly for different periods of time. With the range of doses 100 fg to 100 μg (fg, femtograms), varying levels of immune responsiveness were demonstrable following challenge, but not one of the doses induced complete immunological tolerance, although a reduced antibody response was elicited in rats which received injections of 100 μg of flagellin. In contrast to this finding, complete tolerance could be demonstrated following challenge if rats, previously drained of lymph and lymphocytes from the thoracic duct for 5 days, were injected with either 100 μg of flagellin three times weekly or with 1 μg/g body weight/day for 6 weeks. Similarly, anti-lymphocyte serum treatment prior to the injection of antigen resulted in partial tolerance in adult rats and nearly complete tolerance in adult C57BL/Brad mice. The primary response to flagellin of C57BL mice was abrogated if ALS was administered prior to but not after the injection of antigen. The implications of these findings are discussed