Life span of cytotoxic activity and memory activity following allogeneic skin grafting in the mouse

Bone Marrow Transplantation 1957-2019

Clinical bone marrow transplantation started in 1957 at a time when remarkably little was known about hematopoietic stems cells, immune responses to transplants or the identity of transplant antigens. This review will delineate the substantial increase in knowledge about these three areas gained between then and 1992 when the Ceppellini School course on Bone Marrow Transplantation was held, along with the progress made in clinical application, as well as the stumbling blocks that remained to be overcome by further research to advance knowledge. It will outline the significant progress made between 1992 and the present year, 2019, and the remaining problems.

Medawar's legacy to cellular immunology and clinical transplantation: a commentary on Billingham, Brent and Medawar (1956) 'Quantitative studies on tissue transplantation immunity. III. Actively acquired tolerance'

‘Quantitative studies on tissue transplantation immunity. III. Actively acquired tolerance’, published in Philosophical Transactions B in 1956 by Peter Medawar and his colleagues, PhD graduate Leslie Brent and postdoctoral fellow Rupert Billingham, is a full description of the concept of acquired transplantation tolerance. Their 1953 Nature paper (Billingham RE et al. 1953 Nature172, 603–606. (doi:10.1038/172603a0)) had provided initial evidence with experimental results from a small number of neonatal mice, with mention of similar findings in chicks. The Philosophical Transactions B 1956 paper is clothed with an astonishing amount of further experimental detail. It is written in Peter Medawar's landmark style: witty, perceptive and full of images that can be recalled even when details of the supporting information have faded. Those images are provided not just by a series of 20 colour plates showing skin graft recipient mice, rats, rabbits, chickens and duck, bearing fur or plumage of donor origin, but by his choice of metaphor, simile and analogy to express the questions being addressed and the interpretation of their results, along with those of relevant published data and his prescient ideas of what the results might portend. This work influenced both immunology researchers and clinicians and helped to lay the foundations for successful transplantation programmes. It led to the award of a Nobel prize in 1960 to Medawar, and subsequently to several scientists who advanced these areas. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.

The male-specific histocompatibility antigen, H-Y: a history of transplantation, immune response genes, sex determination and expression cloning

H-Y was originally discovered as a transplantation antigen. In vivo primary skin graft responses to H-Y are controlled by immune response (Ir) genes mapping to the MHC. In vitro T cell responses to H-Y are controlled by MHC class I and II Ir genes, which-respectively, restrict CD8 and CD4 T cells: These can be isolated as T cell clones in vitro. T cell receptor (TCR) transgenic mice have been made from the rearranged TCR genes of several of these, of which that specific for H-Y/Db is the best studied. Non-MHC Ir genes also contribute to the control of in vitro CTL responses to H-Y. The Hya/HYA gene(s) encoding H-Y antigen have been mapped using translocations, mutations, and deletions to Yq in humans and to the short arm of the Y chromosome in mice, where they lie in the deletion defined by the Sxrb mutation between Zfy-1 and Zfy-2. Hya/HYA has been separated from the testis-determining gene, Sry/SRY, in both humans and mice and in humans the azoospermia factor AZF has been separated from HYA. In mice transfection of cosmids and cDNAs mapping to the Sxrb deletion has identified two genes encoding H-Y peptide epitopes. Two such epitopes, H-Y/K(k) and H-Y/D(k), are encoded within different exons of Smcy and a third, H-Y/D(b), by a novel gene, Uty. Peptide elution approaches have isolated a human H-Y epitope, H-Y/HLA-B7, and identified it as a product of SMCY. Each of the Hya genes in mice is ubiquitously expressed but of unknown function. Their X chromosome homologues do not undergo X inactivation.

Suppression of in vitro lymphocyte reactivity by cyclosporin A: existence of a population of drug-resistant cytotoxic lymphocytes

Cyclosporin A (CS-A) is an unusual endecapeptide isolated from the fungi Cylindrocarpon lucidum Booth and Trichoderma polysporum. It is a potent immunosuppressive drug that prevents rejection of kidney and heart allografts whilst having a low myelotoxicity. Its mode of action is still unclear but its main target appears to be the T lymphocyte. The mixed lymphocyte reaction (MLR) and cell-mediated lymphocytoxicity (CML) used here are generally regarded as in vitro correlates of allograft rejection. Our data show that CS-A is a powerful inhibitor of MLR reactivity, regardless of whether the cells were obtained from normal or presensitized donors; that the CML of lymph node cells is likewise totally inhibited if the drug is added early during cell culture; and that, by contrast, the cytotoxic response of spleen cells from presensitized but not from normal mice is only partially inhibited, even with a tenfold increase in dose. It is therefore suggested that there exists a population of cytotoxic spleen cells that is relatively resistant to the action of this drug.

Augmentation of cell-mediated cytotoxicity to a rat lymphoma. I. Stimulation of non-T-cell cytotoxicity in vivo by tumour cells

The injection of a syngeneic Gross-virus-induced lymphoma into W/Fu rats induced peaks of cytotoxicity in the spleen attributable to non-T cells and T cells 3 and 10 days later, respectively. The conditions required for augmenting the cytotoxicity of the non-T cells in various lymphoid compartments (shown elsewhere to closely resemble NK cells) were analysed using the ip and iv routes of inoculation and a variety of tumour cells including those normally susceptible or resistant to lysis by NK cells in vitro. Using an ip inoculation of W/FuG-1 cells (a tumour susceptible to lysis by NK cells), a short-lived, 3-fold increase in cytotoxicity was observed in the spleen at day 3 and a 5-fold increase in the PEC at day 5. Cytotoxicity in other lymphoid organs remained unchanged. Tumours resistant to lysis by NK cells also stimulated cytotoxicity in the spleen or PEC, although the effect depended on the dose and route of inoculation used, and depression of cytotoxicity was observed under some conditions.

Regulation of the immune response by subclasses of T lymphocytes. II. The effect of adult thymectomy upon humoral and cellular responses in mice

The immunologic consequences resulting from thymectomy in adult life were investigated. Primary humoral responses were not diminished shortly after adult thymectomy, as judged by responses of intact thymectomized mice as well as by the ability of spleen cells from such mice to transfer primary responses. However, secondary humoral responses were substantially reduced in irradiated recipients of spleen cells from primed adult-thymectomized mice, suggesting that the thymus is required in adult life to maintain a population of cells important in the generation of immunologic helper memory. By contrast, small doses of anti-thymocyte serum, which primarily affect recirulating T cells, abrogated the primary humoral response, but allowed the subsequent development of immune memory. Using a technique permitting in vitro sensitization of purified T cells to alloantigens, it was shown that adult thymectomy increases the ability of T cells to generate primary cytotoxic responses, but had little effect upon the development of cytotoxic T memory activity. These experiments suggest that in adult life the thymus maintains a regulatory population of T cells in peripheral tissues which suppress early T cell differentiation to cytotoxic effector cells and potentiates the development of immune memory.