Early molecular signals induced by antibodies to GPI-anchored proteins

We have examined intracellular biochemical and metabolic changes induced by antibodies specific for glycosylphosphatidylinositol (GPI)-anchored cell surface molecules. In lymphoid cells the earliest detectable responses are phosphorylation of intracellular substrates. The GPI-linked target antigens are also rapidly redistributed into patches and caps on the cell surface and then internalised. Between two and five hours later, cytokine receptors are expressed. Later, cells become metabolically active and begin to proliferate and express endogenous cytokines, thus promoting autocrine growth. Very early events, such as kinase activity, are induced by antibody binding alone and are characteristic of the cell surface molecule recognised by antibodies. Thus, the initial events in the activation cascade are critical in selecting the metabolic route. Progression down the activation cascade requires further signals such as cross-linking antibodies, exogenous cytokines, phorbol esters, or accessory cells. Once in cycle, cells no longer display evidence of their original route of activation. Activated T lymphocytes acquire resitance to cleavage by GPI-specific phospholipase C, suggesting a possible feedback mechanism to limit cell proliferation

Delipidified cell components of Mycobacterium leprae and its applications.

Delipidified cell components (DCC) of Mycobacterium leprae obtained as an insoluble material consist of several proteins. This preparation, DCC, has ability to differentially bind to sera from lepromatous leprosy patients and antibodies to this complex get reduced as patients improve under chemotherapy. The antigenic complex has no ability to bind to proteins of sera from normal healthy individuals or tuberculoid leprosy patients. The DCC is antigenic and is recognised by immune deficient cells of lepromatous leprosy patients, leading to lymphocyte proliferation, production of Interleukin II and interferon gamma, and resulting in activation of the phagocytes to initiate killing of endocytosed M.leprae through reactive oxygen intermediates, primarily superoxide. The DCC has also immunomodulatory properties to protect mice against M.leprae infection. Experiments with mice and isolated peripheral blood cells from patients have indicated the probable molecular mechanism of immunomodulation by DCC.

Zimbabwe's environmental dilemma : balancing resource inequities

One of the most controversial issues in post-independence Zimbabwe is how the country can tackle the land question in a way that will only address the gross wrongs of the past but also leave its relatively well-developed commercial agricultural sector intact. Indeed; the cautiousness of the Zimbabwe government in developing its land policy and implementing a major land reform programme is as much a result of the Lancaster House Constitution. The message of this book is unequivocal: land redistribution is the only way by which the country can move into the path of sustainable development. Without major reform; it is argued;the spectre of ecological disaster will continue to loom over the country. There is more to benefit than to lose in a major land reform exercise aimed at resolving the conflict over resources which characterises the present situation

Zimbabwe's environmental dilemma : balancing resource inequities

One of the most controversial issues in post-independence Zimbabwe is how the country can tackle the land question in a way that will only address the gross wrongs of the past but also leave its relatively well-developed commercial agricultural sector intact. Indeed; the cautiousness of the Zimbabwe government in developing its land policy and implementing a major land reform programme is as much a result of the Lancaster House Constitution. The message of this book is unequivocal: land redistribution is the only way by which the country can move into the path of sustainable development. Without major reform; it is argued; the spectre of ecological disaster will continue to loom over the country. There is more to benefit than to lose in a major land reform exercise aimed at resolving the conflict over resources which characterises the present situation