Bromocriptine markedly inhibits progression of murine retrovirus-induced immunodeficiency

Abstract

Lithium salts have been demonstrated to induce the production of hematopoietic cells following administration in vivo and to minimize the reduction of these cells following treatment with either radiation, chemotherapeutic or antiviral drugs. We have previously demonstrated that lithium, when administered in vivo to immunodeficient mice infected with LP-BM5 MuLV (MAIDS) significantly reduced the development of lymphadenopathy, splenomegaly, and the lymphoma associated with late-stage immunodeficiency disease in this model, and increased the survival of these animals compared to virus-infected controls not receiving lithium. We report here the results of in vivo studies in the MAIDS model that determined the effect of lithium on peripheral blood indices and the number of myeloid (CFU-GM), erythroid (BFU-E) and megakaryocyte (CFU-Meg) hematopoietic progenitors from bone marrow and spleen harvested from immunodeficient mice receiving lithium carbonate (1 mM) placed in their drinking water compared to virus-infected controls not receiving lithium. Time-points evaluated were at weeks 1, 5, 9, 13, 17, and 21 postviral infection. Virus-control mice not receiving lithium demonstrated all the signs that are characteristic of MAIDS, i.e., splenomegaly, lymphadenopathy, hypergammaglobulinemia, reduced hematopoiesis, and death. Infected mice receiving lithium demonstrated diminished presence of splenomegaly, lymphadenopathy, hypergammaglobulinemia, no suppression of hematopoiesis nor mortality. Enhanced hematopoiesis was demonstrated by neutrophilia, lymphocytosis, thrombocytosis, and erythrocytosis that was evident by increased myeloid, erythroid, and megakaryocyte progenitor cells cultured from bone marrow and spleen. These studies further demonstrate that lithium influences the disease process in the MAIDS model and restricts the development of hematopoietic suppression that develops in this retroviral animal model of immunodeficiency.