Johnan A. R. Kaleeba

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Upregulation of xCT, the inducible subunit of a membrane-bound amino acid transporter, replenishes intracellular glutathione stores to maintain cell viability in an environment of oxidative stress. xCT also serves as a fusion-entry receptor for the Kaposi's sarcoma-associated herpesvirus (KSHV), the causative agent of Kaposi's sarcoma (KS). Ongoing KSHV(More)
The OX-40 receptor, a member of the nerve growth factor/tumor necrosis factor receptor gene family, is expressed preferentially on autoreactive CD4+ T cells isolated from the site of inflammation in rats with clinical signs of experimental autoimmune encephalomyelitis (EAE). To examine whether the OX-40 receptor has biologic relevance to T cell function, we(More)
Kaposi's sarcoma-associated herpesvirus (KSHV, human herpesvirus 8) is the causative agent of Kaposi's sarcoma and other lymphoproliferative syndromes often associated with HIV/AIDS. Functional complementary DNA selection for a receptor mediating KSHV cell fusion identified xCT, the 12-transmembrane light chain of the human cystine/glutamate exchange(More)
The molecular mechanism of Kaposi's sarcoma-associated herpesvirus (KSHV, human herpesvirus 8) entry is poorly understood. We tested a broad variety of cell types of diverse species and tissue origin for their ability to function as targets in a quantitative reporter gene assay for KSHV-glycoprotein-mediated cell fusion. Several human, non-human primate,(More)
Emmprin (CD147; basigin) is a multifunctional glycoprotein expressed at higher levels by cancer cells and stromal cells in the tumor microenvironment. Through direct effects within tumor cells and promotion of tumor-stroma interactions, emmprin participates in induction of tumor cell invasiveness, angiogenesis, metastasis and chemoresistance. Although its(More)
HLA-DR2+ patients with multiple sclerosis (MS) that respond to vaccination with TCR V beta 5.2-38-58 peptides have increased frequencies of TCR peptide-specific T cells, reduced frequencies of myelin basic protein (MBP)-specific T cells, and a better clinical course than non-responders. To evaluate possible network regulation of MBP responses by TCR(More)
The rhesus rhadinovirus strain 17577 (RRV strain 17577) genome is essentially colinear with human herpesvirus 8 (HHV8)/Kaposi's sarcoma-associated herpesvirus (KSHV) and encodes several analogous open reading frames (ORFs), including the homologue of cellular interleukin-6 (IL-6). To determine if the RRV IL-6-like ORF (RvIL-6) is biologically functional, it(More)
Antigen-coupled antigen-presenting cells (APC) serve as potent tolerogens for inhibiting immune responses in vivo and in vitro, apparently by providing an antigen-specific signal through the TCR in the absence of co-stimulation. Although this approach has been well studied in rodents, little is known about its effects on human T cells. We evaluated the(More)
Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of primary effusion lymphoma (PEL), a rapidly progressing malignancy mostly arising in HIV-infected patients. Even under conventional chemotherapy, PEL continues to portend nearly 100% mortality within several months, which urgently requires novel therapeutic strategies. We have(More)
Mechanisms underlying progression to androgen-independent prostate cancer following radical ablation therapy remain poorly defined. Although intraprostatic infections have been highlighted as potential cofactors, pathogen influences on pathways that support tumor regrowth are not known. To explore this provocative concept, we derived androgen-sensitive and(More)