UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

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    The M167 mu+kappa Immunoglobulin Transgene Increases Susceptibility to Pristane-Induced Plasmacytomas In BALB/c Mice
    (2005-04-20) Williams, Kimberly Gayle; Potter, Michael; Molecular and Cell Biology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The goal of this research was to investigate the role of Ig transgenes (Tgs) in plasma cell tumor development as a useful means of examining potential antigen-specific B cell precursors. The Ig Tg M167mk (V1 mu plus Vk24) on a genetically PCT-susceptible BALB/c background was used to determine if B cells expressing anti-phosphorylcholine (PC) B cell receptors are more susceptible than non-Tg littermates to pristane induction of plasma cell tumors. The M167mk Tg mice, which express the anti-PC M167 BCR on >97% of B cells, developed a higher percentage of plasma cell tumors (63%) compared to non-Tg BALB/cAnPt littermates (35%), p<0.01, and had a reduced latent period from 240 to 200 days. Serologic and nucleic acid analysis of Igs expressed by Tg tumors revealed co-expression of the M167-id V1-mu/Vk24 transgenes and a rearranged endogenous VH-alpha/Vk Ig. In an attempt to learn something of the natural history of the PCT precursor B cell, the M167mk transgene and endogenous VH/VL Ig mRNA from Tg PCT cells were sequenced for evidence of somatic hypermutation, a hallmark of T-cell dependent germinal center activity. M167mu and k Tg mRNA transcripts revealed no evidence of mutation of the transgenes; however, sequencing of endogenous Ig mRNA from M167mk Tg PCTs showed that 80% contained somatic hypermutation (SHM) and 20% had germline Ig genes. PCTs from control groups, BALB/c non-Tg littermates and C.B20 mice, also contained 80% SHM and 20% germline Ig genes. M167mk Tg mice have an increased (MZ) B cell population (15-25% B220+), a hyper-activated TI responsive B cell phenotype, compared to non-Tg WT mice (5-10% B220+). These data suggest that PC-responsive M167mk B cells are a PCT-susceptible subset, as the M167mk Tg BCR generates B cell clones that are responsive to bacterial PC antigen that likely enhances overall proliferation of B cells during PCT development, thereby increasing the chances of a neoplastic B cell clone to expand and increasing the susceptibility of M167mk Tg mice to the induction of PCTS.