Publication Date


Document Type


Committee Members

Cheryl Conley (Committee Member), David Cool (Committee Member), Osvaldo Lopez (Advisor)

Degree Name

Master of Science (MS)


Peptides with high affinity to the B-cell receptor (BCR) fused to a toxin could be an effective therapy for Chronic Lymphocytic Leukemia (CLL) patients. We screened captured BCR of a CLL patient with peptides from 7 and 12-mer phage display libraries, using two strategies. Lymphocytes from two patients diagnosed with CLL expressing two different unmutated VH genes (VH 1-3 and VH4-34, respectively) were used. Membrane BCRs were obtained from patient CLL cells by lysis, identified by western blot, semi-quantified and screened with phage libraries. The first strategy involved using patient VH4-34 BCRs which were captured using goat anti-human IgM to deplete bound phages. Unbound-phages were positively screened for those binding to patient VH 1-3 BCRs. Several clones were randomly selected and a sequence consisting of "LLPPAR_" peptide was found in both libraries. A phage clone displaying peptide "LLPPARE" was identified to bind to goat anti-human IgM. By including more goat anti-human IgM negative selections, we identified 3 different phages displaying peptides "GFTFMPA", "QSRPLLP" and "GLPCCSS". Clones "GFTFMPA" and "GLPCCSS" showed binding to goat anti-human IgM, while "QSRPLLP" did not. Phage clone "QSRPLLP" showed no binding to human serum IgM but showed binding to both patients' BCRs. "QSRPLLP" peptide binds a common BCR molecule region present in both patients but not present in human serum IgM. This data suggests that it is possible to use a peptide-phage display library to select peptides unique for the BCRs of CLL patients. However, the critical component in making this process patient-specific resides in enhanced discrimination in phage selection.

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Department or Program

Department of Pharmacology and Toxicology

Year Degree Awarded