Abstract

IL-4, in the presence of macrophages (MΦs), has previously been demonstrated to be tumoricidal in vitro and in vivo, possibly through MΦ activation. In the current study, the biological activities of murine IL-4 on MΦs, and the initial identification of signal transduction mechanisms in IL-4-mediated MΦ activation were determined. Hamster MΦ were activated with IL-4 to study MΦ tumoricidal activity against hamster pancreatic adenocarcinoma in vivo.Through this initial study, it was observed that murine IL-4 is species specific and incapable of crossing the narrow phylogenetic barrier to hamster and perhaps rat (partially). The effects of murine IL-4 on allogeneic peritoneal and bone marrow-derived (14M1 .4 cell line) MΦ were then evaluated. Results showed a marked, dose-dependent stimulation of chemiluminescent oxidative burst by IL-4- activated MΦs, an activity which was IL-4 monoclonal antibody reversible. In addition, it appeared that 14M1.4 MΦ were more responsive than peritoneal MΦs to IL-4 in that they responded quicker and released greater quantities of reactive oxygen intermediates. Based on this preliminary work, the 14M14.4 MΦs were used to study the yet unknown signal transduction mechanisms in IL-4-mediated MΦ activation. By means of flow cytometric techniques and the membrane potential sensitive dye, DIOC6(3), it was shown that IL-4 caused no apparent biological but a statistically significant change in the membrane potential of MΦs. Using flow cytometry and indo-1AM, it was determined that intracellular calcium levels changed. An optimal concentration of 1L-4 caused a rapid increase in the initial (inhibited by BAPTA-AM, a specific intracellular chelator of calcium) and then sustained (inhibited by EGTA) level of intracellular calcium. Through assessments of chemiluminescence oxidative burst activity, it was demonstrated that the initial and sustained increase in intracellular calcium was required and important for IL-4 enhancement of the oxidative burst by 14M1.4 MΦs. Increase in production of IP3 but no change in levels of cAMP, immediate or delayed, were demonstrated using competitive binding assays. These findings were further supported by the fact that cholera toxin and prostaglandin E2 (agents which increase cAMP), did not enhance chemiluminescence, nor did PMA, a potent activator of PKC. Surprisingly, IL-4-stimulated MΦ were not cytolytic to tumor cell targets; yet, IL-4 was directly cytostatic to some of the same cell lines.

LLU Discipline

Microbiology

Department

Microbiology

School

Graduate School

First Advisor

Sandra L. Nehlsen-Cannarella

Second Advisor

Christopher D. Cain

Third Advisor

Benjamin H. S. Lau

Fourth Advisor

Thomas A. Linkhart

Degree Name

Doctor of Philosophy (PhD)

Degree Level

Ph.D.

Year Degree Awarded

1992

Date (Title Page)

6-1992

Language

English

Library of Congress/MESH Subject Headings

Interleukin-4 -- analysis; Macrophages -- immunology; Biological Assay -- methods; Cytotoxicity, Immunologic -- physiology; Pancreatic Neoplasms -- therapy

Type

Dissertation

Page Count

2 xiii; 262

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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Included in

Microbiology Commons

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