Charles Flickinger

Flickinger, Charles J.

Primary Appointment

Professor Emeritus, Cell Biology

Contact Information

PO Box 800732
School Of Medicine, 3099 Jordan Hall
Telephone: 434-924-1916

Research Interests

Male reproductive cell biology: testis, epididymis, sperm, antigens.

Research Description

My laboratory is investigating the secretion of proteins in the epididymis and

the male sex accessory glands. Proteins secreted by the epididymal epithelium,

for example, are believed to play an important role in the post-testicular maturation

of sperm, including acquisition of fertilizing ability. Currently we are studying

natural antimicrobial proteins, part of the innate immune system, that are secreted

by the epididymis and other parts of the male reproductive system. My laboratory

cloned and characterized a novel sperm-associated isoantigen, E-3, which has defensin-

and lectin-like motifs and is expressed in the epididymis, and we have determined

that several defensins and a cathelicidin are expressed in different parts of

the male reproductive tract in rats. One aim of our present work is to identify

novel antimicrobial proteins in fluids of the epididymis and sex accessory glands.

In addition, we are studying changes in the repertoire of defensins and cathelicidins

during development of the male reproductive system, and we are investigating how

the expression patterns of various antimicrobial proteins are regulated.

We are also involved in characterizing and cloning sperm antigens, in collaboration

with Dr. John Herr. We are using immunocytochemistry to localize antigens in

spermatozoa and in the testis, and make use of both northern analysis and immunocytochemistry

to perform tissue specificity studies of putative gamete-specific antigens.

We have also studied testicular gene expression with in situ hybridization methods

to detect specific germ cell mRNAs.

A long-standing research interest in my laboratory is study of the morphologic,

immunologic, and physiologic effects of obstruction of the male reproductive

tract. Vasectomy is a common means of contraception in men, but questions remain

about its reversal, because an individual may remain infertile despite successful

surgical reconnection of the vas deferens. Aims of this research are to determine

the nature of changes after obstruction of the male tract and to determine the

extent to which these are reversible by subsequent repair. We have concentrated

on post-obstruction antibody responses in a rat model system assessed by ELISA,

identification of specific sperm autoantigens using gel electrophoresis and

western blotting techniques, and morphological studies of the testis and epididymis

using light and electron microscopy. Emphasis has been on analysis of sperm

autoantigens by two dimensional gel electrophoresis and blotting, microsequencing,

and cloning of dominant autoantigens. A long term aim is to discern the relation

between the immunologic response to specific antigens and testicular alterations

and/or infertility.

Selected Publications